livescience--2020-09-17--A new solar cycle just started. Here's what that means.

is officially nine months into a new solar weather cycle , scientists have confirmed , and it will likely look much like its predecessor , which ran from 2008 to 2019 .
Scientists predict that the sun 's new activity phase , called 25 , will peak in 2025 but will generally be a less active cycle , quite similar to .
The sun 's weather , which follows an 11-year activity cycle , is a vital phenomenon to predict because its whims impact life and and around Earth , sometimes with devastating consequences .
`` We are very excited @ @ @ @ @ @ @ solar cycle 25 has officially started , '' Lisa Upton , co-chair of the Solar Cycle 25 Prediction Panel and a solar physicist at Space Systems Research Corporation , a mission-support company based in Virginia , said during a NASA news conference today ( Sept. 15 ) to discuss the findings .
Related : The sun 's wrath : Here 's the worst solar storms in history Space weather trackers should expect the sun 's activity to rise and fall in a pattern similar to that of the last 11 years , Doug @ @ @ @ @ @ @ ’ s Space Weather Prediction Center and co-chair of the prediction panel , said .
`` Solar cycle 25 will reach a peak number of 115 in July of 2025 , '' noting that a particularly active solar cycle usually sees a peak sunspot number over 200 .
But just because the new cycle will be relatively quiet does n't mean we should write it off , scientists stressed .
Biesecker pointed to a massive flare the sun produced in 2012 , a few years before last solar cycle 's peak .
`` @ @ @ @ @ @ @ to be like cycle 24 in terms of sunspots , '' he said .
`` Cycle 24 managed to produce an , but it missed the Earth . ''
And even right now , when solar activity is still quite low , we can still feel the effects of our sun , the scientists said .
`` During solar minimum , solar activity does not finish , it just changes form , '' Lika Guhathakurta , a heliophysicist at NASA 's headquarters , said during the news conference .
`` For example , @ @ @ @ @ @ @ high in the space environment , and this has all kinds of implications for space exploration , space tourism , and the aviation industry . ''
Related : Another potential impact of a quieter sun is on , which more active solar cycles can send into Earth 's atmosphere to burn up .
`` A small solar cycle unfortunately means we 're not going to be clearing out a lot of the orbital debris that a big solar cycle would take care of , '' Biesecker said .
In order to monitor and @ @ @ @ @ @ @ a broad range of observations .
Sunspot counts are the most straightforward — the more sunspots the more active the sun .
How far north or south on the sun the earliest spots in a cycle begin to form can also give scientists a sense of what a season will be like , and right now , the sunspots that are popping up are closer to the equator , as is typical for quieter solar cycles .
Although the past few years have seen a host of new solar and space weather missions @ @ @ @ @ @ @ team did n't rely on data from those new spacecraft .
`` When we 're trying to predict something that 's got an 11-year cycle , new data is always useful , but it 's hard to trust , '' he said .
`` So in general , the newer missions have not yet played a role in the process of predicting the cycle but that does n't mean that they wo n't play a role in when we come around to trying to predict solar cycle 26 . ''
Monitoring solar activity @ @ @ @ @ @ @ cycles will be particularly important as astronauts once again venture out beyond the protection of Earth 's magnetic field .
As part of its , NASA is working to send astronauts back to the moon in the coming years , with humans stepping foot on the moon for the first time in five decades in 2024 , the year before the solar cycle 's predicted peak .
That means that NASA needs good enough information about the sun 's activity to feel confident it is n't sending astronauts into a dangerous situation .
@ @ @ @ @ @ @ also incorporating space-weather monitoring into its lead-up Artemis work , Jake Bleacher , chief exploration scientist for NASA Human Exploration and Operations Mission Directorate , said during the news conference , referencing plans to put solar weather instruments on the , NASA 's planned outpost in lunar orbit that will support crew visits to the moon.. '' The Gateway will be in place well before our astronauts are getting to the moon , so we 'll have time to make some measurements and conduct some research there , '' Bleacher said .
`` @ @ @ @ @ @ @ the fleet of spacecraft that are measuring the sun and understanding this environment . ''
Email Meghan Bartels at mbartels @ space.com or follow her on Twitter @ meghanbartels .
Follow us on Twitter @ Spacedotcom and on Facebook .

The sun is officially nine months into a new solar weather cycle, scientists have confirmed, and it will likely look much like its predecessor, which ran from 2008 to 2019.
Scientists predict that the sun's new activity phase, called solar cycle 25, will peak in 2025 but will generally be a less active cycle, quite similar to solar cycle 24, which ended in December . The sun's weather, which follows an 11-year activity cycle, is a vital phenomenon to predict because its whims impact life and and around Earth, sometimes with devastating consequences.
"We are very excited to be here today to announce that solar cycle 25 has officially started," Lisa Upton, co-chair of the Solar Cycle 25 Prediction Panel and a solar physicist at Space Systems Research Corporation, a mission-support company based in Virginia, said during a NASA news conference today (Sept. 15) to discuss the findings.
Related: The sun's wrath: Here's the worst solar storms in history
A split image shows the sun during a solar cycle's maximum on the left (April 2014) and during a solar cycle's minimum on the right (December 2019). (Image credit: NASA/SDO)
Space weather trackers should expect the sun's activity to rise and fall in a pattern similar to that of the last 11 years, Doug Biesecker, a solar physicist at NOAA’s Space Weather Prediction Center and co-chair of the prediction panel, said. "Solar cycle 25 will reach a peak sunspot number of 115 in July of 2025," noting that a particularly active solar cycle usually sees a peak sunspot number over 200.
But just because the new cycle will be relatively quiet doesn't mean we should write it off, scientists stressed.
Biesecker pointed to a massive flare the sun produced in 2012, a few years before last solar cycle's peak. "We're saying cycle 25 is going to be like cycle 24 in terms of sunspots," he said. "Cycle 24 managed to produce an epic, hundred-year kind of solar storm , but it missed the Earth."
And even right now, when solar activity is still quite low, we can still feel the effects of our sun, the scientists said.
"During solar minimum, solar activity does not finish, it just changes form," Lika Guhathakurta, a heliophysicist at NASA's headquarters, said during the news conference. "For example, galactic cosmic rays are at an all-time high in the space environment, and this has all kinds of implications for space exploration, space tourism, and the aviation industry."
Related: World's largest solar telescope produces never-before-seen image of our star
A chart showing the ebb and flow of sunspots over the course of several recent solar cycles, as well as scientists' prediction for the upcoming cycle. (Image credit: SILSO data/image, Royal Observatory of Belgium, Brussels)
Another potential impact of a quieter sun is on space junk , which more active solar cycles can send into Earth's atmosphere to burn up. "A small solar cycle unfortunately means we're not going to be clearing out a lot of the orbital debris that a big solar cycle would take care of," Biesecker said.
In order to monitor and predict solar activity, scientists rely on a broad range of observations. Sunspot counts are the most straightforward — the more sunspots the more active the sun. How far north or south on the sun the earliest spots in a cycle begin to form can also give scientists a sense of what a season will be like, and right now, the sunspots that are popping up are closer to the equator, as is typical for quieter solar cycles.
Although the past few years have seen a host of new solar and space weather missions launch, Biesecker said that the prediction team didn't rely on data from those new spacecraft. "When we're trying to predict something that's got an 11-year cycle, new data is always useful, but it's hard to trust," he said. "So in general, the newer missions have not yet played a role in the process of predicting the cycle but that doesn't mean that they won't play a role in when we come around to trying to predict solar cycle 26."
Monitoring solar activity and making reliable predictions about upcoming solar cycles will be particularly important as astronauts once again venture out beyond the protection of Earth's magnetic field.
As part of its Artemis program , NASA is working to send astronauts back to the moon in the coming years, with humans stepping foot on the moon for the first time in five decades in 2024, the year before the solar cycle's predicted peak. That means that NASA needs good enough information about the sun's activity to feel confident it isn't sending astronauts into a dangerous situation.
To that end, the agency is also incorporating space-weather monitoring into its lead-up Artemis work, Jake Bleacher, chief exploration scientist for NASA Human Exploration and Operations Mission Directorate, said during the news conference, referencing plans to put solar weather instruments on the Gateway , NASA's planned outpost in lunar orbit that will support crew visits to the moon..
"The Gateway will be in place well before our astronauts are getting to the moon, so we'll have time to make some measurements and conduct some research there," Bleacher said. "We're trying to help add to the fleet of spacecraft that are measuring the sun and understanding this environment."
Email Meghan Bartels at mbartels@space.com or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.


livescience--2020-09-16--Cave bear mummy discovered in Siberia still has its internal organs, fur and black nose

