livescience--2020-12-03--What are the symptoms of COVID-19?

What are the symptoms of COVID-19?

How will you know if you have the novel coronavirus that causes the COVID-19 disease ?
People with COVID-19 can have asymptomatic , mild or severe disease .
People who have fallen ill with the virus have reported a wide range of symptoms , according to The Centers for Disease Control and Prevention ( CDC ) .
The CDC has listed 11 coronavirus symptoms that tend to appear about 2 to 14 days after exposure to the virus : fever or chills ; cough ; shortness of breath or difficulty breathing ; fatigue ; muscle or body aches ; headache @ @ @ @ @ @ @ ; sore throat ; congestion or runny nose ; nausea or vomiting and diarrhea .
The following symptoms , the CDC says , are emergency warning signs that you should seek immediate medical attention : trouble breathing ; persistent pain or pressure in the chest ; new confusion ; inability to wake or stay awake ; bluish lips or face ; other severe symptoms that concern you .
But there are many other , less common symptoms that have been reported in COVID-19 patients .
For example , various skin rashes have been @ @ @ @ @ @ @ can take many forms — some appear as tiny red spots , while others appear as larger flat or raised lesions .
Some have a hive-like appearance , while others look like frostbitten toes , '' Live Science reported .
It 's not yet clear whether these rashes are caused by the novel coronavirus or somehow related to other factors , such as a charged-up immune system in those infected with the virus .
[ See for more information on skin conditions that could be caused by COVID ] .
COVID-19 can also @ @ @ @ @ @ @ the loss of smell and taste , the virus can cause muscle weakness , tingling or numbness in the hands and feet , dizziness , confusion , delirium , seizures and stroke , .
A person with COVID-19 may have mild symptoms for about a week before rapidly worsening , according to Harvard Medical School .
`` Let your doctor know if your symptoms quickly worsen over a short period of time , '' according to Harvard .
In more serious cases of COVID-19 , patients experience pneumonia , which means their lungs @ @ @ @ @ @ @ or fluid .
This leads to intense shortness of breath and painful coughing .
In some people , the virus can also cause severe disease indirectly by triggering a `` cytokine storm '' or an overreaction of the immune system that can cause severe damage in the body , according to Harvard .
The CDC recommends that people with COVID-19 or any respiratory illness monitor their symptoms carefully .
Worsening shortness of breath is reason to seek medical care , particularly for older individuals or people with underlying health conditions .
The has @ @ @ @ @ @ @ are sick .
The risk of severe disease `` increases steadily '' with age , but younger people can also become severely ill , according to Harvard Medical School .
Most children with COVID-19 have either mild symptoms or no symptoms , but some can become seriously ill , according to the CDC .
Babies under the age of 1 year old and children with certain underlying conditions such as asthma or chronic lung diseases , diabetes , heart disease and obesity may be at an increased risk of severe illness , according @ @ @ @ @ @ @ the most common symptoms of COVID-19 are fever and cough but they may also develop chills , nasal congestion or runny nose , loss of taste or smell , sore throat , shortness of breath or difficulty breathing , diarrhea , nausea or vomiting , stomach , tiredness , headache , muscle or body aches , poor appetite or poor feeding , especially in infants , according to the CDC .
Parents should `` pay particular attention '' to markers that can indicate COVID-19 in the child such as a fever of 100.4 @ @ @ @ @ @ @ or higher , sore throat , a new uncontrolled cough that causes difficulty breathing , diarrhea , vomiting or stomach ache and a new onset of severe headache especially if it 's along with a fever , according to the CDC .
If the child is showing any emergency signs ( same as the ones listed for adults ) , the CDC recommends seeking emergency medical care immediately .
A multisystem inflammatory syndrome in children ( MIS-C ) has also been associated with the novel coronavirus , according to the CDC .
This @ @ @ @ @ @ @ of the body such as the heart , lungs , kidneys , brain , skin , eyes or gastrointestinal organs become inflamed .
It 's not yet clear what causes MIS-C , but children diagnosed with the condition often had COVID-19 or had been around someone who had COVID-19 , according to the CDC .
Several cases of MIS have also been reported in adults , .
Doctors first spotted the inflammatory syndrome on April 26 in the United Kingdom , when doctors began to notice an increasing number of kids coming in @ @ @ @ @ @ @ Kawasaki disease , a rare childhood disease that causes inflammation of blood vessels and can lead to heart damage .
Some of the symptoms also overlapped with those of toxic shock syndrome , a life-threatening illness caused by toxins released by certain bacteria .
There 's still much unknown about this new illness ; symptoms are still being documented and could vary from child to child , according to Boston Children 's Hospital .
Parents should mainly watch out for a persistent fever that lasts for more than 24 hours and is typically @ @ @ @ @ @ @ whether the child appears fatigued and ill , or if the child has a loss of appetite or is not drinking enough fluids , .
Other symptoms that could indicate MIS-C include gastrointestinal symptoms such as abdominal pain , swollen abdomen , vomiting and/or diarrhea ; skin rashes ( often reddish in color ) ; neck pain ; bloodshot eyes or swollen eyes ; unusually red of strawberry-like tongue ; swollen hands and feet ; swollen lymph nodes ; red , cracked lips ; persistent cough and shortness of breath ; low blood @ @ @ @ @ @ @ rate , according to the CDC and Boston Children 's Hospital .
These are not mild symptoms , so parents will likely notice them , in May .
For instance , the abdominal pain is not just a little bellyache but `` severe enough for the parent to be worried , '' Dr. George Ofori-Amanfo , division chief of pediatric critical care medicine at Mount Sinai Kravis Children 's Hospital in New York , told the Times .
And the rashes , the Times reported , tend to be red , cover a @ @ @ @ @ @ @ the hands , forearms and chest , turning white when you press on them , according to the Times .
If your child has a persistent fever above 101 degrees Fahrenheit ( 38.3 degrees Celsius ) , call your pediatrician .
Treatment includes supportive care to reduce symptoms , including steroids for inflammation , fever reducers and other medications , the Times reported .
Children may also be treated with intravenous immunoglobulin ( IVIG ) , a cocktail of various antibodies that serves as an anti-inflammatory treatment , .
There have now been @ @ @ @ @ @ @ U.S. and 20 associated deaths , according to the CDC .

