Found in Antarctica: A ‘weirdo particle’ that predates the sun


A tiny grain found within a meteorite in Antarctica sheds light on how the solar system itself came to be.

Matt Davis 02 May, 2019

  • Researchers cut open a small meteorite found in the LaPaz icefield in Antarctica to uncover a very surprising find.
  • Inside this meteorite was a small inclusion that they determined came directly from the nova of a white dwarf to Earth.
  • By studying the inclusion’s composition, researchers were able to glean new insights into the thermodynamics of white dwarf novae, ultimately shedding light onto how solar systems like ours formed.

In a meteorite NASA retrieved from the LaPaz icefield in Antarctica, researchers have uncovered a grain of stardust that formed before even our own sun had come into existence. What’s more, this grain of material sheds insight into how solar systems like our own form.

“Sometimes research is about satisfying your curiosity. One of the greatest curiosities is how the universe was formed and how life started,” said Jane Howe, one of the researchers on this project. “And this weirdo particle showed us something we didn’t know before.”

How a white dwarf made ‘this weirdo particle’

In a sense, everything is composed of the same stardust that was found in this meteorite in Antarctica — all matter comes from either the Big Bang or stars, in one way or another. But it’s rare to find matter that originated directly from the source. Specifically, the grain from the LaPaz meteorite, called LAP-149, is believed to have come directly from a white dwarf nova.

There’s no fusion going on in a white dwarf, so they typically aren’t making new stuff in the universe. White dwarfs are the remnants of a certain old stars that have burned through their fuel, and their cold, white glow is just the leftover energy from the old star’s fusion reactions. When a white dwarf orbits another star in a binary system, however, that white dwarf can suck up material from its larger companion star. Once a white dwarf accumulates enough material from its companion star, the matter can periodically reach temperatures high enough to trigger fusion again in a violent explosion.

Most of us are familiar with supernova; this is a similar event, though less violent. When a white dwarf goes nova, it shoots out clouds of stardust composed of different elements that can eventually condense and find their way to Earth. This is what happened with LAP-149, which found its way to Antarctica.

Scanning transmission electron microscopy data of LAP-149 under various imaging modes. Figure d shows a LAP-149’s composition in false colors: carbon, red; oxygen, blue; and silicon, green.

How did the researchers know that LAP-149 truly came from outside the solar system? When analyzing the material, they found that the grain was highly enriched in the carbon isotope 13C, far beyond what one would expect for anything that was formed within the solar system. “The carbon isotopic compositions in anything we have ever sampled that came from any planet or body in our solar system varies typically by a factor on the order of 50,” said lead author Pierre Haenecour in a University of Arizona press release. “The 13C we found in LAP-149 is enriched more than 50,000-fold. These results provide further laboratory evidence that both carbon- and oxygen-rich grains from novae contributed to the building blocks of our solar system.”

Because LAP-149 was extrasolar in origin, the researchers could study its composition and gain insights into the processes from its source, a white dwarf nova. Using ion and electron microscopy, the research team found a small inclusion, just a few hundred nanometers in size, consisting of oxygen-rich silicates within the larger graphite structure. This turned out to be a very exciting find — there have been no other grains of stardust found that match this composition.

The material in a nova depends on the composition and density of the white dwarf star that produced it, and traditional models of the thermodynamics of such novae did not correspond with what was found in LAP-149. Because oxygen-rich silicates were found within LAP-149’s graphite, this work enables scientists to further refine their understanding of the thermodynamic processes that go on in novae, specifically how grains of stardust form and move. It also shows that carbonaceous and silicate dust can be produced in the same ejection from a nova, ultimately providing insight into how solar systems such as ours were formed.

Taking a broader view, however, this work serves as an incredible example of how far science has come. Not only could we identify that a meteorite was formed from the clouds of stardust surrounding a white dwarf star undergoing a violent, explosive, and creative process billions of years ago, we were able to study its composition and learn something about how that process unfolded. Through research such as Howe, Haenecour, and colleagues’, we’ll be able to learn even more about the cosmos in the future.

Denisovans: Primitive humans lived at high altitudes

I’ve read several World History books, by Jared Diamond, Yuval Noah Harari and also Peter Frankopan. Who was here, who they were, and how we got here, are very interesting subjects for sure. Here is another piece of that puzzle to chew on.

