A mysterious fireball that lit up the skies over Northern Florida on Saturday night turned out to be a meteor that was picked up on weather radar, according to officials.
The falling space rock was reported around 11:52 p.m. over Taylor County, the National Weather Service's Tallahassee office said on Twitter.
The flash from the meteor was so bright it was picked up on weather satellites that are typically used to track thunderstorms and lightning.
Officials said they haven't received any reports of where the meteor possibly landed or if it broke up in the atmosphere. Residents in Georgia and South Carolina also reported seeing the flash.
Meteors are what happened when meteoroids -- what we call "space rocks" -- enter Earth’s atmosphere at a high speed and burn up, according to NASA.
"This is also when we refer to them as 'shooting stars,'” the agency notes. "Sometimes meteors can even appear brighter than Venus -- that’s when we call them 'fireballs.'"
Scientists estimate that about 48.5 tons (44,000 kilograms) of meteoritic material falls on Earth each day, according to NASA.
"When a meteoroid survives its trip through the atmosphere and hits the ground, it’s called a meteorite," the space agency states.
A mysterious fireball that lit up the skies over Northern Florida on Saturday night turned out to be a meteor that was picked up on weather radar, according to officials.
The falling space rock was reported around 11:52 p.m. over Taylor County, the National Weather Service's Tallahassee office said on Twitter.
The flash from the meteor was so bright it was picked up on weather satellites that are typically used to track thunderstorms and lightning.
Officials said they haven't received any reports of where the meteor possibly landed or if it broke up in the atmosphere. Residents in Georgia and South Carolina also reported seeing the flash.
Meteors are what happened when meteoroids -- what we call "space rocks" -- enter Earth’s atmosphere at a high speed and burn up, according to NASA.
"This is also when we refer to them as 'shooting stars,'” the agency notes. "Sometimes meteors can even appear brighter than Venus -- that’s when we call them 'fireballs.'"
Scientists estimate that about 48.5 tons (44,000 kilograms) of meteoritic material falls on Earth each day, according to NASA.
"When a meteoroid survives its trip through the atmosphere and hits the ground, it’s called a meteorite," the space agency states.
A mysterious fireball that lit up the skies over Northern Florida on Saturday night turned out to be a meteor that was picked up on weather radar, according to officials.
The falling space rock was reported around 11:52 p.m. over Taylor County, the National Weather Service's Tallahassee office said on Twitter.
The flash from the meteor was so bright it was picked up on weather satellites that are typically used to track thunderstorms and lightning.
Officials said they haven't received any reports of where the meteor possibly landed or if it broke up in the atmosphere. Residents in Georgia and South Carolina also reported seeing the flash.
Meteors are what happened when meteoroids -- what we call "space rocks" -- enter Earth’s atmosphere at a high speed and burn up, according to NASA.
"This is also when we refer to them as 'shooting stars,'” the agency notes. "Sometimes meteors can even appear brighter than Venus -- that’s when we call them 'fireballs.'"
Scientists estimate that about 48.5 tons (44,000 kilograms) of meteoritic material falls on Earth each day, according to NASA.
"When a meteoroid survives its trip through the atmosphere and hits the ground, it’s called a meteorite," the space agency states.
The two galaxies that form NGC 6052 are now so close that the boundaries are no longer clear.ESA/Hubble & NASA, A. Adamo et al.
Originally discovered in 1784, NGC 6052 was first thought to be one galaxy with an unusual shape.
Scientists eventually discovered that it was, in fact, two galaxies in the process of colliding.
Having previously been observed by the Hubble telescope in 2015, NASA recently released a stunning image of the galaxies in even closer detail.
First discovered in 1784 by William Herschel, NGC 6052 was originally thought to be a singular galaxy that simply had an odd shape.
However, scientists eventually figured out that the "oddly shaped galaxy" 230 million light-years away was, in fact, two galaxies in the process of colliding.
Having previously been observed by the Hubble telescope with an older camera in 2015, NASA recently released a stunning image of the galaxies in even better detail.
This object was previously observed by Hubble with its old Wide Field and Planetary Camera 2 (WFPC2) in 2015.ESA/Hubble & NASA, Acknowledgement: Judy Schmidt
The two galaxies that form NGC 6052 are now so close that the boundaries are no longer clear and the original galaxies are losing their shape at a quickening pace.
"Eventually, this new galaxy will settle down into a stable shape, which may not resemble either of the two original galaxies," explained the European Space Agency. A complete fusion would throw the stars out of their original orbits and take new places.
According to NASA, as well as the union of the two galaxies being beautiful and fascinating, it's also very rare due to the fact that galaxies are mostly comprised of empty space.
