3 Areas Where the Most Dinosaur Bones Have Been Found
It’s hard even to fathom what it was like when dinosaurs were the chief inhabitants of the world. Fossils, of course, bring us a connection to these times, and they provide scientists with a way to theorize about what the world was like. If you nerd out about fossils and dinosaurs like we do, read on to learn about the three places where the most dinosaur bones have been found.
While humans find dinosaur bones all over the world, there certainly are hot spots where a higher density of these ancient treasures reside. North America is one of them. The different kinds of fossils are as numerous as you can imagine. But here are some examples of fossils in North America and where you can go to see them for yourself.
The Precambrian Period is the first period we recognize, and there are plenty of Precambrian fossils in North America, according to the Smithsonian. This era of Earth’s history involved a lot of microorganisms, algae, and soft-bodied species such as worms and jellyfish. A great place to see Precambrian fossils in the U.S. is at the Grand Canyon. There you can see algae fossils that are over one billion years old. Glacier National Park in Montana also has fossilized evidence of cyanobacteria dating back 1.5 billion years, as well as stromatolites.
Ancient multi-celled organisms are cool, but you might be wondering where you can see some actual dinosaur bones. Guadalupe Mountains National Park in Texas is a great place to see fish-like fossils and the predecessors to snails from the Permian Period. From the age of mammals — the Cenozoic period — you can spot ancient crocodiles and an animal similar to our modern-day hyenas at the John Day Fossil Beds in Oregon. And the Florissant Fossil Beds in Colorado have one of the most diverse displays in all the world. There, you can find a prehistoric rhinoceros and the first-ever discovered fossilized butterfly.
The vast collection of fossils found in Argentina is one of the country’s claims to fame. One example is Saltasaurus Loricatus, a small sauropod from the Late Cretaceous Period. This discovery, made in 1980, was a big deal in the world of paleontology because it was the first evidence of hard bone plates on the back. These plates operated like an armor of sorts. This dinosaur was an herbivore that was about 12 meters long. Scientists propose it could stand on its hind legs to eat leaves higher up in the trees.
Other treasures from Argentina include the fossils of Noasaurus Leali. This dinosaur looked like a small velociraptor similar to the ones found in North American and China, although it’s an entirely different species. It had sharp talons and teeth — which are definitely the characteristics of a carnivore. A rancher discovered these bones in San Juan in 1958, in what is now known as the Ischigualasto Formation.
For those wanting to travel to Argentina and see fossils for themselves, the Ischigualasto Formation is a great place to start. It’s now a regional park, and visitors can see the fossils still in the ground. Argentinians have also done a great job of providing fossil experiences in a museum setting that still feels authentic. One example is the Ernesto Bachmann Dinosaur Museum in El Chocón. This museum has replicas of fossils as they were found in the ground. They also have tools used by paleontologists on display so visitors can see what archaeological digs are like. There are other museums and parks in Argentina, as well, that educate visitors about the impressive fossils found in this country.
China is a massive country, and there have been fantastic fossil finds throughout the land. One of these places is the Qingjiang River, where paleontologists have found evidence of 101 different species along the river banks, and over half of those were new to science. The site was first discovered in 2007, but paleontologists have been busy exploring it ever since. They’ve found species as old as the first animals in the Cambrian Period. Chinese paleontologists and scientists around the globe are hoping Qingjiang will become a UNESCO World Heritage Site to protect these incredible findings.
A fossil hotspot in China that is already a UNESCO World Heritage Site is the Chengjiang Fossil Site. Chengjiang is located in the Yunnan Province and also has a vast collection of Cambrian Fossils. While there were many mining operations near the site, they’ve been shut down. The sites are starting to be rehabilitated so that further fossil records don’t get destroyed.
The Inner Mongolian Autonomous Region is another place in China rich with fossils. It’s even known as “Dinosaur Town,” and it has an abundance of Ankylosaurus and Ceratopsian fossils. Something unique about these fossils is that there’s evidence of all ages of creatures, from newborns to mature adults. Scientists in China are constantly discovering new fossil areas that are in urgent need of excavation.
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Now you can do just that by looking through a host of science data newly made available to the public. That information was gathered by NASA’s Parker Solar Probe during its first two close passes of the sun. The flybys brought the spacecraft closer to the sun than any previous vehicle had gone, offering scientists an incredible opportunity to learn more about our star.
“Parker Solar Probe is crossing new frontiers of space exploration, giving us so much new information about the sun,” Nour E. Raouafi, Parker Solar Probe project scientist at the Johns Hopkins University Applied Physics Laboratory, said in a statement. “Releasing this data to the public will allow them not only to contribute to the success of the mission along with the scientific community, but also to raise the opportunity for new discoveries to the next level.”