Symptoms of the novel coronavirus can mimic the flu or even a common cold.
COVID-19 symptoms range from mild to severe, and some infected people show no symptoms, meaning they're asymptomatic. Although there are a wide spectrum of symptoms, the Centers for Disease Control and Prevention (CDC) has listed the 11 most common COVID-19 symptoms that appear two to 14 days after exposure to the coronavirus :
Fever or chills
Cough
Shortness of breath or difficulty breathing
Fatigue
Muscle or body aches
Headache
New loss of taste or smell
Sore throat
Congestion or runny nose
Nausea or vomiting
Diarrhea
And according to the U.K. National Health Service, loss of appetite and feeling sick or being sick are also symptoms of COVID-19
Emergency COVID-19 symptoms
The following symptoms are emergency warning signs that you should seek immediate medical attention, according to the CDC:
Trouble breathing
Persistent pain or pressure in the chest
New confusion
Inability to wake or stay awake
Bluish lips or face
Other severe symptoms that concern you
Less common COVID-19 symptoms
There are other, less common symptoms that have been reported in COVID-19 patients.
For example, various skin rashes have been linked to COVID-19. "The rashes can take many forms — some appear as tiny red spots, while others appear as larger flat or raised lesions. Some have a hive-like appearance, while others look like frostbitten toes," with the latter dubbed "COVID toes," Live Science previously reported .
It's not clear whether these rashes are directly caused by the novel coronavirus, SARS-CoV-2, or related to other factors, such as a charged-up immune system in those infected with the virus , or lifestyle factors associated with the stay-at-home orders that were in place around the time the first cases of COVID toes were reported. Several studies found that COVID toes occurred even in cases where patients tested negative for SARS-CoV-2 , raising questions about the underlying cause of the condition.
That said, a more recent study, published Oct. 5, 2021 in the British Journal of Dermatology , hinted that COVID toes might be partially driven by proteins called type 1 interferons, which switch on pathogen-fighting genes in immune cells, and autoantibodies, which inadvertently attack the body's own tissues, Live Science previously reported .
COVID-19 can also cause neurological symptoms. In addition to the loss of smell and taste, the virus can cause muscle weakness, tingling or numbness in the hands and feet, dizziness, confusion, delirium, seizures and stroke, according to Harvard Medical School .
How COVID-19 symptoms progress
A person with COVID-19 may have mild symptoms for about a week before rapidly worsening, according to Harvard Medical School. "Let your doctor know if your symptoms quickly worsen over a short period of time," the Harvard website notes.
In more serious cases of COVID-19, patients can experience pneumonia, which means their lungs begin to fill with pockets of pus or fluid. This leads to intense shortness of breath and painful coughing. In some people, the virus can also cause severe disease indirectly by triggering a "cytokine storm" or an overreaction of the immune system that can cause severe damage in the body, according to Harvard.
The CDC recommends that people with COVID-19 or any respiratory illness monitor their symptoms carefully. Worsening shortness of breath is a reason to seek medical care, particularly for older individuals or people with underlying health conditions, the agency notes.
COVID-19 symptoms in children
The risk of severe disease "increases steadily" with age, but younger people can also become severely ill when infected with SARS-CoV-2, according to Harvard Medical School.
Most children with COVID-19 have either mild symptoms or no symptoms, but some can become seriously sick, according to the CDC . Babies under the age of 1 year old and children with certain underlying conditions such as asthma or chronic lung diseases, diabetes , heart disease and obesity may be at an increased risk of severe illness, according to the CDC. A potentially serious but uncommon condition tied to COVID-19 in children is known as multisystem inflammatory syndrome in children (MIS-C).
In children, the most common symptoms of COVID-19 are fever and cough but they may also develop chills, nasal congestion or runny nose, loss of taste or smell, sore throat, shortness of breath or difficulty breathing, diarrhea, nausea or vomiting, stomach, tiredness, headache, muscle or body aches, poor appetite or poor feeding, especially in infants, according to the CDC.
Parents should "pay particular attention" to markers that can indicate COVID-19 in the child such as a fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher, sore throat, a new uncontrolled cough that causes difficulty breathing, diarrhea, vomiting or stomach ache and a new onset of severe headache, especially if it's along with a fever, according to the CDC. If the child is showing any emergency signs (same as the ones listed for adults), the CDC recommends seeking medical care immediately.
What is MISC in kids?
A multisystem inflammatory syndrome in children (MIS-C) has also been associated with the novel coronavirus, according to the CDC . This syndrome is a condition in which parts of the body such as the heart , lungs , kidneys , brain , skin, eyes or gastrointestinal organs become inflamed. It's not yet clear what causes MIS-C, but children diagnosed with the condition often had COVID-19 or had been around someone who had COVID-19, according to the CDC. Several cases of MIS have also been reported in adults, and in these instances, the condition is known as MIS-A, Live Science previously reported .
The inflammatory syndrome was first described in April 2020 in the United Kingdom, when doctors began to notice an increasing number of kids coming in with severe symptoms that seemed to resemble Kawasaki disease, a rare childhood disease that causes inflammation of blood vessels and can lead to heart damage. Some of the symptoms also overlapped with those of toxic shock syndrome, a life-threatening illness caused by toxins released by certain bacteria . There have since been thousands of cases reported in the U.S. and worldwide, according to the CDC.
According to the CDC, symptoms of MIS-C include an ongoing fever plus two or more of the following symptoms:
Stomach pain
Bloodshot eyes
Diarrhea
Dizziness or lightheadedness (signs of low blood pressure)
Skin rash
Vomiting
These are not mild symptoms, so parents will likely notice them, The New York Times reported . For instance, the abdominal pain is not just a little bellyache but "severe enough for the parent to be worried," Dr. George Ofori-Amanfo, division chief of pediatric critical care medicine at Mount Sinai Kravis Children's Hospital in New York, told the Times. And the rashes, the Times reported, tend to be red, cover a large area, and usually appear on the hands, forearms and chest, turning white when you press on them, according to the Times.
If your child has a persistent fever above 101 degrees Fahrenheit (38.3 degrees Celsius), call your pediatrician.
Treatment includes supportive care to reduce symptoms, including steroids for inflammation, fever reducers and other medications, the Times reported. Children may also be treated with intravenous immunoglobulin (IVIG), a cocktail of various antibodies that serves as an anti-inflammatory treatment, Live Science reported .
As of March 1, 2022, there have been 7,459 reported cases of MIS-C across the U.S. and 63 associated deaths, according to the CDC .
Symptoms of omicron and other variants
The omicron variant of SARS-CoV-2 emerged in late 2021 and rapidly spread across the world, outcompeting the previous delta variant. Studies suggest that omicron is less adept at invading lung cells than other versions of the virus, Live Science previously reported. This fact, combined with the widespread availability of vaccination, means that infections with omicron tend to be less severe, on average, than delta infections.
The symptoms of omicron are similar to those of previous variants, according to the CDC . Because of the virus' tendency to invade the upper respiratory tract, symptoms may feel like a cold or sinus infection. Because the virus replicates much more quickly in the bronchi, or respiratory passages that carry air from your windpipe to your lungs, than delta, according to a paper posted to the preprint database bioRxiv on Jan. 3, 2022, symptom onset may be more rapid after exposure.
In general, the public health advice has not changed: COVID-19 can present as a mild head cold all the way up to a serious respiratory infection, and any respiratory symptom signals the need for a test.
Breakthrough COVID-19 symptoms
COVID-19 vaccines protect against infection with SARS-CoV-2, but they aren't 100% effective. As such, fully vaccinated people may still catch COVID-19, which is known as a breakthrough infection. But fully vaccinated people are much less likely to develop serious illness from COVID-19 compared with those who are unvaccinated, according to the CDC .
In particular, the omicron variant evades antibodies from vaccination and infection with previous variants, leading to an increased rate of breakthrough infections compared with previous variants. A third dose of an mRNA vaccine reduces the risk of a symptomatic infection, according to a March 2022 study in the New England Journal of Medicine ; the mRNA vaccines include those produced by Moderna and Pfizer-BioNTech. The booster dose also provided 90% protection against hospitalization with omicron, according to a January CDC report , and reduced the risk of emergency room and urgent care visits 95% and 82%, respectively.
Omicron breakthrough cases are typically reminiscent of a cold or flu, according to MD Anderson Cancer Center Chief Infection Control Officer Dr. Roy Chemaly . Cough, runny nose, congestion, fatigue, sore throat, and headache are common. According to a Kaiser Family Foundation analysis of hospitalizations during the time period when the more-severe delta variant predominated, 69% of breakthrough hospitalizations were in people 65 and older, and 21% were in people 50 to 64. Only 10% were in younger patients. (In unvaccinated individuals, by contrast, 29% of hospitalizations were in those over 65, 30% were in 50 to 64-year-olds, and 41% were in those younger than 50.) These findings indicate that vaccines are protective, but that breakthrough infections can be more serious in older and immunocompromised people.
Additional resources
The CDC maintains a clearinghouse of coronavirus information and public health recommendations at its COVID-19 page . The United Kingdom's ZOE COVID Symptom Study provides information on COVID-19 infection rates and symptoms, provided by volunteers who opt in to report their experiences with the disease. The Mayo Clinic has more information on COVID-19 symptoms, including a self-check tool to help decide if you need to take a coronavirus test. You can also check out The American Academy of Dermatology Association for more information on skin conditions that could be caused by COVID-19.
U.S. residents can order a limited number of free at-home coronavirus tests at covidtests.gov .
Editor's note: This article was updated on March 15, 2022 to include updated information on common COVID-19 symptoms as well as those related to different types of infections.
Bibliography
Andrews, N., et al. (2022, March 2). Covid-19 Vaccine Effectiveness against the Omicron (B.1.1.529) Variant. The New England Journal of Medicine. doi: 10.1056/NEJMoa2119451
Demarco, C. (2021, December 29). COVID-19 breakthrough infections and the omicron variant: What to know now. MD Anderson Cancer Center. https://www.mdanderson.org/cancerwise/covid-19-breakthrough-infections-and-the-omicron-variant--what-t.h00-159466368.html
Harvard Medical School. (2022, January 26). COVID-19 basics. Harvard Health Publishing. https://www.health.harvard.edu/diseases-and-conditions/covid-19-basics
Hernandez, C., Bruckner, A. (2020). Focus on "COVID Toes." JAMA Dermatology, 156(9):1003. doi:10.1001/jamadermatol.2020.2062
Moyer, M.W. (2020, July 13). What We Know About the Covid-Related Syndrome Affecting Children. The New York Times. https://www.nytimes.com/2020/05/19/parenting/pmis-coronavirus-children.html
Peacock, T.P., et al. (2022, January 3). The SARS-CoV-2 variant, Omicron, shows rapid replication in human primary nasal epithelial cultures and efficiently uses the endosomal route of entry. bioRxiv. https://doi.org/10.1101/2021.12.31.474653
Thompson, M.G., et al. (2022, January 28). Effectiveness of a Third Dose of mRNA Vaccines Against COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Adults During Periods of Delta and Omicron Variant Predominance — VISION Network, 10 States, August 2021–January 2022. Morbidity and Mortality Weekly Report, 71(4);139–145. doi: http://dx.doi.org/10.15585/mmwr.mm7104e3
U.S. Centers for Disease Control and Prevention. (2021, August 2). Families & Children. https://www.cdc.gov/coronavirus/2019-ncov/groups/families-children.html
U.S. Centers for Disease Control and Prevention. (2022, March 1). Health Department-Reported Cases of Multisystem Inflammatory Syndrome in Children (MIS-C) in the United States. https://covid.cdc.gov/covid-data-tracker/#mis-national-surveillance
U.S. Centers for Disease Control and Prevention. (n.d.). Multisystem Inflammatory Syndrome (MIS). Retrieved March 12, 2022, from https://www.cdc.gov/mis/index.html
U.S. Centers for Disease Control and Prevention. (2021, February 22). Symptoms of COVID-19. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html
U.S. Centers for Disease Control and Prevention. (2021, December 17). The Possibility of COVID-19 after Vaccination: Breakthrough Infections. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/why-measure-effectiveness/breakthrough-cases.html
Originally published on Live Science.


livescience--2020-12-03--Ghostly circles in the sky can't be explained. And astronomers are excited.