In about four billion years the Milky Way and Andromeda are to collide and join to form one single galaxy. For now, however, the scientists are still researching NGC 6052.
Den Originalartikel gibt es auf Business Insider Deutschland. This post originally appeared on Business Insider Deutschland and has been translated from German. Copyright 2019. Und ihr könnt Business Insider Deutschland auf Twitter folgen.
SCIENTISTS have uncovered a dinosaur graveyard formed by the immediate fallout of the asteroid impact that hit Earth 66 million years ago - wiping out the giants.
Digs at a site called Tanis in North Dakota reveal fossils that were sprayed with scorching shards which fell from the sky during the extinction event.
Robert DePalma/ Berkeley University
How the aftermath of the asteroid impact could have looked
The deposits show evidence also of having been swamped with water - the consequence of the colossal Tsunami-style sea surge that was generated by the deadly impact.
Experts say the new find may be the best evidence yet that the massive meteor set off the sequence of events that led to the mass extinction of the dinosaurs, reports Berkeley News.
The results of the excavations are now to be published in the journal Proceedings of the National Academy of Sciences.
“A tangled mass of freshwater fish, terrestrial vertebrates, trees, branches, logs, marine ammonites and other marine creatures was all packed into this layer by the inland-directed surge,” said Robert DePalma, from the University of Kansas.
"A tsunami would have taken at least 17 or more hours to reach the site from the crater, but seismic waves - and a subsequent surge - would have reached it in tens of minutes."
Besides fish the 'graveyard' also contains evidence of dinosaurs, mammals and sea reptiles killed in the aftermath of the asteroid’s impact.
Among the amazing remnants were reported to be the remains of a Triceratops and a duck-billed hadrosaur.
The Chicxulub impact, caused by an eight-mile wide object smashing into the Gulf of Mexico, is thought to have triggered the extinction of 75 per cent of animal and plant life on Earth.
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Researchers were able to date the site’s fish skeletons and amber from tree sap to the point around 66m years ago when the giant space rock struck.
The fish were found with the impact-induced debris embedded in their gills which means they would have breathed in the fragments that filled the water around them.
The scientists have spent the past six years building a picture of how the beasts came to die so quickly after the initial impact.
Robert DePalma/ Berkeley University
A perfectly-preserved fish tail from the Hell Creek Formation, in North Dakota
AFP or licensors
Robert DePalma and field assistant Kylie Ruble excavate fossil carcasses at the site in North Dakota
Getty - Contributor
Dinosaurs 'thrived' before a mass extinction event wiped them out, experts say
Robert DePalma/ Berkeley University
The site appears to date to the day 66m years ago when an asteroid hit Earth
Baby T-rex revealed as 'adorable and fluffy' in stunning 3D video remake of deadly dinosaur
Scientists have uncovered the fossil motherlode – an incredible mash-up of fish, animals and plant life that was flash-preserved in the moments after the asteroid impact that probably killed the dinosaurs.
At a site called Tanis in North Dakota’s Hell Creek Formation, a team of palaeontologists from the University of Kansas unearthed the remains, so finely preserved that the gills of the fishes still contain debris that they breathed right before they died.
“We’ve understood that bad things happened right after the impact, but nobody’s found this kind of smoking-gun evidence,” said co-author David Burnham, preparator of vertebrate paleontology at the KU Biodiversity Institute, in a statement. “People have said, ‘We get that this blast killed the dinosaurs, but why don’t we have dead bodies everywhere?’ Well, now we have bodies. They’re not dinosaurs, but I think those will eventually be found, too.”
Illustration of a ten-kilometre-wide asteroid entering the Earth's atmosphere as dinosaurs, including T. rex, look on. (Credit: Getty)
Getty
The massive Chicxulub impact – the most cataclysmic event known to have befallen life on Earth – is widely held responsible for the end of the dinosaurs. This single event toppled the prehistoric lizards from the top of the food chain and allowed mammals to inherit the Earth.
“It’s difficult not to get choked up and passionate about this topic,” said lead author Robert DePalma, a KU doctoral student in geology who works in the KU Biodiversity Institute and Natural History Museum. “We look at moment-by-moment records of one of the most notable impact events in Earth’s history. No other site has a record quite like that. And this particular event is tied directly to all of us — to every mammal on Earth, in fact. Because this is essentially where we inherited the planet. Nothing was the same after that impact. It became a planet of mammals rather than a planet of dinosaurs.”
Of course, not only dinosaurs were hit by this awesome event, a plethora of animals were wiped out. The fossil find by the KU palaeontologists shows a snapshot of this vibrant ecosystem.