Parker Solar Probe launched in August 2018 for a seven-year mission that is targeting the constant stream of highly charged plasma leaving the sun, called the solar wind, and the star’s outer atmosphere, called the corona. Studying these phenomena requires getting incredibly close to the sun; the spacecraft primarily gathers data while within about 23 million miles (37 million kilometers) of our star.
Onboard are four science experiments: Fields Experiment, which studies electric and magnetic fields; Integrated Science Investigation of the Sun, which measures high-energy charged particles in the solar wind and corona; Wide-Field Imager for Solar Probe, which images the solar wind and other structures; and Solar Wind Electrons Alphas and Protons Investigation, which measures different types of particles in the solar wind.
Data gathered by a Parker Solar Probe instrument, the Wide-Field Imager for Solar Probe, in November 2018, during the spacecraft’s first solar flyby.
(Image credit: NASA/Naval Research Laboratory/Parker Solar Probe)
And now, you too can pore through data gathered by those instruments during the first two flybys: Oct. 31-Nov. 12, 2018, and March 30-April 19, 2019. During the second flyby, mission engineers were able to increase the amount of data the spacecraft sent home, thanks to better data-return rates than expected. There is no central hub for the data, but NASA has provided a list of websites to explore.
According to the same NASA statement, the first full-fledged science results from the mission should be published later this year.
Parker Solar Probe has also already made its third flyby of the sun; the spacecraft’s next closest approach is on Jan. 29, 2020.
International team detected radio bubbles with South Africa’s MeerKAT telescope.
A gigantic, balloon-like structure has been hiding in plain sight, right in the center of our own galaxy.
An international team of astronomers, including Northwestern’s Farhad Yusef-Zadeh, discovered the structure, which is one of the largest ever observed in the Milky Way’s center. The newly spotted pair of radio-emitting bubbles reach hundreds of light-years tall, dwarfing all other structures in the central region of the galaxy.
The team believes the enormous, hourglass-shaped structure likely is the result of a phenomenally energetic burst that erupted near the Milky Way’s super massive black hole several million years ago.
“The center of our galaxy is relatively calm when compared to other galaxies with very active central black holes,” said Ian Heywood of the University of Oxford, first author of study. “Even so, the Milky Way’s central black hole can — from time to time — become uncharacteristically active, flaring up as it periodically devours massive clumps of dust and gas. It’s possible that one such feeding frenzy triggered powerful outbursts that inflated this previously unseen feature.”
Why couldn’t we see such a massive figure before? We simply did not have the technology. Until now, the enormous bubbles were hidden by extremely bright radio emissions from the center of the galaxy. For this work, the team used the South African Radio Astronomy Observatory (SARAO) MeerKAT telescope, the largest science project in Africa. The radio light seen by MeerKAT can easily penetrate the dense clouds of dust that block visible light from the center of the galaxy.
This is the first paper detailing research completed with MeerKAT’s full 64-dish array since its launch in July 2018.
More turbulent and unusually active compared to rest of the Milky Way, the environment surrounding our galaxy’s central black hole holds many mysteries. Northwestern’s Yusef-Zadeh, a senior author of the paper, has dedicated his career to studying the physical processes that occur in the Milky Way’s mystifying center.
In the early 1980s, Yusef-Zadeh discovered large-scale, highly organized magnetic filaments in the center of the Milky Way, 25,000 light-years from Earth. While their origin has remained an unsolved mystery ever since, the filaments are radio structures stretching tens of light-years long and one light-year wide.
“The radio bubbles discovered with MeerKAT now shed light on the origin of the filaments,” Yusef-Zadeh said. “Almost all of the more than 100 filaments are confined by the radio bubbles.”
Researchers believe the close association of the filaments with the bubbles implies that the energetic event that created the radio bubbles also is responsible for accelerating the electrons required to produce the radio emission from the magnetized filaments.
The team of astronomers on this project represents 15 institutions, including Northwestern, Oxford, the South African Radio Astronomy Observatory in Cape Town and the National Radio Astronomy Observatory in Virginia.