In September 2019 , my colleague Anna Kapinska gave a presentation showing interesting objects she ’ d found while browsing our new radio astronomical data .
She had started noticing very weird shapes she couldn ’ t fit easily to any known type of object .
Among them , labeled by Anna as WTF ?
, was a picture of a ghostly circle of radio emission , hanging out in space like a cosmic smoke-ring .
None of us had ever seen anything like it before , and we had no idea what it was .
A few days later @ @ @ @ @ @ @ second one , even more spooky than Anna ’ s .
Anna and Emil had been examining the new images from our pilot observations for the Evolutionary Map of the Universe ( EMU ) project , made with CSIRO ’ s revolutionary new Australian Square Kilometre Array Pathfinder ( ASKAP ) telescope .
EMU plans to boldly probe parts of the Universe where no telescope has gone before .
It can do so because ASKAP can survey large swathes of the sky very quickly , probing to a depth previously only reached in @ @ @ @ @ @ @ especially sensitive to faint , diffuse objects like these .
I predicted a couple of years ago this exploration of the unknown would probably make unexpected discoveries , which I called WTFs .
But none of us expected to discover something so unexpected , so quickly .
Because of the enormous data volumes , I expected the discoveries would be made using machine learning .
But these discoveries were made with good old-fashioned eyeballing .
Our team searched the rest of the data by eye , and we found a few more of @ @ @ @ @ @ @ them ORCs , which stands for “ odd radio circles ” .
But the big question , of course , is : “ what are they ?
” At first we suspected an imaging artefact , perhaps generated by a software error .
But we soon confirmed they are real , using other radio telescopes .
We still have no idea how big or far away they are .
They could be objects in our galaxy , perhaps a few light-years across , or they could be far away in the Universe and @ @ @ @ @ @ @ When we look in images taken with optical telescopes at the position of ORCs , we see nothing .
The rings of radio emission are probably caused by clouds of electrons , but why don ’ t we see anything in visible wavelengths of light ?
We don ’ t know , but finding a puzzle like this is the dream of every astronomer .
We know what they aren't We have ruled out several possibilities for what ORCs might be .
Could they be supernova remnants , the clouds of debris left @ @ @ @ @ @ @ explodes ?
No .
They are far from most of the stars in the Milky Way and there are too many of them .
Could they be the rings of radio emission sometimes seen in galaxies undergoing intense bursts of star formation ?
Again , no .
We don ’ t see any underlying galaxy that would be hosting the star formation .
Could they be the giant lobes of radio emission we see in radio galaxies , caused by jets of electrons squirting out from the environs of a supermassive black hole @ @ @ @ @ @ @ are very distinctly circular , unlike the tangled clouds we see in radio galaxies .
Could they be Einstein rings , in which radio waves from a distant galaxy are being bent into a circle by the gravitational field of a cluster of galaxies ?
Still no .
ORCs are too symmetrical , and we don ’ t see a cluster at their centre .
In our paper about ORCs , which is forthcoming in the Publications of the Astronomical Society of Australia , we run through all the possibilities and conclude these @ @ @ @ @ @ @ anything we already know about .
So we need to explore things that might exist but haven ’ t yet been observed , such as a vast shockwave from some explosion in a distant galaxy .
Such explosions may have something to do with fast radio bursts , or the neutron star and black hole collisions that generate gravitational waves .
Or perhaps they are something else entirely .
Two Russian scientists have even suggested ORCs might be the “ throats ” of wormholes in spacetime .
From the handful we ’ ve @ @ @ @ @ @ @ are about 1,000 ORCs in the sky .
My colleague Bärbel Koribalski notes the search is now on , with telescopes around the world , to find more ORCs and understand their cause .
It ’ s a tricky job , because ORCS are very faint and difficult to find .
Our team is brainstorming all these ideas and more , hoping for the eureka moment when one of us , or perhaps someone else , suddenly has the flash of inspiration that solves the puzzle .
It ’ s an exciting time @ @ @ @ @ @ @ aimed at refining our knowledge of the Universe , or testing theories .
Very rarely do we get the challenge of stumbling across a new type of object which nobody has seen before , and trying to figure out what it is .
Is it a completely new phenomenon , or something we already know about but viewed in a weird way ?
And if it really is completely new , how does that change our understanding of the Universe ?
Watch this space !
This article is republished from The Conversation under @ @ @ @ @ @ @ original article .
Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook and Twitter .
The views expressed are those of the author and do not necessarily reflect the views of the publisher .

The ghostly ORC1 (blue/green fuzz), on a backdrop of the galaxies at optical wavelengths. There’s an orange galaxy at the centre of the ORC, but we don’t know whether it’s part of the ORC, or just a chance coincidence.
In September 2019, my colleague Anna Kapinska gave a presentation showing interesting objects she’d found while browsing our new radio astronomical data. She had started noticing very weird shapes she couldn’t fit easily to any known type of object.
Among them, labeled by Anna as WTF?, was a picture of a ghostly circle of radio emission, hanging out in space like a cosmic smoke-ring. None of us had ever seen anything like it before, and we had no idea what it was. A few days later, our colleague Emil Lenc found a second one, even more spooky than Anna’s.
Anna and Emil had been examining the new images from our pilot observations for the Evolutionary Map of the Universe (EMU) project, made with CSIRO’s revolutionary new Australian Square Kilometre Array Pathfinder (ASKAP) telescope.
EMU plans to boldly probe parts of the Universe where no telescope has gone before. It can do so because ASKAP can survey large swathes of the sky very quickly, probing to a depth previously only reached in tiny areas of sky, and being especially sensitive to faint, diffuse objects like these.
I predicted a couple of years ago this exploration of the unknown would probably make unexpected discoveries, which I called WTFs. But none of us expected to discover something so unexpected, so quickly. Because of the enormous data volumes, I expected the discoveries would be made using machine learning. But these discoveries were made with good old-fashioned eyeballing.
Hunting ORCs
Our team searched the rest of the data by eye, and we found a few more of the mysterious round blobs. We dubbed them ORCs, which stands for “odd radio circles”. But the big question, of course, is: “what are they?”
At first we suspected an imaging artefact, perhaps generated by a software error. But we soon confirmed they are real, using other radio telescopes. We still have no idea how big or far away they are. They could be objects in our galaxy, perhaps a few light-years across, or they could be far away in the Universe and maybe millions of light years across.
When we look in images taken with optical telescopes at the position of ORCs, we see nothing. The rings of radio emission are probably caused by clouds of electrons, but why don’t we see anything in visible wavelengths of light? We don’t know, but finding a puzzle like this is the dream of every astronomer.
We know what they aren't
We have ruled out several possibilities for what ORCs might be.
Could they be supernova remnants, the clouds of debris left behind when a star in our galaxy explodes? No. They are far from most of the stars in the Milky Way and there are too many of them.
Could they be the rings of radio emission sometimes seen in galaxies undergoing intense bursts of star formation? Again, no. We don’t see any underlying galaxy that would be hosting the star formation.
Could they be the giant lobes of radio emission we see in radio galaxies, caused by jets of electrons squirting out from the environs of a supermassive black hole? Not likely, because the ORCs are very distinctly circular, unlike the tangled clouds we see in radio galaxies.
Could they be Einstein rings, in which radio waves from a distant galaxy are being bent into a circle by the gravitational field of a cluster of galaxies? Still no. ORCs are too symmetrical, and we don’t see a cluster at their centre.
A genuine mystery
In our paper about ORCs, which is forthcoming in the Publications of the Astronomical Society of Australia, we run through all the possibilities and conclude these enigmatic blobs don’t look like anything we already know about.
So we need to explore things that might exist but haven’t yet been observed, such as a vast shockwave from some explosion in a distant galaxy. Such explosions may have something to do with fast radio bursts, or the neutron star and black hole collisions that generate gravitational waves.
Or perhaps they are something else entirely. Two Russian scientists have even suggested ORCs might be the “throats” of wormholes in spacetime.
From the handful we’ve found so far, we estimate there are about 1,000 ORCs in the sky. My colleague Bärbel Koribalski notes the search is now on, with telescopes around the world, to find more ORCs and understand their cause.
It’s a tricky job, because ORCS are very faint and difficult to find. Our team is brainstorming all these ideas and more, hoping for the eureka moment when one of us, or perhaps someone else, suddenly has the flash of inspiration that solves the puzzle.
It’s an exciting time for us. Most astronomical research is aimed at refining our knowledge of the Universe, or testing theories. Very rarely do we get the challenge of stumbling across a new type of object which nobody has seen before, and trying to figure out what it is.
Is it a completely new phenomenon, or something we already know about but viewed in a weird way? And if it really is completely new, how does that change our understanding of the Universe? Watch this space!
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook and Twitter. The views expressed are those of the author and do not necessarily reflect the views of the publisher.


livescience--2020-12-03--Lost islands beneath the North Sea survived a mega-tsunami 8,000 years ago

