A Message From Aliens in Our DNA?
Davies’s research focuses on the “big questions” of existence, ranging from the origin of the universe to the origin of life, and include the nature of time, the search for life in the universe, and foundational questions in quantum mechanics. He helped create the theory of quantum fields in curved spacetime, with which he provided explanations for how black holes can radiate energy, and what caused the ripples in the cosmic afterglow of the Big Bang. In astrobiology, he was a forerunner of the theory that life on Earth may have come from Mars. He is currently championing the theory that Earth may host a shadow biosphere of alternative life forms.
Davies has lectured on scientific topics at institutions as diverse as The World Economic Forum, the United Nations, the Commission of the European Union, Google, Windsor Castle, The Vatican and Westminster Abbey, as well as mainstream academic establishments such as The Royal Society, The Smithsonian Institution, and the New York Academy of Sciences. Davies devised and presented a series of 45 minute BBC Radio 3 science documentaries and a one-hour television documentary about his work in astrobiology, entitled "The Cradle of Life." Among his bestselling books are "The Mind of God," "How to Build a Time Machine," and "The Goldilocks Enigma." His latest book, "The Eerie Silence," was published by Houghton Mifflin Harcourt in 2010.
Question: What future technologies might \r\nenhance the search\r\nfor extraterrestrials?\r\n\r\n
Paul\r\nDavies: I think we need to\r\nget away from the idea of leaving this to a small and heroic band of \r\nradio\r\nastronomers and try and spread the burden across the entire scientific\r\ncommunity. I think all the\r\nsciences can contribute, and I’ll give you some examples. \r\n One of the things that is baffling\r\nabout ET, and this is an idea that goes back to Enrico Fermi at the end \r\nof the\r\nSecond World War is, why haven’t the alien civilizations spread across \r\nthe\r\ngalaxy and colonized it or at the very least visited? “Where is \r\neverybody?” is\r\nthe way Fermi put it, and so he took that as evidence that there is \r\nnobody out\r\nthere, the fact that Earth has not been visited or colonized, that the \r\naliens\r\nhaven’t come here a long time ago is evidence that they’re not out there\r\neither, but I think one can put a spin on this particular story and say,\r\n well\r\nhow do we know that the aliens didn’t come and it doesn’t have to be \r\nflesh and\r\nblood aliens literally stepping out of a spacecraft. It\r\n could be their machines or their probes or robots or\r\nsomething of that sort that they could well have come a very long time \r\nago, and\r\nin this game you’ve got to think not in thousands or even millions of \r\nyears, but hundreds of millions or billions of years, so \r\nit's that sort of timescale we have to think on, and the question is, \r\nwould any trace remain of alien activity, say in our solar system, \r\nafter—let's pluck a figure out of midair—100 million years? If \r\nyou came back in another 100 million\r\nyears from now would any trace of human activity remain? \r\n The answer is not very much, but there\r\nare some things that we could look for. \r\nIf ET did pass through the solar system obviously didn’t stop for\r\n 100\r\nmillion years what would we find? \r\nWell there are some things like nuclear waste. If\r\n you dumped nuclear waste that will certainly survive for\r\nthat length of time. We could go\r\nlook for that. Any sort of large\r\nscale mining or quarrying activities would leave scars although they \r\nmight be\r\nburied beneath rock strata would still be discernible to a geologist \r\ndoing a\r\nsurvey. We could look for that\r\ntoo.\r\n\r\n
And then there is one other idea that is crazy, but\r\n it’s\r\ndear to my heart and this comes back to the message in the bottle \r\nconcept, so\r\nup to now SETI has been involved in looking for messages that are being\r\ndeliberately beamed at us and as I’ve explained that’s pretty unlikely, \r\nbut\r\nthere is another type of messaging of which the beacon is an example. It’s a one way message. When \r\nyou put a message in a bottle and\r\nthrow it into the sea you don’t think to yourself "Well, I expect a \r\nreply." It’s you don’t know if anybody is ever\r\ngoing to find it and certainly don’t know who is going to find it, so \r\nit’s just\r\nsort of left to its own devices. \r\nWell in the same way we might imagine that an alien civilization \r\nmight\r\nhave put a message in a bottle for anyone who might find it and that \r\nanyone\r\ncould be us, could be human beings, so where is the bottle and where is \r\nthe\r\nmessage? I’m open to\r\nsuggestions. One idea I’ve had is\r\nthat maybe the bottles are living cells, terrestrial organisms and that \r\nthe\r\nmessage is encoded in DNA. Viruses\r\nare continually infecting organisms on Earth and uploading their DNA \r\ninto the\r\ngenomes of those organisms, so there is a well understood pathway for \r\ngetting\r\ninformation into DNA. We’re\r\nlittered with it. Our own genomes\r\nhave got huge amounts of this junk that has climbed onboard from viruses\r\n over\r\nevolutionary history, so if viruses can to it ET can do it and it seems \r\nto me\r\nthat we could in addition to scouring the skies for radio waves with a \r\nmessage\r\nencoded we could scour terrestrial genomes, which are being sequenced \r\nanyway, to\r\nsee if there is a message from ET encoded in it. You\r\n know, it could be some striking string of nucleotide\r\nbases, the famous four letter alphabet that is the language of life, the\r\n A’s,\r\nG’s, C’s and T’s in the DNA. It\r\nmight just spell out some sort of message that would attract our\r\nattention. Now of course this is a\r\ncrazy idea. I’m not actually\r\nsuggesting that there really is a message from ET in genomes. What I’m saying is that is the type of\r\nthinking we need. Maybe it is no\r\nmore crazy than expecting it to be etched into radio waves coming from \r\nthe sky.