Reference: “Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event” by I. Heywood, F. Camilo, W. D. Cotton, F. Yusef-Zadeh, T. D. Abbott, R. M. Adam, M. A. Aldera, E. F. Bauermeister, R. S. Booth, A. G. Botha, D. H. Botha, L. R. S. Brederode, Z. B. Brits, S. J. Buchner, J. P. Burger, J. M. Chalmers, T. Cheetham, D. de Villiers, M. A. Dikgale-Mahlakoana, L. J. du Toit, S. W. P. Esterhuyse, B. L. Fanaroff, A. R. Foley, D. J. Fourie, R. R. G. Gamatham, S. Goedhart, S. Gounden, M. J. Hlakola, C. J. Hoek, A. Hokwana, D. M. Horn, J. M. G. Horrell, B. Hugo, A. R. Isaacson, J. L. Jonas, J. D. B. L. Jordaan, A. F. Joubert, G. I. G. Józsa, R. P. M. Julie, F. B. Kapp, J. S. Kenyon, P. P. A. Kotzé, H. Kriel, T. W. Kusel, R. Lehmensiek, D. Liebenberg, A. Loots, R. T. Lord, B. M. Lunsky, P. S. Macfarlane, L. G. Magnus, C. M. Magozore, O. Mahgoub, J. P. L. Main, J. A. Malan, R. D. Malgas, J. R. Manley, M. D. J. Maree, B. Merry, R. Millenaar, N. Mnyandu, I. P. T. Moeng, T. E. Monama, M. C. Mphego, W. S. New, B. Ngcebetsha, N. Oozeer, A. J. Otto, S. S. Passmoor, A. A. Patel, A. Peens-Hough, S. J. Perkins, S. M. Ratcliffe, R. Renil, A. Rust, S. Salie, L. C. Schwardt, M. Serylak, R. Siebrits, S. K. Sirothia, O. M. Smirnov, L. Sofeya, P. S. Swart, C. Tasse, D. T. Taylor, I. P. Theron, K. Thorat, A. J. Tiplady, S. Tshongweni, T. J. van Balla, A. van der Byl, C. van der Merwe, C. L. van Dyk, R. Van Rooyen, V. Van Tonder, R. Van Wyk, B. H. Wallace, M. G. Welz and L. P. Williams, 11 September 2019, Nature.
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Growing up in Israel, Gili Greenbaum would give tours of local caves once inhabited by Neanderthals and wonder along with others why our distant cousins abruptly disappeared about 40,000 years ago. Now a scientist at Stanford, Greenbaum thinks he has an answer.
In a new study published in the journal Nature Communications, Greenbaum and his colleagues propose that complex disease transmission patterns can explain not only how modern humans were able to wipe out Neanderthals in Europe and Asia in just a few thousand years but also, perhaps more puzzling, why the end didn’t come sooner.
“Our research suggests that diseases may have played a more important role in the extinction of the Neanderthals than previously thought. They may even be the main reason why modern humans are now the only human group left on the planet,” said Greenbaum, who is the first author of the study and a postdoctoral researcher in Stanford’s Department of Biology.
The slow kill
Archeological evidence suggests that the initial encounter between Eurasian Neanderthals and an upstart new human species that recently strayed out of Africa—our ancestors—occurred more than 130,000 years ago in the Eastern Mediterranean in a region known as the Levant.
Yet tens of thousands of years would pass before Neanderthals began disappearing and modern humans expanded beyond the Levant. Why did it take so long?
Employing mathematical models of disease transmission and gene flow, Greenbaum and an international team of collaborators demonstrated how the unique diseases harbored by Neanderthals and modern humans could have created an invisible disease barrier that discouraged forays into enemy territory. Within this narrow contact zone, which was centered in the Levant where first contact took place, Neanderthals and modern humans coexisted in an uneasy equilibrium that lasted tens of millennia.
Ironically, what may have broken the stalemate and ultimately allowed our ancestors to supplant Neanderthals was the coming together of our two species through interbreeding. The hybrid humans born of these unions may have carried immune-related genes from both species, which would have slowly spread through modern human and Neanderthal populations.
As these protective genes spread, the disease burden or consequences of infection within the two groups gradually lifted. Eventually, a tipping point was reached when modern humans acquired enough immunity that they could venture beyond the Levant and deeper into Neanderthal territory with few health consequences.
At this point, other advantages that modern humans may have had over Neanderthals—such as deadlier weapons or more sophisticated social structures—could have taken on greater importance. “Once a certain threshold is crossed, disease burden no longer plays a role, and other factors can kick in,” Greenbaum said.
To understand why modern humans replaced Neanderthals and not the other way around, the researchers modeled what would happen if the suite of tropical diseases our ancestors harbored were deadlier or more numerous than those carried by Neanderthals.
“The hypothesis is that the disease burden of the tropics was larger than the disease burden in temperate regions. An asymmetry of disease burden in the contact zone might have favored modern humans, who arrived there from the tropics,” said study co-author Noah Rosenberg, the Stanford Professor of Population Genetics and Society in the School of Humanities and Sciences.
