The Comet That Cooled the Earth - Unpacking the Younger Dryas Mystery

This is Spacetime Series twenty eight, episode one hundred and one, for broadcast on the twenty second of August twenty twenty five. Coming up on Space Time, did a comet trigger Earth's Younger Dryas cool off? The discovery of a rare white dwarf merger remnant, and China tests its new manned lun orlanda All that and more Coming up on space Time. Welcome to space Time with Stuart Gary. A new study has raised serious questions as to whether a massive comet may have triggered planet Earth's Younger Dryas cool off event. The massive climate change is generally thought to have been caused by glacial milt water. That analysis of ocean sediments reported in the journal plus one one by suggesting geochemical clues in line with the possibility that an encounter with a disintegrating comet eight hundred years ago may well have triggered rapid cooling of Earth's air and oceans. The studies lead author, Christopher Moore from the University of South Carolina, says that during the abrupt cool off the Younger Dryous event, temperatures dropped by around ten degrees celsius in a year or less. With cooler temperatures lasting for some twelve hundred years. Many scientists believe that no comet was involved, and that it was glacial melt water in the northern Hemisphere causing a freshening of the Atlantic Ocean, significantly weakening currents that transport warm tropical water northwards, such as the Golf Stream Now. In contrast, the Younger Dryas impact hypothesis proposes that Earth pass through a debris trail left from the disintegrating comet, with numerous impacts and shark waves to stabilizing ice sheets and causing massive melt water flooding, which then shut down key ocean currents. However, the impact hypothesis has been less well supported, lacking any evidence from ocean sediment that address this gap. More on, colleagues analyzed the geochemistry of four sea four cores from Baffin Biny, Greenland. Radiocarbon dating suggest that the cause include sediments deposited when the Younger Drys event began. To study them, the authors use several techniques including scanning, electro microscopy, single particle inductivity coupled with plasma time of flight, mass spectrometry, energy dispersive spectroscopy and laser a Bleason inductivity coupled plasma mass spectrometry. The analysis detected metallic debris whose geochemistry would be consistent with comet dust. These occurred alongside microscopic spherical particles whose composition indicates a mostly terrestrial origin, with some materials believed to be extraterrestrial. That suggests these microspherals could have famed when cometary fragments exploded just above or a bond hitting the ground melting materials together. The analysis also uncovered even smaller nanoparticles with high levels of platinum, iridium, cobalt, and these can all be signs of extraterrestrial origin, especially iridium, which is rare on Earth but common in asteroids and comets. Together, the findings indicate a geochemical anomaly occurring around the time that the Younger dryse event began. Of course, they don't provide direct evidence supporting the impact hypothesis. More research will be needed to confirm whether the findings are indeed evidence of an impact and to firmly link the impact climate cooling. Moore says identification of the Younger Drys impact layer in the deep marine sediments underscores the potential of oceanic records, the broadened sciences understanding of this event and its climatological impacts. He says, the debt is suggests that the amount of comet dust in the atmosphere was enough to cause a short term impact winter, followed by a fourteen hundred year cooling off period. This is space time still to come. Discovery of a rare white dwarf merger remnant and China tests its new manned Luna Lander. All that and more still to come on space time. Astronomers have discovered a cosmic rarity, an ultra massive white dwarf star, resulting from a white dwarf merging with another star rather than through the evolution of just a single star. The discovery, which is made possible by NASA's Hubble Space telescope sensitive ultraviolet observations, suggested these very rare white dwarf mergers may be more common than previously thought. One of the studies authors, Boriskin Ziki from the University of Warwick, says the discovery underlines how things can be different from what they appear to be at first sight. Until now, this object appeared to be a normal white dwarf but Hubble's ultraviolet vision revealed that it had a very different history from what astronomers would have guessed. Now. A white dwarf is the dead stella core of a sun like star. After fusing their core hydrogen into helium, they then fuse their core helium into carbon and oxygen. The process is expanding out to become a red giant, and because they're not massive enough to fuse carbon and oxygen into heavier elements, the fusion process turns off and the star dies. Eventually, they puff off their outer gaseous envelope, which gradually floats away as a spectacular colorful object called a planetary nebula, and that exposes their white, ultra hot stellar core. The white dwarf a super dense object composed mostly of oxygen and carbon, usually about the size of the Earth, which will slowly cool over the eons. Our Sun will eventually become a white dwarf when it drops off the main sequence in around five to seven billion years from now now. In theory, a white dwarf can have a massive up to one point four times that of the Sun, but usually white dwarfs heavier than our Sun are fairly rare. These objects, which astronomers call ultra massive White dwarfs, can form either through the evolution of a single massive star or through the merger of a white dwarf with another star, such as a binary companion. This new discovery, reported in the journal Nature Astronomy, marks the first time that a white dwarf borne from merging stars has been identified by its ultraviolet signature now. Prior to this study, only six white dwarf merger room thats have been discovered, all by their carbon spectral lines in their visible light spectra. Now, all seven of these objects are part of a larger group of stars that were found to be blue with and expected for their masses and ages from a study by the European Space AGENCYSGAIA mission in twenty nineteen, providing new insights into their formation history. For this lattice discovery, astronomers