Over sixty years of space exploration have left their mark in Low Earth Orbit (LEO), where thousands of objects create the risk of collisions. These objects include the spent first stages of rockets, fragments of broken-up spacecraft, and satellites that are no longer operational. As Donald Kessler predicted, the growing presence of “space junk” could result in regular collisions, leading to a cascading effect (aka. Kessler Syndrome).
This evening – on Wednesday, Jan. 29th – such a collision might take place. These satellites are the Infrared Astronomical Satellite (IRAS), an old space telescope launched by NASA, the Netherlands, and the UK; and the GGSE-4 gravitational experiment launched by the US Air Force. These two satellites run the risk of colliding when their orbits cross paths at 06:40 p.m. EST (03:40 p.m. PST) about 900 km (560 mi) above Pittsburgh, Pennsylvania.
The task of tracking these satellites and keeping the public up to date on the likelihood of their collision is being carried out by LEOLabs, a that uses a worldwide network of orbital tracking arrays to provide mapping data and services. This data is made available to the public and private sector and allows for rapid orbit determination, early operational support, and assessment of collision risks.
As they indicated on Monday, Jan. 27th, on Twitter, LeoLabs calculated that the two objects will come within 15 to 30 meters (50 to 100 ft) of one another. As they wrote:
“On Jan 29 at 23:39:35 UTC, these two objects will pass close by one another at a relative velocity of 14.7 km/s (900km directly above Pittsburgh, PA). Our latest metrics on the event show a predicted miss distance of between 15-30 meters… These numbers are especially alarming considering the size of IRAS at 3.6m x 3.24m x 2.05m. The combined size of both objects increases the computed probability of a collision, which remains near 1 in 100.”
However, since then, LeoLabs has updated those odds to factor in some previously unforeseen factors. This includes the 18 m (59 ft) boom that was deployed by the GGSE-4 and the fact that they “do not know which direction it is facing relative to IRAS.” This altered their computations about a possible collision and “yields an updated collision probability closer to 1 in 20.”
To make matters worse, there is nothing that can be done to reduce the likelihood of a collision. Whereas the International Space Station (ISS) and operative spacecraft are able to adjust their orbits to avoid collisions, both the IRAS and the GGSE-4 have been inoperable for decades and can’t perform any corrective maneuvers.
Of the two satellites, the IRAS is the larger, measuring 3.6 x 3.24 x 2.05 meters (11.8 x 10.6 x 6.7 feet) and weighing 1,083 kg (2,388 lb) when it was launched. This was NASA’s first infrared space telescope and was responsible for a number of discoveries, which included six new comets, the core of the Milky Way, and protoplanetary disks around Vega and Fomalhaut.
Since both satellites are orbiting Earth at a velocity of 14.7 km/s (9.1 mps), this makes a collision a major risk for generating orbital debris that will spread into other orbits. According to calculations performed by The Aerospace Corporation, which also monitors and tracks orbital debris, a collision would generate 90,000 chunks of debris that are at least 1 cm (0.4 inches) in diameter.
This would place them on the cusp between the 900,000 objects tracked by the European Space Agency’s that measure between 1 cm and 10 cm and the 128 million objects that measure between 1 mm and 1 cm. While small, objects of this size pose a severe risk to the ISS, spacecraft, operational satellites, and space telescopes.
If there is a takeaway from this, it is just how important it is to track defunct satellites and assorted pieces of debris in orbit. As LeoLabs was sure to add:
“Events like this highlight the need for responsible, timely deorbiting of satellites for space sustainability moving forward. We will continue to monitor this event through the coming days and provide updates as available.”
As the orbital lanes become increasingly crowded due to the deployment of thousands of more telecom satellites, internet satellites, and CubeSats, mitigation strategies will also be needed. Many concepts are on the drawing board and several have already been validated in orbit. In the meantime, regular monitoring and vigilance are the best defense against collisions.
Further Reading: Business Insider
One Great Shot: Bucktoothed Bumpheads on the Great Barrier Reef – Hakai Magazine
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When I set out to photograph bumphead parrotfish on a three-week dive trip to the northern reaches of Australia’s Great Barrier Reef in the winter of 2021, I had a specific goal in mind: I wanted to see a school of these strange animals swimming together.
There are so many weird and wonderful ocean-dwelling creatures, but this particular parrotfish species stands alone with its bizarre overbite, formidable size, prominent forehead, and tendency to travel in large groups. Bumpheads can grow to more than a meter long and about 46 kilograms—about the same weight as the average adult chimpanzee—making them the largest parrotfish and one of the world’s biggest reef fish. They also play an important role in the ecosystem: with their beaklike teeth, they munch algae off corals. In the process, they swallow other reef material and excrete it as sand.
One morning, on a pre-sunrise dive, I descended toward a reef where other divers had spotted bumpheads, hoping for my chance. Luck was on my side—it wasn’t long before I found a cluster of about 40 individuals huddled near the coral. The fish appeared to be completely still above a small bommie (reef) and were packed so tightly that their bodies were touching one another. When I edged closer, the parrotfish squeezed together even more, monitoring my every move. Reef fish are notoriously skittish, but this school stayed put while I took a picture.
The underwater world is full of fascinating species. Photographing them in their habitat is both challenging and rewarding, and I love sharing these moments with others.
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Cite this Article:
Cite this Article:
Josh Blank “One Great Shot: Bucktoothed Bumpheads on the Great Barrier Reef,” Hakai Magazine, Dec 9, 2022, accessed December 9th, 2022, https://hakaimagazine.com/videos-visuals/one-great-shot-bucktoothed-bumpheads-on-the-great-barrier-reef/.
