- A dead NASA telescope and an old Air Force satellite have a 1-in-10 chance of crashing in space above Pittsburgh, Pennsylvania, on Wednesday evening.
- Experts call the odds „dangerous“ and „alarming,“ since a head-on collision could produce nearly 300,000 chunks of debris that would threaten other spacecraft.
- LeoLabs, a company that tracks satellites and space debris, calculated that the two objects will pass dangerously close to one another - as close as 15 meters (50 feet) apart.
- The US Air Force, which tracks satellites for the government, has not notified NASA of any potential collision, according to the space agency.
- Visit Business Insider’s homepage for more stories.
Two satellites might collide in space on Wednesday evening, when their orbits cross paths 560 miles (900 kilometers) above Pittsburgh, Pennsylvania.
The larger object is an old space telescope called the Infrared Astronomical Satellite (IRAS), which was a joint mission between NASA, the Netherlands, and the UK. It ran out of fuel and died in November 1983. The other is a gravitational experiment called GGSE-4 that the US Air Force launched in May 1967.
The satellites will pass dangerously close to each other just 25 seconds before 6:40 p.m. ET on Wednesday, according to LeoLabs, a company that uses radar to track satellites and debris in space.
LeoLabs calculated that the two objects will come within 15 to 30 meters (50 to 100 feet) of one another, a distance the group called „alarming“ on Twitter.
LeoLabs calculated a 1-in-100 chance of collision, but experts at The Aerospace Corporation ran their own simulation on Tuesday and found a 1-in-10 chance. Roger Thompson, a senior engineering specialist at The Aerospace Corporation, confirmed LeoLabs’s other calculations.
„This is one of the closest that we have ever seen,“ Thompson told Business Insider. „LeoLabs has pointed out a very dangerous conjunction.“
Foto: An illustration of the Infrared Astronomical Satellite (IRAS).sourceNASA
The US Air Force, which tracks satellites for the government, had not notified NASA of any potential satellite collision as of Tuesday morning, the space agency told Business Insider in an email.
If the satellites collide, they could break apart and create a new cloud of debris orbiting Earth, which could then threaten other satellites and the International Space Station. If such orbital junk were ever to get too plentiful and out of control, it could cut off our access to space for hundreds of years.
Because IRAS is quite large, a collision would be dangerous, according to both satellite-tracking companies. LeoLabs said that space telescope is 3.6 meters (11.8 feet) long and 3.2 meters (10.5 feet) wide. Both satellites are moving quickly: 14.7 kilometers (9.1 miles) per second.
„Any time you have a high-velocity collision like that it’s serious, because the energy of the collision is so high that the debris gets spread into other orbits,“ Thompson said.
A head-on collision would produce about 290,000 chunks of debris that are at least 1 centimeter wide – the size that experts consider dangerous – Thompson calculated.
If the satellites crash, he added, observers on the ground in Pittsburgh would likely see a bright flash in the sky like a shooting star.
Foto: A projectile strikes a mock-up of a spacecraft in a NASA-Air Force test meant to simulate space debris collisions.sourceArnold Engineering Development Complex/Air Force
While a 1% to 10% chance of a hit may seem low, NASA routinely moves the International Space Station when the orbiting laboratory faces a 0.001% (1-in-100,000) chance or greater of a collision with an object.
But these two satellites can’t be controlled, Ted Muelhaupt, who leads The Aerospace Corporation’s satellite system analysis, told Business Insider.
„Nobody can do a thing about this no matter how well we’re tracking it because these are both dead objects,“ he said.
Thompson and Muelhaupt said the probability of a collision will probably change as the satellites approach each other, so researchers may have more precise estimates late Wednesday morning.
More space junk raises the risk of more dangerous collisions
Over 100 million bits of junk surround Earth, from abandoned satellites, spacecraft that broke apart, and other missions. Each piece of that debris, no matter how small, travels at speeds high enough to inflict catastrophic damage to vital equipment. A single hit could be deadly to astronauts on a spacecraft.
Each collision that occurs makes the problem worse, since it fragments satellites or debris into smaller pieces.
„Each time there’s a big collision, it’s a big change in the LEO [low-Earth orbit] environment,“ LeoLabs CEO Dan Ceperley previously told Business Insider.
In 2007, China tested an anti-satellite missile by blowing up one of its own weather satellites. Two years later, an American spacecraft accidentally collided with a Russian one. Those two events alone increased the amount of large debris in low-Earth orbit by about 70%.