According to the models, even small differences in disease burden between the two groups at the outset would grow over time, eventually giving our ancestors the edge. “It could be that by the time modern humans were almost entirely released from the added burden of Neanderthal diseases, Neanderthals were still very much vulnerable to modern human diseases,” Greenbaum said. “Moreover, as modern humans expanded deeper into Eurasia, they would have encountered Neanderthal populations that did not receive any protective immune genes via hybridization.”
The researchers note that the scenario they are proposing is similar to what happened when Europeans arrived in the Americas in the 15th and 16th centuries and decimated indigenous populations with their more potent diseases.
If this new theory about the Neanderthals’ demise is correct, then supporting evidence might be found in the archeological record. “We predict, for example, that Neanderthal and modern human population densities in the Levant during the time period when they coexisted will be lower relative to what they were before and relative to other regions,” Greenbaum said.
More information: Gili Greenbaum et al. Disease transmission and introgression can explain the long-lasting contact zone of modern humans and Neanderthals, Nature Communications (2019). DOI: 10.1038/s41467-019-12862-7
(THIS ARTICLE IS COURTESY OF THE SHANGHAI CHINA NEWS AGENCY ‘SHINE’)
China moon base to aid deep space exploration
00:00 UTC+8, 2019-10-29
China is carrying out in-depth research and long-term planning for its manned lunar exploration, and has formed a consensus and a preliminary plan, a senior space engineer has said.
At the 1st China Space Science Assembly in Xiamen in southeast China’s Fujian Province, from last Friday to on Monday, Chen Shanguang, deputy chief designer of China’s manned space program, said the trend of manned space travel is to explore the moon, establish a lunar base for scientific research, gather technology and experience for going deeper into space.
“The long-term goal is to send people to Mars,” Chen said.
Manned lunar exploration will help improve humans’ understanding of the evolution of the moon, as astronauts may set up facilities to obtain scientific data and samples, Chen said.
Astronauts may carry out multi-disciplinary research in fields such as physics, chemistry, astronomy and geology, and in-situ resource utilization by taking advantage of the characteristics of the moon, such as low gravity, its weak magnetic field and high vacuum. The research could promote innovation and the development of basic science.
Solving the scientific problems of human survival on the moon could lay a foundation for humans to go further into deep space.
Source: Xinhua Editor: Shen Ke
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NASA’s picture features a detailed portrait of the distant galaxy NGC 4380. The spiral body sits nearly 63 million light-years from Earth in the constellation Virgo. The European Space Agency (ESA), which operates Hubble together with NASA, likened the image to a special effect in a Hollywood blockbuster.
ESA said: “In this image taken by Hubble Space Telescope, the galaxy NGC 4380 looks like a special effect straight out of a science fiction or fantasy film, swirling like a gaping portal to another dimension.
“In the grand scheme of things, though, the galaxy is actually quite ordinary.
“Spiral galaxies like NGC 4380 are common in the universe.
“These colossal collections of stars, often numbering in the hundreds of billions, are shaped like a flat disc, sometimes with a rounded bulge in the center.
Picture this. You’re camping with your family and it’s a clear night. As you look up into the night sky, it feels like there are a thousand stars, and they’re bright enough to touch. You feel the impact of how small you are in the grand scheme of things. And then your mind wanders as you try to wrap your head around how big the universe is. If this question has been keeping you up at night, we have the answer.
So, how big is the universe?
There was a time when we couldn’t give you a hard figure. But as far back as 1920, astronomers have been sharing estimates on the size of the known universe. Before we dig into hard figures, best guesses, and even erroneous ones, we need to set some ground rules.
First, the universe is constantly expanding. Any measurements given today won’t be accurate in the future. Likewise, scientists and astronomers can give only measurements based on the observable or known universe. This references what can be seen through their telescope, whether on the ground or with a satellite. Much like the expanding universe factor, dimensions based on the observable universe can be limited.
In other words, based on current research, observations and mathematical equations, the experts can estimate the universe’s size within a fair degree of certainty. But the caveat will always apply that these figures are impacted by the universe’s growth rate and the limitation of the observable universe.
What’s the number?
Slow down there! Another important note is that we aren’t measuring in miles or kilometers like we would the distance between New York and London. Instead, we use light-years when we’re discussing the distance between two bodies in space. Standard forms of measurement would be too impractical because, in space, celestial bodies are very far apart.