Reindeer hunters in Siberia have unearthed the remains of an extinct ice age beast : a mummified — the only adult of its species ever discovered that still has intact soft tissues , including its fur and even its black nose , according to news reports .
The hunters found the cave bear ( Ursus spelaeus ) mummy on Bolshoy Lyakhovsky island , in the East Siberian Sea .
Meanwhile , on the mainland in the Republic of Sakha ( also known as Yakutia ) , another group discovered the mummy of a cave bear cub , according to a @ @ @ @ @ @ @ NEFU ) in Yakutsk .
`` This is the first and only find of its kind — a whole bear carcass with soft tissues , '' Lena Grigorieva , a molecular paleontologist at NEFU , said in the statement , referring to the mummy found on Bolshoy Lyakhovsky island .
`` It is completely preserved , with all internal organs in place '' Until the adult cave bear mummy was discovered , `` only skulls and bones were found , '' Grigorieva said .
`` This find is of great importance for the @ @ @ @ @ @ @ today 's bears , which are omnivorous , cave bears likely did n't eat meat ( except for maybe the ) , making them largely vegetation-eating machines .
These bears must have eaten a lot , because they were huge — up to 11.5 feet ( 3.5 meters ) tall when they reared up on their hind legs , .
Although most cave bears likely weighed about 1,100 lbs .
( 500 kilograms ) , some weighed as much as 3,300 lbs .
( 1,500 kg ) , according to a 2018 study @ @ @ @ @ @ @ more than their closest living relatives , the brown bear ( U. arctos ) and the ( U. maritimus ) .
After living in Eurasia since at least 300,000 years ago , cave bears mysteriously went extinct about 25,000 to 20,000 years ago , during the Last Glacial Maximum .
Humans likely hunted the bears to extinction , a 2019 study in the journal found .
( Many other big animals , known as megafauna , went extinct at the end of the , 2.5 million to 11,700 years ago , but it @ @ @ @ @ @ @ at the end of the last ice age or human interference played a larger role in their demise . )
Cave bears likely lived in Siberia during the Karaginsky interglacial ( a warm period between colder glacial periods ) , meaning the adult and cub likely date to this time , between 39,500 and 22,000 years ago , according to NEFU .
`` It is necessary to carry out radiocarbon analysis to determine the precise age of the bear , '' Maxim Cheprasov , a senior researcher at the Mammoth Museum laboratory in @ @ @ @ @ @ @ The scientists have yet to examine the adult cave bear mummy in person , but the reindeer hunters have given them permission to do so , Cheprasov added .
As melts the permafrost in Siberia , more of these ice age mummies will likely emerge .
However , discovering , preserving and studying these mummies is a mammoth effort , and many of the mummies that go undetected will likely rot .
`` For every one that they do recover , there are 10 if not 20 lost , '' Daniel Fisher , @ @ @ @ @ @ @ at the University of Michigan , who was n't involved in the cave bear finding , .

Reindeer hunters in Siberia have unearthed the remains of an extinct ice age beast: a mummified cave bear — the only adult of its species ever discovered that still has intact soft tissues, including its fur and even its black nose, according to news reports.
The hunters found the cave bear (Ursus spelaeus) mummy on Bolshoy Lyakhovsky island, in the East Siberian Sea. Meanwhile, on the mainland in the Republic of Sakha (also known as Yakutia), another group discovered the mummy of a cave bear cub, according to a statement from the North-Eastern Federal University (NEFU) in Yakutsk.
"This is the first and only find of its kind — a whole bear carcass with soft tissues," Lena Grigorieva, a molecular paleontologist at NEFU, said in the statement, referring to the mummy found on Bolshoy Lyakhovsky island. "It is completely preserved, with all internal organs in place"
Related: 10 extinct giants that once roamed North America
Until the adult cave bear mummy was discovered, "only skulls and bones were found," Grigorieva said. "This find is of great importance for the whole world."
Unlike many of today's bears, which are omnivorous, cave bears likely didn't eat meat (except for maybe the occasional scavenging of other dead cave bears ), making them largely vegetation-eating machines. These bears must have eaten a lot, because they were huge — up to 11.5 feet (3.5 meters) tall when they reared up on their hind legs, according to Ars Technica . Although most cave bears likely weighed about 1,100 lbs. (500 kilograms), some weighed as much as 3,300 lbs. (1,500 kg), according to a 2018 study in the journal PLOS One . That's way more than their closest living relatives, the brown bear (U. arctos) and the polar bear (U. maritimus).
After living in Eurasia since at least 300,000 years ago, cave bears mysteriously went extinct about 25,000 to 20,000 years ago , during the Last Glacial Maximum. Humans likely hunted the bears to extinction, a 2019 study in the journal Scientific Reports found. (Many other big animals, known as megafauna, went extinct at the end of the Pleistocene epoch , 2.5 million to 11,700 years ago, but it's still unclear whether the changing temperatures at the end of the last ice age or human interference played a larger role in their demise.)
Cave bears likely lived in Siberia during the Karaginsky interglacial (a warm period between colder glacial periods), meaning the adult and cub likely date to this time, between 39,500 and 22,000 years ago, according to NEFU.
"It is necessary to carry out radiocarbon analysis to determine the precise age of the bear," Maxim Cheprasov, a senior researcher at the Mammoth Museum laboratory in Yakutsk, said in the statement.
The scientists have yet to examine the adult cave bear mummy in person, but the reindeer hunters have given them permission to do so, Cheprasov added.
As climate change melts the permafrost in Siberia, more of these ice age mummies will likely emerge. However, discovering, preserving and studying these mummies is a mammoth effort, and many of the mummies that go undetected will likely rot.
"For every one that they do recover, there are 10 if not 20 lost," Daniel Fisher, a curator at the Museum of Paleontology at the University of Michigan, who wasn't involved in the cave bear finding, previously told Live Science .
Originally published on Live Science.


livescience--2020-09-16--These could be the funniest animal pictures ever

Feast your eyes on some of the most amusing animal photos ever , as the finalists are unveiled for the @ @ @ @ @ .
The competition is designed to raise awareness of the need for conservation , and @ @ @ @ @ with Born Free .
This year 's winners will be revealed on October 22 , @ @ @ @ @ a chortle at these amazing photos , including this smiley Mediterranean parrotfish ( Sparisoma cretense @ @ @ @ @ Thiemenn in El Hierro , Canary Islands .

The Comedy Wildlife Photography Awards finalists have been announced
Feast your eyes on some of the most amusing animal photos ever, as we unveil the winner of the Comedy Wildlife Photography Awards 2020. The competition is designed to raise awareness of the need for conservation, and it's run in association with Born Free.
Competing against 7,000 entries, this year's overall winner was Mark Fitzpatrick for this rebellious turtle picture. "I was swimming with this turtle at Lady Elliot Island on the Great Barrier Reef when he flipped me the bird!" said Fitzpatrick. His picture also won the 'Creatures under the water' award category.
"It's been amazing to see the reaction to my photo of Terry the Turtle flipping the bird, with Terry giving people a laugh in what has been a difficult year for many, as well as helping spread an important conservation message," said Fitzpatrick. "Hopefully, Terry the Turtle can encourage more people to take a moment and think about how much our incredible wildlife depend on us and what we can do to help them. Flippers crossed that this award puts Terry in a better mood the next time I see him at Lady Elliot Island!”
We have also included category winners, highly commended and the finalists in this gallery, so go on and have a chortle at these amazing photos.


livescience--2020-09-16--Could wearing glasses lower the risk of COVID-19?

People who wear eyeglasses may be at lower risk for catching COVID-19 than those who do n't wear glasses , early research from China suggests .
The study researchers analyzed information from 276 patients at a hospital in China 's Hubei province and found that only about 6 % said they wore glasses for more than 8 hours a day , all of whom had myopia , or .
That 's much lower than the estimated rate of myopia in Hubei from previous research , which was 31.5 % .
The new study , published Wednesday ( Sept. 16 ) @ @ @ @ @ @ @ and raises the possibility that use of eye protection by the general public might offer some degree of protection from COVID-19 , '' Dr. Lisa Maragakis , an associate professor of medicine and epidemiology at Johns Hopkins University School of Medicine , who was not involved in the study , wrote in an editorial accompanying the study .
However , Maragakis cautions that it 's much too early to recommend that everyone don eyeglasses , goggles or face shields in public , in addition to already wearing , to protect against COVID-19 .
@ @ @ @ @ @ @ limitations — for starters , the study was relatively small and included patients at a single hospital .
Importantly , the study found only an association and can not prove a `` cause-effect '' relationship between wearing glasses and being protected from COVID-19 , Maragakis said .
Maragakis called for more studies to confirm the findings and to determine `` whether there is any incremental benefit to wearing eyeglasses or other forms of eye protection in public settings , in addition to wearing a mask and physical distancing , to reduce the risk @ @ @ @ @ @ @ Although it 's recommended that health care workers wear face shields or goggles , along with face masks , to lower the risk of catching COVID-19 , public health guidelines generally do n't promote the use of eye protection for the public ; they instead stress the importance of masks , and .
( The CDC does not recommend face shields as a substitute for face masks . )
The study authors , from Suizhou Zengdu Hospital in Suizhou , China , decided to look into the link between eyeglasses and COVID-19 prevention @ @ @ @ @ @ @ COVID-19 at their hospital wore glasses .
They enrolled the 276 patients in their study between Jan. 27 and March 13 , 2020 .
All participants were asked if they wore eyeglasses , how long they wore glasses during the day and why they needed glasses .
Overall , 30 participants , or about 11 % , said they wore glasses , but only 16 participants , or 5.8 % , wore glasses for more than 8 hours a day and that was for myopia .
( The other 14 participants wore reading @ @ @ @ @ @ @ the general population , the researcher drew on a study conducted in 1985 among students in Hubei province , which showed that about one-third had myopia , nearly all of whom wore glasses .
However , Maragakis noted that this comparison group is a limitation of the study because the research took place `` decades earlier '' and was n't specific to Suizhou .
But in general , myopia is a common condition , estimated to affect 27 % of the world 's population in 2010 , with the highest prevalence in East @ @ @ @ @ @ @ of the participants in the study wore contact lenses , so whether wearing contact lenses affects the risk of COVID-19 still needs to be studied , the authors said .
The researchers did not examine why glasses may reduce the risk of COVID-19 , but they hypothesize that wearing glasses discourages people from touching their eyes , which would reduce the chances that people transfer virus from their hands to their eyes .
It 's known that eye cells have receptors that allow SARS-CoV-2 , the virus that causes COVID-19 , to enter @ @ @ @ @ @ @ been detected in the .
Maragakis added that eyeglasses may also `` serve as a partial barrier that reduces the inoculum [ amount ] of virus in a manner similar to what has been observed for cloth masks . ''
`` These findings suggest that the eye may be an important infection route for COVID-19 , and more attention should be paid to preventive measures such as frequent hand washing and avoiding touching the eyes , '' the study authors concluded .
Still , in addition to further studies to confirm the findings @ @ @ @ @ @ @ unintended consequences of a general recommendation to wear eye protection in public .
People who are n't accustomed to wearing glasses or goggles might actually touch their face more often when removing , replacing or adjusting the eyewear , Maragakis said .