“A tangled mass of freshwater fish, terrestrial vertebrates, trees, branches, logs, marine ammonites and other marine creatures was all packed into this layer by the inland-directed surge,” said DePalma.
“Timing of the incoming ejecta spherules matched the calculated arrival times of seismic waves from the impact, suggesting that the impact could very well have triggered the surge.”
This wasn’t a tsunami that arrived after the impact – but a seismic surge that pushed the waters into chaos.
“A tsunami would have taken at least 17 or more hours to reach the site from the crater, but seismic waves - and a subsequent surge - would have reached it in tens of minutes,” said DePalma.
Just before the surge arrived, the animals in the area had already breathed in the first clouds of dust, ash and debris thrown up by the incredible impact.
“The fish were buried quickly, but not so quickly they didn’t have time to breathe the ejecta that was raining down to the river,” said Burnham.
“These fish weren’t bottom feeders, they breathed these in while swimming in the water column. We’re finding little pieces of ejecta in the gill rakers of these fish, the bony supports for the gills. We don’t know if some were killed by breathing this ejecta, too.”
Unlike most fossilisation, these remains are preserved in three dimensions, a catalogue of many hundreds of ancient fish that show the biodiversity of the region.
“The sedimentation happened so quickly everything is preserved in three dimensions — they’re not crushed,” Burnham said. “It’s like an avalanche that collapses almost like a liquid, then sets like concrete. They were killed pretty suddenly because of the violence of that water. We have one fish that hit a tree and was broken in half.”
The fossil find has not only uncovered new species and given researchers some of their best specimens of known ancient fish, but also offers new opportunities to learn about cataclysmic events like this one.
"As human beings, we descended from a lineage that literally survived in the ashes of what was once the glorious kingdom of the dinosaurs. And we’re the only species on the planet that has ever been capable of learning from such an event to the benefit of ourselves and every other organism in our world,” said DePalma.
This handout shows a tangled mass of articulated fish fossils uncovered in North Dakota at a site believed to date to the day 66 million years ago when an asteroid sruck Earth, killing nearly all life on the planet
This handout shows a tangled mass of articulated fish fossils uncovered in North Dakota at a site believed to date to the day 66 million years ago when an asteroid sruck Earth, killing nearly all life on the planet. (AFP Photo/Robert DePalma)
Washington (AFP) - Scientists in the US say they have discovered the fossilized remains of a mass of creatures that died minutes after a huge asteroid slammed into the Earth 66 million years ago, sealing the fate of the dinosaurs.
In a paper to be published Monday, a team of paleontologists headquartered at the University of Kansas say they found a "mother lode of exquisitely preserved animal and fish fossils" in what is now North Dakota.
The asteroid's impact in what is now Mexico was the most cataclysmic event ever known to befall Earth, eradicating 75 percent of the planet's animal and plant species, extinguishing the dinosaurs and paving the way for the rise of humans.
Researchers believe the impact set off fast-moving, seismic surges that triggered a sudden, massive torrent of water and debris from an arm of an inland sea known as the Western Interior Seaway.
At the Tanis site in North Dakota's Hell Creek Formation, the surge left "a tangled mass of freshwater fish, terrestrial vertebrates, trees, branches, logs, marine ammonites and other marine creatures," according to Robert DePalma, the report's lead author.
Some of the fish fossils were found to have inhaled "ejecta" associated with the Chicxulub event, suggesting seismic surges reached North Dakota within "tens of minutes," he said.
"The sedimentation happened so quickly everything is preserved in three dimensions -- they're not crushed," said co-author David Burnham.
"It's like an avalanche that collapses almost like a liquid, then sets like concrete. They were killed pretty suddenly because of the violence of that water. We have one fish that hit a tree and was broken in half."
The fossils at Tanis include what were believed to be several newly identified fish species, and others that were "the best examples of their kind," said DePalma, a graduate student and curator of the Palm Beach Museum of Natural History in Florida.
"We look at moment-by-moment records of one of the most notable impact events in Earth's history. No other site has a record quite like that," he said.
"And this particular event is tied directly to all of us -- to every mammal on Earth, in fact. Because this is essentially where we inherited the planet. Nothing was the same after that impact. It became a planet of mammals rather than a planet of dinosaurs."
The paper is to be published in the Proceedings of the Academy of Natural Sciences.
Washington • New research released Friday captures a fossilized snapshot of the day nearly 66 million years ago when an asteroid smacked Earth, fire rained from the sky and the ground shook far worse than any modern earthquake.
The researchers say they found evidence in North Dakota of the asteroid hit in Mexico, including fish with hot glass in their gills from flaming debris that showered back down on Earth. They also reported the discovery of charred trees, evidence of an inland tsunami and melted amber.