Recorded April 15, 2010
\r\nInterviewed by Austin Allen
OK, Paul Davies admits it’s a "crazy idea." But if we want to improve our search for ET, it’s the kind of idea we might need.
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The brain of an ancient bird offers clues to the survival of its modern-day relatives.
- A new study looked at a well-preserved fossil of an Ichthyornis that lived about 70 million years ago.
- The scientists compared the brain of the ancient bird to that of modern birds.
- Modern birds' brains are structurally different, which might have allowed them to survive the mass extinction that killed the dinosaurs.
That beautiful singing bird on your fence is a descendent of dinosaurs. As all dinosaurs have gone extinct, what allowed the birds to adapt and survive? New research published in Science Advances points to a special feature of birds' brains that could explain why they are still with us today.
Are birds dinosaurs?
Bird origins have been traced to a mostly meat-eating group of two-legged dinosaurs known as theropods ("beast-footed") that lived about 231 million years ago in the Triassic Period. The mighty Tyrannosaurus rex also belonged to that group. Theropods and modern birds share a few traits in common, such as feathers and the ability to lay eggs. Of course, one big difference is flight, which is the defining characteristic of birds.
And just like humans are part of a larger group (mammals) with whom we share key characteristics, birds too are part of a larger group that includes dinosaurs.
"Birds are living dinosaurs, just as we are mammals," explained the study's co-author paleontologist Julia Clarke of the University of Texas at Austin in a 2020 interview. "They're firmly nested in that one part of the dinosaur tree," she stated. "All of the species of birds we have today are descendants of one lineage of dinosaur: the theropod dinosaurs."
Most birds are much smaller than dinosaurs, so researchers believe that a process of miniaturization started to take place about 200 million years ago. As discussed in Scientific American, coelurosaurs — the subgroup of theropods that resulted in modern birds — began getting smaller and smaller due to an intense evolutionary process that favored smaller animals rather than larger ones.
Differences in brain shapes likely influenced the survival of birds during the mass extinction that killed off non-avian dinosaurs.Credit: Christopher Torres / The University of Texas at Austin
The fossil discovery
In the current study, a fossil from about 70 million years ago may help explain the survival of birds. The fossil is a nearly complete skull belonging to a bird named Ichthyornis, which lived in the late Cretaceous period in what is now Kansas. Ichthyornis had characteristics resembling both birds and dinosaurs. For instance, its jaws were full of teeth, yet it had a beak. The well-preserved nature of the skull allowed scientists to compare the prehistoric bird's brain to those of birds today.
"Living birds have brains more complex than any known animals except mammals," said lead researcher Christopher Torres. "This new fossil finally lets us test the idea that those brains played a major role in their survival."
The phases of the evolving avian brain shape.Credit: Christopher Torres / The University of Texas at Austin
The researchers used CT-imaging data to make a 3D replica of the bird's brain, known as an endocast. This allowed them to make comparisons to endocasts of various living birds and their dinosaur ancestors.
Their research revealed that Ichthyornis' brain was more similar to those of dinosaurs than to those of modern birds. In particular, the cerebral hemispheres — the area of the brain responsible for higher cognitive functions like thought and emotion in humans — of Ichthyornis' brain were much smaller than those found in birds today.Different brains may have helped birds survive the mass extinction that wiped out the dinosaurs. "If a feature of the brain affected survivorship, we would expect it to be present in the survivors but absent in the casualties, like Ichthyornis," said Torres. "That's exactly what we see here."
Scientists discover surviving viruses in 15,000-year-old glacier ice on the Tibetan Plateau in China.