People who wear eyeglasses may be at lower risk for catching COVID-19 than those who don't wear glasses, early research from China suggests.
The study researchers analyzed information from 276 patients at a hospital in China's Hubei province and found that only about 6% said they wore glasses for more than 8 hours a day, all of whom had myopia, or nearsightedness . That's much lower than the estimated rate of myopia in Hubei from previous research, which was 31.5%.
The new study, published Wednesday (Sept. 16) in the journal JAMA Ophthalmology , "is provocative and raises the possibility that use of eye protection by the general public might offer some degree of protection from COVID-19," Dr. Lisa Maragakis, an associate professor of medicine and epidemiology at Johns Hopkins University School of Medicine, who was not involved in the study, wrote in an editorial accompanying the study.
However, Maragakis cautions that it's much too early to recommend that everyone don eyeglasses, goggles or face shields in public, in addition to already wearing face masks , to protect against COVID-19. The new study has a number of limitations — for starters, the study was relatively small and included patients at a single hospital. Importantly, the study found only an association and cannot prove a "cause-effect" relationship between wearing glasses and being protected from COVID-19, Maragakis said.
Maragakis called for more studies to confirm the findings and to determine "whether there is any incremental benefit to wearing eyeglasses or other forms of eye protection in public settings, in addition to wearing a mask and physical distancing, to reduce the risk of acquiring [COVID-19]."
Related: 14 coronavirus myths busted by science
Eye protection
Although it's recommended that health care workers wear face shields or goggles, along with face masks, to lower the risk of catching COVID-19, public health guidelines generally don't promote the use of eye protection for the public; they instead stress the importance of masks, physical distancing and hand washing . (The CDC does not recommend face shields as a substitute for face masks.)
The study authors, from Suizhou Zengdu Hospital in Suizhou, China, decided to look into the link between eyeglasses and COVID-19 prevention after they noticed that few patients with COVID-19 at their hospital wore glasses.
They enrolled the 276 patients in their study between Jan. 27 and March 13, 2020. All participants were asked if they wore eyeglasses, how long they wore glasses during the day and why they needed glasses.
Overall, 30 participants, or about 11%, said they wore glasses, but only 16 participants, or 5.8%, wore glasses for more than 8 hours a day and that was for myopia. (The other 14 participants wore reading glasses.)
To compare this with the general population, the researcher drew on a study conducted in 1985 among students in Hubei province, which showed that about one-third had myopia, nearly all of whom wore glasses.
However, Maragakis noted that this comparison group is a limitation of the study because the research took place "decades earlier" and wasn't specific to Suizhou.
But in general, myopia is a common condition, estimated to affect 27% of the world's population in 2010, with the highest prevalence in East Asia, according to the World Health Organization .
None of the participants in the study wore contact lenses, so whether wearing contact lenses affects the risk of COVID-19 still needs to be studied, the authors said.
Behind the link
The researchers did not examine why glasses may reduce the risk of COVID-19, but they hypothesize that wearing glasses discourages people from touching their eyes, which would reduce the chances that people transfer virus from their hands to their eyes. It's known that eye cells have receptors that allow SARS-CoV-2, the virus that causes COVID-19, to enter the body; and the virus has been detected in the eyes of COVID-19 patients .
Maragakis added that eyeglasses may also "serve as a partial barrier that reduces the inoculum [amount] of virus in a manner similar to what has been observed for cloth masks."
"These findings suggest that the eye may be an important infection route for COVID-19,
and more attention should be paid to preventive measures such as frequent hand washing and avoiding touching the eyes," the study authors concluded.
Still, in addition to further studies to confirm the findings, researchers also need to consider possible unintended consequences of a general recommendation to wear eye protection in public. People who aren't accustomed to wearing glasses or goggles might actually touch their face more often when removing, replacing or adjusting the eyewear, Maragakis said.
Originally published on Live Science.


livescience--2020-09-16--Hidden rivers of warm water threaten vast Antarctic glacier

One of the largest , most unstable glaciers in is sliding into the ocean .
That 's due , in large part , to hidden rivers of warm water that lubricate its underbelly , more so now than ever in the era of .
Now , researchers know what those unseen channels look like .
By using equipment that can measure fluctuations in gravity , radar and seismic waves , scientists were able to map precisely where these glacier-melting channels cut through the deep seabed .
`` It was fantastic to be able to map the channels and cavity system @ @ @ @ @ @ @ are deeper than expected — some are more than 800 meters [ 2,600 feet ] deep , '' study lead researcher Tom Jordan , an aero-geophysicist at the British Antarctic Survey , .
`` They form the critical link between the ocean and the glacier . ''
Thwaites Glacier is a vast brick of ice flowing into Pine Island Bay in western Antarctica .
If you took off in an airplane from El Paso , Texas and flew due south — across about 590 miles ( 950 kilometers ) of western Mexico and @ @ @ @ @ @ @ Pacific Ocean — you 'd see it out your window as a white expanse with sheer cliffs where it meets open water .
Thwaites has moved toward the ocean its entire existence , but that rate of motion has increased fivefold over the last 30 years , to the point where snowfall at the rear of the glacier can no longer replenish ice lost in the front .
That lost ice has contributed to about 4 % of global sea level rise over those three decades .
If the entire glacier were to @ @ @ @ @ @ @ would increase by about a whopping 25 inches ( 65 centimeters ) .
This dramatic increase would devastate current coastlines , so scientists are trying to understand the dynamics driving Thwaites ' seaward motion and how fast these processes are accelerating the melt .
This new research , published Sept. 9 as a of in the journal Cryosphere , combined several under-glacier detection techniques to build detailed maps of those hidden channels .
A key method : directly detecting gravity from the seafloor .
The action happens where the seabed , water and @ @ @ @ @ @ @ meet .
Ice is less dense , and therefore lighter , than water and this difference in mass causes gravity to fluctuate from one part of the glacier to the next .
Sensitive instruments on boats or airplanes flying overhead can pick up those fluctuations — revealing details hidden deep below the ice surface .
By combining that data with radar and seismic measurements taken on the ice 's surface , scientists have created the most complete description yet of that hidden world , where warm water slicks the glacier bottom — its @ @ @ @ @ @ @ `` Our results confirm a major marine channel more than 800 meters deep extends tens of kilometers to the front of Thwaites Glacier , '' they wrote in the study , `` while the adjacent ice shelves are underlain by more complex bathymetry . ''
One key revelation : The bottoms of younger ice conform tightly to the jagged seafloor , while older ice shelves ( right now , blocks of ice older than 1993 ) tend to have flatter bottoms .
Details like that will help scientists refine models of how ice @ @ @ @ @ @ @ research has filled a critical data gap , '' Kelly Hogan , a British Antarctic Survey marine geophysicist and lead author of one of the papers , said in the statement .
`` Together , the new coastal sea floor maps and the cavity maps track the deep channels for over 100 km [ 60 miles ] to where the glacier sits on the bed .
For the first time , we have a clear view of the pathways along which warm water can reach the underside of the glacier , causing it @ @ @ @ @ @ @ rise . ''

One of the largest, most unstable glaciers in Antarctica is sliding into the ocean. That's due, in large part, to hidden rivers of warm water that lubricate its underbelly, more so now than ever in the era of climate change . Now, researchers know what those unseen channels look like.
By using equipment that can measure fluctuations in gravity, radar and seismic waves, scientists were able to map precisely where these glacier-melting channels cut through the deep seabed.
"It was fantastic to be able to map the channels and cavity system hidden beneath the ice shelf; they are deeper than expected — some are more than 800 meters [2,600 feet] deep," study lead researcher Tom Jordan, an aero-geophysicist at the British Antarctic Survey, said in a statement . "They form the critical link between the ocean and the glacier."
Related: Time-lapse images of retreating glaciers
Thwaites Glacier is a vast brick of ice flowing into Pine Island Bay in western Antarctica. If you took off in an airplane from El Paso, Texas and flew due south — across about 590 miles (950 kilometers) of western Mexico and 5,700 miles (9,200 km) of Pacific Ocean — you'd see it out your window as a white expanse with sheer cliffs where it meets open water.
Thwaites has moved toward the ocean its entire existence, but that rate of motion has increased fivefold over the last 30 years, to the point where snowfall at the rear of the glacier can no longer replenish ice lost in the front. That lost ice has contributed to about 4% of global sea level rise over those three decades. If the entire glacier were to collapse into the ocean, sea levels would increase by about a whopping 25 inches (65 centimeters). This dramatic increase would devastate current coastlines, so scientists are trying to understand the dynamics driving Thwaites' seaward motion and how fast these processes are accelerating the melt.
This new research, published Sept. 9 as a pair of papers in the journal Cryosphere, combined several under-glacier detection techniques to build detailed maps of those hidden channels. A key method: directly detecting gravity from the seafloor.
The action happens where the seabed, water and ice at the bottom of the glacier meet. Ice is less dense, and therefore lighter, than water and this difference in mass causes gravity to fluctuate from one part of the glacier to the next. Sensitive instruments on boats or airplanes flying overhead can pick up those fluctuations — revealing details hidden deep below the ice surface.
By combining that gravity data with radar and seismic measurements taken on the ice's surface, scientists have created the most complete description yet of that hidden world, where warm water slicks the glacier bottom — its "bathymetry," in scientific-speak.
"Our results confirm a major marine channel more than 800 meters deep extends tens of kilometers to the front of Thwaites Glacier," they wrote in the study, "while the adjacent ice shelves are underlain by more complex bathymetry."
Related: The vanishing glaciers of Europe's Alps
One key revelation: The bottoms of younger ice conform tightly to the jagged seafloor, while older ice shelves (right now, blocks of ice older than 1993) tend to have flatter bottoms. Details like that will help scientists refine models of how ice moves over ocean floors.
"This research has filled a critical data gap," Kelly Hogan, a British Antarctic Survey marine geophysicist and lead author of one of the papers, said in the statement . "Together, the new coastal sea floor maps and the cavity maps track the deep channels for over 100 km [60 miles] to where the glacier sits on the bed. For the first time, we have a clear view of the pathways along which warm water can reach the underside of the glacier, causing it to melt and contribute to global sea-level rise."
Originally published on Live Science.