By Paul Rincon Science editor, BBC News website

Scientists have found evidence that an ancient species of human called Denisovans lived at high altitudes in Tibet.

The ability to survive in such extreme environments had previously been associated only with our species – Homo sapiens.

The ancient ancestor seems to have passed on a gene that helps modern people cope at high elevations.

Details of the study are published in the journal Nature.

The Denisovans were a mysterious human species living in Asia before modern humans like us expanded across the world tens of thousands of years ago.

Until recently, the only fossils came from a few fragments of bone and teeth from a single site in Siberia – Denisova Cave.

But DNA had shown that they were a distinct branch of the human family.

Now, scientists have identified the first Denisovan fossil from another site. It’s a mandible (lower jawbone) discovered in 1980 at Baishiya Karst Cave, 3,280m up on the Tibetan Plateau.

A technique called uranium-series dating was used on carbonate deposits on the bone. This yielded a date of 160,000 years ago for the mandible.

Co-author Jean Jacques Hublin, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said finding evidence of an ancient – or archaic – species of human living at such high elevations was a surprise.

“When we deal with ‘archaic hominins’ – Neanderthals, Denisovans, early forms of Homo sapiens – it’s clear that these hominins were limited in their capabilities to dwell in extreme environments.

“If you look at the situation in Europe, we have a lot of Neanderthal sites and people have been studying these sites for a century-and-a-half now.

“The highest sites we have are at 2,000m altitude. There are not many, and they are clearly sites where these Neanderthals used to go in summer, probably for special hunts. But otherwise, we don’t have these types of sites.”

Of the Denisovans on the Tibetan Plateau, he said: “It’s a plateau… and there are obviously enough resources for people to live there and not just come occasionally.”

While the researchers could not find any traces of DNA preserved in this fossil, they managed to extract proteins from one of the molars, which they then analysed applying something called ancient protein analysis.

“Our protein analysis shows that the Xiahe mandible belonged to a hominin population that was closely related to the Denisovans from Denisova Cave,” said co-author Frido Welker, from the University of Copenhagen, Denmark.

The discovery may explain why individuals studied at Denisova Cave had a gene variant known to protect against hypoxia (oxygen deficiency) at high altitudes. This had been a puzzle because the Siberian cave is located just 700m above sea level.

Present-day Sherpas, Tibetans and neighbouring populations have the same gene variant, which was probably acquired when Homo sapiens mixed with the Denisovans thousands of years ago.

In fact, the gene variant appears to have undergone positive natural selection (which can result in mutations reaching high frequencies in populations because they confer an advantage).

“We can only speculate that living in this kind of environment, any mutation that was favourable to breathing an atmosphere impoverished in oxygen would be retained by natural selection,” said Prof Hublin.

“And it’s a rather likely scenario to explain how this mutation made its way to present-day Tibetans.”

Guns Germs and Steel

The Fates of Human Societies, by Jared Diamond

Have you ever wondered, how did we get here? Where did we come from?  Why here and Why now? Why are some countries rich, and others poor? Why do human live where they live today, and where did the first peoples come from?

Being an avid reader poses challenges now and then. Picking up a substantive book, and reading it from cover to cover, requires time, treasure and commitment. I have several substantial books in my “read” library stack. It took me quite a while to consume Guns, Germs and Steel. Not only does this book require time and treasure, it demands of its reader, patience, understanding, and a desire to learn; something that I found, was enlightening and educational.

Jared Diamond begins some 13,000 years ago, when the world was first populated with hunter gatherers. The continents were finding their places, ice ages, came and went. And early humans, as archeologists have studied began to populate the earth. When oceans were shallower, and land bridges existed, in several locations on the earth, people moved here and there.

Indigenous peoples worldwide don’t garner very much respect from the conquering peoples who overtook them. There were multiple indigenous communities worldwide, before the proverbial “white man” came and either infected them with disease, enslaved them to serve, relegated them to reserves or killed them outright in wars and conquests.

This book is methodical in its approach to humanity. And in pain staking detail we learn what peoples lived in prehistory. We learn where they lived to begin with and where they moved, on the earth as time progresses.

We learn how advances in food production, disasters of germs and disease, and the advancing industrial revolution, where guns and steel overpower those who did not have them.