Some ancient islands now submerged beneath the North Sea survived a devastating tsunami about 8,000 years ago and may have played a key part in Britain 's human prehistory , according to a new study .
The research suggests some parts of the ancient plain known as Doggerland — which connected Great Britain with the Netherlands — withstood the massive Storegga tsunami that submerged most of the region in about 6200 B.C .
The so-called Storegga tsunami was caused by the underwater collapse of part of Norway 's continental shelf , about 500 miles ( 800 kilometers ) to the @ @ @ @ @ @ @ towering wave entirely submerged the between the east coast of England and the European continent .
But the new research , based on submerged sediment cores sampled during ship expeditions in the North Sea , suggests some parts of Doggerland survived the ancient tsunami and may have remained inhabited by Stone Age humans for thousands of years .
And if they did , the surviving islands of Doggerland might have played a part in the later development of Britain , such as the introduction of agriculture about a thousand years later said study @ @ @ @ @ @ @ the University of Bradford .
`` If you were standing on some of that coastline on the day it happened , it would be a bad day for you , '' Gaffney told Live Science .
`` However , that did not mean it was the end for Doggerland . ''
Scientists think the now-submerged region of Doggerland was exposed by the retreating northern ice cap at the end of the last ice age about 12,000 years ago .
By about 10,000 years ago , Doggerland was a landscape of lagoons , marshes @ @ @ @ @ @ @ it may have been one of the richest hunting and fishing grounds in Europe in the .
The Europe 's Lost Frontiers project is leading the effort to investigate Doggerland 's archaeology and to reconstruct the ancient landscape as it appeared before it sank beneath the waves .
They found that by the time of the Storegga tsunami , much of Doggerland would have been already underwater due to slowly rising sea levels , Gaffney said .
But a remarkable sediment core from the seafloor near the eastern English estuary of the River @ @ @ @ @ @ @ shows land there remained above water many years after the tsunami — and computer modeling suggests other regions nearby survived as isolated islands too , he said .
The researchers have now dubbed these islands the `` Dogger Archipelago , '' and it 's thought the highest parts of a central region now known as the `` DoggerHills '' also survived the Storegga tsunami , becoming `` Dogger Island . ''
Although they initially stayed dry land , the islands would all sink a bit more than 1000 years later as the sea @ @ @ @ @ @ @ climate .
Some parts of Doggerland may even have been better suited to humans after the devastation of the tsunami and the retreat of its waters , Gaffney said .
`` People will have gone back and lived where they were previously , and it may have perhaps been a bit more open , and that may even have been quite useful in some of these areas , '' he said .
The surviving islands may contain early evidence of the introduction of agricultural technologies into Britain , which presumably spread there from @ @ @ @ @ @ @ `` It is these coastal areas which are where contact with farming and farmers are likely to occur . ''
For now , the researchers on the Europe 's Lost Frontiers project are working to reconstruct the ancient geography of the Doggerland region .
One day , they hope to locate a Stone Age settlement , and the now-submerged islands of the Dogger Archipelago are emerging as some of their best bets .
`` The last 20 years has revolutionized how we understand Doggerland , '' Gaffney said .
`` We have been @ @ @ @ @ @ @ to get environmental data , where we can get information on the plants and animals that lived there . ''
[ But ] we do not have yet a single archaeological settlement site , '' he said .
`` It 's still essentially an unexplored landscape . ''
The research was published Monday ( Nov. 30 ) in the journal .

Doggerland once covered a vast swath of land between what is now the east coast of England and the European mainland.
Some ancient islands now submerged beneath the North Sea survived a devastating tsunami about 8,000 years ago and may have played a key part in Britain's human prehistory, according to a new study.
The research suggests some parts of the ancient plain known as Doggerland — which connected Great Britain with the Netherlands — withstood the massive Storegga tsunami that submerged most of the region in about 6200 B.C.
The so-called Storegga tsunami was caused by the underwater collapse of part of Norway's continental shelf, about 500 miles (800 kilometers) to the north. Scientists had long thought the towering wave entirely submerged the Doggerland region between the east coast of England and the European continent.
Photos: Ancient human remains found beneath the North Sea
But the new research, based on submerged sediment cores sampled during ship expeditions in the North Sea, suggests some parts of Doggerland survived the ancient tsunami and may have remained inhabited by Stone Age humans for thousands of years.
And if they did, the surviving islands of Doggerland might have played a part in the later development of Britain, such as the introduction of agriculture about a thousand years later said study co-author Vincent Gaffney, an archeologist at the University of Bradford.
"If you were standing on some of that coastline on the day it happened, it would be a bad day for you," Gaffney told Live Science. "However, that did not mean it was the end for Doggerland."
The Storegga tsunami in about 6200 B.C. caused a mega-tsunami throughout the North Atlantic; tell-tale sediments left by the tsunami have been discovered around the region. (Image credit: Europe's Lost Frontiers Project/University of Bradford/M. Muru)
Sunken lands
Scientists think the now-submerged region of Doggerland was exposed by the retreating northern ice cap at the end of the last ice age about 12,000 years ago. By about 10,000 years ago, Doggerland was a landscape of lagoons, marshes, rivers, lakes and forests; it may have been one of the richest hunting and fishing grounds in Europe in the Mesolithic period .
The Europe's Lost Frontiers project is leading the effort to investigate Doggerland's archaeology and to reconstruct the ancient landscape as it appeared before it sank beneath the waves.
Analysis of the sediment cores from the Doggerland region reveal its largest extent was before 10,000 years ago (a); much of Doggerland was later inundated by rising sea levels, by a warming climate (b); the Storegga tsunami about 8,200 years ago reduced Doggerland to a few surviving islands (c); all of Doggerland but its coastal regions were submerged by about 7000 years ago (d). (Image credit: Europe's Lost Frontiers Project/University of Bradford/M. Muru)
They found that by the time of the Storegga tsunami, much of Doggerland would have been already underwater due to slowly rising sea levels, Gaffney said.
But a remarkable sediment core from the seafloor near the eastern English estuary of the River Ouse, known as the Wash, shows land there remained above water many years after the tsunami — and computer modeling suggests other regions nearby survived as isolated islands too, he said.
The researchers have now dubbed these islands the "Dogger Archipelago," and it's thought the highest parts of a central region now known as the "DoggerHills" also survived the Storegga tsunami, becoming "Dogger Island."
Although they initially stayed dry land, the islands would all sink a bit more than 1000 years later as the sea level rose, caused by the warming climate.
Image 1 of 2 Two research ships, including the Belgian vessel RV Belgica seen here, were used to collect sediment cores from the Doggerland region of the North Sea. (Image credit: Europe's Lost Frontiers Project/University of Bradford) The sediment cores from the submerged Doggerland region of the North Sea were carefully analyzed to reveal thousands of years of geographic history. (Image credit: Europe's Lost Frontiers Project/University of Bradford)
Surviving islands
Some parts of Doggerland may even have been better suited to humans after the devastation of the tsunami and the retreat of its waters, Gaffney said.
"People will have gone back and lived where they were previously, and it may have perhaps been a bit more open, and that may even have been quite useful in some of these areas," he said.
The surviving islands may contain early evidence of the introduction of agricultural technologies into Britain, which presumably spread there from the European continent, he said. "It is these coastal areas which are where contact with farming and farmers are likely to occur."
For now, the researchers on the Europe's Lost Frontiers project are working to reconstruct the ancient geography of the Doggerland region.
One day, they hope to locate a Stone Age settlement, and the now-submerged islands of the Dogger Archipelago are emerging as some of their best bets.
"The last 20 years has revolutionized how we understand Doggerland," Gaffney said. "We have been going down [submerged] river valleys to get environmental data, where we can get information on the plants and animals that lived there."
[But] we do not have yet a single archaeological settlement site," he said. "It's still essentially an unexplored landscape."
The research was published Monday (Nov. 30) in the journal Antiquity .
Originally published on Live Science.


livescience--2020-12-04--World's largest atom smasher could seed microscopic black holes

The cosmos may be studded with black holes so tiny they could slip in between atoms , a wild new theory suggests .
And we could be making these teensy singularities all the time at the world 's largest atom smasher , a new study shows .
If we could make these objects , they could be a window into the mysterious nature of gravity .
We have ( at least , that we know about so far ) : electromagnetism , , and .
All four forces operate at different ranges , have different carriers and interact in different @ @ @ @ @ @ @ strengths .
And no matter how you slice it , gravity always comes out the weakest .
Gravity is such a feeble force that if it were a billion billion times stronger than it currently is , it would still be the weakest force by a factor of about 10 million .
Go ahead and lift whatever device you 're reading on above your head .
Congratulations .
The muscles in your arm temporarily overcame the gravitational pull of the entire planet .
Gravity is so laughably weak that physicists have started to @ @ @ @ @ @ @ that strange , that odd , that out-of-place is practically begging for an explanation .
Related to this gravity-is-so-weirdly-weak problem ( known as the `` hierarchy problem '' in physics circles ) is another problem with how the fundamental forces are tied together .
At high energies , the electromagnetic and weak nuclear forces merge together into a single , unified force ( called , of course , the `` electroweak '' force ) .
We have evidence that at even higher energies , the strong nuclear force also joins the unification party @ @ @ @ @ @ @ exceedingly high energies , gravity too merges with the other forces .
But the required energy is so high that we could n't hope to reach it , even with a particle accelerator the size of our galaxy .
Why is gravity so weak , and why does it take so much energy to potentially merge it with the other forces ?
The short version is that we do n't know .
One hypothesis is that there is more to the universe than meets the eye .
Specifically , there are more spatial @ @ @ @ @ @ @ .
In this view , there 's the usual up-down , left-right , and back-forth directions , plus … some others .
The exact number depends on the theory .
In this potential explanation for the weakness of gravity , the extra dimensions are so large that our universe is embedded in a much vaster , higher-dimensional bulk made of the extra dimensions .
In this story , gravity is actually very strong , but unlike the other forces ( which are constrained to our 3D universe ) , gravity gets to roam @ @ @ @ @ @ @ dilutes the force , making it seem wea .
In these models , since gravity is actually so strong , it would be possible to merge gravity at much lower energy levels .
In other words , we may not need a galaxy-sized particle accelerator to see gravity join the unification party .
We may even only need something far smaller .
Like , say , the , a 16.5-mile-long ( 27 kilometers ) ring on the border of France and Switzerland , where protons are sent smashing into each other at near @ @ @ @ @ @ @ How would the LHC spot those hidden extra dimensions ?
One way would be through the production of microscopic black holes .
It normally requires an insane amount of density and pressure to form a black hole –- compressing matter so that it collapses to a point of infinite density is no easy trick .
And if gravity truly is as weak as it seems , then we do n't have nearly enough energy inside the LHC to make it happen .
But if the force of gravity is actually a lot stronger @ @ @ @ @ @ @ forces of nature and produce black holes .
If gravity is strong enough , we could already be manufacturing tiny black holes in the LHC right now .
These tiny black holes are not a cause for alarm — they would evaporate in less than 10^minus 27 seconds , transmuting into a shower of particles well before they did anything interesting like .
But to date we have n't seen any of particle sprays suggestive of microscopic black holes or extra dimensions .
But in a paper accepted to be published in the @ @ @ @ @ @ @ the preprint database , a team of theoretical physicists have pointed out that we may be missing something .
Previous calculations of how often the LHC would create microscopic black holes made some simple assumptions about how the black holes would form and how they would interact with the universe around them .
This group 's more precise calculations reveal that , assuming all those extra dimensions exist and gravity is secretly superstrong , the LHC can produce far fewer microscopic black holes than we previously realized .
Depending on the number of @ @ @ @ @ @ @ these teensy black holes could be as low as one-tenth of the previous estimates .
This means that all hope is not lost in the search of extra dimensions and gravity 's potential hidden strength .
We may just have to keep running the LHC longer before we can rule these models out .
And if a microscopic black hole does make an appearance in our data , it would mean that what we think of as the universe is just a small bubble embedded in a much larger framework — and we @ @ @ @ @ @ @ of gravity .