Separately, University of Amsterdam's Jan Smit disclosed that he and his colleagues even found dinosaur footsteps from just before their demise.
Smit said the footprints — one from a plant-eating hadrosaur and the other of a meat eater, maybe a small Tyrannosaurus Rex — is "definite proof that the dinosaurs were alive and kicking at the time of impact ... They were running around, chasing each other" when they were swamped.
"This is the death blow preserved at one particular site. This is just spectacular," said Purdue University geophysicist and impact expert Jay Melosh, who wasn't part of the research but edited the paper released Friday by the journal Proceedings of the National Academy of Sciences .
Melosh called it the field's "discovery of the century." But other experts said that while some of the work is fascinating, they have some serious concerns about the research, including the lack of access to this specific Hell Creek Formation fossil site for outside scientists. Hell Creek — which spans Montana, both Dakotas and Wyoming — is a fossil treasure trove that includes numerous types of dinosaurs, mammals, reptiles and fish trapped in clay and stone from 65 to 70 million years ago.
Kirk Johnson , director of the Smithsonian National Museum of Natural History who also has studied the Hell Creek area for 38 years, said that the work on the fish, the glass and trees "demonstrates some of the details of what happened on THE DAY. That's all quite interesting and very valid stuff." But Johnson said that because there is restricted access to the site, other scientists can't confirm the research. Smit said the restrictions were to protect the site from poachers.
Johnson also raised concerns about claims made by the main author, Robert DePalma, a University of Kansas doctoral student, that appeared in a New Yorker magazine article published Friday but not in the scientific paper. DePalma did not return an email or phone message seeking comment.
For decades, the massive asteroid crash that caused the Chicxulub crater in Mexico's Yucatan Peninsula has been considered the likely cause of the mass extinction often called the "KT boundary" for the division between two geologic time periods. But some scientists have insisted that massive volcanic activity played a role. Johnson and Melosh said this helps prove the asteroid crash case.
There were only a few dinosaur fossils from that time, but the footsteps are most convincing, Smit said.
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There was more than dinosaurs, he said. The site includes ant nests, wasp nests, fragile preserved leaves and fish that were caught in the act of dying. He said that soon after fish die they get swollen bellies and these fossils didn't show swelling.
The researchers said the inland tsunami points to a massive earthquake generated by the asteroid crash, somewhere between a magnitude 10 and 11. That's more than 350 times stronger than the 1906 San Francisco earthquake.
Purdue's Melosh said as he read the study, he kept saying "wow, wow, what a discovery."
The details coming out of this are "mind-blowing," he said.
Plaster cast of a Tanis deposit fossil showing a freshwater fish (dark brown) next to a marine ammonite (iridescence at top left).Photo: DePalma et al (PNAS 2019)
At one of the most important ancient graveyards on Earth in North Dakota, paleontologists unearthed the fossilized remains of fish seemingly killed by the effects of the asteroid that ended the Cretaceous.
We know that a large asteroid struck the Earth 66 million years ago, and around the same time, the dinosaurs went extinct. We’re not completely sure whether the asteroid was solely responsible for the mass extinction, but you might ask, “Shouldn’t we see remnants of animals killed by the asteroid’s effects?” Well, now we have found some.
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“This is the last day of the Cretaceous,” David Burnham, professor in the Department of Geology at the University of Kansas and one of the study’s authors, told Gizmodo.
When a giant meteorite strikes, you’d expect chaotic effects, like rocks altered by the impact’s high pressures and temperatures, enormous earthquakes, and tsunamis. But Earth’s rocks don’t directly preserve single days of the planet’s several billion-year-old history. You’ve got to get creative when it comes to teasing apart the geologic record. For example, around the world, layers of rock 66 million years old seem to contain excess iridium, presumably deposited by the Chicxulub impactor that struck near what is today the Yucatán Peninsula of Mexico. Then there are tektites, small, glassy spheres of compressed and heated rock. Theoretically, there should also be fossilized evidence of animals killed by the asteroid’s effects.
The Tanis formationScreenshot: DePalma et al (PNAS)
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This is what makes the new research, led by Robert DePalma at the University of Kansas, so exciting—the description of a pair of sediment laters at the Tanis site of the The Hell Creek Formation in southwestern North Dakota. Both layers contain an excess of iridium, but only the lower level contains glass pieces that seemed to have been deposited from an inland-moving force. They take this to mean that they’re observing two events: The upper layer is the settling dust from after the impact. The lower is a large deposit of sediment from the hours following the impact.