Researchers have found 15,000-year-old viruses in ice samples taken from the Tibetan Plateau in China, the majority of which are unlike any of the viruses currently known to science. The study, published in the journal Microbiome, could help scientists understand virus evolution and climate change.
Two ice cores were collected in 2015 at extremely high altitudes — above 22,000 feet — from the Guliya ice cap in western China.
Lead author Zhi-Ping Zhong, a researcher at the Ohio State University's Byrd Polar and Climate Research Center, explained that the glaciers they examined were formed over a long period of time, collecting dust and gases as well as the viruses. "The glaciers in western China are not well-studied, and our goal is to use this information to reflect past environments," he said. "And viruses are a part of those environments."
Poring over the samples, the scientists identified 33 viral genomes, 28 of which are novel and have not been described previously. Four of the known viruses infect bacteria.
Watch a film on the ice core extraction in the Guliya glacier in 2015 -
Co-author Matthew Sullivan, professor of microbiology at Ohio State, said that these viruses were made for extreme conditions. "These viruses have signatures of genes that help them infect cells in cold environments — just surreal genetic signatures for how a virus is able to survive in extreme conditions," he stated.
The ultra-clean method developed by the scientists to decontaminate the cores to study the microbes inside can be applied to samples taken from other harsh settings, like Mars or the moon. The technique involves stripping away the core's outer layer of ice. Then, the core is cleaned with alcohol and water.
Dangerous viruses in the ice?
Is it dangerous to dig up ancient viruses? Could they infect humans? Sullivan told Gizmodo that the viruses were made inactive by the "chemistry of nucleic acids extraction."
So, there's no need to worry this time. However, some researchers believe that the thawing of permafrost due to climate change could eventually release some viruses that might infect humans.
"You dream about these kinds of moments when you're a kid," said lead paleontologist David Schmidt.
- The triceratops skull was first discovered in 2019, but was excavated over the summer of 2020.
- It was discovered in the South Dakota Badlands, an area where the Triceratops roamed some 66 million years ago.
- Studying dinosaurs helps scientists better understand the evolution of all life on Earth.
David Schmidt, a geology professor at Westminster College, had just arrived in the South Dakota Badlands in summer 2019 with a group of students for a fossil dig when he received a call from the National Forest Service. A nearby rancher had discovered a strange object poking out of the ground. They wanted Schmidt to take a look.
"One of the very first bones that we saw in the rock was this long cylindrical bone," Schmidt told St. Louis Public Radio. "The first thing that came out of our mouths was, 'That kind of looks like the horn of a triceratops.'"
After authorities gave the go-ahead, Schmidt and a small group of students returned this summer and spent nearly every day of June and July excavating the skull.
Credit: David Schmidt / Westminster College
"We had to be really careful," Schmidt told St. Louis Public Radio. "We couldn't disturb anything at all, because at that point, it was under law enforcement investigation. They were telling us, 'Don't even make footprints,' and I was thinking, 'How are we supposed to do that?'"
Another difficulty was the mammoth size of the skull: about 7 feet long and more than 3,000 pounds. (For context, the largest triceratops skull ever unearthed was about 8.2 feet long.) The skull of Schmidt's dinosaur was likely a Triceratops prorsus, one of two species of triceratops that roamed what's now North America about 66 million years ago.
Credit: David Schmidt / Westminster College
The triceratops was an herbivore, but it was also a favorite meal of the Tyrannosaurus rex. That probably explains why the Dakotas contain many scattered triceratops bone fragments, and, less commonly, complete bones and skulls. In summer 2019, for example, a separate team on a dig in North Dakota made headlines after unearthing a complete triceratops skull that measured five feet in length.
Michael Kjelland, a biology professor who participated in that excavation, said digging up the dinosaur was like completing a "multi-piece, 3-D jigsaw puzzle" that required "engineering that rivaled SpaceX," he jokingly told the New York Times.
Morrison Formation in Colorado
James St. John via Flickr
The Badlands aren't the only spot in North America where paleontologists have found dinosaurs. In the 1870s, Colorado and Wyoming became the first sites of dinosaur discoveries in the U.S., ushering in an era of public fascination with the prehistoric creatures — and a competitive rush to unearth them.
Since, dinosaur bones have been found in 35 states. One of the most fruitful locations for paleontologists has been the Morrison formation, a sequence of Upper Jurassic sedimentary rock that stretches under the Western part of the country. Discovered here were species like Camarasaurus, Diplodocus, Apatosaurus, Stegosaurus, and Allosaurus, to name a few.
|Credit: Nobu Tamura/Wikimedia Commons|
As for "Shady" (the nickname of the South Dakota triceratops), Schmidt and his team have safely transported it to the Westminster campus. They hope to raise funds for restoration, and to return to South Dakota in search of more bones that once belonged to the triceratops.