Speaking literally, a light-year describes the distance a beam of light can travel in one year. To help you quantify that and realize why light years are better than traditional Earth-distance measurements, one light0year is the equivalent of 6 trillion miles. If you got dizzy just hearing that, now you know why astronomers prefer light-years over miles or kilometers.
Is there an estimate?
Initial size estimates of our universe began with measuring our galaxy, the Milky Way. In 1920 the American astronomer Harlow Shapley was one of the first experts who attempted to measure the Milky Way and came up with a diameter of 300,000 light-years. It turns out he was very wrong, as today most astronomers believe our Milky Way is somewhere between 100,000 and 150,000 light years in diameter.
For perspective, we know that the Milky Way isn’t the only galaxy in our universe — nor is it the biggest. Current counts estimate that there are at least 100 billion galaxies in the known universe and the largest discovered galaxy to date is IC 1101 with a diameter of 6 million light-years (although this figure is contested). So if our little corner of the universe is 100,000 light-years wide, and the biggest galaxy is around 6 million light-years in diameter, that can give you a hint that the known universe is quite large.
Just say how big the universe is!
Current measurements place the observable universe at roughly 93 billion light-years in diameter. There are a variety of methods used to reach this figure, but popular options include measuring radio wavelengths, parallax measurements, main sequence fitting, and cepheid variables. Radio wavelengths are a great option within our solar system because astronomers can measure the time it takes for a radio wave to bounce off the surface of a planet or asteroid and translate that into an actual light-year reading. But for celestial bodies farther out in the universe, it’s not practical.
Beyond our solar system, parallax measurement is preferred as it relies on comparing distances to an object based on measurements from multiple angles. This method relies on telescopes and satellites to compute various distance readings over time and scientists to extrapolate accurate positions from the data. But beyond 100 light-years, even parallax measurement is inefficient.
At great distances, main sequence fitting and cepheid variables are the preferred measurement tools. Main sequence fitting relies on a basic understanding of a star’s brightness and color compared to its age to determine distance. Cepheid variables focus on the actual “twinkle” or pulsating factor to determine age and position.
So what does this all mean?
If we haven’t given you a headache yet, it means that even though astronomers and experts have a great grasp on the general size of the universe, figures can change as our methods for analyzing data improve. And for the average Joe, just know that the universe is huge, and we’re in one little corner of it!
Astronomers have discovered the oldest cluster of galaxies ever seen, which dates to the early universe.
The discovery, which could help explain the shape of the modern cosmos, reveals 12 galaxies that existed in a clump 13 billion years ago — just about 700 million years after the Big Bang. We can see them now because they’re so far away in the expanding universe (13 billion light-years) that their starlight is only now reaching Earth. One of the galaxies, a mammoth named Himiko after a mythological Japanese queen, was discovered a decade ago by the same team.
Surprisingly, the other 11 galaxies aren’t clustered around the giant Himiko, the researchers wrote in a paper that will be published on Sept. 30 in The Astrophysical Journal and is available as a draft on the website arXiv. Instead, Himiko sits at the edge of the system, which the researchers call a “protocluster” because it’s so small and ancient compared to most of the clusters we can see in the universe..
“It is reasonable to find a protocluster near a massive object, such as Himiko. However, we’re surprised to see that Himiko was located not in the center of the protocluster but on the edge, 500 million light-years away from the center,” Masami Ouchi, a co-author of the paper and an astronomer at the National Astronomical Observatory of Japan and the University of Tokyo, said in a statement.
Understanding how galaxy clusters came to be turns out to be important for understanding the galaxies they contain. Most galaxies, including the Milky Way, show up in clumps with other galaxies, so the galaxies aren’t evenly distributed throughout the universe. And that clumping seems to affect their behavior, astronomers have said. Galaxies in high-density, clumped environments full of galaxies form stars in different ways than do galaxies in low-density environments empty of galaxies. And the impact of clumping seems to have changed over time, the researchers said.
In more recent times, the researchers wrote in the paper, “there is a clear trend that the star-formation activity of galaxies tends to be lower in high-density environment than low-density environment.”
So, clumped-up galaxies these days form stars less often than their more independent cousins do. It’s as if they’re aging faster in their clusters, the researchers wrote, becoming geriatric and giving up on making new stars.
But in the ancient universe, the trend seems to have been reversed. Galaxies in highly packed clusters formed stars faster, not slower, remaining young and spry compared with their cousins not in dense clusters.
Still, “protoclusters” like this one from the early eons of the universe are rarely found and are poorly understood, the researchers wrote. These clumps tend to be much smaller than modern examples, which can contain hundreds of galaxies.