livescience--2020-09-16--Hurricane Sally makes landfall as Category 2 storm, bringing extreme winds and flooding

Hurricane Sally made landfall near Gulf Shores , Alabama , early Wednesday morning ( Sept. 16 ) as a Category 2 hurricane after strengthening overnight .
The slow-moving storm hit with sustained winds of 105 mph ( 169 km/h ) , toppling trees , cutting power and dropping extreme amounts of rain , according to CNN .
After landfall , the storm weakened into a Category 1 hurricane .
It is now about 15 miles west/northwest of Pensacola , Florida and has maximum sustained winds of 80 mph ( 130 km/h ) , according to the National Hurricane Center ( @ @ @ @ @ @ @ flooding is unfolding , '' from Mobile Bay , Alabama to near Tallahassee , Florida , according to the NHC .
This rainfall will likely lead to widespread river flooding , according to the NHC .
This morning , Hurricane Sally was moving at an extremely slow pace , near 3 mph ( 6 km/h ) , prolonging exposure to rainfall and high winds .
As of 11 a.m. EDT , the storm has sped up slightly to 5 mph ( 7 km/h ) .
Sally has already dropped up to 18 inches @ @ @ @ @ @ @ `` creating catastrophic flash flooding , '' the National Weather Service Weather Prediction Center wrote on Twitter this morning .
The storm may drop somewhere between 10 to 35 inches ( 25 to 89 cm ) of rain across parts of Alabama and the Florida Panhandle , according to the NHC .
`` Life-threatening '' storm surges are occurring along portions of the coast from Alabama to the western Florida Panhandle , including Pensacola Bay in Florida according to the NHC .
More than 430,000 people in the Florida Panhandle and southern Alabama @ @ @ @ @ @ @ poweroutage.us .
At least 3 to 4 feet ( 0.9 to 1.2 meters ) of water flooded downtown Pensacola , according to a photo retweeted by the National Weather Service in Mobile .
Water levels at the National Oceanic and Atmospheric Administration ( NOAA ) tide stations recorded `` moderate flood levels , '' with more than 5.5 feet ( 1.6 m ) above normal high tide this morning , NOAA 's Ocean Service tweeted .
High-water rescues were underway Wednesday morning , according to CNN .
The storm is currently moving in @ @ @ @ @ @ @ to hasten its pace `` slightly '' later today and tonight and quicken even more on Thursday .
The center of Sally will move across the western Florida panhandle and southeastern Alabama through early Thursday and move over central Georgia on Thursday and over South Carolina Thursday night , according to the NHC .

Hurricane Sally captured over Alabama and the Florida Panhandle on Sept. 16 at 9:30 am ET
Hurricane Sally made landfall near Gulf Shores, Alabama, early Wednesday morning (Sept. 16) as a Category 2 hurricane after strengthening overnight. The slow-moving storm hit with sustained winds of 105 mph (169 km/h), toppling trees, cutting power and dropping extreme amounts of rain, according to CNN.
After landfall, the storm weakened into a Category 1 hurricane. It is now about 15 miles west/northwest of Pensacola, Florida and has maximum sustained winds of 80 mph (130 km/h), according to the National Hurricane Center (NHC).
"Historic and catastrophic flooding is unfolding," from Mobile Bay, Alabama to near Tallahassee, Florida, according to the NHC. This rainfall will likely lead to widespread river flooding, according to the NHC. This morning, Hurricane Sally was moving at an extremely slow pace, near 3 mph (6 km/h), prolonging exposure to rainfall and high winds. As of 11 a.m. EDT, the storm has sped up slightly to 5 mph (7 km/h).
Related: A history of destruction: 8 great hurricanes
Sally has already dropped up to 18 inches (46 centimeters) of rain, "creating catastrophic flash flooding," the National Weather Service Weather Prediction Center wrote on Twitter this morning. The storm may drop somewhere between 10 to 35 inches (25 to 89 cm) of rain across parts of Alabama and the Florida Panhandle, according to the NHC.
Hurricane Sally has made landfall and is continuing to move slowly in a north/northeastern direction. (Image credit: NOAA/National Hurricane Center)
"Life-threatening" storm surges are occurring along portions of the coast from Alabama to the western Florida Panhandle, including Pensacola Bay in Florida according to the NHC. More than 430,000 people in the Florida Panhandle and southern Alabama have already lost power, according to poweroutage.us. At least 3 to 4 feet (0.9 to 1.2 meters) of water flooded downtown Pensacola, according to a photo retweeted by the National Weather Service in Mobile.
Water levels at the National Oceanic and Atmospheric Administration (NOAA) tide stations recorded "moderate flood levels," with more than 5.5 feet (1.6 m) above normal high tide this morning, NOAA's Ocean Service tweeted. High-water rescues were underway Wednesday morning, according to CNN.
The storm is currently moving in a north/northeastern direction. It is expected to hasten its pace "slightly" later today and tonight and quicken even more on Thursday. The center of Sally will move across the western Florida panhandle and southeastern Alabama through early Thursday and move over central Georgia on Thursday and over South Carolina Thursday night, according to the NHC.
Originally published on Live Science.


livescience--2020-09-16--Venus, once billed as Earth's twin, is a hothouse (and a tantalizing target in the search for life)