But if the rocks alone don’t convince you, perhaps the fossils in the event deposit will. A large swath of ocean traveled up the interior of the United States during the Cretaceous, terminating not far from the Tanis region. But the rocks at Tanis preserve a mixture of both freshwater fish, like paddlefish and sturgeon, and marine mollusks called ammonites—implying that around this time, the ocean had mixed with freshwater rivers. And lodged inside the fossilized paddlefish’s gills were more of the glass spherules. It appeared that wave containing shocked glass from the impact over 3,050 kilometers (1,895 miles) away had inundated the area, and in their dying breaths, the fish had inhaled some of them.
X-ray image showing spherules embedded in a paddlefish gill.Image: DePalma et al (PNAS)
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Other researchers were impressed by the work. “When I first read it, I kept saying ‘wow, wow, wow,’” H. Jay Melosh, distinguished professor of Earth, atmospheric, and planetary science at Purdue University, told Gizmodo. “I think this is one of the most spectacular paleontological discoveries of the century. It’s a snapshot of the moment at which major deaths were occurring right after the impact.”
The researchers point out that there are other scenarios that might have brought the glass particles up to Tanis. Maybe there were meteorological events like gale-force winds, or landslides, the authors write in the paper, published in PNAS.
But the observations have far-reaching implications. The authors write:
“Observations at Tanis expand our knowledge of the Chicxulub impact’s damaging effects and their far-reaching scope. The highly probable link between impact-induced seismic shaking and the onshore inundation surge at Tanis reveals an important additional mechanism by which the Chicxulub impact could have caused catastrophic conditions in the Western Interior, and possibly worldwide, far from the impact site.
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It’s amazing to imagine how abruptly life on Earth changed in the hours and days after the Chicxulub asteroid hit. And it’s equally amazing that we could find direct evidence from that time locked away in the remains of the creatures who experienced it.
NASA has created the perfect job for anyone who really enjoys staying in bed all day, as long as they don't mind continuing to do just that for 60 days without a break.
The study hopes to figure out what effective countermeasures there are against bone and muscle atrophy when humans are placed in a weightless environment and how artificial gravity can have a positive impact. This is important for the astronauts who will eventually spend extended periods of time in space beyond the limited stays currently experienced aboard the International Space Station.
As part of the study, 12 male and 12 female volunteers will spend 60 days in bed in the :envihab facility at the DLR Institute of Aerospace Medicine in Cologne. Their full stay will actually be 89 days, with the remaining 19 days used as pre-test and recovery periods. In return for their time, each volunteer will receive $19,000 in compensation.
More From PCmag
While that may sound like easy money to make, the test is sure to be quite stressful and potentially unpleasant. As DLR explains, "All experiments, meals, and leisure pursuits will take place lying down during the bed-rest phase. The participants will be restricted in their movements, so that the strain on muscles, tendons and the skeletal system is reduced. The beds are angled downwards towards the head end by six degrees. This will simulate the displacement of bodily fluids experienced by astronauts in a microgravity environment."
According to Leticia Vega, Associate Chief Scientist for International Collaborations for NASA's Human Research Program, the restrictions placed on the volunteers produce effects that are "similar to what astronauts experience in space," which can then be combined with what's known from studying humans in the weightless environment aboard ISS.
File photos - Kangaroo rat in mid-jump/A poisonous neotropical rattlesnake (Crotalus simus)
(Photo by Loomis Dean/The LIFE Picture Collection/Getty Images/YURI CORTEZ/AFP/Getty Images)
Even Jackie Chan would be jealous of this kick.
A remarkable video has captured a kangaroo rat in Yuma, Az. leaping high into the air and kicking a rattlesnake in its face after the snake attempted to strike at the rat.
Timothy Higham, an associate professor in the Department of Evolution, Ecology and Organismal Biology at UC Riverside published two papers that can be found here and here on the incredible athleticism and behaviors of both species, describing both as "extreme athletes."
"Both rattlesnakes and kangaroo rats are extreme athletes, with their maximum performance occurring during these interactions," Higham said in a statement. "This makes the system excellent for teasing apart the factors that might tip the scale in this arms race."
"We found that kangaroo rats escaping from snake strikes relied on rapid response times to initiate effective evasions," one of the study's abstract reads. "During jumps, their enlarged hindlimbs propelled vertical leaps that were multiple body lengths into the air, and these leaps were often accompanied by mid-air kicks and other maneuvers that deterred snakes."
For kangaroo rats, who generally eat seeds, these attacks are commonplace, but the tracking of the encounters by the researchers revealed that the two are evenly matched and show for the first time ever the defensive maneuvers the kangaroo rats use.
