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890 million-year-old fossils may be oldest sign of animal life on Earth, Canadian geologist says – The Washington Post

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A geologist may have uncovered the oldest sign of animal life on Earth: sponge fossils that potentially date back 890 million years. That’s some 350 million years earlier than the oldest undisputed findings of animal fossils.

Elizabeth Turner, a professor at Laurentian University in Ontario, Canada, chanced upon the fossilized structures in rock formations while doing field work as a graduate student in the country’s remote northwest more than two decades ago.

Recently, she went back to collect more samples and — aided by present-day advances in the study of far more modern sponges, which are simple aquatic animals with dense yet porous skeletons — she became confident enough in her theory to publish her findings in the journal Nature.

Scientists believe life on Earth emerged around 3.5 billion years ago. The earliest animals appeared much later, but exactly when is still the subject of debate because of a lack of fossilized evidence.

“The fossil record you see in a museum or geology teaching lab, fossils of animals, appear in the rock record in rocks that are younger than 540 million years,” Turner told The Washington Post. “Me suggesting that I have possibly found evidence of the bodies of sponges 890 million years ago seems pretty radical right at the outset.”

The oldest undisputed fossils date back to the Cambrian period when animals first developed hard skeletons, exoskeletons and shells, which were more likely to be preserved. Turner’s discovery could help prove the scientific theory that sponges existed before those more complicated creatures.

Examined under a microscope, the tiny sections of rock Turner uncovered contain a meshwork of three-dimensional structures — branching out in a distinctive way and rejoining — that closely resembles modern sponge skeletons.

Given that the sponge is among the most basic forms of animal life, “if we’re going to find early animals, it seems reasonable that they’re going to be spongelike,” Turner said in a Zoom interview.

If Turner’s discovery is proved correct, then the organisms would have lived on Earth before the time when most scientists previously believed there was enough oxygen to support animal life. They also would have lived before widespread ice ages on Earth.

Turner said it is possible the sponges pre-date these two major Earth system events, in part because modern rock records show sponges can be tolerant of low oxygen levels. Her samples were uncovered in giant fossil reefs, which she described as an “oxygen oasis.”

In the past five years or so, scientists have extensively researched how sponges get preserved — in what Turner describes as “a race between decay and preservation of their soft tissues.” They’ve experimented on modern sponges and worked on sponge preservation in ancient rocks, “all of which is very, very closely related to the structure that I describe,” Turner said.

Writing in the journal Nature, Turner leaned on those recent discoveries to describe how the fossils may have formed when sponges, measuring a few millimeters to a centimeter across, became mineralized. The soft tissue was first to fossilize, encasing the 3-D network of collagen-like fibers that formed the sponge’s skeleton. Over time, these skeletal fibers decayed, leaving hollow tubules that filled up with calcite crystals.

“I think she’s got a pretty strong case. I think this is very worthy of publishing — it puts the evidence out there for other people to consider,” David Bottjer, a paleobiologist at University of Southern California, who was not involved in the research, told the Associated Press.

“This is not a normal science story. This is slow science. It’s a story about early animal evolution,” Turner told The Post.

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How to spot the International Space Station across the US this month | Curated – Daily Hive

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Keep your eyes on the sky over the next several weeks, because if you look closely, you might catch a glimpse of the International Space Station.

According to Nasa and its Spot the Station tool, the station will be visible from now through early October, offering stargazers something new to search for as it travels through the night sky.

The space station looks like an “airplane or a very bright star.” It moves faster than the typical airplane and always travels in a straight line. It also doesn’t have any flashing lights.

Astronauts aboard the football-field-sized space station are conducting research in a microgravity lab that should benefit people on Earth.

Here’s when the space station will be visible near Seattle and Portland, but NASA also has information for smaller communities on its website.

Seattle

Spot the Station for Seattle (Nasa).

Portland

Spot the Station for Portland (Nasa).

Viewing opportunities with higher maximum heights are easier to spot because the space station won’t be blocked by surrounding trees or buildings.

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Astronomers Discover an Intermediate-Mass Black Hole as it Destroys a Star – Universe Today

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Supermassive black holes (SMBH) reside in the center of galaxies like the Milky Way. They are mind-bogglingly massive, ranging from 1 million to 10 billion solar masses. Their smaller brethren, intermediate-mass black holes (IMBH), ranging between 100 and 100,000 solar masses, are harder to find.