used Hubble's Cosmic Origin Spectrograph to investigate a white dwarf catalog as WD zero five two five plus five twenty six. It's located one hundred and twenty six light years away and is about twenty percent more massive than our Sun now in visible light, the spectrum of the atmosphere of WD zero five twenty five plus five twenty six resembles that of a typical white dwarf. However, Hubble's ultraviolet spectrum revealed something unusual, evidence of carbon in the white dwarf's atmosphere. White dwarfs that form through the evolution of a single star have atmospheres composed of hydrogen and helium. As we mentioned earlier, the core of the white dwarf is typically composed mostly of carbon and oxygen, but a thick atmosphere usually prevents these elements from appearing in the white dwarf spectra. So when carbon does appear in the spectrum of a white dwarf, it's a signal of a more violent origin than a typical single star scenario. In other words, the collision of two white dwarfs or a white dwarf and another star, and these collisions can burn away the hydrogen and helium atmospheres of the colliding stars, leaving behind a scant layer of hydrogen and helium around the merger room that allows carbon from the white dwarf's core to float upwards where it can be detected. D E zero five twenty five plus five twenty six is remarkable even within the small group of white dwarves known to be the result of merging stars. With the temperature of almost twenty one thousand kelvin and some one point two solar masses, this object is harder and more massive than other white dwarfs in this group. Its extreme temperature posts something of a mystery. For cooler white dwarfs, such as the six previously discovered, merger products a process called convection and mixed carbon into the thin hydrogen helium atmosphere. The problem is wdzero five twenty five plus five twenty six is simply too hot for convection to take place, so instead, the authors concluded that a more subtle process called sindic convection brings small amounts of carbon up into the atmosphere, and this object has the smallest amount of atmospheric carbon of any white dwarf known to result from a merger, about one hundred thousand times less than other merger remnants. The high temperature, low carbon abundance means that identifying this white dwarf as a product of a merger would have been in possible without hubble sensitivity to ultraviolet light see the spectral lines from elements heavier than helium like carbon become fainter at visible wave links for hotter white dwarfs, but these spectral signatures remain bright in the ultraviolet. Hubble is uniquely positioned to spot them because WD zero five twenty five plus five twenty six's unusual origins were only revealed once astronomer's glimpsed its ultraviolet spectrum. It's highly likely that other shavingly normal white dwarfs may actually be out there as a result of other cosmic collisions, and so the search is underway. This report from MASSTV. Astronomers using NASA's Hubble Space Telescope have found a rare ultramassive white dwarf formed from merging stars. The discovery was made possible by Hubble sensitive ultraviolet observations and suggests these unusual white dwarfs may be more common than once thought. The white dwarf is one hundred and twenty eight light years away and twenty percent more massive than the Sun. Invisible light, it looked like a typical white dwarf, but hubbles altered violet data revealed something unusual, evidence of carbon in its atmosphere. A white dwarf is what stars like the sun become after they exhaust their nuclear fuel. Near the end of its life, this type of star expels most of its outer material, creating a planetary nebula. Only the hot core of the star remains. White dwarfs that form from a single star usually have atmospheres made of hydrogen and helium. These thick layers cover its carbon and oxygen or oxygen and neon surface, preventing their detection in the star's spectrum. When carbon shows up in a white dwarf spectrum, it can point to a more violent origin, such as a collision between two white dwarfs, or between a white dwarf and a subgiant star. These collisions can burn off most of the hydrogen and helium, leaving only a thin layer behind, allowing the astronomers to detect carbon on the white dwarf's surface. This white dwarf's merger origin would be impossible to identify without Hubble's ultraviolet sensitivity and hotter white dwarfs. Spectral lines from elements heavier than helium fade in visible light and stay bright and ultraviolet where Hubble can detect them. Researchers discover this white dwarf's unusual origin by looking at its ultraviolet spectrum, suggesting that other white dwarfs with a typical visible light spectrum may also be the result of cosmic collisions. The team plans to explore this possibility further and hopes to continue this research by studying how common carbon stars are among similar white dwarfs and how many stellar mergers might be hiding among the normal white dwarf family. This research will help improve our understanding of the environments in which stars evolve and the paths that lead to supernova explosions. This space time to come, China tests its new manned Luna lander and later in the science report, researchers have developed new solar powered floating devices so light they can support instruments high up in the atmosphere. All that and more still to come on space time, China has successfully carried out what it claims is the first test of its future manned lunar landing craft. The China Manned Space Agency does the test flight at a facility in Hebi Province, included both the controlled landing and takeoff marking. At major milestone in Beijing's manned lunar space exploration program, the land U, which means embracing the Moon in Mandarin is similar in concept and as this original Apollo era Lunar Excursion Module or LEM, which brought the first humans to the lunar surface on Apollo eleven nineteen sixty nine. LANDU is composed of both a landing module and a propulsion module, and it's designed to carry two Taygan notes from lunar orbit down to the surface and back again. It also has enough room for a lunar rover and scientific equipment. Again just like Apollo, China says it plans to hab its first tiger notts walking on the lunar's surface by twenty thirty and will develop a permanent base on the Moon with the Russians during the early twenty thirties. This is space time, and time