We learn that in historical times, conquest and war, dispensed with entire groups of people. You did not only get the peoples who took up conquest, but the people who suffered because of it. The people who were here, before we got here, grew into some, successful communities. In the end, those vibrant indigenous communities were laid wasted by diseases brought by the conquerors, and the wars perpetuated in the names of Kings, Queens or Country.

As the continents were solidified, where people lived either assisted their success or advanced their demise. Where you lived, in relation to the latitude of your environs, either helped you, or harmed you. The success of peoples, farming, livestock, and growth all depended greatly, on where you sat, on the earth, in terms of latitude and longitude.

The spread of all things necessary for life, worked well, in areas with an expansive East – West axes. Those countries with North – South, axes, did not fare so well, the population and spread of food, animals and technology flourished in the Eurasian, East West Expanse of location.

There is a direct correlation between the location of a people, and the environment they found themselves in. From the Equator, reaching either North or South, temperate regions flourished. Guns, Germs and Steel tells the story of how the world became what it has.

Time, Distance, Location and the problems associated with location either helped peoples grow and succeed, or they took much longer to achieve certain benchmarks in their human existence. All things moving East – West grew faster than those things moving North – South.

Time is measured in hundreds of years,  The movement of people, goods, animals, and agriculture took TIME. And it seems that in pre-history, time is a very important component in the building of peoples, world wide.

Jared Diamond spins a very intricate web of story telling about Time, Talent, and Treasure. How the world built itself, learned how to govern itself, farm the land, produce food, and be able to store that food over Time, and then industrialize, are very important factors in human existence.

Guns, Germs and Steel is not a simple story, it is complex on many levels and explains the difficulty early peoples faced, in maintaining a home, finding food to eat, and learning the hard way, especially, “what not to eat.”

Every continent on the earth has a particular Origin Story. Every peoples who populate the earth, where ever that may be, also have complex Origin Stories. This very complex but wonderful study of humanity is one of the best books I have ever read, on the subject of just How We Got Here !

How each continent and how each people on each continent arrived where they did, and prospered to the level they are at today is studied exhaustively in this text. The Origins of People, Language, Customs and Lives and how all these things moved from one area of the world to other areas of the world is fascinating.

No stone is left un-turned by page 444 …

Pulitzer Prize books must contain certain factors that I always look for, IF a particular book has been awarded a Pulitzer Prize. Because I have read a handful of winners, that turned out to be real losers.

Guns, Germs and Steel is a Winner !!!

Read This Book !

Cassini Probe Images and Final Plunge

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On October 15, 1997, the Cassini Probe was launched from Cape Canaveral on a seven year voyage through the inner planets, past Jupiter and the Asteroid Belt, on its way to the Saturnian system.

Here are some amazing photos that Cassini took3on her voyage to Saturn.

Handout image of Saturn from space, the first in which Saturn, its moons and rings, and Earth, Venus and Mars are all visible

 

 

  • Image One: Saturn in all its heavenly glory

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  • Image Two: The Hexagonal Storm on the North Pole of Saturn

Painting for NASA/STScI

  • Image Three: The Aurora on Saturn’s South Pole

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  • Image Four: Cassini’s final plunge into Saturn’s Atmosphere

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  • Image Five: Saturn in all its glory

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  • Image Six: Cassini Stats

In order to preserve the pristine nature of Enceladus and Titan, and all the other moons and moonlets that orbit Saturn, the choice was made to send Cassini into the atmosphere to insure no contamination of the moons of Saturn for future exploration, and not to contaminate worlds yet explored by microbes that might contaminate pristine worlds so far away. On Friday morning Cassini took its final bow, transmitting all the data in real time to Australia as she streaked into Saturn’s upper atmosphere and disintegrated.

The end of Cassini is sad, but what we know today was worth every minute Cassini orbited the Saturnian world.

We have a wealth of Data coming down in data link as we speak. And further research will last for years to come as that data is analyzed and poured over by scientists and researches.

Cassini gave us insight of Saturn and its system, moons and rings that we could not have imagined and found water ice on Enceladus, and methan and ethane on Titan. Maybe one day we might find that, indeed, we are not alone in the universe on some cosmic level.

When that day comes, we can all thank the massive team at NASA and the JPL and the folks in Australia for all their hard work in collecting data that takes 87 minutes from Saturn to reach earth, after the Cassini probe pointed its antenna at Earth from across the galaxy.

We will miss Cassini, at least I will because I have followed this mission since its inception and launch so many years ago.