As Earth 's sister planet , has endured a love-hate relationship when it comes to exploration .
Now , new results suggest the presence of a signal of , and the long-forgotten sibling may find itself back in the spotlight .
With its orbit near the rising or setting sun , Venus shone clearly to the first ancient astronomers .
As humanity began to explore the solar system , a world with nearly the same mass and radius as Earth seemed like the most promising target .
Venus sits on the border of our sun 's habitable zone , the @ @ @ @ @ @ @ should be able to host liquid water on its surface , and ideas of a veritable twin planet swam before the eyes of scientists and the public alike .
Related : Venus clouds join shortlist of places to search for alien life More : '' Ideas of a temperate or jungle-style environment at the Venus surface persisted until the mid-60s , '' Stephen Kane , a planet-hunter at the University of California , Riverside , told Space.com by email .
He noted that `` , '' the last Hollywood movie to feature astronauts @ @ @ @ @ @ @ , the same year the Soviet Venera 3 probe launched , bound to crash-land on the planet .
In the movie , the fictional astronauts landing in 2020 encountered a swampland filled with dinosaurs , a very different environment from the Venus scientists know today .
When NASA 's Mariner 5 flew by Venus in 1967 , it revealed a surface temperature of 860 degrees Fahrenheit ( 460 degrees Celsius ) .
`` The swamps digitally evaporated before their eyes , '' Suzanne Smrekar of NASA 's Jet Propulsion Laboratory in California told @ @ @ @ @ @ @ principal investigator of NASA 's .
( The name is short for Venus Emissivity , Radio Science , InSAR , Topography and Spectroscopy . )
No longer a swampy sister , our vision of with thick clouds , losing much of the attention it had previously garnered in science-fiction lore .
With a surface hot enough to melt lead , the planet was too broiling to host water on its surface .
Its potential for life seemed to evaporate with the swamps .
But while the fickle public turned its eyes toward the @ @ @ @ @ @ @ to study Earth 's twin .
`` We started the task of trying to understand how the surface of Venus could be so far removed from previous ideas , '' Kane said .
Over the past 50 years , humans have tried to solve that puzzle .
The Soviet Union until the early 1980s , some to orbit the world and others to land on its surface .
NASA 's Viking and Pioneer missions blew by , snapping photos and collecting data on their way to the outskirts of the solar system .
@ @ @ @ @ @ @ mapped the surface of the planet and the European Space Agency 's orbited the world for eight long years , studying its atmosphere .
In 2015 , began a probe of the Venusian atmosphere that continues today .
Meanwhile , missions across the solar system regularly use Venus as a gravitational boost to distant worlds , taking a few brief observations on their way past .
The myriad observations , along with advances made in understanding how planets evolve , have presented a slowly changing picture of Venus .
The results may help @ @ @ @ @ @ @ life .
`` Although the realization during the '60s regarding the hellish conditions of Venus caused many to believe that Venus has nothing to do with habitability , we have since changed our perspective to understand that Venus has everything to do with habitability , '' Kane said .
During the initial phases of exploration , scientists quickly realized that Venus was suffering a severe case of the .
The planet 's thick atmosphere worked as a blanket to trap heat , raising the temperatures to unbearable extremes .
`` Many people assumed @ @ @ @ @ @ @ where a runaway greenhouse scenario had run amuck and that was the end of the story , '' Kane said .
`` However , we 're realizing now that it is only the beginning . ''
The conditions that once led scientists to suspect Venus could be an Earth-like world had n't changed .
Both planets appear to have the same origins : rocky worlds large enough to hold onto their atmospheres with initial conditions ripe to collect water on the surface .
So where did Venus go wrong ?
That 's a @ @ @ @ @ @ @ they seek to determine the conditions that lead to habitability and those that lead to an overheated catastrophe .
Close behind is the question of whether the Venusian atmosphere changed dramatically in a single catastrophe or whether it was a slow change over time .
Ongoing observations have also revealed that Venus is anything but inactive .
Low-resolution radar images of the surface have shown evidence for , within the past 100 million years .
If our twin planet continues to belch gases into the air through its peaks , that would argue @ @ @ @ @ @ @ rather than a single cataclysm .
These questions are especially relevant for Earth , where human-produced greenhouse gases continue to build up in the atmosphere .
Some point to Venus as a sign of our planet 's future if human behavior does n't change .
But the planet next door may not only reveal our future , it may also show our past .
According to Smrekar , Venus is the only place in the solar system that may have continents and subduction , the first step in kicking off plate tectonics .
@ @ @ @ @ @ @ that have toured the planet , however , our view of the surface remains tantalizingly scanty .
If Venus does have continents , planetary scientists want to know when and how they formed , which could help researchers to better understand early Earth .
`` Earth 's continents and system of plate tectonics have shaped the evolution of Earth 's climate and habitability , '' Smrekar said .
`` But they came into existence billions of years ago ; little data from that time remains . ''
It 's even possible that it @ @ @ @ @ @ @ life first appeared in the solar system .
According to Smrekar , our twin planet has many of the characteristics required for a habitable world — an internal geologic engine to drive volcanism , tectonics , surface weathering , and even a potential ocean in the past .
`` Even though its surface appears supremely inhospitable today , in the past it may have been the first habitable planet , '' she said .
As the number of known exoplanets climbs into the thousands , Venus may be the key to unlocking and @ @ @ @ @ @ @ .
Planets around other stars are viewed from an incredible distance , and it is unlikely that humans will step on any of them in the near future .
But from a distance , a potentially habitable exo-Earth looks just like an exo-Venus .
`` If viewed as exoplanets , Venus and Earth are identical , '' Smrekar said .
`` Yet they are entirely different today . ''
In 2015 , Kane established a `` , '' the region around a star where a planet 's atmosphere could devolve into a greenhouse @ @ @ @ @ @ @ said that he wanted to emphasize that size alone , one of the primary methods of characterizing a world as `` Earth-like , '' is not enough to indicate habitability .
Sorting out the hellish Venus-like worlds requires knowing what made Venus into the planet it is today .
`` The key to understanding planetary habitability and how it evolves with time resides in understanding the evolution of our sister planet , '' Kane said .
That 's one reason scientists like Smrekar and Kane advocate for another mission to Venus .
Further @ @ @ @ @ @ @ existed on the surface relatively recently , which could indicate the planet slowly lost its habitable state rather than suffering from a quick catastrophe .
`` We absolutely must go back to Venus in order to answer the many outstanding questions , especially related to when Venus lost its liquid water , '' Kane said .
Kane adds that Venus can help provide better insight into the evolution of life on other worlds than other non-Earth terrestrial planets in the solar system .
`` The topic of habitability in the context of exoplanets @ @ @ @ @ @ @ planets , not Mars-size , '' Kane said .
`` The quest for detecting life in the universe necessarily requires understanding the incredible Venus-Earth dichotomy . ''
After decades of being ignored , Venus may soon be taking center stage .
, released Monday ( Sept. 14 ) , reveal the presence of a potentially biological signal that could come from life hidden in the planet 's clouds .
The clouds of Earth ’ s twin have long been considered a , but the discovery of phosphine , a flammable gas that , @ @ @ @ @ @ @ breakdown of organic material , gives the topic new urgency .
`` Biology in the atmosphere could be the last surviving members of a prior Venusian biosphere , '' Kane said .
`` If confirmed as being the result of life in the clouds , this result would be an extraordinary lesson in how life can really adapt to all available riches within an environment . ''
But Kane did issue a few caveats for that conclusion .
If life currently lives in the clouds of Venus , it must have found a @ @ @ @ @ @ @ atmosphere rather than falling back to the planet 's surface , which he calls `` a difficult problem to solve . ''
While life has been discovered in the clouds of Earth , that material has been lofted upward from the surface through convection , as hotter and less dense material moved upward .
That mechanism does n't exist on Venus , Kane said .
Additionally , the atmosphere of Venus is hot , dry , and surrounded by large reservoirs of sulfuric acid , all of which can make it difficult for @ @ @ @ @ @ @ years , from the time when the surface may have once hosted life , Kane said .
And the new research is based on phosphine production on Earth , while the surface and atmosphere of Venus are significantly different .
She thinks that the new results highlight the need to look for active and recent volcanism .
While the authors dismissed active volcanism as an explanation for their detection , she points out that the process is difficult to observe on Venus , where the signal of lava can disappear within days or @ @ @ @ @ @ @ processes that produce volcanism is key to interpreting the new research , which she said `` is intriguing and highlights the need to understand our sister planet better . ''
For Kane , the new results underscore the need to return to Earth 's twin in the near future .
`` Since the claim has been made and we do n't currently have a good explanation for the observations , we have a responsibility to investigate further and determine what the true source of the phosphine is , '' he said .
He @ @ @ @ @ @ @ , that will help scientists understand the atmosphere and geology of the planet .
`` It is through these kinds of missions that we will be able to fully answer this question of possible life in the Venusian clouds , '' Kane said .
Follow Nola on Facebook and on Twitter at @ NolaTRedd .
Follow us on Twitter @ Spacedotcom and on Facebook .

As Earth's sister planet, Venus has endured a love-hate relationship when it comes to exploration. Now, new results suggest the presence of a signal of potential habitability on Venus , and the long-forgotten sibling may find itself back in the spotlight.
With its orbit near the rising or setting sun, Venus shone clearly to the first ancient astronomers. As humanity began to explore the solar system, a world with nearly the same mass and radius as Earth seemed like the most promising target. Venus sits on the border of our sun's habitable zone , the region around a star where a planet should be able to host liquid water on its surface, and ideas of a veritable twin planet swam before the eyes of scientists and the public alike.
Related: Venus clouds join shortlist of places to search for alien life
More: The greatest mysteries of Venus
"Ideas of a temperate or jungle-style environment at the Venus surface persisted until the mid-60s," Stephen Kane, a planet-hunter at the University of California, Riverside, told Space.com by email. He noted that " Voyage to the Prehistoric Planet ," the last Hollywood movie to feature astronauts visiting Venus, came out in 1965, the same year the Soviet Venera 3 probe launched, bound to crash-land on the planet. In the movie, the fictional astronauts landing in 2020 encountered a swampland filled with dinosaurs, a very different environment from the Venus scientists know today.
When NASA's Mariner 5 flew by Venus in 1967, it revealed a surface temperature of 860 degrees Fahrenheit (460 degrees Celsius). "The swamps digitally evaporated before their eyes," Suzanne Smrekar of NASA's Jet Propulsion Laboratory in California told Space.com by email. Smrekar is the principal investigator of NASA's proposed VERITAS mission to Venus . (The name is short for Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy.)
No longer a swampy sister, our vision of Venus became a hellish world with thick clouds, losing much of the attention it had previously garnered in science-fiction lore. With a surface hot enough to melt lead, the planet was too broiling to host water on its surface. Its potential for life seemed to evaporate with the swamps.
But while the fickle public turned its eyes toward the redder world of Mars, scientists continued to study Earth's twin. "We started the task of trying to understand how the surface of Venus could be so far removed from previous ideas," Kane said.
Over the past 50 years, humans have tried to solve that puzzle. The Soviet Union continued to send Venera missions to Venus until the early 1980s, some to orbit the world and others to land on its surface. NASA's Viking and Pioneer missions blew by, snapping photos and collecting data on their way to the outskirts of the solar system.
In 1990, NASA's Magellan mission mapped the surface of the planet and the European Space Agency's Venus Express orbited the world for eight long years, studying its atmosphere. In 2015, Japan's Akatsuki mission began a probe of the Venusian atmosphere that continues today. Meanwhile, missions across the solar system regularly use Venus as a gravitational boost to distant worlds, taking a few brief observations on their way past.
The myriad observations, along with advances made in understanding how planets evolve, have presented a slowly changing picture of Venus. The results may help to resolve questions about the evolution of life .
"Although the realization during the '60s regarding the hellish conditions of Venus caused many to believe that Venus has nothing to do with habitability, we have since changed our perspective to understand that Venus has everything to do with habitability," Kane said.
Earth's future, Earth's past
During the initial phases of exploration, scientists quickly realized that Venus was suffering a severe case of the greenhouse effect . The planet's thick atmosphere worked as a blanket to trap heat, raising the temperatures to unbearable extremes.
"Many people assumed Venus was a 'solved problem,' where a runaway greenhouse scenario had run amuck and that was the end of the story," Kane said. "However, we're realizing now that it is only the beginning."
The conditions that once led scientists to suspect Venus could be an Earth-like world hadn't changed. Both planets appear to have the same origins: rocky worlds large enough to hold onto their atmospheres with initial conditions ripe to collect water on the surface. So where did Venus go wrong?
That's a question that still plagues Venus researchers as they seek to determine the conditions that lead to habitability and those that lead to an overheated catastrophe. Close behind is the question of whether the Venusian atmosphere changed dramatically in a single catastrophe or whether it was a slow change over time.
Ongoing observations have also revealed that Venus is anything but inactive. Low-resolution radar images of the surface have shown evidence for recent explosive volcanism , within the past 100 million years. If our twin planet continues to belch gases into the air through its peaks, that would argue for a slow shift in the atmosphere rather than a single cataclysm.
These questions are especially relevant for Earth, where human-produced greenhouse gases continue to build up in the atmosphere. Some point to Venus as a sign of our planet's future if human behavior doesn't change.
But the planet next door may not only reveal our future , it may also show our past. According to Smrekar, Venus is the only place in the solar system that may have continents and subduction, the first step in kicking off plate tectonics. Despite an apparently long list of missions that have toured the planet, however, our view of the surface remains tantalizingly scanty. If Venus does have continents, planetary scientists want to know when and how they formed, which could help researchers to better understand early Earth.
"Earth's continents and system of plate tectonics have shaped the evolution of Earth's climate and habitability," Smrekar said. "But they came into existence billions of years ago; little data from that time remains."
It's even possible that it was Venus, not Earth, where life first appeared in the solar system. According to Smrekar, our twin planet has many of the characteristics required for a habitable world — an internal geologic engine to drive volcanism, tectonics, surface weathering, and even a potential ocean in the past. "Even though its surface appears supremely inhospitable today, in the past it may have been the first habitable planet," she said.
The exoplanet next door
As the number of known exoplanets climbs into the thousands, Venus may be the key to unlocking and understanding which of those worlds are habitable. Planets around other stars are viewed from an incredible distance, and it is unlikely that humans will step on any of them in the near future. But from a distance, a potentially habitable exo-Earth looks just like an exo-Venus.
"If viewed as exoplanets, Venus and Earth are identical," Smrekar said. "Yet they are entirely different today."
In 2015, Kane established a " Venus zone ," the region around a star where a planet's atmosphere could devolve into a greenhouse world. At the time, he said that he wanted to emphasize that size alone, one of the primary methods of characterizing a world as "Earth-like," is not enough to indicate habitability.
Sorting out the hellish Venus-like worlds requires knowing what made Venus into the planet it is today. "The key to understanding planetary habitability and how it evolves with time resides in understanding the evolution of our sister planet," Kane said.
That's one reason scientists like Smrekar and Kane advocate for another mission to Venus. Further exploration could hunt for signs that water existed on the surface relatively recently, which could indicate the planet slowly lost its habitable state rather than suffering from a quick catastrophe.
"We absolutely must go back to Venus in order to answer the many outstanding questions, especially related to when Venus lost its liquid water," Kane said.
Kane adds that Venus can help provide better insight into the evolution of life on other worlds than other non-Earth terrestrial planets in the solar system.
"The topic of habitability in the context of exoplanets will always focus on Earth and Venus-size planets, not Mars-size," Kane said. "The quest for detecting life in the universe necessarily requires understanding the incredible Venus-Earth dichotomy."
New results
After decades of being ignored, Venus may soon be taking center stage.
New results , released Monday (Sept. 14), reveal the presence of a potentially biological signal that could come from life hidden in the planet's clouds. The clouds of Earth’s twin have long been considered a potential home to life , but the discovery of phosphine, a flammable gas that, on Earth, can come from the breakdown of organic material, gives the topic new urgency.
"Biology in the atmosphere could be the last surviving members of a prior Venusian biosphere," Kane said. "If confirmed as being the result of life in the clouds, this result would be an extraordinary lesson in how life can really adapt to all available riches within an environment."
But Kane did issue a few caveats for that conclusion. If life currently lives in the clouds of Venus, it must have found a way to continue to linger in the atmosphere rather than falling back to the planet's surface, which he calls "a difficult problem to solve." While life has been discovered in the clouds of Earth, that material has been lofted upward from the surface through convection, as hotter and less dense material moved upward. That mechanism doesn't exist on Venus, Kane said.
Additionally, the atmosphere of Venus is hot, dry, and surrounded by large reservoirs of sulfuric acid, all of which can make it difficult for life to have survived the past billion years, from the time when the surface may have once hosted life, Kane said. And the new research is based on phosphine production on Earth, while the surface and atmosphere of Venus are significantly different.
Smrekar agreed.
She thinks that the new results highlight the need to look for active and recent volcanism. While the authors dismissed active volcanism as an explanation for their detection, she points out that the process is difficult to observe on Venus, where the signal of lava can disappear within days or weeks. Understanding surface chemistry and the processes that produce volcanism is key to interpreting the new research, which she said "is intriguing and highlights the need to understand our sister planet better."
For Kane, the new results underscore the need to return to Earth's twin in the near future.
"Since the claim has been made and we don't currently have a good explanation for the observations, we have a responsibility to investigate further and determine what the true source of the phosphine is," he said. He pointed to upcoming missions, including VERITAS, that will help scientists understand the atmosphere and geology of the planet.
"It is through these kinds of missions that we will be able to fully answer this question of possible life in the Venusian clouds," Kane said.
Follow Nola on Facebook and on Twitter at @NolaTRedd. Follow us on Twitter @Spacedotcom and on Facebook.


