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.

Found in Antarctica: A 'weirdo particle' that predates the sun
NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester)
  • 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.

The secrets gleaned from LAP-149's composition

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.

Haenecour et al., 2019

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.

A landslide is imminent and so is its tsunami

An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.

Image source: Christian Zimmerman/USGS/Big Think
Surprising Science
  • A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
  • A wall of rock exposed by a receding glacier is about crash into the waters below.
  • Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.

The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.

Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .

"It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.

The Barry Arm Fjord

Camping on the fjord's Black Sand Beach

Image source: Matt Zimmerman

The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.

Not Alaska’s first watery rodeo, but likely the biggest

Image source: whrc.org

There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.

The Barry Arm event will be larger than either of these by far.

"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."

Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.

What the letter predicts for Barry Arm Fjord

Moving slowly at first...

Image source: whrc.org

"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."

The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.

Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.

Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.

While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.

Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."

How do you prepare for something like this?

Image source: whrc.org

The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:

"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."

In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.

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