"These lightning-fast and powerful maneuvers, especially when executed in nature, tell us about the effective strategies for escaping high-performing predators," Higham continued. "Those that are successful at evading the strike will suggest ways in which the kangaroo rat might be evolving in response to the intricacies of the predatory movements."
The "lightning-fast" description Higham provided might be considered hyperbole by some, but it is accurate. The researchers found that the snakes on average reached their prey in less than 100 milliseconds, but the rats were significantly faster, reacting in as little as 38 milliseconds and jumping clear of the snakes in 70 milliseconds, according to the researchers.
A typical bolt of lightning bolt moves at 224,000 mph, or roughly 3,700 miles per second. The speed of an average blink of a human eye is between 300 and 400 milliseconds and be as little as 150 milliseconds, according to the statement.
Timothy Higham is an associate professor at UC Riverside. (Credit: I. Pittalwala, UC Riverside)
Although the kangaroo rats are mind-bogglingly quick, some of them did not react quick enough to avoid the strikes, Rulon Clark, an associate professor of biology at San Diego State University and a coauthor on both research papers, added.
However, they had another trick to avoiding the danger: "they often were able to avoid being envenomated by reorienting themselves in mid-air and using their massive haunches and feet to kick the snakes away, ninja-style," Clark said.
Image of the Galactic Centre. Credit: European Southern Observatory (ESO).
The GRAVITY Collaboration, a team of researchers at several renowned institutes including the Max Planck Institute, LESIA Paris Observatory and the European Southern Observatory, has recently tested part of the Einstein Equivalence Principle, namely the local positon invariance (LPI), near the galactic center supermassive black hole. Their study, published on Physics Review Letters (PRL), investigated the dependency of different atomic transitions on the gravitational potential in order to give an upper limit on LPI violations.
"General relativity and in general all metric theories of gravity are based on the equivalence of inertial mass and gravitational mass, formalized in the Einstein equivalence principle," Maryam Habibi, one of the researchers who carried out the study, told Phys.org. "General relativity is the best theory of gravity that we have, however, there are still many unanswered puzzles that are closely tied to our incomplete understanding of gravity."
The equivalence principle, a crucial part of Einstein's general relativity theory, states that the gravitational force experienced in any small region of space-time is the same as the pseudo-force experienced by an observer in an accelerated frame of reference. Testing this principle is of key importance, as it could lead to interesting observations and broaden our current understanding of gravity.
"Einstein's equivalence principle consists of three main principles," Habibi explained. "One of them, called the local position invariance (LPI), states that non-gravitational measurements should be independent of the location in space time (characterized by gravitational potential) where they are carried out. The main part of our study focuses on testing the LPI principle."
Past observations suggest that most, if not all, massive galaxies contain a supermassive black hole, which is typically located at the center of a galaxy. The mass of the Milky Way's galactic center supermassive black hole is 4 million times greater than that of the sun. It thus generates the strongest gravitational field in the galaxy, which makes it the ideal place to hunt for unexplored phenomena and test general relativity principles.
Star S2, one of the brightest stars in the Milky Way's innermost region, has its closest encounter with the galactic center supermassive black hole at a distance of 16.3 light hours. In other words, the star takes 16 years to make a complete orbit around the black hole, which in astronomical time scales is extremely short. S2 moves in and out of the black hole's gravitational field, hence the GRAVITY collaboration team decided to use it to test part of Einstein's equivalence principle.
"As it was predicted, and we showed in a previous study published in June 2018, during the closest approach of the star S2 to the black hole we observe the 'gravitational redshift' in the light of the star," Habibi explained. "Gravitational redshift occurs because intense gravity on the star's surface slows the vibration of light waves, stretching them and making the star appear redder than normal from Earth."
To test Einstein's LPI principle, the researchers used two different types of atoms in S2's stellar atmosphere: hydrogen and helium atoms. The LPI principle states that the gravitational redshift seen in a star that is flying in and out of a strong gravitational field only depends on the gravitational potential and does not rely on other parameters, such as the internal structure of the atom.
Image shows one of the Unit Telescopes of ESO’s Very Large Telescope (VLT) array, pointing a laser beam towards the Milky Way to create an artificial star. Credit: European Southern Observatory (ESO).
"We measured the frequency change of light from these atoms moving through a varying potential," Habibi said. "The vibration of light waves was measured by fitting the line-of-sight velocity of the S2's spectrum using the Hydrogen and Helium spectral lines separately. By measuring the difference in frequency change for both atoms we were able to give an upper limit on the LPI violation during the pericenter passage. If there was an obvious violation of LPI, we should have measured very different vibration of light waves, from the helium and hydrogen lines."