Astronomers have spotted an intermediate-mass black hole destroying a star that got too close. They’ve learned a lot from their observations and hope to find even more of these black holes. Observing more of them may lead to understanding how SMBHs got so massive.

When a star gets too close to a powerful black hole, a tidal disruption event (TDE) occurs. The star is torn apart and its constituent matter is drawn to the black hole, where it gets caught in the hole’s accretion disk. The event releases an enormous amount of energy, outshining all the stars in the galaxy for months, even years.

That’s what happened with TDE 3XMM J215022.4-055108, which is more readily known as TDE J2150. Astronomers were only able to spot the elusive IMBH because of the burst of x-rays emitted by the hot gas from the star as it was torn apart. J2150 is about 740 million light-years from Earth in the direction of the Aquarius constellation. Now a team of researchers has used observations of the distant J2150 and existing scientific models to learn more about the IMBH.

They’ve published their results in a paper titled “Mass, Spin, and Ultralight Boson Constraints from the Intermediate Mass Black Hole in the Tidal Disruption Event 3XMM J215022.4?055108.” The lead author is Sixiang Wen from the University of Arizona. The paper is published in The Astrophysical Journal.

“The fact that we were able to catch this invisible black hole while it was devouring a star offers a remarkable opportunity to observe what otherwise would be invisible.”

Ann Zabludoff, co-author University of Arizona.

IMBHs are elusive and difficult to study. Astronomers have found several of them in the Milky Way and in nearby galaxies. Mostly they’ve been spotted because of their low-luminosity active galactic nuclei. In 2019 the LIGO and Virgo gravitational wave observatories spotted a gravitational wave from the merger of two IMBHs. As it stands now, there’s a catalogue of only 305 IMBH candidates, even though scientists think they could be common in galactic centers.

One of the problems in seeing them is their low mass itself. While SMBHs can be found by observing how their mass affects the stellar dynamics of nearby stars, IMBHs are typically too small to do the same. Their gravity isn’t powerful enough to change the orbits of nearby stars.

“The fact that we were able to catch this black hole while it was devouring a star offers a remarkable opportunity to observe what otherwise would be invisible,” said Ann Zabludoff, UArizona professor of astronomy and co-author on the paper. “Not only that, by analyzing the flare we were able to better understand this elusive category of black holes, which may well account for the majority of black holes in the centers of galaxies.”

This is a Hubble image of J2150 in the white circle. It’s situated inside a dense cluster of stars about 740 million light-years away. X-ray emissions from the TDE were used to spot the IMBH, but Hubble’s visible-light capabilities were needed to pinpoint its location. Image Credit: NASA, ESA, and D. Lin (University of New Hampshire)

It was the eruption of x-rays that made the event visible. The team compared the observed x-rays with models and was able to confirm the presence of an IMBH. “The X-ray emissions from the inner disk formed by the debris of the dead star made it possible for us to infer the mass and spin of this black hole and classify it as an intermediate black hole,” lead author Wen said.

This is the first time that observations have been detailed enough to be able to use a TDE flare to confirm the presence of an IMBH. It’s a big deal, because though we know that SMBHs lie in the center of galaxies like the Milky Way and larger, our understanding of smaller galaxies and their IMBHs is much more limited. They’re just really hard to see.

“We still know very little about the existence of black holes in the centers of galaxies smaller than the Milky Way,” said co-author Peter Jonker of Radboud University and SRON Netherlands Institute for Space Research, both in the Netherlands. “Due to observational limitations, it is challenging to discover central black holes much smaller than 1 million solar masses.”

The mystery surrounding IMBHs feeds into the mystery surrounding SMBHs. We can see SMBHs at the heart of large galaxies, but we don’t know exactly how they got that massive. Did they go through mergers? Maybe. Through the accretion of matter? Maybe. Astrophysicists mostly agree that both mechanisms may play a role.

Another question surrounds SMBH “seeds.” The seeds could be IMBHs of tens or hundreds of solar masses. The IMBHs themselves could’ve grown from stellar-mass black holes that grew into IMBHs through the accretion of matter. Another possibility is that long before there were actual stars, there were large gas clouds that collapsed into quasi-stars, that then collapsed into black holes. These strange entities would collapse directly from quasi-star to black hole without ever becoming a star, and are known as direct collapse black holes. But these are all hypotheses and models. Astrophysicists need more actual observations, like in the case of TDE J2150, to confirm or rule anything out.