„Because of that, now there’s sort of a debris belt,“ Ceperley said.
India also generated thousands of bits of debris in March 2019 when it blew up one of its spacecraft in an anti-satellite missile test.
If the space-junk problem gets extreme, a disastrous chain of collisions could spiral out of control and surround Earth in an impassable field of debris. This possibility is known as a Kessler event, after Donald J. Kessler, who worked for NASA’s Johnson Space Center. Kessler calculated in a 1978 paper that it could take hundreds of years for such debris to clear up enough to make spaceflight safe again.
„It is a long-term effect that takes place over decades and centuries,“ Thompson said. „Anything that makes a lot of debris is going to increase that risk.“
If the two satellites collide head-on Wednesday evening, half of the cloud of debris would shoot up away from Earth, and the other half would spread into lower orbits among other satellites and the space station, Thompson said. At first, it would be a cylinder-shaped field of debris that would be dangerous to pass through. After a few days, he said, the debris cloud would spread out.
Collisions in space are becoming more likely as more satellites fill the sky. Companies like SpaceX, Amazon, OneWeb, and perhaps even Apple plan to launch tens of thousands of new satellites this decade to form internet-providing „megaconstellations.“
In September, the European Space Agency (ESA) had to maneuver one of its spacecraft at the last minute to avoid colliding with a SpaceX satellite. The chance of that crash was 1-in-1,000.
Foto: The first batch of 60 high-speed Starlink internet satellites, each weighing about 500 pounds, flat-packed into a stack prior to their launch aboard a Falcon 9 rocket on May 23, 2019.sourceSpaceX via Twitter
What’s more, as older satellites like IRAS die, there is no system in place to remove them from orbit.
„Events like this highlight the need for responsible, timely deorbiting of satellites for space sustainability moving forward,“ LeoLabs tweeted about Wednesday’s potential crash.
Pulling dead satellites out of orbit could prevent crashes
The Federal Communications Commission (FCC), which licenses private companies‘ satellite launches, is considering new regulations to address the issue of space debris.
But as of yet, there is no silver bullet for the many metal chunks rocketing around Earth, nor for the swarms of dead satellites that threaten to create more debris.
One potential solution, however, is a proposed ESA clean-up mission that aims to capture one of the agency’s defunct satellites in a net, drag it into Earth’s atmosphere, and burn it there. Private companies – including Tethers Unlimited, TriSept Corp., and a Boeing subsidiary called Millennium Space Systems - have explored similar concepts for larger-scale space clean-up.
Foto: An illustration of the ESA’s e.Deorbit system to net and remove old satellites from orbit.sourceDavid Ducros/ESA
Those companies could one day use LeoLabs’s data to identify high-risk satellites, track them down, and pull them out of orbit to reduce the chances of space collisions and the clouds of debris that they create.
„A lot of the risk comes from this small debris, all this stuff that’s never been tracked before. Nobody’s got a good solution to clean that up,“ Ceperley previously told Business Insider. „Let’s make sure we don’t make more of it.“
Dave Mosher contributed reporting for this story.
By Looking Back Through Hubble Data, Astronomers Have Identified six Massive Stars Before They Exploded as Core-Collapse Supernovae – Universe Today
The venerable Hubble Space Telescope has given us so much during the history of its service (32 years, 7 months, 6 days, and counting!) Even after all these years, the versatile and sophisticated observatory is still pulling its weight alongside more recent addition, like the James Webb Space Telescope (JWST) and other members of NASA’s Great Observatories family. In addition to how it is still conducting observation campaigns, astronomers and astrophysicists are combing through the volumes of data Hubble accumulated over the years to find even more hidden gems.
A team led by Caltech’s recently made some very interesting finds in the Hubble archives, where they observed the sites of six supernovae to learn more about their progenitor stars. Their observations were part of the Hubble Space Telescope Snapshot program, where astronomers use HST images to chart the life cycle and evolution of stars, galaxies, and other celestial objects. From this, they were able to place constraints on the size, mass, and other key characteristics of the progenitor stars and what they experienced before experiencing core collapse.
The team was led by Dr. Schuyler D. Van Dyk, a senior research scientist with Caltech’s Infrared Processing and Analysis Center (IPAC). His teammates included researchers from the University of California, Berkeley, the Space Telescope Science Institute, the University of Arizona’s Steward Observatory, the University of Hawai’i’s Institute for Astronomy, and the School of Physics and Astronomy at the University of Minnesota. Their findings were published in a paper titled “The disappearance of six supernova progenitors” that will appear in the Monthly Notices of the Royal Astronomical Society.
