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Our galaxy’s black hole may have produced a huge x-ray flare 205 years ago



A region of space around Sagittarius A*, the supermassive black hole at the center of our galaxy.

NASA/CXC/Univ. Wisconsin/S.Ba

The colossal black hole at the center of the Milky Way hasn’t always been this quiet.

Our galaxy’s supermassive black hole, called Sagittarius A* (Sgr A*), is currently relatively inactive, but observations of gas clouds around it hint that it may have emitted a powerful X-ray blast about 205 years ago.

When a black hole emits an X-ray flash, this radiation can be reflected from any gas in …


Saturn adds 62 newly discovered moons to its total



In the red corner is Jupiter, the largest planet orbiting our Sun, which has shaped our solar system with its gravitational mass.

In the blue corner is Saturn, a magnificent ringed world with stunning hexagonal storms at the poles.

These two gigantic worlds are overdue in the struggle for satellite-based dominance. But now the battle over which planet has the most moons in its orbit has turned decisively in Saturn’s favor.

This month, the International Astronomical Union intends to recognize 62 more satellites of Saturn based on a series of objects discovered by astronomers. Small objects would give Saturn 145 moons, dwarfing Jupiter’s 95.

“They both have many, many satellites,” said Scott Sheppard, an astronomer at the Carnegie Institution of Science in Washington, DC.

The newly discovered moons of Saturn look nothing like a bright object in Earth’s night sky. They are irregularly shaped, like potatoes, and no more than a mile or two across. They also orbit far from the planet, between six million and 18 million miles, compared to larger moons like Titan, which mostly orbit within a million miles of Saturn. However, these little irregular moons are charming in their own right. They are mostly clustered and may be the remnants of larger moons that crashed while orbiting Saturn.

“These moons are key to understanding some important questions about the solar system,” said Bonnie Buratti of NASA’s Jet Propulsion Laboratory in California and deputy project scientist for the upcoming Europa Clipper mission to Jupiter. “They have fingerprints of events that took place in the early solar system.”

The growing number of moons is also highlighting a potential debate about what constitutes a moon.

“A simple definition of a moon is that it’s an object that orbits a planet,” says the doctor. Sheppard said. The size of the object doesn’t matter at the moment.

The new moons were discovered by two teams, one led by Dr. J. Sheppard and the other recently made by Edward Ashton of the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan. Dr. Sheppard’s team in the mid-2000s used the Subaru telescope in Hawaii to search for additional satellites around Saturn.

In March Dr. Sheppard was also responsible for discovering 12 new moons of Jupiter, which temporarily topped Saturn in the fray to become the biggest hoarder of moons. This entry appears to have been short-lived.

doctor Ashton Group, from 2019 to 2021, used the Canadian-French Hawaiian Telescope, a neighbor of the Subaru Telescope on Mauna Kea, to find more moons of Saturn and check out some of the doctor’s moons. Sheppard’s discoveries. To authenticate a moon, it needs to be detected multiple times to “be sure it’s a satellite and not just an asteroid that happens to be near the planet,” said Mike Alexandersen, who is responsible for officially confirming moons at the International Astronomical Union.

Most of Saturn’s irregularly shaped moons orbit the planet in what astronomers call the Inuit, Scandinavian, and Gaulish groups. Objects in each group could be the remnants of larger moons up to 150 miles in diameter that once orbited Saturn but were destroyed by asteroid or comet impacts or by collisions between two moons. “This shows that there has been a large history of collisions around these planets,” says the doctor. Sheppard said.

These primordial moons may have been captured by Saturn “very early in the solar system.” Ashton said perhaps in the first few hundred million years after its formation 4.5 billion years ago. However, not all orbits in these groups, with several rogue satellites, rotate in a retrograde direction, that is, in the opposite direction to the orbits of other satellites.

“We don’t know what’s going on with these retrograde moons,” the doctor says. Sheppard said. Dr. Ashton suspects that these may be remnants of a recent collision.

Learning more about new moons is difficult due to their small size and distant orbits. It appears to be a special class of objects, distinct from asteroids formed in the inner solar system and comets in the outer solar system, but little is known.

“These objects can be unique,” ​​says the doctor. Sheppard said. “They may be the last remnants of what formed in the region of the giant planet, probably very ice-rich objects.”

NASA’s Cassini spacecraft observed about two dozen moons around Saturn until its death in 2017. Although these data are not close enough to study in detail, they have allowed scientists to “determine the period of rotation” of some satellites, the axis of rotation, and “even the shape,” Tilmann Denk said. from the German Aerospace Center in Berlin, who directed the observations. Cassini also found a lot of ice on the surface one of the largest irregular moonsPhoebe.

Closer observation of Saturn’s tiny moons could give scientists a glimpse into turbulent times in the early solar system. Collisions were more frequent during this period, and the planets fought for position, and Jupiter was thought to have migrated from closer to the Sun further to its current orbit. “This gives you additional information about the formation of the solar system,” says the doctor. Think said.

However, the irregular moons we see so far may only be the beginning. “We calculated that there could potentially be several thousand of them,” around Saturn and Jupiter. Ashton said. Uranus and Neptune may also have many of these irregular moons, but their great distance from the Sun makes them difficult to spot.

Saturn, despite being smaller than Jupiter, has many more irregular moons. It may have three times the size of Jupiter and is about two miles across. The reason is unclear, doctor. Ashton said.