livescience--2020-09-16--100 million-year-old sperm is the oldest ever found. And it's giant.

The oldest known sperm in the world has been discovered , locked in a piece of amber that solidified when behemoths like Spinosaurus dominated the .
The giant sperm comes from a much more miniscule creature than the toothy Spinosaurus : an ostracod , a crustacean that looks like a shrimp dressing up as a clam for Halloween .
Known colloquially as `` seed shrimp , '' ostracods typically grow just a few tenths of an inch long .
Their bodies are protected by a bivalve shell , from which tiny , crab-like appendages sometimes protrude .
There are thousands @ @ @ @ @ @ @ many boast giant sperm cells , the longest of which unspools to a jaw-dropping 0.46 inches ( 11.8 millimeters ) , far longer than the animal that produces it .
Now , scientists have found an example of this enormous sperm in an ostracod from the , 100 million years ago .
It 's the oldest unambiguous example of any animal sperm by 50 million years .
Related : See images of the oldest 'petrified ' giant sperm The sperm was found inside a disc of amber about the size of a postage @ @ @ @ @ @ @ .
In this tiny blob of tree resin were 39 ostracods , 31 of which belong to a never-before-seen species now called Myanmarcypris hui .
Individuals grew only 0.02 inches ( 0.59 millimeters ) in length .
Most exciting , though , was what researchers found inside an adult female M. hui .
The female 's soft tissues were preserved , including four tiny eggs ( each just 50 micrometers in diameter , less than the diameter of a human hair ) and a mass of something that looked like spaghetti within the @ @ @ @ @ @ @ Wang , a paleontologist and postdoctoral researcher at the Chinese Academy of Science , used computed tomography to reconstruct a three-dimensional image of this mass and sent it to Renate Matzke-Karasz , an ostracod expert and paleontologist at Ludwig Maximilian University of Munich .
`` I immediately congratulated him on having reconstructed the oldest animal sperm , '' Matzke-Karasz told Live Science .
Wang , Matzke-Karasz and their colleagues estimate that each sperm was 200 micrometers long .
They published their findings today ( Sept. 16 ) in the journal Proceedings of the @ @ @ @ @ @ @ , the oldest confirmed animal sperm dated to about 50 million years ago .
It was found in a .
The oldest ostracod sperm found prior to this discovery dates back only 17 million years ( though it was the when it was first found ) .
The discovery of giant sperm dating back 100 million years is exciting , Matzke-Karasz said , because giant sperm are an energy-intensive way to reproduce .
They require lots of energy to make and lots of space within the animal devoted to the reproductive tract .
@ @ @ @ @ @ @ giant sperm are involved , Matzke-Karasz said .
`` You might think that this does n't make sense from an evolutionary standpoint , '' she said .
`` But in ostracods , it seemed to work for more than 100 million years . ''
There are only 20 or so examples of ostracod soft tissue preserved by fossilization , Matzke-Karasz said .
It was surprising to find these aquatic animals in fossilized plant resin , so the next step is to seek out other amber specimens from other time periods that might contain @ @

The oldest known sperm in the world has been discovered, locked in a piece of amber that solidified when behemoths like Spinosaurus dominated the Earth .
The giant sperm comes from a much more miniscule creature than the toothy Spinosaurus: an ostracod, a crustacean that looks like a shrimp dressing up as a clam for Halloween. Known colloquially as "seed shrimp," ostracods typically grow just a few tenths of an inch long. Their bodies are protected by a bivalve shell, from which tiny, crab-like appendages sometimes protrude.
There are thousands of ostracod species alive today, and many boast giant sperm cells, the longest of which unspools to a jaw-dropping 0.46 inches (11.8 millimeters), far longer than the animal that produces it. Now, scientists have found an example of this enormous sperm in an ostracod from the Cretaceous period , 100 million years ago. It's the oldest unambiguous example of any animal sperm by 50 million years.
Related: See images of the oldest 'petrified' giant sperm
Locked in amber
The sperm was found inside a disc of amber about the size of a postage stamp in a mine in northern Myanmar. In this tiny blob of tree resin were 39 ostracods, 31 of which belong to a never-before-seen species now called Myanmarcypris hui. Individuals grew only 0.02 inches (0.59 millimeters) in length.
Most exciting, though, was what researchers found inside an adult female M. hui. The female's soft tissues were preserved, including four tiny eggs (each just 50 micrometers in diameter, less than the diameter of a human hair) and a mass of something that looked like spaghetti within the female’s seminal receptacles.
Related: Photos: Ancient ants & termites locked in amber
Image 1 of 6 Only a few of the ostracods in the amber piece could be studied using light microscopy, like this individual of the new species Myanmarcypris hui. Its antennae extend from the bivalved shell. (Image credit: He Wang & Xiangdong Zhao) The scientists found 39 ostracod crustaceans were entrapped in this tiny piece of Cretaceous amber found in Myanmar. (Image credit: He Wang & Xiangdong Zhao) Here, reconstructions of a female of the Cretaceous ostracod crustacean Myanmarcypris hui. Upper left: the tips of both pairs of antennae can be seen extending from the front of the strongly ornamented bivalved shell. Upper right: inside the shell (now transparent) some of the appendages can be seen, as well as eggs (green) and the sperm receptacles (purple). Lower right: reconstruction of the paired sperm receptacles. Lower left: one of the sperm receptacles in more detail, filled with filamentous giant sperms. (Image credit: He Wang) A reconstruction of a male of the Cretaceous ostracod crustacean Myanmarcypris hui. The paired antennae – typical of crustaceans – extend from the strongly ornamented bivalved shell. (Image credit: Renate Matzke-Karasz) This reconstruction shows one of the sperm storage organs (seminal receptacles) of a female of the ostracod crustacean Myanmarcypris hui. (Image credit: He Wang & Xiangdong Zhao)
This artist's reconstruction shows the Cretaceous ostracod crustacean Myanmarcypris hui male (right) and female (left) during mating. (Image credit: Dinghua Yang)
He Wang, a paleontologist and postdoctoral researcher at the Chinese Academy of Science, used computed tomography to reconstruct a three-dimensional image of this mass and sent it to Renate Matzke-Karasz, an ostracod expert and paleontologist at Ludwig Maximilian University of Munich.
"I immediately congratulated him on having reconstructed the oldest animal sperm," Matzke-Karasz told Live Science.
Wang, Matzke-Karasz and their colleagues estimate that each sperm was 200 micrometers long. They published their findings today (Sept. 16) in the journal Proceedings of the Royal Academy B.
The evolution of giant sperm
Before this discovery, the oldest confirmed animal sperm dated to about 50 million years ago. It was found in a worm cocoon from Antarctica . The oldest ostracod sperm found prior to this discovery dates back only 17 million years (though it was the oldest sperm on record when it was first found).
The discovery of giant sperm dating back 100 million years is exciting, Matzke-Karasz said, because giant sperm are an energy-intensive way to reproduce. They require lots of energy to make and lots of space within the animal devoted to the reproductive tract. Mating also takes a long time when giant sperm are involved, Matzke-Karasz said.
"You might think that this doesn't make sense from an evolutionary standpoint," she said. "But in ostracods, it seemed to work for more than 100 million years."
There are only 20 or so examples of ostracod soft tissue preserved by fossilization, Matzke-Karasz said. It was surprising to find these aquatic animals in fossilized plant resin, so the next step is to seek out other amber specimens from other time periods that might contain ostracods.
Originally published on Live Science.