Remove All Ads on Universe Today
Join our Patreon for as little as $3!
Get the ad-free experience for life
box-shadow: 0 0 .5rem black inset;
#go-ad-free div p
text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.5);
#go-ad-free div p:first-child
@media (max-width: 940px)
#go-ad-free img, #go-ad-free div
margin: 0 auto;
As they indicate in their paper, the targets of their study were all nearby core-collapse supernovae (SNe) that Hubble imaged at high spatial resolutions. The images were part of the Hubble Snapshot program, created by the Space Telescope Science Institute (STScI) to provide a large sample of images for various targets. Every target is observed in a single orbit of Hubble around the Earth between other observation programs, allowing a degree of flexibility that is not possible with other observatories.
For their study, Van Dyk and his colleagues examined images of six extragalactic supernovae before and after they exploded – designated SN 2012A, SN 2013ej, SN 2016gkg, SN 2017eaw, SN 2018zd, and SN 2018aoq. With extragalactic targets, astronomers have difficulty knowing if the stars they identified were progenitors to the supernova, given the distance involved. As Van Dyk to Universe Today via email, the only way to be sure is to wait for the supernova to dim, then confirm that the progenitor star has disappeared:
“Since the supernova explosion is so luminous, we have to wait a number of years until it has faded enough that it is less luminous than was the progenitor. In a few of the cases we show in our paper, there is little question that the star that was there pre-explosion is now gone. In the other cases, we’re reasonably sure, but the supernova is still detectable and is just faint enough for us to infer that the progenitor has vanished. “
In a previous study, Van Dyk and several colleagues who were co-authors of this study investigated another supernova (iPTF13bvn) whose progenitor star disappeared. In this case, the research team relied on data obtained by Hubble of the SN site – as part of the Ultraviolet Ultra Deep Field (UVUDF) campaign – roughly 740 days after the star exploded. In 2013, Van Dyk led a study that used images from an earlier Snapshot program to confirm that the progenitor of SN 2011dh in the Whirlpool Galaxy (Messier 51) had disappeared.
These and other papers over the years have shown that progenitor candidates can be directly identified from pre-explosion images. In this most recent study, Van Dyk and his colleagues observed supernovae in the later stages of their evolution to learn what mechanisms are powering them. In many cases, the mechanism is the decay of radioactive nuclei (in particular, radioactive nickel, cobalt, and iron) that were synthesized by the enormous energy of the explosion. But as he explained, they suspected that other mechanisms might be involved:
“However, we have indications that some supernovae inevitably have additional power sources — one possibility is that the light of the supernova has been scattered by interstellar dust immediate to the explosion, in the form of a ‘light echo’; another more likely possibility is that the shockwave associated with the explosion is interacting with gas that was deposited around the progenitor star by the star itself during the course of the star’s life, in the form of wind or outburst, that is, circumstellar matter. The ejecta from the explosion moving through and interacting with this circumstellar matter can result in luminous energy that can persist for years, even for decades.”
In short, the team was trying to estimate how many of the supernovae they observed evolved through radioactive decay versus more exotic powering mechanisms. Their results showed that SN 2012A, SN 2018zd, and SN 2018aoq had faded to the point where they were no longer detectable in the Hubble Snapshot images, whereas SN 2013ej, SN 2016gkg, and SN 2017eaw had faded just enough. Therefore, they could infer in all six cases that the progenitors had disappeared. However, not all were the result of a single massive star undergoing core collapse.
In the case of SN 2016gkg, the images acquired by Hubble’s Wide Field Camera 3 (WFC3) were of much higher spatial resolution and sensitivity than the images of the host galaxy, previously taken by the now-retired WFC2. This allowed them to theorize that SN 2016gkg was not the result of a single core-collapse supernova but a progenitor star interacting with a neighboring star. Said Van Dyk:
“So, in the old image, the progenitor looked like one “star,” whereas in the new images, we could see that the progenitor had to have been spatially distinct from the neighboring star. Therefore, we were able to obtain a better estimate of the progenitor’s luminosity and color, now uncontaminated by the neighbor, and from that, we were able to make some new inferences about the overall properties of the progenitor, or, in this case, progenitor system, since we characterized the new results using existing models of binary star systems.”