The cosmos may be studded with black holes so tiny they could slip in between atoms, a wild new theory suggests.
And we could be making these teensy singularities all the time at the world's largest atom smasher, a new study shows. If we could make these objects, they could be a window into the mysterious nature of gravity.
Related: Photos: The world's largest atom smasher
One size too small
We have four fundamental forces of nature (at least, that we know about so far): electromagnetism, strong force , weak force and gravity . All four forces operate at different ranges, have different carriers and interact in different ways. They also have very different strengths.
And no matter how you slice it, gravity always comes out the weakest. Gravity is such a feeble force that if it were a billion billion times stronger than it currently is, it would still be the weakest force by a factor of about 10 million.
Go ahead and lift whatever device you're reading on above your head. Congratulations. The muscles in your arm temporarily overcame the gravitational pull of the entire planet Earth .
Gravity is so laughably weak that physicists have started to wonder why. After all, something that strange, that odd, that out-of-place is practically begging for an explanation.
Related to this gravity-is-so-weirdly-weak problem (known as the "hierarchy problem" in physics circles) is another problem with how the fundamental forces are tied together.
At high energies, the electromagnetic and weak nuclear forces merge together into a single, unified force (called, of course, the "electroweak" force). We have evidence that at even higher energies, the strong nuclear force also joins the unification party. And it's hypothesized that at exceedingly high energies, gravity too merges with the other forces. But the required energy is so high that we couldn't hope to reach it, even with a particle accelerator the size of our galaxy.
Why is gravity so weak, and why does it take so much energy to potentially merge it with the other forces?
A flood of darkness
The short version is that we don't know. One hypothesis is that there is more to the universe than meets the eye. Specifically, there are more spatial dimensions than the three we know of. In this view, there's the usual up-down, left-right, and back-forth directions, plus … some others. The exact number depends on the theory.
In this potential explanation for the weakness of gravity, the extra dimensions are so large that our universe is embedded in a much vaster, higher-dimensional bulk made of the extra dimensions.
In this story, gravity is actually very strong, but unlike the other forces (which are constrained to our 3D universe), gravity gets to roam freely among all the dimensions. This dilutes the force, making it seem wea.
In these models, since gravity is actually so strong, it would be possible to merge gravity at much lower energy levels. In other words, we may not need a galaxy-sized particle accelerator to see gravity join the unification party. We may even only need something far smaller. Like, say, the Large Hadron Collider , a 16.5-mile-long (27 kilometers) ring on the border of France and Switzerland, where protons are sent smashing into each other at near light-speed.
The rules of the game
How would the LHC spot those hidden extra dimensions? One way would be through the production of microscopic black holes. It normally requires an insane amount of density and pressure to form a black hole –- compressing matter so that it collapses to a point of infinite density is no easy trick. And if gravity truly is as weak as it seems, then we don't have nearly enough energy inside the LHC to make it happen.
Related: The biggest black hole findings
But if the force of gravity is actually a lot stronger, we could easily overwhelm the other forces of nature and produce black holes. If gravity is strong enough, we could already be manufacturing tiny black holes in the LHC right now.
These tiny black holes are not a cause for alarm — they would evaporate in less than 10^minus 27 seconds, transmuting into a shower of particles well before they did anything interesting like swallowing Earth . But to date we haven't seen any of particle sprays suggestive of microscopic black holes or extra dimensions.
But in a paper accepted to be published in the journal Physical Review D and posted to the preprint database arXiv , a team of theoretical physicists have pointed out that we may be missing something. Previous calculations of how often the LHC would create microscopic black holes made some simple assumptions about how the black holes would form and how they would interact with the universe around them.
This group's more precise calculations reveal that, assuming all those extra dimensions exist and gravity is secretly superstrong, the LHC can produce far fewer microscopic black holes than we previously realized. Depending on the number of hypothetical extra dimensions, the number of these teensy black holes could be as low as one-tenth of the previous estimates.
This means that all hope is not lost in the search of extra dimensions and gravity's potential hidden strength. We may just have to keep running the LHC longer before we can rule these models out.
And if a microscopic black hole does make an appearance in our data, it would mean that what we think of as the universe is just a small bubble embedded in a much larger framework — and we would have to completely rewrite our understanding of gravity.
Originally published on Live Science.


livescience--2020-12-04--China's Chang'e 5 probe lifts off from moon carrying lunar samples

China has launched a small spacecraft from the surface of the moon in the critical next step in the ambitious to bring lunar samples to Earth .
The small probe , which sat on top of the Chang ' e 5 lander , lifted off from Oceanus Procellarum at 10:10 EST Thursday ( 15:10 GMT/23:10 Beijing time ) carrying with it the first fresh lunar samples since 1976 .
Six minutes later , the ascent spacecraft achieved lunar orbit , marking a huge milestone in the .
The ascent vehicle 's job now is to meet up with the Chang @ @ @ @ @ @ @ the moon , and then transfer its precious cargo to a return capsule for the journey home .
That next stage is an extremely challenging rendezvousing and docking between the small ascent vehicle and the Chang ' e 5 orbiter while orbiting the moon .
The activity needs to be automated due to the time delay in communicating across the roughly 236,000 miles ( 380,000 kilometers ) between the Earth and the moon .
The two spacecraft will begin a final approach sometime on Saturday ( Nov. 5 ) and complete the docking @ @ @ @ @ @ @ well , China will then prepare for the final leg of the journey to deliver the first lunar samples to Earth in 44 years .
The lunar samples wo n't be coming home immediately however .
The Chang ' e 5 spacecraft will need to wait in lunar orbit for a number of days for a narrow window in which to fire its engines and head for Earth .
The careful timing of this trans-Earth injection maneuver will allow the orbiter to deliver the reentry module to Earth at the precise time in @ @ @ @ @ @ @ Inner Mongolia — the same site used by the China National Space Administration to return astronauts home aboard Shenzhou spacecraft .
Photos : Amazing panorama shows the Chang ' e 5 landing site on the moon The journey back to Earth will last 112 hours — just over four and a half days — before the reentry attempt .
As spacecraft returning from the moon are traveling faster than those reentering from low Earth orbit , such as trips from the International Space Station , the Chang ' e 5 reentry module will @ @ @ @ @ @ @ it slow down before taking a final , fiery plunge to Earth .
The Chang ' e 5 quest to collect lunar samples and bring them home from south China .
The spacecraft four and a half days later .
The Chang ' e 5 lander made its and almost immediately began and collecting lunar samples with a drill and scoop .
A special container for the lunar samples was filled and sampling completed within 19 hours of the landing and transferred to the ascent vehicle .
The ascent vehicle weighs just a @ @ @ @ @ @ @ to speeds of over 3,735 miles ( 6,011 kilometers ) per hour per hour or just over 1 mile ( 1.67 kilometers ) per second to achieve lunar orbit .
The Chang ' e 5 orbiter , from which the lander and ascent vehicle separated in late November ahead of the lunar landing , is currently in lunar orbit awaiting the chance to rendezvous and dock with the ascender .
It will take around two days for the two spacecraft to synchronize their orbits enough to allow a rendezvous and docking attempt .
@ @ @ @ @ @ @ 3.5-hour window in which to conduct the maneuver successfully .
If the spacecraft dock successfully the container with the samples will be transferred to the reentry capsule attached to the orbiter .
Follow us on Twitter @ Spacedotcom and on Facebook .