livescience--2020-09-15--Hurricane Sally expected to bring 'historic flooding' to the Gulf Coast

Hurricane Sally may bring `` historic flooding , '' including `` extreme life-threatening flash flooding , '' to the central U.S. Gulf Coast from the western Florida Panhandle to southeastern Mississippi , according to the National Hurricane Center ( NHC ) .
As of 11 a.m. EDT , the storm is about 55 miles ( 85 kilometers ) east of the mouth of the Mississippi River and is expected to pass near the coast of southeastern Louisiana today ( Sept. 15 ) and make landfall later tonight or Wednesday morning ( Sept. 16 ) .
Sally is currently a Category @ @ @ @ @ @ @ 85 mph ( 140 km/h ) , and it is n't expected to strengthen much before hitting land .
But forecasters still expect Sally to be `` a dangerous hurricane when it moves onshore along the north-central Gulf coast , '' according to the NHC .
Hurricane warnings are in effect from the east of Bay St. Louis in Mississippi to Navarre , Florida , and tropical storm warnings are in effect for the areas east of Navarre to Indian Pass , Florida , and westward of Bay St. Louis to Grand Isle @ @ @ @ @ @ @ today in parts of the hurricane warning area , according to the NHC .
Louisiana and Mississippi governors have each declared a state of emergency , according to CNN .
The storm is n't moving fast , which may prolong flooding from rainfall , storm surges and strong winds in the areas it hits , according to Weather.com .
Sally is creeping toward the northwest at 2 mph ( 4 km/h ) and is expected to head north/ north-westward in the afternoon and north/north-eastward tonight through Wednesday night .
The storm is expected @ @ @ @ @ @ @ 25 to 51 centimeters ) of rain , with some parts of the Gulf Coast getting up to 30 inches ( 76 cm ) .
A storm surge warning is in effect for the mouth of the Mississippi River to the Okaloosa/Walton County Line in Florida and for Mobile Bay , Alabama .
Those areas may see `` life-threatening '' storm surges , according to the NHC .
From Ocean Springs , Mississippi , to Dauphin Island , Alabama , storm surges could reach up to 6 to 9 feet ( 1.8 to @ @ @ @ @ @ @ NHC .
In other areas , including the mouth of the Mississippi River , surges could reach 4 to 7 feet ( 1.2 to 2 m ) .
Louisiana was already hard-hit from tropical storm Marco and Hurricane Laura in August , according to a previous Live Science report .
This past weekend , two weeks after Laura hit , 134,000 people were still without power , and some 23,000 people are still living in shelters , according to the report .

Five storms in the Atlantic and one in the Pacific can be seen in a satellite image from today (Sept. 15)
Hurricane Sally may bring "historic flooding," including "extreme life-threatening flash flooding," to the central U.S. Gulf Coast from the western Florida Panhandle to southeastern Mississippi, according to the National Hurricane Center (NHC).
As of 11 a.m. EDT, the storm is about 55 miles (85 kilometers) east of the mouth of the Mississippi River and is expected to pass near the coast of southeastern Louisiana today (Sept. 15) and make landfall later tonight or Wednesday morning (Sept. 16).
Sally is currently a Category 1 hurricane with maximum sustained winds of 85 mph (140 km/h), and it isn't expected to strengthen much before hitting land. But forecasters still expect Sally to be "a dangerous hurricane when it moves onshore along the north-central Gulf coast," according to the NHC.
Related: A history of destruction: 8 great hurricanes
Hurricane Sally is crawling toward land and is expected to bring historic flooding. (Image credit: National Oceanic and Atmospheric Administration/National Hurricane Center)
Hurricane warnings are in effect from the east of Bay St. Louis in Mississippi to Navarre, Florida, and tropical storm warnings are in effect for the areas east of Navarre to Indian Pass, Florida, and westward of Bay St. Louis to Grand Isle, Louisiana. Hurricane conditions are expected today in parts of the hurricane warning area, according to the NHC. Louisiana and Mississippi governors have each declared a state of emergency, according to CNN.
The storm isn't moving fast, which may prolong flooding from rainfall, storm surges and strong winds in the areas it hits, according to Weather.com. Sally is creeping toward the northwest at 2 mph (4 km/h) and is expected to head north/ north-westward in the afternoon and north/north-eastward tonight through Wednesday night. The storm is expected to drop 10 to 20 inches (25 to 51 centimeters) of rain, with some parts of the Gulf Coast getting up to 30 inches (76 cm).
A storm surge warning is in effect for the mouth of the Mississippi River to the Okaloosa/Walton County Line in Florida and for Mobile Bay, Alabama. Those areas may see "life-threatening" storm surges, according to the NHC. From Ocean Springs, Mississippi, to Dauphin Island, Alabama, storm surges could reach up to 6 to 9 feet (1.8 to 2.7 meters), according to the NHC. In other areas, including the mouth of the Mississippi River, surges could reach 4 to 7 feet (1.2 to 2 m).
Louisiana was already hard-hit from tropical storm Marco and Hurricane Laura in August, according to a previous Live Science report. This past weekend, two weeks after Laura hit, 134,000 people were still without power, and some 23,000 people are still living in shelters, according to the report.
Originally published on Live Science.


livescience--2020-09-15--Lost humpback whale abandoned by friends in croc-infested river in Australia

A is swimming the wrong way up an alligator-filled river in Australia 's Northern Territory , according to media reports .
The lost whale is traveling further inland than any whale has ever been seen on the continent , government experts said on Monday ( Sept. 14 ) .
`` It 's something that 's never been recorded before — not just in the Northern Territory , but in Australia , '' Carol Palmer , a marine ecosystems scientist for the Northern Territory Government , ( ABC ) .
`` It 's really , really unusual . ''
The stranded @ @ @ @ @ @ @ Megaptera novaeangliae ) spotted last week swimming in the not-at-all-ominously-named East Alligator River , which connects Kakadu National Park in northern Australia with the nearby sea .
Saltwater inhabit the river 's murky , brown waters as far as 100 miles ( 160 kilometers ) inland , , where they wait to ambush a variety of prey , including the occasional human .
Related : Humpback whale charges swimmers in Australia , sends two to hospital As of Monday , two of the whales appear to have made a U-turn back to sea @ @ @ @ @ @ @ miles ( 30 km ) upstream , seemingly lost .
The threat of a croc attack seems slim for now , Palmer said , given the whale 's massive size ( it measures an estimated 52 feet , or 16 meters long ) — however , if the whale becomes stranded in shallow waters , it could become an easy target .
To avoid that , Palmer and other experts are considering some acoustic strategies to force the whale to head back downriver , including blasting the river with underwater noise pollution or @ @ @ @ @ @ @ upstream to try and coax the humpback into reversing course .
In the meantime , the government has set up an `` exclusion zone '' along the first 19 miles of the river to keep boaters out of the whale 's way .
How did the humpback trio end up so far inland in the first place ?
It 's likely they took a wrong turn on their way toward , Palmer said .
Every summer ( which is about to kick off in the Southern Hemisphere ) , humpbacks migrate from their @ @ @ @ @ @ @ grounds .
On their way south , these whales could have swum accidentally into an estuary that fed them deeper into the river system .
The river 's murky brown waters do n't help either , as they are hard to navigate by sight .
A recent boom in the local humpback population also means there are simply more whales around to get lost .
( In 2019 , for instance , a young humpback whale got sick and disoriented before winding up in the Amazon Jungle , . )
`` We have @ @ @ @ @ @ @ recent years , '' Palmer said .
`` There are probably upwards of 40,000 whales in the west coast population and 35,000 along the east coast . ''