Studying dinosaurs helps scientists gain a more complete understanding of our evolution, illuminating a through-line that extends from "deep time" to present day. For scientists like Schmidt, there's also the simple joy of coming to face-to-face with a lost world.
"You dream about these kinds of moments when you're a kid," Schmidt told St. Louis Public Radio. "You don't ever think that these things will ever happen."
The eastern inner core located beneath Indonesia's Banda Sea is growing faster than the western side beneath Brazil.
More than 5,000 kilometres beneath us, Earth's solid metal inner core wasn't discovered until 1936.
Almost a century later, we're still struggling to answer basic questions about when and how it first formed.
These aren't easy puzzles to solve. We can't directly sample the inner core, so the key to unravelling its mysteries lies in collaboration between seismologists, who indirectly sample it with seismic waves, geodynamicists, who create models of its dynamics, and mineral physicists, who study the behaviour of iron alloys at high pressures and temperatures.
Combining these disciplines, scientists have delivered an important clue about what's happening miles beneath our feet. In a new study, they reveal how Earth's inner core is growing faster on one side than the other, which could help explain how old the inner core is, and the intriguing history of Earth's magnetic field.
Earth's core was formed very early in our planet's 4.5 billion-year history, within the first 200 million years. Gravity pulled the heavier iron to the centre of the young planet, leaving the rocky, silicate minerals to make up the mantle and crust.
Earth's formation captured a lot of heat within the planet. The loss of this heat, and heating by ongoing radioactive decay, have since driven our planet's evolution. Heat loss in Earth's interior drives the vigorous flow in the liquid iron outer core, which creates Earth's magnetic field. Meanwhile, cooling within Earth's deep interior helps power plate tectonics, which shape the surface of our planet.
As Earth cooled over time, the temperature at the centre of the planet eventually dropped below the melting point of iron at extreme pressures, and the inner core started to crystallise. Today, the inner core continues to grow at roughly 1mm in radius each year, which equates to the solidification of 8,000 tonnes of molten iron every second. In billions of years, this cooling will eventually lead to the whole core becoming solid, leaving Earth without its protective magnetic field.
One might assume that this solidification creates a homogeneous solid sphere, but this isn't the case. In the 1990s, scientists realised that the speed of seismic waves travelling through the inner core varied unexpectedly. This suggested that something asymmetrical was happening in the inner core.
Specifically, the eastern and western halves of the inner core showed different seismic wavespeed variations. The eastern part of the inner core is beneath Asia, the Indian Ocean and the western Pacific Ocean, and the west lies under the Americas, the Atlantic Ocean and the eastern Pacific.
Sanne Cottaar, Author provided
The new study probed this mystery, using new seismic observations combined with geodynamic modelling and estimates of how iron alloys behave at high pressure. They found that the eastern inner core located beneath Indonesia's Banda Sea is growing faster than the western side beneath Brazil.
You can think of this uneven growth as like trying to make ice cream in a freezer that's only working on one side: ice crystals form only on the side of the ice cream where the cooling is effective. In the Earth, the uneven growth is caused by the rest of the planet sucking heat more quickly from some parts of the inner core than others.
But unlike the ice cream, the solid inner core is subject to gravitational forces which distribute the new growth evenly through a process of creeping interior flow, which maintains the inner core's spherical shape. This means that Earth is in no danger of tipping, though this uneven growth does get recorded in the seismic wavespeeds in our planet's inner core.
Dating the core
So does this approach help us understand how old the inner core might be? When the researchers matched their seismic observations with their flow models, they found that it's likely that the inner core – at the centre of the entire core which formed much earlier – is between 500 million and 1,500 million years old.
The study reports that the younger end of this age range is the better match, although the older end matches an estimate made by measuring changes in the strength of Earth's magnetic field. Whichever number turns out to be correct, it's clear that the inner core is a relative youngster, somewhere between a ninth and a third as old as Earth itself.
This new work presents a powerful new model of the inner core. However, a number of physical assumptions the authors made would have to be true for this to be correct. For example, the model only works if the inner core consists of one specific crystalline phase of iron, about which there is some uncertainty.
And does our uneven inner core make the Earth unusual? It turns out that many planetary bodies have two halves which are somehow different to each other. On Mars, the surface of the northern half is lower-lying while the southern half is more mountainous. The Moon's near-side crust is chemically different to the far-side one. On Mercury and Jupiter it's not the surface which is uneven but the magnetic field, which doesn't form a mirror image between north and south.
So while the causes for all of these asymmetries vary, Earth appears to be in good company as a slightly asymmetrical planet in a solar system of lopsided celestial bodies.