China has launched a small spacecraft from the surface of the moon in the critical next step in the ambitious Chang’e 5 mission to bring lunar samples to Earth.
The small probe, which sat on top of the Chang'e 5 lander, lifted off from Oceanus Procellarum at 10:10 EST Thursday (15:10 GMT/23:10 Beijing time) carrying with it the first fresh lunar samples since 1976.
Six minutes later, the ascent spacecraft achieved lunar orbit, marking a huge milestone in the Chang'e 5 mission to return lunar samples to Earth . The ascent vehicle's job now is to meet up with the Chang'e 5 orbiter while still circling the moon, and then transfer its precious cargo to a return capsule for the journey home.
Video: Watch China's Chang'e 5 mission land on the moon
China's Chang'e 5 moon sample-return ascent vehicle lifts off from the lunar surface in this view captured by the lander itself at Mons Rumker in the Ocean of Storms on Dec. 3, 2020. (Image credit: CNSA/CLEP)
That next stage is an extremely challenging rendezvousing and docking between the small ascent vehicle and the Chang'e 5 orbiter while orbiting the moon. The activity needs to be automated due to the time delay in communicating across the roughly 236,000 miles (380,000 kilometers) between the Earth and the moon.
The two spacecraft will begin a final approach sometime on Saturday (Nov. 5)and complete the docking 3.5 hours later. If all goes well, China will then prepare for the final leg of the journey to deliver the first lunar samples to Earth in 44 years.
An artist's illustration of China's Chang'e 5 moon sample-return ascent vehicle lifting off from the lunar surface. (Image credit: CNSA/CLEP)
The lunar samples won't be coming home immediately however. The Chang'e 5 spacecraft will need to wait in lunar orbit for a number of days for a narrow window in which to fire its engines and head for Earth.
The careful timing of this trans-Earth injection maneuver will allow the orbiter to deliver the reentry module to Earth at the precise time in order to land in Siziwang Banner, Inner Mongolia — the same site used by the China National Space Administration to return astronauts home aboard Shenzhou spacecraft.
Photos: Amazing panorama shows the Chang'e 5 landing site on the moon
The journey back to Earth will last 112 hours — just over four and a half days — before the reentry attempt. As spacecraft returning from the moon are traveling faster than those reentering from low Earth orbit, such as trips from the International Space Station, the Chang'e 5 reentry module will bounce off the atmosphere once to help it slow down before taking a final, fiery plunge to Earth.
The Chang'e 5 quest to collect lunar samples and bring them home began Nov. 23 with a launch on a Long March 5 rocket from south China. The spacecraft entered orbit around the moon four and a half days later.
The Chang'e 5 lander made its spectacular touchdown on Dec. 1 and almost immediately began taking images and collecting lunar samples with a drill and scoop. A special container for the lunar samples was filled and sampling completed within 19 hours of the landing and transferred to the ascent vehicle.
Related: The latest news about China's space program
The ascent vehicle weighs just a few hundred kilograms and needed to accelerate to speeds of over 3,735 miles (6,011 kilometers) per hour per hour or just over 1 mile (1.67 kilometers) per second to achieve lunar orbit.
The Chang'e 5 orbiter, from which the lander and ascent vehicle separated in late November ahead of the lunar landing, is currently in lunar orbit awaiting the chance to rendezvous and dock with the ascender.
It will take around two days for the two spacecraft to synchronize their orbits enough to allow a rendezvous and docking attempt. The pair will have a small, 3.5-hour window in which to conduct the maneuver successfully.
If the spacecraft dock successfully the container with the samples will be transferred to the reentry capsule attached to the orbiter.
Follow us on Twitter @Spacedotcom and on Facebook.


livescience--2020-12-04--Physicists recorded the flowing sound of a 'perfect' fluid for the first time

For the first time , physicists have recorded sound waves moving through a perfect fluid with the lowest possible viscosity , as permitted by the laws of quantum mechanics , an ascending glissando of the frequencies at which the fluid resonates .
This research can help us to understand some of the most extreme conditions in the Universe - the interiors of ultradense neutron stars , and the quark-gluon plasma 'soup ' that filled the Universe in the years just after the Big Bang .
`` It 's quite difficult to listen to a neutron star , '' said physicist @ @ @ @ @ @ @ now you could mimic it in a lab using atoms , shake that atomic soup and listen to it , and know how a neutron star would sound . ''
( You can listen to the recording here . )
Fluids encompass a range of matter states .
Most people probably think of them as liquids , but a fluid is any substance that is incompressible and conforms to the shape of its container : Gases and plasmas are also fluids .
All three of these fluid states - liquid , gas and @ @ @ @ @ @ @ of the fluid , which creates viscosity , or thickness .
Honey , for instance , is highly viscous .
Water is less viscous .
In supercooled liquid helium , a fraction of the fluid becomes a zero-viscosity superfluid .
But it 's still not necessarily a perfect fluid .
`` Helium-3 is a Fermi gas , so one might think that 's close to the situation we have .
But instead , it turns out that helium-3 is very sticky , even when it turns superfluid .
Helium-3 is effectively a weakly @ @ @ @ @ @ @ very large viscosities - even as it becomes superfluid , '' Zwierlein told ScienceAlert .
`` The viscosity of superfluid helium-3 is a thousand times the quantum limit ! ''
A perfect fluid , according to quantum mechanics , is one with the lowest possible friction and viscosity , which can be described with equations based on the mass of the average fermionic particle it 's made of , and a fundamental constant of physics called Planck 's constant .
And , since the viscosity of a fluid can be measured by the @ @ @ @ @ @ @ property called sound diffusion - a team of researchers devised an experiment to propagate sound waves through a fluid of fermionic particles to determine its viscosity .
Fermions are a class of particles that include the building blocks of atoms , such as electrons and quarks , as well as particles that are made of fermions , such as neutrons and protons , which are made of three quarks .
Fermions are bound by the quantum mechanical Pauli exclusion principle , which states that no two such particles in a system ( like @ @ @ @ @ @ @ quantum state .
This means that they ca n't occupy the same space as each other .
Chill a bunch of fermions , like 2 million atoms of lithium-6 , down to a whisker above absolute zero and squeeze them into a cage of lasers , and their quantum fuzziness will let them jostle in waves that have barely any friction - the perfect fluid .
The experiment had to be designed to maximize the number of collisions between the fermions , and the lasers tuned so that fermions running into the boundaries @ @ @ @ @ @ @ This gas was maintained at temperatures between 50 and 500 nanoKelvin ( -273.15 degrees Celsius , or -459.67 degrees Celsius ) .
`` We had to make a fluid with uniform density , and only then could we tap on one side , listen to the other side , and learn from it , '' Zwierlein said .
`` It was actually quite difficult to get to this place where we could use sound in this seemingly natural way . ''
To `` tap '' on the side of the container , the @ @ @ @ @ @ @ end of the cylindrical container .
This , according to the intensity , sent vibrations like different types of sound waves through the gas , which the team recorded through thousands of images - a bit like ultrasound technology .
This allowed them to find ripples in the fluid 's density analogous to a sound wave .
In particular , they were looking for acoustic resonances - an amplification in the sound wave that 's produced when the frequency of the sound wave matches the frequency of the natural vibration of the medium @ @ @ @ @ @ @ tells me about the fluid 's viscosity , or sound diffusivity , '' Zwierlein said .
`` If a fluid has low viscosity , it can build up a very strong sound wave and be very loud , if hit at just the right frequency .
If it 's a very viscous fluid , then it does n't have any good resonances . ''
The researchers found very clear resonances in their gas , particularly at low frequencies .
From these , they calculated the fluid 's sound diffusion .
This was the @ @ @ @ @ @ @ the fermionic particle mass and Planck 's constant - indicating that the lithium-6 gas was indeed behaving as a perfect fluid .
This has some pretty interesting implications .
The interiors of spinning neutron stars , although many orders of magnitude higher in temperature and density , are also thought to be perfect fluids .
They also have many oscillation modes , in which sound waves propagate through the star .
We could use fluids such as the team 's lithium-6 gas to understand the diffusivity of neutron stars , which could , @ @ @ @ @ @ @ understanding of their interiors , and the gravitational wave signals generated by merging neutron stars .
And it could help scientists better understand superconductivity , in which electrons can flow freely through materials .
`` This work connects directly to resistance in materials , '' Zwierlein says .
`` Having figured out what 's the lowest resistance you could have from a gas tells us what can happen with electrons in materials , and how one might make materials where electrons could flow in a perfect way .
That 's exciting . ''
@ @ @ @ @ @ @ .
This article was originally published by ScienceAlert .
Read the original article here .