The further back telescopes peer into time, the fewer proto-clusters turn up. It’s possible many of them are simply obscured by intergalactic dust. The astronomers hope, they wrote, that the new discovery will help flesh out the picture and explain how the state of things 13 billion years ago changed over time to produce that clustered universe we see today.
So there you are, about to leap into a black hole. What could possibly await should — against all odds — you somehow survive? Where would you end up and what tantalizing tales would you be able to regale if you managed to clamor your way back?
The simple answer to all of these questions is, as Professor Richard Massey explains, “Who knows?” As a Royal Society research fellow at the Institute for Computational Cosmology at Durham University, Massey is fully aware that the mysteries of black holes run deep. “Falling through an event horizon is literally passing beyond the veil — once someone falls past it, nobody could ever send a message back,” he said. “They’d be ripped to pieces by the enormous gravity, so I doubt anyone falling through would get anywhere.”
If that sounds like a disappointing — and painful — answer, then it is to be expected. Ever since Albert Einstein’s general theory of relativity was considered to have predicted black holes by linking space-time with the action of gravity, it has been known that black holes result from the death of a massive star leaving behind a small, dense remnant core. Assuming this core has more than roughly three-times the mass of the sun, gravity would overwhelm to such a degree that it would fall in on itself into a single point, or singularity, understood to be the black hole’s infinitely dense core.
The resulting uninhabitable black hole would have such a powerful gravitational pull that not even light could avoid it. So, should you then find yourself at the event horizon — the point at which light and matter can only pass inward, as proposed by the German astronomer Karl Schwarzschild — there is no escape. According to Massey, tidal forces would reduce your body into strands of atoms (or ‘spaghettification’, as it is also known) and the object would eventually end up crushed at the singularity. The idea that you could pop out somewhere — perhaps at the other side — seems utterly fantastical.
What about a wormhole?
Or is it? Over the years scientists have looked into the possibility that black holes could be wormholes to other galaxies. They may even be, as some have suggested, a path to another universe.
Such an idea has been floating around for some time: Einstein teamed up with Nathan Rosen to theorize bridges that connect two different points in space-time in 1935. But it gained some fresh ground in the 1980’s when physicist Kip Thorne — one of the world’s leading experts on the astrophysical implications of Einstein’s general theory of relativity — raised a discussion about whether objects could physically travel through them.
“Reading Kip Thorne’s popular book about wormholes is what first got me excited about physics as a child,” Massey said. But it doesn’t seem likely that wormholes exist.
Indeed, Thorne, who lent his expert advice to the production team for the Hollywood movie Interstellar, wrote: “We see no objects in our universe that could become wormholes as they age,” in his book “The Science of Interstellar” (W.W. Norton and Company, 2014). Thorne told Space.com that journeys through these theoretical tunnels would most likely remain science fiction, and there is certainly no firm evidence that a black hole could allow for such a passage.
Artist’s concept of a wormhole. If wormholes exist, they might lead to another universe. But, there’s no evidence that wormholes are real or that a black hole would act like one.
(Image credit: Shutterstock)
But, the problem is that we can’t get up close to see for ourselves. Why, we can’t even take photographs of anything that takes place inside a black hole — if light cannot escape their immense gravity, then nothing can be snapped by a camera. As it stands, theory suggests that anything which goes beyond the event horizon is simply added to the black hole and, what’s more, because time distorts close to this boundary, this will appear to take place incredibly slowly, so answers won’t be quickly forthcoming.
“I think the standard story is that they lead to the end of time,” said Douglas Finkbeiner, professor of astronomy and physics at Harvard University. “An observer far away will not see their astronaut friend fall into the black hole. They’ll just get redder and fainter as they approach the event horizon [as a result of gravitational red shift]. But the friend falls right in, to a place beyond ‘forever.’ Whatever that means.”
Maybe a black hole leads to a white hole
Certainly, if black holes do lead to another part of a galaxy or another universe, there would need to be something opposite to them on the other side. Could this be a white hole — a theory put forward by Russian cosmologist Igor Novikov in 1964? Novikov proposed that a black hole links to a white hole that exists in the past. Unlike a black hole, a white hole will allow light and matter to leave, but light and matter will not be able to enter.
Scientists have continued to explore the potential connection between black and white holes. In their 2014 study published in the journal Physical Review D, physicists Carlo Rovelli and Hal M. Haggard claimed that “there is a classic metric satisfying the Einstein equations outside a finite space-time region where matter collapses into a black hole and then emerges from a while hole.” In other words, all of the material black holes have swallowed could be spewed out, and black holes may become white holes when they die.