New branch on tree of life includes ‘lions of the microbial world’
There’s a new branch on the tree of life and it’s made up of predators that nibble their prey to death.
These microbial predators fall into two groups, one of which researchers have dubbed “nibblerids” because they, well, nibble chunks off their prey using tooth-like structures. The other group, nebulids, eat their prey whole. And both comprise a new ancient branch on the tree of life called “Provora,” according to a paper published today in Nature.
Like lions, cheetahs, and more familiar predators, these microbes are numerically rare but important to the ecosystem, says senior author Dr. Patrick Keeling, professor in the UBC department of botany. “Imagine if you were an alien and sampled the Serengeti: you would get a lot of plants and maybe a gazelle, but no lions. But lions do matter, even if they are rare. These are lions of the microbial world.”
Using water samples from marine habitats around the world, including the coral reefs of Curaçao, sediment from the Black and Red seas, and water from the northeast Pacific and Arctic oceans, the researchers discovered new microbes. “I noticed that in some water samples there were tiny organisms with two flagella, or tails, that convulsively spun in place or swam very quickly. Thus began my hunt for these microbes,” said first author Dr. Denis Tikhonenkov, senior researcher at the Institute for Biology of Inland Waters of the Russian Academy of Sciences.
Dr. Tikhonenkov, a long-time collaborator of the UBC co-authors, noticed that in samples where these microbes were present, almost all others disappeared after one to two days. They were being eaten. Dr. Tikhonenkov fed the voracious predators with pre-grown peaceful protozoa, cultivating the organisms in order to study their DNA.
“In the taxonomy of living organisms, we often use the gene ’18S rRNA’ to describe genetic difference. For example, humans differ from guinea pigs in this gene by only six nucleotides. We were surprised to find that these predatory microbes differ by 170 to 180 nucleotides in the 18S rRNA gene from every other living thing on Earth. It became clear that we had discovered something completely new and amazing,” Dr. Tikhonenkov said.
New branch of life
On the tree of life, the animal kingdom would be a twig growing from one of the boughs called “domains,” the highest category of life. But sitting under domains, and above kingdoms, are branches of creatures that biologists have taken to calling “supergroups.” About five to seven have been found, with the most recent in 2018 — until now.
Understanding more about these potentially undiscovered branches of life helps us understand the foundations of the living world and just how evolution works.
“Ignoring microbial ecosystems, like we often do, is like having a house that needs repair and just redecorating the kitchen, but ignoring the roof or the foundations,” said Dr. Keeling. “This is an ancient branch of the tree of life that is roughly as diverse as the animal and fungi kingdoms combined, and no one knew it was there.”
The researchers plan to sequence whole genomes of the organisms, as well as build 3D reconstructions of the cells, in order to learn about their molecular organization, structure and eating habits.
Culturing the microbial predators was no mean feat, since they require a mini-ecosystem with their food and their food’s food just to survive in the lab. A difficult process in itself, the cultures were initially grown in Canada and Russia, and both COVID and Russia’s war with Ukraine prevented Russian scientists from visiting the lab in Canada in recent years, slowing down the collaboration.
How A Hellish Planet Made Of Diamonds Covered By A Lava Ocean Got Where It Is Today
In recent decades it’s become clear that the universe is teeming with planets and astronomers have begun to catalog them by the hundreds. Most of the worlds we’ve discovered so far are remarkably inhospitable and the closer we look at some, the more hellacious they seem to appear.
Case in point is 55 Cancri e, also known as 55 Cnc or by its nickname, Janssen. This world orbits so close to its star, known as Copernicus or 55 Cnc, that a year on its surface passes in only 18 hours and temperatures can soar over 4,000 degrees Fahrenheit.
Enduring such extreme conditions for so long has led scientists to suggest that the scalding world could have an interior full of diamonds, covered by a surface ocean of molten lava.
Makes Mauna Loa seem almost minor league on the cosmic scale of volcanism.
There’s a reason that we keep spotting so many relatively hot planets next to their stars. Call it an inherent bias of our existing tech: it’s just easier to see planets orbiting close in to their stars.
In fact, most exoplanets discovered and cataloged so far have a very good chance of being so-called “hot Jupiters” — giant planets orbiting close-in. Being massive and next to your local source of light makes you especially easy to spot.
So 55 Cancri e is actually an important exoplanet as one of the first small, rocky planets found orbiting extremely close to its star.
Now researchers have made use of a new tool called EXPRES (for EXtreme PREcision Spectrometer) at the Lowell Discovery Telescope in Arizona to make ultra-precise measurements that helped them determine the orbit of this hellish world in more detail.
They found that the planet orbits Copernicus right along the equator of the star and that it likely originally orbited further out and was slowly pulled into its current alignment by the gravitational pull of the star and other objects in the unusual star system.
The system is located only 40 light years from Earth and consists of main-sequence star Copernicus paired with a red dwarf star. The binary duo also count at least five exoplanets that all have very different orbits among their cosmic family.
The new research, led by Lily Zhao at Flatiron Institute’s Center for Computational Astrophysics and published in Nature Astronomy, posits that the interactions between these oddball family members shifted Janssen to its current, insufferable orbit.
Although it was pushed, pulled and prodded into its current position, Zhao says that even in its original orbit, the planet “was likely so hot that nothing we’re aware of would be able to survive on the surface.”
What a waste of so much diamond.
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