Scientists have captured the sound of a "perfect fluid," which flows with the smallest amount of friction allowed by the laws of quantum mechanics.
For the first time, physicists have recorded sound waves moving through a perfect fluid with the lowest possible viscosity, as permitted by the laws of quantum mechanics, an ascending glissando of the frequencies at which the fluid resonates.
This research can help us to understand some of the most extreme conditions in the Universe - the interiors of ultradense neutron stars, and the quark-gluon plasma 'soup' that filled the Universe in the years just after the Big Bang.
"It's quite difficult to listen to a neutron star," said physicist Martin Zwierlein of MIT.
"But now you could mimic it in a lab using atoms, shake that atomic soup and listen to it, and know how a neutron star would sound." (You can listen to the recording here.)
Fluids encompass a range of matter states. Most people probably think of them as liquids, but a fluid is any substance that conforms to the shape of its container: Gases and plasmas are also fluids.
All three of these fluid states - liquid, gas and plasma - experience internal friction between layers of the fluid, which creates viscosity, or thickness. Honey, for instance, is highly viscous. Water is less viscous. In supercooled liquid helium, a fraction of the fluid becomes a zero-viscosity superfluid. But it's still not necessarily a perfect fluid.
"Helium-3 is a Fermi gas, so one might think that's close to the situation we have. But instead, it turns out that helium-3 is very sticky, even when it turns superfluid. Helium-3 is effectively a weakly interacting Fermi system, and it displays very large viscosities - even as it becomes superfluid," Zwierlein told ScienceAlert.
"The viscosity of superfluid helium-3 is a thousand times the quantum limit!"
A perfect fluid, according to quantum mechanics, is one with the lowest possible friction and viscosity, which can be described with equations based on the mass of the average fermionic particle it's made of, and a fundamental constant of physics called Planck's constant.
And, since the viscosity of a fluid can be measured by the way sound dissipates through it - a property called sound diffusion - a team of researchers devised an experiment to propagate sound waves through a fluid of fermionic particles to determine its viscosity.
Fermions are a class of particles that include the building blocks of atoms, such as electrons and quarks, as well as particles that are made of fermions, such as neutrons and protons, which are made of three quarks.
Fermions are bound by the quantum mechanical Pauli exclusion principle, which states that no two such particles in a system (like an atom) can occupy the same quantum state. This means that they can't occupy the same space as each other.
Chill a bunch of fermions, like 2 million atoms of lithium-6, down to a whisker above absolute zero and squeeze them into a cage of lasers, and their quantum fuzziness will let them jostle in waves that have barely any friction - the perfect fluid.
The experiment had to be designed to maximize the number of collisions between the fermions, and the lasers tuned so that fermions running into the boundaries would bounce back into the gas. This gas was maintained at temperatures between 50 and 500 nanoKelvin (-273.15 degrees Celsius, or -459.67 degrees Celsius).
"We had to make a fluid with uniform density, and only then could we tap on one side, listen to the other side, and learn from it," Zwierlein said. "It was actually quite difficult to get to this place where we could use sound in this seemingly natural way."
To "tap" on the side of the container, the team varied the light intensity at one end of the cylindrical container. This, according to the intensity, sent vibrations like different types of sound waves through the gas, which the team recorded through thousands of images - a bit like ultrasound technology.
This allowed them to find ripples in the fluid's density analogous to a sound wave. In particular, they were looking for acoustic resonances - an amplification in the sound wave that's produced when the frequency of the sound wave matches the frequency of the natural vibration of the medium.
"The quality of the resonances tells me about the fluid's viscosity, or sound diffusivity," Zwierlein said. "If a fluid has low viscosity, it can build up a very strong sound wave and be very loud, if hit at just the right frequency. If it's a very viscous fluid, then it doesn't have any good resonances."
The researchers found very clear resonances in their gas, particularly at low frequencies. From these, they calculated the fluid's sound diffusion. This was the same value that could be derived from the fermionic particle mass and Planck's constant - indicating that the lithium-6 gas was indeed behaving as a perfect fluid.
This has some pretty interesting implications. The interiors of spinning neutron stars, although many orders of magnitude higher in temperature and density, are also thought to be perfect fluids. They also have many oscillation modes, in which sound waves propagate through the star.
We could use fluids such as the team's lithium-6 gas to understand the diffusivity of neutron stars, which could, in turn, lead to a better understanding of their interiors, and the gravitational wave signals generated by merging neutron stars.
And it could help scientists better understand superconductivity, in which electrons can flow freely through materials.
"This work connects directly to resistance in materials," Zwierlein says. "Having figured out what's the lowest resistance you could have from a gas tells us what can happen with electrons in materials, and how one might make materials where electrons could flow in a perfect way. That's exciting."
The research has been published in Science.
This article was originally published by ScienceAlert. Read the original article here.


livescience--2020-12-04--COVID-19: When are you most infectious?

COVID-19: When are you most infectious?

A close friend – let ’ s call him John – recently called , asking for advice .
He woke up with severe muscle aches and fatigue .
Understandably worried that it could be COVID-19 , he asked whether he should go to work , run to get a test or stay home .
Because he didn ’ t have other symptoms , such as a fever , cough or shortness of breath , he was unsure what to do .
Of course , this could be any other respiratory infection , such as the flu or the common cold @ @ @ @ @ @ @ ?
What is the risk of him transmitting the virus to others ?
To understand when people with COVID-19 are most likely to be infectious , our team conducted a study which was recently published in The Lancet Microbe .
We investigated three things : viral load ( how the amount of the virus in the body changes throughout infection ) , viral shedding ( the length of time someone sheds viral genetic material , which does not necessarily mean a person is infectious ) , and isolation of the live virus ( @ @ @ @ @ @ @ s infectiousness , as the live virus is isolated and tested to see if it can replicate in the laboratory ) .
We found that viral load reached its peak in the throat and nose ( which is thought to be the main source of transmission ) very early in the disease , particularly from the first day of symptoms to day five of symptoms – even in people with mild symptoms .
We also found that genetic material can still be detected in throat swab or stool samples for several weeks .
@ @ @ @ @ @ @ any sample collected beyond nine days of symptoms .
Although some people , especially those with severe illness or with a weakened immune system ( say from chemotherapy ) , may have longer viral shedding , the results suggest that those infected with SARS-CoV-2 are most likely to be highly infectious a few days before symptoms start and the following five days .
In comparison , the viral load of Sars peaks at 10-14 days and for Mers at 7-10 days after symptoms start ( Sars and Mers are both diseases caused by @ @ @ @ @ @ @ transmission of these viruses was effectively reduced by immediately finding and isolating people who had symptoms .
It also explains why it has been so difficult to contain COVID-19 as it spreads very quickly early in the disease course .
Contact tracing and modelling studies also show that transmission is highest in the first five days of experiencing symptoms .
According to a recent study , the period of highest infectiousness is within about five days of symptoms starting .
A contact tracing study from Taiwan and the UK found that most contacts @ @ @ @ @ @ @ the infected person within five days of their symptom onset .
By the time most people get their test result , they may already be beyond their most infectious period .
This early viral load peak suggests that to prevent onward transmission , a person with COVID-19 needs to self-isolate as soon as symptoms start without waiting for test results .
John self-isolated immediately and called everyone that he had been in contact with in the previous few days .
The next day , he woke up with a mild fever .
He @ @ @ @ @ @ @ , but was able to get an appointment at a later time .
The results were available by day five of his symptoms .
He tested positive for COVID .
Fortunately , John managed to self-isolate throughout his most infectious period and his contacts started quarantining immediately .
John was fortunate in that he was able to work from home and continue to get paid .
But according to a UK survey , only one in five people are able to self-isolate .
Barriers include having a dependent child at home , having @ @ @ @ @ @ @ during the pandemic , and being a key worker , such as a nurse or teacher .
Governments could do more to help How will a diagnosis help if your living situation doesn ’ t allow for isolation , if you have a job that can ’ t be done from home , and your work doesn ’ t provide sick leave ?
And how will a diagnosis help if your family depends on your income to meet basic needs , or your access to care is linked to your employment ?
This @ @ @ @ @ @ @ people with COVID-19 to self-isolate early in the disease course .
Here are four ways to help people self-isolate : • Income relief to avoid undue pressure to work when sick ( the proportion of salary covered by sick pay is 29 % in the UK ) .
• Housing for disadvantaged communities , especially those living in crowded houses and those living with vulnerable people , as has been successfully done in Vermont , in the US .
• Services to support people who are self-isolating , as is done in New @ @ @ @ @ @ @ • Remove barriers to accessing healthcare and consider making isolation periods shorter – five to seven days after symptoms begin .
This could cover the most infectious period and might improve people ’ s ability to comply with isolation .
In September , France dropped isolation period for cases to seven days , and Germany is considering shortening it to five days .
The benefit of shortening isolation may more than offset any risk to the community .
With these measures in place , we should be in a much better position to @ @ @ @ @ @ @ republished from The Conversation under a Creative Commons license .
Read the original article .
Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook and Twitter .
The views expressed are those of the author and do not necessarily reflect the views of the publisher .

A close friend – let’s call him John – recently called, asking for advice. He woke up with severe muscle aches and fatigue. Understandably worried that it could be COVID-19, he asked whether he should go to work, run to get a test or stay home. Because he didn’t have other symptoms, such as a fever, cough or shortness of breath, he was unsure what to do. Of course, this could be any other respiratory infection, such as the flu or the common cold, but what if it is COVID-19? What is the risk of him transmitting the virus to others?
To understand when people with COVID-19 are most likely to be infectious, our team conducted a study which was recently published in The Lancet Microbe.
We investigated three things: viral load (how the amount of the virus in the body changes throughout infection), viral shedding (the length of time someone sheds viral genetic material, which does not necessarily mean a person is infectious), and isolation of the live virus (a better indicator of a person’s infectiousness, as the live virus is isolated and tested to see if it can replicate in the laboratory).
We found that viral load reached its peak in the throat and nose (which is thought to be the main source of transmission) very early in the disease, particularly from the first day of symptoms to day five of symptoms – even in people with mild symptoms.
We also found that genetic material can still be detected in throat swab or stool samples for several weeks. But no live virus was found in any sample collected beyond nine days of symptoms. Although some people, especially those with severe illness or with a weakened immune system (say from chemotherapy), may have longer viral shedding, the results suggest that those infected with SARS-CoV-2 are most likely to be highly infectious a few days before symptoms start and the following five days.
In comparison, the viral load of Sars peaks at 10-14 days and for Mers at 7-10 days after symptoms start (Sars and Mers are both diseases caused by coronaviruses). This explains why the transmission of these viruses was effectively reduced by immediately finding and isolating people who had symptoms. It also explains why it has been so difficult to contain COVID-19 as it spreads very quickly early in the disease course.
Contact tracing and modelling studies also show that transmission is highest in the first five days of experiencing symptoms. According to a recent study, the period of highest infectiousness is within about five days of symptoms starting. A contact tracing study from Taiwan and the UK found that most contacts got infected if they were exposed to the infected person within five days of their symptom onset.
By the time most people get their test result, they may already be beyond their most infectious period. This early viral load peak suggests that to prevent onward transmission, a person with COVID-19 needs to self-isolate as soon as symptoms start without waiting for test results.
John self-isolated immediately and called everyone that he had been in contact with in the previous few days. The next day, he woke up with a mild fever. He couldn’t get a test immediately, but was able to get an appointment at a later time. The results were available by day five of his symptoms. He tested positive for COVID.
Fortunately, John managed to self-isolate throughout his most infectious period and his contacts started quarantining immediately.
John was fortunate in that he was able to work from home and continue to get paid. But according to a UK survey, only one in five people are able to self-isolate. Barriers include having a dependent child at home, having low income, experiencing greater financial hardship during the pandemic, and being a key worker, such as a nurse or teacher.
Governments could do more to help
How will a diagnosis help if your living situation doesn’t allow for isolation, if you have a job that can’t be done from home, and your work doesn’t provide sick leave? And how will a diagnosis help if your family depends on your income to meet basic needs, or your access to care is linked to your employment?
This highlights why we must focus on supporting people with COVID-19 to self-isolate early in the disease course. Here are four ways to help people self-isolate:
Income relief to avoid undue pressure to work when sick (the proportion of salary covered by sick pay is 29% in the UK).
Housing for disadvantaged communities, especially those living in crowded houses and those living with vulnerable people, as has been successfully done in Vermont, in the US.
Services to support people who are self-isolating, as is done in New York and many south-east Asian countries.
Remove barriers to accessing healthcare and consider making isolation periods shorter – five to seven days after symptoms begin. This could cover the most infectious period and might improve people’s ability to comply with isolation. In September, France dropped isolation period for cases to seven days, and Germany is considering shortening it to five days. The benefit of shortening isolation may more than offset any risk to the community.
With these measures in place, we should be in a much better position to beat the pandemic.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook and Twitter. The views expressed are those of the author and do not necessarily reflect the views of the publisher.