Specifically, they determined that the progenitor belonged to the class of “stripped-envelope” supernovae (SESNe), in which the outer hydrogen H-rich envelope of the progenitor star has been significantly or entirely removed. They further estimated that the progenitor was the primary and its companion was likely a main sequence star. They even placed constraints on their respective masses before the explosion (4.6 and 17–20.5 solar masses, respectively).
After consulting images taken around the same time by another Snapshot program, they also noticed something interesting about SN 2017eaw. These images indicated that this supernova was especially luminous in the UV band (an “ultraviolet excess”). By combining these images with their data, Va Dyk and his team speculated that SN 2017eaw had an excess of light in the UV at the time it was observed, which was likely caused by interaction between the supernova shock and the circumstellar medium around that progenitor.
The team also noted that the dust created by a supernova explosion is a complicating factor due to how it cools as it expands outward. This dust, said Van Dyk, can obscure light from distant sources and lead to complications with the observations:
“The caveat here, then, is that the star that we saw pre-explosion might not be the progenitor at all, for instance and — again, because of the distances to the host galaxies — that star is within fractions of a pixel of the actual progenitor (physically, in the immediate neighborhood of the progenitor), such that, if the supernova has made dust, that dust is effectively blanketing both the supernova and that neighboring star. This is possible, but not inordinately likely. And it becomes a harder argument to make in those few cases where nothing is seen at the supernova position years later — as we point out in the paper, that would require enormous amounts of dust, which is likely physically not possible.”
Tracing the origins of supernovae is one of the many ways astronomers can learn more about the life cycle of stars. With improved instruments, data collection, and flexibility, they are able to reveal more about how our Universe evolved and will continue to change over time.
Further Reading: arXiv
Clamshells Face the Acid Test
It’s low tide in Bodega Bay, north of San Francisco, California, and Hannah Hensel is squishing through thick mud, on the hunt for clams. The hinged mollusks are everywhere, burrowed into the sediment, filtering seawater to feed on plankton. But Hensel isn’t looking for living bivalves—she’s searching the mudflat for the shells of dead clams.
“I did lose a boot or two,” she recalls. “You can get sunk into it pretty deep.”
Hensel, a doctoral candidate at the University of California, Davis, is studying shells, which are composed of acid-buffering calcium carbonate, as a tool that could one day help shelled species survive in the world’s rapidly acidifying oceans.
The inspiration for Hensel’s research comes from Indigenous sea gardening practices. On beaches from Alaska to Washington State, First Nations and tribal communities built rock-walled terraces in the intertidal zone to bolster populations of shellfish and other invertebrates. Although these sea gardens have not been documented farther south, clams were also vital sustenance in central California. Coast Miwok and Southern Pomo people harvested clams for food and shaped shells into bead money, says Tsim Schneider, an archaeologist at the University of California, Santa Cruz, and a member of the Federated Indians of Graton Rancheria. “So taking care of your clam beds was actually kind of protecting your vault, your bank,” says Schneider.
In the sea gardens of the Pacific Northwest, caretakers crushed the shells of harvested clams and mixed the fragments back into the beach. Recent research has shown multiple positive effects of this broken shell “hash,” from opening spaces in the sediment so young clams can more easily burrow and grow, to releasing chemical cues that encourage larval clams to settle nearby.
This millennia-old practice may hold the key to addressing a new crisis. As humans burn fossil fuels, oceans are absorbing carbon dioxide from the atmosphere, making seawater more acidic. At lower pH levels, clams and other shellfish struggle to build shells. As their protective structures weaken and dissolve, the animals become vulnerable to damage and predation. But studies suggest that adding shell fragments to clam beds could release carbonate into the water, potentially neutralizing acidity caused by the greenhouse gas.
To find out whether shell hash could help California’s clams survive increasingly acidic conditions, Hensel brought shells from the tidal flat back to the lab, where she crushed them with a mortar and pestle and mixed the fragments into four plastic buckets of sand. Hensel filled these buckets, and four others containing sand alone, with local seawater and added the pinky nail–sized progeny of Pacific littleneck clams collected from Bodega Bay. She bubbled carbon dioxide through the seawater in half of the buckets to increase acidity. With their delicate shells, young clams are thought to be especially vulnerable to acidification.
After 90 days, Hensel dug up all the clams. Comparing the buckets containing more acidic seawater, she observed that the bivalves burrowed in shell hash had grown bigger than the clams in sand alone. Strangely, though, the larger clams were not heavier, and Hensel plans to cross-section the shells to assess whether the new growth was thinner or less dense.