Far from destroying the information that it absorbs, the collapse of a black hole would be halted. It would instead experience a quantum bounce, allowing information to escape. Should this be the case, it would shed some light on a proposal by former Cambridge University cosmologist and theoretical physicist Stephen Hawking who, in the 1970’s, explored the possibility that black holes emit particles and radiation — thermal heat — as a result of quantum fluctuations.
Red shifting Star Orbiting Super massive Black Hole Demonstrates Einstein Prediction
“Hawking said a black hole doesn’t last forever,” Finkbeiner said. Hawking calculated that the radiation would cause a black hole to lose energy, shrink and disappear, as described in his 1976 paper published in Physical Review D. Given his claims that the radiation emitted would be random and contain no information about what had fallen in, the black hole, upon its explosion, would erase loads of information.
This meant Hawking’s idea was at odds with quantum theory, which says information can’t be destroyed. Physics states information just becomes more difficult to find because, should it become lost, it becomes impossible to know the past or the future. Hawking’s idea led to the ‘black hole information paradox’ and it has long puzzled scientists. Some have said Hawking was simply wrong, and the man himself even declared he had made an error during a scientific conference in Dublin in 2004.
So, do we go back to the concept of black holes emitting preserved information and throwing it back out via a white hole? Maybe. In their 2013 study published in Physical Review Letters, Jorge Pullin at Louisiana State University and Rodolfo Gambini at the University of the Republic in Montevideo, Uruguay, applied loop quantum gravity to a black hole and found that gravity increased towards the core but reduced and plonked whatever was entering into another region of the universe. The results gave extra credence to the idea of black holes serving as a portal. In this study, singularity does not exist, and so it doesn’t form an impenetrable barrier that ends up crushing whatever it encounters. It also means that information doesn’t disappear.
Maybe black holes go nowhere
Yet physicists Ahmed Almheiri, Donald Marolf, Joseph Polchinski and James Sully still believed Hawking could have been on to something. They worked on a theory that became known as the AMPS firewall, or the black hole firewall hypothesis. By their calculations, quantum mechanics could feasibly turn the event horizon into a giant wall of fire and anything coming into contact would burn in an instant. In that sense, black holes lead nowhere because nothing could ever get inside.
This, however, violates Einstein’s general theory of relativity. Someone crossing the event horizon shouldn’t actually feel any great hardship because an object would be in free fall and, based on the equivalence principle, that object — or person — would not feel the extreme effects of gravity. It could follow the laws of physics present elsewhere in the universe, but even if it didn’t go against Einstein’s principle it would undermine quantum field theory or suggest information can be lost.
Artist’s impression of a tidal disruption event which occurs when a star passes too close to a super massive black hole.
(Image credit: All About Space magazine)
A black hole of uncertainty
Step forward Hawking once more. In 2014, he published a study in which he eschewed the existence of an event horizon — meaning there is nothing there to burn — saying gravitational collapse would produce an ‘apparent horizon’ instead.
This horizon would suspend light rays trying to move away from the core of the black hole, and would persist for a “period of time.” In his rethinking, apparent horizons temporarily retain matter and energy before dissolving and releasing them later down the line. This explanation best fits with quantum theory — which says information can’t be destroyed — and, if it was ever proven, it suggests that anything could escape from a black hole.
Hawking went as far as saying black holes may not even exist. “Black holes should be redefined as metastable bound states of the gravitational field,” he wrote. There would be no singularity, and while the apparent field would move inwards due to gravity, it would never reach the center and be consolidated within a dense mass.
And yet anything which is emitted will not be in the form of the information swallowed. It would be impossible to figure out what went in by looking at what is coming out, which causes problems of its own — not least for, say, a human who found themselves in such an alarming position. They’d never feel the same again!
One thing’s for sure, this particular mystery is going to swallow up many more scientific hours for a long time to come. Rovelli and Francesca Vidotto recently suggested that a component of dark matter could be formed by remnants of evaporated black holes, and Hawking’s paper on black holes and ‘soft hair’ was released in 2018, and describes how zero-energy particles are left around the point of no return, the event horizon — an idea that suggests information is not lost but captured.
This flew in the face of the no-hair theorem which was expressed by physicist John Archibald Wheeler and worked on the basis that two black holes would be indistinguishable to an observer because none of the special particle physics pseudo-charges would be conserved. It’s an idea that has got scientists talking, but there is some way to go before it’s seen as the answer for where black holes lead. If only we could find a way to leap into one.