The equivalence principle and general relativity at large are merely theories, thus they need to be tested in order to ascertain their validity. So far, most researchers have carried out tests on Earth and in the solar system.
However, these theories should also be tested in extreme scenarios, as this can determine whether they still hold and lead to more conclusive evidence. Such tests could rule out some of the principles that shape our current understanding of gravity or identify violations from the theory of general relativity.
"Testing the equivalence principle in all different regimes is important as several alternative theories of gravitation predict a violation from it under extreme conditions," Felix Widmann, another researcher involved in the study, told Phys.org. "For me the most meaningful finding of our study is that we were able to test the equivalence principle in this most extreme case: close to a supermassive black hole that is over 20 thousand light years away. The limits we put on a violation are not very restrictive yet, but they are in a gravitational regime that was completely untested before."
Habibi, Widmann and their colleagues were among the first to test part of the equivalence principle near the Milky Way's central supermassive black hole. Their work provides valuable insight about the validity of general relativity, particularly the LPI principle.
"The past year was exceptionally successful for the GRAVITY collaboration," Widmann said. "For the first time, we observed relativistic effects in the orbit of a star around a supermassive black hole and used this star to test the Equivalence Principle. We also observed material orbiting very close to the black hole, another observation which would have been impossible without GRAVITY. However, this is more of a start than an end for us."
With the optimal season for galactic center observation just around the corner, the researchers at GRAVITY collaboration will continue to point their telescopes to S2 and the galactic center supermassive black hole. According to Widmann, the team might soon be able to detect subtler relativistic effects in the orbit of S2, which will allow them to test the theory of general relativity once again. In their future observations, the researchers also hope that they will see more flare activity around the black hole, as this would enable further studies aimed at broadening their understanding of the Milky Way's galactic center black hole and black holes in general.
"With future telescopes like the Extremely Large Telescope, which has a mirror of 39m in diameter, we will be able to perform similar experiments and look for 1 million times smaller effects of possible violations of LPI, compared to what it is possible today," Widmann added. "This will allow us to test the other part of Einstein's equivalence principle, called weak equivalence principle, which states that an object in gravitational free fall is physically equivalent to an object that is accelerating with the same amount of force in the absence of gravity. The galactic center is a unique observatory and with GRAVITY and future telescopes we want to learn as much about it as possible."
More information:
A. Amorim et al. Test of the Einstein Equivalence Principle near the Galactic Center Supermassive Black Hole, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.101102
Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole, Astronomy & Astrophysics (2018). DOI: 10.1051/0004-6361/201833718
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Testing Einstein's equivalence principle near a supermassive black hole (2019, March 29)
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After NASA canceled the first all-female spacewalk in history due to a lack of spacesuits small enough to fit the average woman, Clinton chimed in with her advice. "Make another suit," she tweeted on Tuesday (March 26).
Clinton has long advocated for gender equality and the empowerment of women, and she almost became the first female president of the United States, when she narrowly lost the 2016 election. So, it should come as no surprise that she's still advocating for equal treatment of women in her post-election life. But NASA won't be taking Clinton's advice to "make another suit" in order to hit this big milestone for women in space, because the situation is unfortunately not that simple.
Make another suit. https://t.co/mu9w13xsi0March 26, 2019
For one, building another spacesuit in orbit would take about 12 hours of crew labor, NASA spokesperson Stephanie Schierholz told Space.com. "Given the very busy operational schedule onboard the station this spring — the spacewalks as well as several resupply missions that will begin arriving in April — the teams made the decision to keep the schedule by swapping spacewalkers rather than reconfiguring a spacesuit," she said.
But why didn't NASA have two of the right-size suits available to begin with, knowing that two women would be taking a spacewalk together? If the agency had all the parts in space already, why didn't it plan to use them? While many have speculated that NASA failed to sufficiently plan for its own spacewalk, a point that remains debatable, it's important to note that NASA made the decision to substitute one of the female spacewalkers with one of her male counterparts after she herself made that request.
This decision was based on my recommendation. Leaders must make tough calls, and I am fortunate to work with a team who trusts my judgement. We must never accept a risk that can instead be mitigated. Safety of the crew and execution of the mission come first. https://t.co/VU9QNaHHlKMarch 27, 2019
When NASA astronaut Anne McClain was training for her spacewalks on Earth, she was able to perform all of her tasks in both the medium and large spacesuits. Meanwhile, NASA astronaut Christina Koch, who was originally supposed to be McClain's spacewalking partner this Friday, has always worn a medium, Schierholz said. Medium is the smallest suit that NASA offers, and it's usually the size that women wear during spacewalks. McClain just so happened to be in between sizes, and she felt she could wear either one.