The results inform researchers that shell hash does have a buffering effect under certain conditions, says Leah Bendell, a marine ecologist at Simon Fraser University in British Columbia, who was not involved in the study. “It was a well-done lab experiment.”
Bendell also studies the buffering power of shell hash. Working with the Tsleil-Waututh Nation, Bendell and graduate student Bridget Doyle added shell fragments to clam beds in Burrard Inlet, near Vancouver, British Columbia. In that study, hash reduced pH fluctuations in seawater seeping through the sediment, which can vary markedly with rising and falling tides. Although the reduction was limited to areas with coarse sediments, and the hash did not reduce the overall pH, Bendell sees the results as a hint of something promising. Given a longer period of time, shell hash could have a greater effect on pH in certain clam beds, she says.
Shell hash may not be a panacea for ocean acidification everywhere, but Bendell and Hensel are slowly piecing together how carbonate might help individual beaches weather caustic conditions. Next summer, when Hensel begins adding shell hash to Bodega Bay’s clam beds, she will incorporate another element of traditional sea gardening. Indigenous caretakers regularly tilled clam beds, loosening the sediment and mixing in shell fragments. This repeated digging could bring oxygen to burrowed clams, open more space in the sediments, and alter seawater chemistry, Hensel says, and she plans to measure how the physical process affects both seawater chemistry and clam growth.
Schneider is hopeful that Hensel’s work will improve the health of his community’s clam beds, and the two researchers are discussing ways to involve the Indigenous communities around Bodega Bay. “I think it would just be really rewarding to see community members from my tribe having opportunities to be back out on the landscape to interact with traditional resources in the ways that our ancestors did,” Schneider says.
Australia begins construction of its section of giant radio telescope
Construction has got underway in Australia and South Africa of a network of antennas which, when complete, together will form the world’s largest radio telescope, the Square Kilometre Array (SKA).
The giant cross-continental telescope is expected to produce scientific results that will change our understanding of the universe.
Both South Africa and Australia have huge expanses of land in remote areas with little radio disturbance which is ideal for this kind of installation.
The idea for the telescope was first conceived in the early 1990s, but the project was plagued by delays, funding issues, and diplomatic jockeying.
The SKA is headquartered in the United Kingdom and has 14 members: Britain, Australia, South Africa, Canada, China, France, Germany, India, Italy, New Zealand, Spain, Sweden, Switzerland, and The Netherlands.
The director general of the Square Kilometre Array Organisation, Philip Diamond, has described the beginning of its construction as ‘momentous’ saying it will be ‘one of humanity’s biggest-ever scientific endeavours’.
More than 130,000 Christmas tree-shaped antennas are planned in Western Australia, to be built on the traditional lands of the Wajarri Aboriginal people. In South Africa, the site will feature nearly 200 dishes in the remote Karoo region.
The large distances between the antennas, and their sheer number, mean that the telescope will pick up radio signals with unprecedented sensitivity as the SKA probes targets in the sky.
‘The two complementary telescopes will be the ears on either side of the planet, allowing us to listen to those murmurings from the deep universe which are driving such excitement in both science and deepen our understanding of the universe in which we live and the origins of life,’ says George Freeman, Britain’s Minister of State for Science, Research and Innovation.
Construction of the SKA is due to be completed in 2028.
After Backlash, Overwatch 2's New Tank Will Be Easier To Unlock For Free – Kotaku
Health officials in B.C. urge flu vaccination for young children as hospitalization rates surge – The Globe and Mail
UK's Economy To Dip Into Recession This Winter – OilPrice.com
Silver investment demand jumped 12% in 2019
Iran anticipates renewed protests amid social media shutdown
Search for life on Mars accelerates as new bodies of water found below planet’s surface
Politics24 hours ago
How Harlem Shaped Warnock’s Faith and Politics
Health12 hours ago
Serial cross-sectional estimation of vaccine-and infection-induced SARS-CoV-2 seroprevalence in British Columbia, Canada
Economy23 hours ago
Vermont Outdoor Recreation Economy
Investment23 hours ago
Consumption, not investment, now key to growth
Science11 hours ago
Clamshells Face the Acid Test
Sports22 hours ago
Jets score three goals in third period to complete comeback win over Ducks
Health22 hours ago
Theatre review: Memorializing HIV/AIDS in Vancouver
Media14 hours ago
PBR Tries To Buck Media Trend With New Print Magazine