that to take another brief look at some of the other stories making use in science this week. With a science report, scientists are warning that Argentina is Prito Marina glacier, previously considered to be one of the most stable in the region, has now began retreating faster than previously thought. Reporting the journal Communications, Earth and Environment looked at a combination of satellite data radar images from helicopter flights and mapping of the lake bed to estimate how the glacier has changed between the year two thy and twenty twenty four. Despite retreating less than one hundred meters from the year two thousand through to twenty nineteen, the authors found that some areas of the glacier have been retreating by as much as eight hundred meters in recent years, with a more than sixteen fold increase in thinning rates at the glacier's lowest point since twenty nineteen. The authors wiarn it's now possible that this glacier is following a similar pattern in other retreating glaciers around the world. Anthropologists have found that two different groups of Neanderthals living in two nearby caves butchered the same prey, but in very different ways. The discovery, reported in the General Frontiers of Environmental Archaeology, suggests that each group practiced its own unique local traditions. These Neanderthals, who lived between fifty thousand and sixty five years ago, used the same tools and hunted the same prey, but the cut marks on the remains of their food revealed they were preparing it in very different ways. Ways that can be explained simply by the skill of the butchers or the resources or tools that each of these communities were using. The authors say that Neanderthals that one cave may have been drying their meat before cooking it, while the other group didn't do that. Scientists have developed tiny, solar powered floating devices that could support instruments high up in the atmosphere. The devices, reported in the journal Nature, work through a process called photophoresis, in which motion is generated by heating particles to spend it in a gas or liquid by exposing them to sunlight. The authors developed a new type of flying structure made from two thin, perforated membranes connected by tiny vertical supports, which they say can levitate under the amount of light available at high altitudes on Earth. They're now proposing a three centimeter wide version of this vehicle, capable of carrying a ten milligram payload that's enough to support a small communications system panning a radio frequency antenna, a solar cell, and integrated circuits. They say the devices have the potential to help monitor the planet's atmosphere and even help with the expiration of other planets. It seems a medieval saint may have wrongly predicted the number of popes before the end of times. Saint Malachi of Armah, who died in eleven forty eight, is alleged to have stated in the Prophecy of the Popes that one undred and ten pontiffs would rain until Judgment Day. But there may have been some confusion with the prophecy. That's because of political events within the Catholic Church which have impacted exactly how many people were anointed as Bishop of Rome. Tim Mendem from Australian's Skeptics says, then again, Alahai may simply have got it all wrong. Well, we do know about the end of the world and when it's going to happen, because this saint called Saint Malachi of Armagh in Ireland made a prediction. He't from the eleven hundred on his way to Rome. He hadn't manly said, oh, how many popes have there been? And based on the number of popes, when you get to one hundred and eleven actually he said one hundred and ten, someone else out of another one to when you get to one hundred and eleven or one hundred and ten, that'll be the last pope. Unfortunately we just passed that now to thee and twelve, I think top Yes, we'll see. In other words, the headline of this story was did they medieval saint wrong, we predict the number of popes before the end time? The answer is yes. The issue is that with only way they assume he lived, they pretty got They're pretty sure this fellow was a real person, but it is a real saint in the eleven hundreds. But this these predictions started appearing a few hundred years later that he supposedly wrote, so he didn't necessarily write them, but they's been applied to him and they're wrong anyway. So it might have been written during a period of anti popery, great disgiven of the Catholic Church. Catholic Church can't take their saint wood away from someone which they've already given to him. Even if he got his prediction wrong, they're probably quite happy anyway. So the story goes, this guy made his prediction. It's unfortunately, like a lot of predictions, we've passed the time. The world hasn't ended. It is supposed to be the end times, and the whole thing comes to apocalypse and aged and whatever sort of particular and you're looking for it was supposed to be the last post, but was supposed to be Petrius Romanus, which is Peter the Roman. He identified as the final pope, and the story goes in the final persecution of the Holy Roman Church, there will reign Peter the Roman, who will save his flock amid many tribulations, after which the seven Hill city will be destroyed and a dreadful judge will judge the people. So they haven't got a pope called Petrus or Peter or the Rock. And therefore whoopsy, as you say, prophecy has not come true and probably won't come true. That's timendum from Austria and Scape Diggs, and that's the show for now. Space Time is available every Monday, Wednesday and Friday through Apple podcast, iTunes, Stitcher, Google Podcast, pocket Casts, Spotify, Acast, Amazon Music, bytes dot Com, SoundCloud YouTube, your favorite podcast download provider, and from space Time with Stuart Gary dot com. Space Time's also broadcast through the National Science Foundation, on Science Own Radio and on both iHeartRadio and tune in Radio. And you can help to support our show by visiting the Spacetime store for a range of promotional merchandising goodies, or by becoming a Spacetime Patron, which gives you access to triple episode, commercial free versions of the show, as well as lots of burness audio content which doesn't go to wear, access to our exclusive Facebook group, and other rewards. Just go to space Time with Stewart Gary dot com for full details. You've been listening to space Time with Stuart Gary. 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