To prepare three spacewalks (scheduled for March 22, March 29 and April 29), the Expedition 59 crew put together two suits, officially known as extravehicular mobility units (EMUs), to be worn by the pairs of spacewalkers. One is a size medium, and the other is a large.
McClain wore both sizes of suits not only during her training on Earth, but also on the space station for fit checks, tailoring them to account for the way her body had changed in microgravity. For example, earlier this month she reported that she had grown 2 inches (5 centimeters) in space. Astronauts often grow taller in space because their spines relax and elongate elongate when not exposed to Earth's gravitational pull.
After McClain finished her first spacewalk last week, she decided that she did not want to try wearing the large suit for her second spacewalk. Even though she fit the large while training on Earth and then grew even taller while in space, she felt that the larger suit would be less comfortable and more difficult to work in, thereby adding even more risk to an already-risky job, Schierholz said. Instead, McClain will be replaced by NASA astronaut Nick Hague, who wore the large suit during last week's spacewalk.
It's true that NASA's 40-year-old spacesuits were built to fit the "average" astronaut at the time — in other words, the average male astronaut, considering the lack of women who had traveled to space back then. NASA has also long been plagued by gender inequality, much like most institutions in this country. But the fact that McClain will not be joining Koch for the first all-female spacewalk has less to do with gender bias and more to do with an astronaut's personal preferences — a decision that NASA argues it could not have foreseen.
Today, Christina Koch and Anne McClain were scheduled to perform the first all-female spacewalk together on the ISS. NASA cancelled the plan last minute though, due to a lack of spacesuits of the right sizes, replacing Ms McClain with Nick Hague, in a move that has sparked controversy. After the event, a number of conspiracy theories have emerged surrounding the ISS Spacewalk mission.
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Eagled-eyed viewers watching the live stream noticed something bizarre floating around behind Mr Hague as he worked on the space station.
It was quickly shared online by popular conspiracy channel Secureteam10, where presenter Tyler Glockner wildly claimed he thought it could be a UFO.
He said: “This is yet another example of NASA cutting the live feed after a UFO was spotted while one of the astronauts is out doing their spacewalk.
“You’ll notice for the good portion of the video there is no UFO.
The strange object hurtled past the ISS (Image: YOUTUBE)
The astronaut was working on the ISS (Image: YOUTUBE)
This is yet another example of NASA cutting the live feed after a UFO was spotted
Tyler Glockner
“The UFO appears just above the Earth’s horizon line and I want you guys to notice that, up until the UFO appears, the video feed is pretty stable.
“I want you guys to watch here, right as the UFO appears you’ll notice the live feed get more and moe interference until they finally decide to cut it.”
He went on to reveal how the live feed was then cut, claiming the astronaut was not aware a UFO had come into shot.
He added: “Here’s the point the UFO actually comes into view and you’ll notice the interference ramping up.
“Then finally the feed cuts.
The camera panned roung behind the astronaut (Image: YOUTUBE)
A strange anomaly appeared in the background (Image: YOUTUBE)
“Oddly enough, it incidentally happens right as the UFO comes in to view.
“Either the astronaut doesn’t see it, or there is a delay in communication, so they just cut the feed.”
Bizarrely, this incident is not the first of its kind.
A similar incident occured during the Soyuz mission (Image: GETTY)
During a pass-by of Chicago, two bright objects were seen flying across the screen, which appeared to startle the flight controller back at Mission Control in Houston.
He said: “Atlantis is approaching sunrise as it passes the Great Lakes area.
“There’s a, there’s a view of Chicago and some, uh, ice crystals, or other items being illuminated by the rising sun.
“Atlantis now moving into the sunrise, in just about the next minute or so.
“As that occurs ice crystals that come off the shuttle becomes illuminated."
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The bizarre event left conspiracy theorists, including Jeff Challender, convinced NASA had just captured something they should not have.
During Amazon Prime’s “Secret Space”, he revealed his view on how the event went down.
He said in 2017: “Just as the shuttle was passing over Chicago, two unusual objects were seen flying below.
“The first object appeared smaller and further away, but the second was very bright and moved at speed.
“Mission Control tried to zoom in and follow its progress until it was out of sight.
Mission Control were also baffled by an anomaly (Image: AMAZON PRIME)
The ISS is a low-Earth orbit satellite (Image: GETTY)
“Or perhaps they realised that the video goes out to the public.”
Mr Challender then went on to reveal why he believed the anomalies were not ice crystals.
He added: “The anomalies are not ice crystals sparkling in the sun.
“The announcer even said the sun will rise in a few minutes, this proves the objects were self-luminous.
“Good one, ice in the rising sun when the sun hasn’t even risen yet.”
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