“Therefore, if we get a better handle of how many bona fide intermediate black holes are out there, it can help determine which theories of supermassive black hole formation are correct,” Jonker said.

This artist's illustration depicts what astronomers call a "tidal disruption event," or TDE, when an object such as a star wanders too close to a black hole and is destroyed by tidal forces generated from the black hole's intense gravitational forces. (Credit: NASA/CXC/M.Weiss.
This artist’s illustration depicts what astronomers call a “tidal disruption event,” or TDE, when an object such as a star wanders too close to a black hole and is destroyed by tidal forces generated from the black hole’s intense gravitational forces. (Credit: NASA/CXC/M.Weiss.

The team of researchers was also able to measure the black hole’s spin, which has implications for black hole growth, and maybe for particle physics, too. The black hole is spinning quickly, but it’s not spinning as fast as possible. It begs the question, how did the IMBH attain a speed in this range? The spin opens up some possibilities and eliminates others.

“It’s possible that the black hole formed that way and hasn’t changed much since, or that two intermediate-mass black holes merged recently to form this one,” Zabludoff said. “We do know that the spin we measured excludes scenarios where the black hole grows over a long time from steadily eating gas or from many quick gas snacks that arrive from random directions.”

The spin rate may shed some light on potential particle candidates for dark matter, too. One of the hypotheses says that dark matter is made up of particles never seen in a laboratory, called ultralight bosons. These exotic particles, if they exist, would have less than one-billionth the mass of an electron. The IMBHs spin rate may preclude the existence of these candidate particles.

“If those particles exist and have masses in a certain range, they will prevent an intermediate-mass black hole from having a fast spin,” co-author Nicholas Stone said. “Yet J2150’s black hole is spinning fast. So, our spin measurement rules out a broad class of ultralight boson theories, showcasing the value of black holes as extraterrestrial laboratories for particle physics.”

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This discovery will build toward a better understanding of dwarf galaxies and their black holes, too. But for that to happen, astrophysicists need to observe more of these IMBH tidal disruption events.

“If it turns out that most dwarf galaxies contain intermediate-mass black holes, then they will dominate the rate of stellar tidal disruption,” Stone said. “By fitting the X-ray emission from these flares to theoretical models, we can conduct a census of the intermediate-mass black hole population in the universe,” Wen added.

As is often the case in astronomy, astrophysics, and cosmology, future telescopes and observatories should advance our knowledge considerably. In this, the Vera C. Rubin Observatory could play a role. The Rubin could discover thousands of TDEs each year.

Then we may finally be able to piece together the story of not only IMBHs but also SMBHs.

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NASA splits human spaceflight unit in two, reflecting new orbital economy – CTV News

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NASA is splitting its human spaceflight department into two separate bodies – one centred on big, future-oriented missions to the moon and Mars, the other on the International Space Station and other operations closer to Earth.

The reorganization, announced by NASA chief Bill Nelson on Tuesday, reflects an evolving relationship between private companies, such as SpaceX, that have increasingly commercialized rocket travel and the federal agency that had exercised a U.S. monopoly over spaceflight for decades.

Nelson said the shake-up was also spurred by a recent proliferation of flights and commercial investment in low-Earth orbit even as NASA steps up its development of deep-space aspirations.

“Today is more than organizational change,” Nelson said at a press briefing. “It’s setting the stage for the next 20 years, it’s defining NASA’s future in a growing space economy.”

The move breaks up NASA’s Human Exploration and Operations Mission Directorate, currently headed by Kathy Leuders, into two separate branches.

Leuders will keep her associate administrator title as head of the new Exploration Systems Development Mission Directorate, focusing on NASA’s most ambitious, long-term programs, such as plans to return astronauts to the moon under project Artemis, and eventual human exploration of Mars.

A retired deputy associate administrator, James Free, who played key roles in NASA’s space station and commercial crew and cargo programs, will return to the agency as head of the new Space Operations Mission Directorate.

His branch will primarily oversee more routine launch and spaceflight activities, including missions involving the space station and privatization of low-Earth orbit, as well as sustaining lunar operations once those have been established.

“This approach with two areas focused on human spaceflight allows one mission directorate to operate in space while the other builds future space systems,” NASA said in a press release announcing the move.

The announcement came less than a week after SpaceX, which had already flown numerous astronaut missions and cargo payloads to the space station for NASA, launched the first all-civilian crew ever to reach orbit and returned them safely to Earth.

(Reporting by Steve Gorman in Los Angeles; Editing by Leslie Adler)

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