A humpback whale is swimming the wrong way up an alligator-filled river in Australia's Northern Territory, according to media reports. The lost whale is traveling further inland than any whale has ever been seen on the continent, government experts said on Monday (Sept. 14).
"It's something that's never been recorded before — not just in the Northern Territory, but in Australia," Carol Palmer, a marine ecosystems scientist for the Northern Territory Government, told the Australian Broadcasting Company (ABC). "It's really, really unusual."
The stranded whale is one of three humpbacks (Megaptera novaeangliae) spotted last week swimming in the not-at-all-ominously-named East Alligator River, which connects Kakadu National Park in northern Australia with the nearby sea. Saltwater crocodiles inhabit the river's murky, brown waters as far as 100 miles (160 kilometers) inland, CNN reported , where they wait to ambush a variety of prey, including the occasional human.
Related: Humpback whale charges swimmers in Australia, sends two to hospital
As of Monday, two of the whales appear to have made a U-turn back to sea, while one remains swimming roughly 19 miles (30 km) upstream, seemingly lost. The threat of a croc attack seems slim for now, Palmer said, given the whale's massive size (it measures an estimated 52 feet, or 16 meters long) — however, if the whale becomes stranded in shallow waters, it could become an easy target.
To avoid that, Palmer and other experts are considering some acoustic strategies to force the whale to head back downriver, including blasting the river with underwater noise pollution or playing pre-recorded killer whale (Orcinus orca) calls upstream to try and coax the humpback into reversing course. In the meantime, the government has set up an "exclusion zone" along the first 19 miles of the river to keep boaters out of the whale's way.
How did the humpback trio end up so far inland in the first place? It's likely they took a wrong turn on their way toward Antarctica , Palmer said. Every summer (which is about to kick off in the Southern Hemisphere), humpbacks migrate from their Australian breeding grounds to their Antarctic feeding grounds. On their way south, these whales could have swum accidentally into an estuary that fed them deeper into the river system. The river's murky brown waters don't help either, as they are hard to navigate by sight.
A recent boom in the local humpback population also means there are simply more whales around to get lost. (In 2019, for instance, a young humpback whale got sick and disoriented before winding up in the Amazon Jungle, Live Science previously reported .)
"We have seen a spike in their population in recent years," Palmer said. "There are probably upwards of 40,000 whales in the west coast population and 35,000 along the east coast."
Originally published on Live Science.


livescience--2020-09-18--The four most promising worlds for alien life in the solar system

The Earth 's biosphere contains all the known ingredients necessary for life as we know it .
Broadly speaking these are : liquid water , at least one source of energy , and an inventory of biologically useful elements and molecules .
But the recent discovery of possibly biogenic phosphine in the clouds of Venus reminds us that at least some of these ingredients exist elsewhere in the solar system too .
So where are the other most promising locations for extraterrestrial life ?
Mars is one of the most Earth-like worlds in the solar system .
It has a @ @ @ @ @ @ @ expand and contract with the seasons , and a large array of surface features that were sculpted by water during the planet 's history .
The detection of the southern polar ice cap and methane in the Martian atmosphere ( which varies with the seasons and even the ) make Mars a very interesting candidate for life .
Methane is significant as it can be produced by biological processes .
But the actual source for the methane on Mars is not yet known .
It is possible that life may have gained a @ @ @ @ @ @ @ once had a much more benign environment .
Today , Mars has a very thin , dry atmosphere comprised almost entirely of carbon dioxide .
This offers scant protection from solar and cosmic radiation .
If Mars has managed to retain some reserves of water beneath its surface , it is not impossible that life may still exist .
Read more : Life on Mars ?
Europe commits to groundbreaking mission to bring back rocks to Earth Europa was discovered by Galileo Galilei in 1610 , along with Jupiter 's three other larger @ @ @ @ @ @ @ Earth 's moon and orbits the gas giant at a distance of some 670,000km once every 3.5 days .
Europa is constantly squeezed and stretched by the competing gravitational fields of Jupiter and the other , a process known as tidal flexing .
The moon is believed to be a geologically active world , like the Earth , because the strong tidal flexing heats its rocky , metallic interior and keeps it partially molten .
The surface of Europa is a vast expanse of water ice .
Many scientists think that beneath the @ @ @ @ @ @ @ water — a global ocean — which is prevented from freezing by the heat from flexing and which maybe over 100km deep .
Evidence for this ocean includes geysers erupting through , a and on the surface , which could have been deformed by ocean currents swirling beneath .
This icy shield insulates the subsurface ocean from the extreme cold and vacuum of space , as well as Jupiter 's ferocious radiation belts .
At the bottom of this ocean world it is conceivable that we might find and ocean floor volcanoes .
@ @ @ @ @ @ @ very rich and diverse ecosystems .
Read more : Europa : there may be life on Jupiter 's moon and two new missions will pave the way for finding it Like Europa , is an ice-covered moon with a subsurface ocean of liquid water .
Enceladus orbits Saturn and first came to the attention of scientists as a potentially habitable world following the of enormous geysers near the moon 's south pole .
These jets of water escape from large cracks on the surface and , given Enceladus ' weak gravitational field , @ @ @ @ @ @ @ clear evidence of an underground store of liquid water .
Not only was water detected in these geysers but also an array of organic molecules and , crucially , tiny grains of rocky silicate particles that can only be present if the subsurface ocean water was in physical contact with the rocky ocean floor at a temperature of at least 90˚C .
This is very strong evidence for the existence of hydrothermal vents on the ocean floor , providing the chemistry needed for life and localized sources of energy .
Titan is the @ @ @ @ @ @ @ moon in the solar system with a substantial atmosphere .
It contains a thick orange haze of complex organic molecules and a methane weather system in place of water — complete with seasonal rains , dry periods and surface sand dunes created by wind .
The atmosphere consists mostly of nitrogen , an important chemical element used in the construction of proteins in all known forms of life .
Radar observations have detected the presence of of liquid methane and ethane and possibly the presence of cryovolcanoes — volcano-like features that erupt liquid @ @ @ @ @ @ @ that Titan , like Europa and Enceladus , has a subsurface reserve of liquid water .
At such an enormous distance from the Sun , the surface temperatures on Titan are a frigid -180˚C — way too cold for liquid water .
However , the bountiful chemicals available on Titan has raised speculation that lifeforms — potentially with fundamentally different chemistry to terrestrial organisms — there .
This article was originally published at The Conversation .
The publication contributed the article to Live Science 's Expert Voices : Op-Ed & Insights .

The Earth's biosphere contains all the known ingredients necessary for life as we know it. Broadly speaking these are: liquid water, at least one source of energy, and an inventory of biologically useful elements and molecules.
But the recent discovery of possibly biogenic phosphine in the clouds of Venus reminds us that at least some of these ingredients exist elsewhere in the solar system too. So where are the other most promising locations for extraterrestrial life?
Mars
Mars is one of the most Earth-like worlds in the solar system. It has a 24.5-hour day, polar ice caps that expand and contract with the seasons, and a large array of surface features that were sculpted by water during the planet's history.
The detection of a lake beneath the southern polar ice cap and methane in the Martian atmosphere (which varies with the seasons and even the time of day ) make Mars a very interesting candidate for life. Methane is significant as it can be produced by biological processes. But the actual source for the methane on Mars is not yet known.
It is possible that life may have gained a foothold, given the evidence that the planet once had a much more benign environment. Today, Mars has a very thin, dry atmosphere comprised almost entirely of carbon dioxide. This offers scant protection from solar and cosmic radiation. If Mars has managed to retain some reserves of water beneath its surface, it is not impossible that life may still exist.
Read more: Life on Mars? Europe commits to groundbreaking mission to bring back rocks to Earth
Europa
Europa was discovered by Galileo Galilei in 1610, along with Jupiter's three other larger moons. It is slightly smaller than Earth's moon and orbits the gas giant at a distance of some 670,000km once every 3.5 days. Europa is constantly squeezed and stretched by the competing gravitational fields of Jupiter and the other Galilean moons , a process known as tidal flexing.
The moon is believed to be a geologically active world, like the Earth, because the strong tidal flexing heats its rocky, metallic interior and keeps it partially molten.
The surface of Europa is a vast expanse of water ice. Many scientists think that beneath the frozen surface is a layer of liquid water — a global ocean — which is prevented from freezing by the heat from flexing and which maybe over 100km deep.
An artist's concept of the subsurface of Jupiter moon Europa. (Image credit: NASA/JPL-Caltech)
Evidence for this ocean includes geysers erupting through cracks in the surface ice , a weak magnetic field and chaotic terrain on the surface, which could have been deformed by ocean currents swirling beneath. This icy shield insulates the subsurface ocean from the extreme cold and vacuum of space, as well as Jupiter's ferocious radiation belts.
At the bottom of this ocean world it is conceivable that we might find hydrothermal vents and ocean floor volcanoes. On Earth, such features often support very rich and diverse ecosystems.
Read more: Europa: there may be life on Jupiter's moon and two new missions will pave the way for finding it
Enceladus
Like Europa, Enceladus is an ice-covered moon with a subsurface ocean of liquid water. Enceladus orbits Saturn and first came to the attention of scientists as a potentially habitable world following the surprise discovery of enormous geysers near the moon's south pole.
These jets of water escape from large cracks on the surface and, given Enceladus' weak gravitational field, spray out into space. They are clear evidence of an underground store of liquid water.
14 hours watching the plume at Saturn's moon Enceladus, our last dedicated observation of this singular scene https://t.co/EqLPb6MsbO pic.twitter.com/hW3BVUExczSeptember 10, 2017 See more
Not only was water detected in these geysers but also an array of organic molecules and, crucially, tiny grains of rocky silicate particles that can only be present if the subsurface ocean water was in physical contact with the rocky ocean floor at a temperature of at least 90˚C . This is very strong evidence for the existence of hydrothermal vents on the ocean floor, providing the chemistry needed for life and localized sources of energy.
Titan
Seas on Saturn moon Titan. (Image credit: NASA/JPL-Caltech/Univ. Arizona/Univ. Idaho)
Titan is the largest moon of Saturn and the only moon in the solar system with a substantial atmosphere. It contains a thick orange haze of complex organic molecules and a methane weather system in place of water — complete with seasonal rains, dry periods and surface sand dunes created by wind.
The atmosphere consists mostly of nitrogen, an important chemical element used in the construction of proteins in all known forms of life. Radar observations have detected the presence of rivers and lakes of liquid methane and ethane and possibly the presence of cryovolcanoes — volcano-like features that erupt liquid water rather than lava. This suggests that Titan, like Europa and Enceladus, has a subsurface reserve of liquid water.
At such an enormous distance from the Sun, the surface temperatures on Titan are a frigid -180˚C — way too cold for liquid water. However, the bountiful chemicals available on Titan has raised speculation that lifeforms — potentially with fundamentally different chemistry to terrestrial organisms — could exist there.
This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.