ByCHALMERS UNIVERSITY OF TECHNOLOGYSEPTEMBER 22, 2019
For DNA to be read, replicated or repaired, DNA molecules must open themselves. This happens when the cells use a catalytic protein to create a hydrophobic environment around the molecule. Illustration Credit: Yen Strandqvist/Chalmers University of Technology
Researchers at Chalmers University of Technology, Sweden, disprove the prevailing theory of how DNA binds itself. It is not, as is generally believed, hydrogen bonds which bind together the two sides of the DNA structure. Instead, water is the key. The discovery opens doors for new understanding in research in medicine and life sciences. The researchers’ findings are presented in the journal PNAS.
DNA is constructed of two strands, consisting of sugar molecules and phosphate groups. Between these two strands are nitrogen bases, the compounds which make up organisms’ genes, with hydrogen bonds between them. Until now, it was commonly thought that those hydrogen bonds were what held the two strands together.
But now, researchers from Chalmers University of Technology show that the secret to DNA’s helical structure may be that the molecules have a hydrophobic interior, in an environment consisting mainly of water. The environment is therefore hydrophilic, while the DNA molecules’ nitrogen bases are hydrophobic, pushing away the surrounding water. When hydrophobic units are in a hydrophilic environment, they group together, to minimize their exposure to the water.
The role of the hydrogen bonds, which were previously seen as crucial to holding DNA helixes together, appear to be more to do with sorting the base pairs, so that they link together in the correct sequence.
The discovery is crucial for understanding DNA’s relationship with its environment.
Bobo Feng, Postdoc, Chemistry and Chemical Engineering, Chalmers University of Technology. Credit: Johan Bodell/Chalmers University of Technology
“Cells want to protect their DNA, and not expose it to hydrophobic environments, which can sometimes contain harmful molecules,” says Bobo Feng, one of the researchers behind the study. “But at the same time, the cells’ DNA needs to open up in order to be used.”
“We believe that the cell keeps its DNA in a water solution most of the time, but as soon as a cell wants to do something with its DNA, like read, copy or repair it, it exposes the DNA to a hydrophobic environment.”
Reproduction, for example, involves the base pairs dissolving from one another and opening up. Enzymes then copy both sides of the helix to create new DNA. When it comes to repairing damaged DNA, the damaged areas are subjected to a hydrophobic environment, to be replaced. A catalytic protein creates the hydrophobic environment. This type of protein is central to all DNA repairs, meaning it could be the key to fighting many serious sicknesses.
Understanding these proteins could yield many new insights into how we could, for example, fight resistant bacteria, or potentially even cure cancer. Bacteria use a protein called RecA to repair their DNA, and the researchers believe their results could provide new insight into how this process works – potentially offering methods for stopping it and thereby killing the bacteria.Rad51
In human cells, the protein Rad51 repairs DNA and fixes mutated DNA sequences, which otherwise could lead to cancer.
“To understand cancer, we need to understand how DNA repairs. To understand that, we first need to understand DNA itself,” says Bobo Feng. “So far, we have not, because we believed that hydrogen bonds were what held it together. Now, we have shown that instead it is the hydrophobic forces which lie behind it. We have also shown that DNA behaves totally differently in a hydrophobic environment. This could help us to understand DNA, and how it repairs. Nobody has previously placed DNA in a hydrophobic environment like this and studied how it behaves, so it’s not surprising that nobody has discovered this until now.”
More information on the methods the researchers used to show how DNA binds together:
The researchers studied how DNA behaves in an environment which is more hydrophobic than normal, a method they were the first to experiment with.
They used the hydrophobic solution polyethylene glycol, and step-by-step changed the DNA’s surroundings from the naturally hydrophilic environment to a hydrophobic one. They aimed to discover if there is a limit where DNA starts to lose its structure, when the DNA does not have a reason to bind, because the environment is no longer hydrophilic. The researchers observed that when the solution reached the borderline between hydrophilic and hydrophobic, the DNA molecules’ characteristic spiral form started to unravel.
Upon closer inspection, they observed that when the base pairs split from one another (due to external influence, or simply from random movements), holes are formed in the structure, allowing water to leak in. Because DNA wants to keep its interior dry, it presses together, with the base pairs coming together again to squeeze out the water. In a hydrophobic environment, this water is missing, so the holes stay in place.
Reference: “Hydrophobic catalysis and a potential biological role of DNA unstacking induced by environment effects” by Bobo Feng, Robert P. Sosa, Anna K. F. Mårtensson, Kai Jiang, Alex Tong, Kevin D. Dorfman, Masayuki Takahashi, Per Lincoln, Carlos J. Bustamante, Fredrik Westerlund and Bengt Nordén, 27 August 2019, Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1909122116