Jupiter’s original moons may have tended to be larger and less likely to collapse. Or Saturn may have captured more objects into its orbit than Jupiter. Or Saturn’s moons may have been in orbits that were more likely to overlap and collide, creating smaller, irregular moons.

Whatever the reason, the result is clear. Jupiter is on the brink and is unlikely to regain the title of the planet with the most moons. As astronomers’ ability to find smaller and smaller moons improves, “Saturn will win by miles,” says the doctor. Alexandersen said. “I don’t think it’s more of a competition.”

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The DNA you’ve lost can identify you



The following essay is reprinted with permission. Talkonline publication dedicated to the latest research.

Human DNA can be sequenced from small amounts of water, sand and air in the environment to potentially extract identifiable information like genetic background, gender and health risks, according to our new study.

Every cell of the body contains DNA. Because each person has a unique genetic code, DNA can be used to identify individuals. Typically, practitioners and researchers obtain human DNA through direct sampling, such as blood tests, swabs, or biopsies. However, all living beings, including animals, plants and microbes, constantly shedding DNA. Water, soil and even air contain microscopic particles of the biological material of living organisms.

The DNA that an organism releases into the environment is called ecological DNA or eDNA. Over the past couple of decades, scientists have been able to collect and sequence eDNA from soil or water samples in monitoring of biodiversity, populations of wild animals another pathogens. Tracking rare or elusive endangered species through their eDNA has been a boon to researchers, as traditional monitoring methods such as observation or trapping can be difficult, often unsuccessful, and intrusive to the species of interest.

Researchers using eDNA tools typically only focus on the species they are studying and ignore the DNA of other species. However, people so shedcough and flush DNA into their environment. And as our team of geneticists says, ecologists another marine biologists V Duffy’s lab found at the University of Florida, signs of human life can be found everywhere but in the most isolated places.

Animals, humans and viruses in eDNA

Our team uses environmental DNA to study endangered sea turtles and viral tumors to which they are subject. Tiny hatchling sea turtles lose their DNA as they crawl along the shore on their way to the ocean shortly after birth. Sand scooped from their footprints contains enough DNA to provide valuable information about tortoises and chelonid herpesviruses and fibropapillomatous tumors affecting them. Scoop up a liter tank water a recovering sea turtle under veterinary care equally provides a wealth of genetic information for research. Unlike blood or skin samples, eDNA collection does not stress the animal.

Genetic sequencing technology The methods used to decipher DNA have improved rapidly in recent years and it is now possible to easily sequence the DNA of each organism in an environmental sample. Our team suspected that the sand and water samples we used to study sea turtles might also contain DNA from a number of other species, including, of course, humans. that we didn’t know that how informative the human DNA we could extract would be like this.

To find out, we took samples from a variety of places in Florida, including the ocean and rivers in urban and rural areas, sand from isolated beaches, and a remote island not normally visited by humans. We found human DNA in all of these locations, except for the remote island, and these samples were of high enough quality for analysis and sequencing.

We also tried this technique in Ireland, following a river that flows from a remote mountaintop, through small rural villages, and into the sea in a larger city of 13,000 people. We have found human DNA everywhere except in a remote mountain tributary where a river flows, away from human habitation.

We also took air samples from a room at our Florida Wildlife Veterinary Hospital. The people present in the room allowed us to take air samples. We recovered DNA matching DNA from humans, the animal patient, and common animal viruses present at the time of collection.

Surprisingly, the human eDNA found in the local environment was intact enough for us to be able to identify mutations associated with the disease and determine the genetic origins of people living in the area. DNA sequencing, left by volunteers in the form of footprints in the sand, even made it possible to identify part of their sex chromosomes.

Ethical implications of human eDNA collection

Our team duplicates the unintentional extraction of human DNA from environmental samples “Human genetics by catch”. We call for a deeper discussion on how to ethically handle the human DNA of the environment.

Human EDNA could provide significant advances in research in areas as diverse as conservation, epidemiology, forensics, and agriculture. If handled correctly, human eDNA could help archaeologists track down unexplored ancient human settlementsallow biologists Monitoring cancer mutations in a given population or provide law enforcement useful forensic information.

However, there are many ethical implications associated with the unintentional or intentional collection and analysis of human genetic by-catch. Identifiable information can be retrieved from eDNA and access to this level of detail on individuals or populations is responsibilities related to consent and confidentiality.

Although we conducted our study with the approval of our institutional review boardwhich guarantees that human research complies with the ethical principles of research, there is no guarantee that everyone will treat this type of information ethically.

Many questions arise regarding the human DNA of the environment. For example, who should have access to human eDNA sequences? Should this information be publicly available? Is consent required before human eDNA sampling and from whom? Should researchers remove human genetic information from samples originally collected to identify other species?

We believe it is critical to put in place policies that ensure that data is collected, analyzed and stored ethically and appropriately. Policy makers, the scientific community, and other stakeholders must take the collection of human eDNA seriously and balance consent and privacy with the possible benefits of studying eDNA. Raising these questions now can help ensure that everyone is aware of the potential of eDNA and allow more time to develop protocols and regulations to ensure the proper use of eDNA techniques and the ethical management of human genetic by-catch.

This article was originally published on Talk. Read original article.

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