livescience--2020-12-04--Mysterious minimoon circling Earth is actually a 1960s rocket booster

Researchers had an inkling that the , but it was n't until this week that they confirmed it , after analyzing its composition from afar at NASA 's Infrared Telescope Facility ( IRTF ) .
In fact , scientists made the finding just after the elusive near-Earth object — known as 2020 SO — made its closest approach to our planet on Tuesday ( Dec. 1 ) .
However , 2020 SO is n't here to stay .
Minimoons are small satellites that orbit Earth for only a short time .
Over the next several months , 2020 SO will @ @ @ @ @ @ @ '' — a region that extends about 930,000 miles ( 1.5 million kilometers ) from Earth — until it escapes from our gravitational force and starts orbiting the sun instead in March 2021 , .
But even though 2020 SO is leaving Earth 's immediate neighborhood , scientists plan to monitor its travels for years to come , NASA said .
Scientists first spotted the 2020 SO in September of this year , when astronomers looking for near-Earth asteroids at Pan-STARRS1 , a NASA-funded survey telescope on Maui , Hawaii , noticed its @ @ @ @ @ @ @ soon learned that 2020 SO was n't a stranger to Earth ; an analysis of its orbit indicated that 2020 SO had swung around our planet several times in the past few decades , even making a fairly close approach in 1966 , suggesting it was a human-made object launched into space .
After combing through NASA 's launch records , Paul Chodas , director at NASA 's Center for Near-Earth Object Studies ( CNEOS ) , suggested that 2020 SO was a Centaur upper stage rocket booster from , an uncrewed NASA @ @ @ @ @ @ @ on the moon , but instead ended up crashing there in 1966 .
To investigate this claim , a team led by Vishnu Reddy , a planetary scientist at the Lunar and Planetary Laboratory at the University of Arizona , took follow-up spectroscopy observations of the object using NASA 's IRTF on the Big Island of Hawaii , so they could determine the space oddity 's chemical makeup .
( In spectroscopy , light waves from a certain part of the electromagnetic spectrum are measured to reveal an object 's makeup . )
@ @ @ @ @ @ @ object following [ the ] CNEOS prediction , it was a challenging object to characterize '' Reddy said in the statement .
`` We got color observations with the Large Binocular Telescope , or LBT , that suggested 2020 SO was not an asteroid . ''
However , the team did n't have enough evidence to tie 2020 SO to Surveyor 2 .
So , the researchers went a step further and compared its spectral data with that of 301 stainless steel , the material in the 1960s Centaur rocket boosters .
But @ @ @ @ @ @ @ , Reddy found .
The discrepancy revealed itself soon enough ; Reddy 's team had analyzed fresh steel in their lab , while the steel from 2020 SO had weathered the harsh conditions of space for the past 54 years , he said .
`` We knew that if we wanted to compare apples to apples , we 'd need to try to get spectral data from another Centaur rocket booster that had been in Earth orbit for many years to then see if it better matched 2020 SO 's spectrum , '' @ @ @ @ @ @ @ extreme speed at which Earth-orbiting Centaur boosters travel across the sky , we knew it would be extremely difficult to lock on with the IRTF long enough to get a solid and reliable data set . ''
An opportunity to finally solve the mystery happened on the morning of Dec. 1 .
At that time , the team managed to analyze a Centaur D rocket booster from the 1971 launch of a communication satellite that was orbiting Earth .
After comparing the data from the 1971 rocket booster and 2020 SO , the @ @ @ @ @ @ @ conclusion was the result of a tremendous team effort , '' Reddy said .
`` We were finally able to solve this mystery because of the great work of Pan-STARRS , Paul Chodas and the team at CNEOS , LBT , IRTF , and the observations around the world . ''

This animation shows the sped-up orbit of 2020 SO, which was captured by Earth's gravity on Nov. 8, 2020. The space oddity will escape in March 2021.
A mysterious minimoon temporarily orbiting Earth isn't a chunky space rock, but a 1960s rocket booster, NASA reported Wednesday (Dec. 2).
Researchers had an inkling that the minimoon might be human-made , but it wasn't until this week that they confirmed it, after analyzing its composition from afar at NASA's Infrared Telescope Facility (IRTF).
In fact, scientists made the finding just after the elusive near-Earth object — known as 2020 SO — made its closest approach to our planet on Tuesday (Dec. 1).
Related: Top 10 ways to destroy Earth
However, 2020 SO isn't here to stay. Minimoons are small satellites that orbit Earth for only a short time. Over the next several months, 2020 SO will hang out in the "hill sphere" — a region that extends about 930,000 miles (1.5 million kilometers) from Earth — until it escapes from our gravitational force and starts orbiting the sun instead in March 2021, NASA reported in a statement .
But even though 2020 SO is leaving Earth's immediate neighborhood, scientists plan to monitor its travels for years to come, NASA said.
NASA's Infrared Telescope Facility (IRTF) on the Big Island of Hawaii helped scientists figure out the composition of a strange near-Earth object. (Image credit: Michael Connelley/ University of Hawaii Institute for Astronomy)
That's no moon
Scientists first spotted the 2020 SO in September of this year, when astronomers looking for near-Earth asteroids at Pan-STARRS1, a NASA-funded survey telescope on Maui, Hawaii, noticed its small size and unusual orbit.
They soon learned that 2020 SO wasn't a stranger to Earth; an analysis of its orbit indicated that 2020 SO had swung around our planet several times in the past few decades, even making a fairly close approach in 1966, suggesting it was a human-made object launched into space.
After combing through NASA's launch records, Paul Chodas, director at NASA's Center for Near-Earth Object Studies (CNEOS), suggested that 2020 SO was a Centaur upper stage rocket booster from Surveyor 2 , an uncrewed NASA spacecraft that was supposed to softly land on the moon, but instead ended up crashing there in 1966.
A 1964 photograph of a Centaur upper-stage rocket, before it was joined with an Atlas booster. NASA used a similar Centaur during the launch of Surveyor in 1966. (Image credit: NASA)
To investigate this claim, a team led by Vishnu Reddy, a planetary scientist at the Lunar and Planetary Laboratory at the University of Arizona, took follow-up spectroscopy observations of the object using NASA's IRTF on the Big Island of Hawaii, so they could determine the space oddity's chemical makeup. (In spectroscopy, light waves from a certain part of the electromagnetic spectrum are measured to reveal an object's makeup.)
"Due to extreme faintness of this object following [the] CNEOS prediction, it was a challenging object to characterize" Reddy said in the statement. "We got color observations with the Large Binocular Telescope, or LBT, that suggested 2020 SO was not an asteroid."
However, the team didn't have enough evidence to tie 2020 SO to Surveyor 2. So, the researchers went a step further and compared its spectral data with that of 301 stainless steel, the material in the 1960s Centaur rocket boosters. But the results weren't a perfect match, Reddy found.
The discrepancy revealed itself soon enough; Reddy's team had analyzed fresh steel in their lab, while the steel from 2020 SO had weathered the harsh conditions of space for the past 54 years, he said.
"We knew that if we wanted to compare apples to apples, we'd need to try to get spectral data from another Centaur rocket booster that had been in Earth orbit for many years to then see if it better matched 2020 SO's spectrum," Reddy said. "Because of the extreme speed at which Earth-orbiting Centaur boosters travel across the sky, we knew it would be extremely difficult to lock on with the IRTF long enough to get a solid and reliable data set."
An opportunity to finally solve the mystery happened on the morning of Dec. 1. At that time, the team managed to analyze a Centaur D rocket booster from the 1971 launch of a communication satellite that was orbiting Earth. After comparing the data from the 1971 rocket booster and 2020 SO, the team had a match.
"This conclusion was the result of a tremendous team effort," Reddy said. "We were finally able to solve this mystery because of the great work of Pan-STARRS, Paul Chodas and the team at CNEOS, LBT, IRTF, and the observations around the world."
Originally published on Live Science.