Science
Interstellar Stardust Found Inside Australian Meteorite Is a Staggering 7 Billion Years Old – Gizmodo
A meteorite that crashed into Australia back in 1969 contains stardust dating back some 7 billion years, predating the formation of Earth by 2.5 billion years. The remarkable discovery offers a snapshot of the conditions that existed long before our solar system came into existence.
Ancient grains found inside the Murchison meteorite have been dated to between 5 billion and 7 billion years old, according to new research published in Proceedings of the National Academy of Sciences. The new paper was led by astronomer Philipp Heck from the University of Chicago.
These grains originated as interstellar dust, and they’re now considered to be the oldest known solid materials on Earth, which formed around 4.5 billion years ago. It’s a remarkable finding, as these materials are evidence of the conditions that existed prior to the formation of our solar system. And indeed, these grains are already providing new astronomical information, including evidence of a “baby boom” period of star formation that happened several billion years ago.
“This is one of the most exciting studies I’ve worked on,” said Heck in a press release.
Stardust comes from stars (shocking, I know) and is hurled into space by stellar winds. Eventually, these bits of stellar matter re-accumulate, forming yet more stars, and sometimes planets, moons, and meteorites (fun fact: you’re also made from this stuff). On Earth, traces of these grains are scant, appearing in only 5 percent of meteorites. They’re also very tiny. As a University of Chicago press release notes, “a hundred of the biggest ones would fit on the period at the end of this sentence.” More specifically, they’re about 8 microns across, which is roughly the size of a single red blood cell.
David Bekaert, a researcher at the Center for Petrographic and Geochemical Research (CPRG) in Nancy, France, who wasn’t involved with the new study, said interstellar dust particles that predate our Sun are known as “presolar grains,” a portion of which reached rocky bodies that arose during the formation of our solar system.
“We’ve known their existence in primitive meteorites for a long time,” Bekaert told Gizmodo. “However, assessing how old they are, and whether or not they were generated in a single star formation episode that predated the formation of our own solar system, had remained hampered by the lack of reliable techniques to date individual presolar grains.”
Key to the new study was an abundance of presolar grains packed inside the Murchison meteorite and a new strategy to date them. But the first step was to isolate the grains.
“It starts with crushing fragments of the meteorite down into a powder,” Jennika Greer, a co-author of the study and a graduate student at the Field Museum and the University of Chicago, said in the press release. “Once all the pieces are segregated, it’s a kind of paste, and it has a pungent characteristic—it smells like rotten peanut butter.”
This putrid-smelling stuff was then dissolved with acid, leaving a few dozen of these presolar grains behind. To date these isolated grains, the researchers applied a technique that measured the degree to which the grains were bombarded by cosmic rays—high-energy particles that zip through space and can penetrate solid objects. Because prolonged exposure to cosmic rays results in heavier elements, the researchers took note of the quantity of these easily detectable elements found in the grains to infer their relative age.
Results showed that the presolar grains were quite ancient, having absorbed a tremendous amount of cosmic rays over the eons. The oldest grains were dated to about 7 billion years ago, with the majority dating to between 4.6 billion and 4.9 billion years ago and a small handful dating to 5.6 billion years ago. So all the interstellar particles found in the Murchison meteorite originated before the formation of our solar system and Sun.
Interestingly, this result shows that star formation was not constant in the galaxy. The glut of particles dating to 4.6 million-4.9 billion years ago suggests these grains originated during a time of intense stellar formation—a kind of baby boom for stars in the Milky Way (our galaxy formed around 8 billion years ago). And in fact, Heck said it was “one of the key findings of our study.”
Bekaert agreed, saying the new paper “relates an impressive technical achievement, as well as an important scientific discovery, providing us with new insights into the evolution of matter within our galactic neighborhood,” up to around 7 billion years ago, he told Gizmodo.
With this new technique, astronomers would be wise to re-visit similar meteorites containing presolar grains to corroborate these findings. There’s still plenty of history to be found in these primordial objects.
Brenna Owen, The Canadian Press
Published Wednesday, April 24, 2024 7:27PM EDT
Last Updated Wednesday, April 24, 2024 7:27PM EDT
The artwork and publicity materials showcasing a giant salmon that lived five million years ago were ready to go to promote a new exhibit, when the discovery of two fossilized skulls immediately changed what researchers knew about the fish.
Initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and had led researchers to mistakenly suggest the fish had fang-like teeth.
It was dubbed the “sabre-toothed salmon” and became a kind of mascot for the Museum of Natural and Cultural History at the University of Oregon, says researcher Edward Davis.
But then came discovery of two skulls in 2014.
Davis, a member of the team that found the skulls, says it wasn’t until they got back to the lab that he realized the significance of the discovery that has led to the renaming of the fish in a new, peer-reviewed study.
“There were these two skulls staring at me with sideways teeth,” says Davis, an associate professor in the department of earth sciences at the university.
In that position, the tusk-like teeth could not have been used for biting, he says.
“That was definitely a surprising moment,” says Davis, who serves as director of the Condon Fossil Collection at the university’s Museum of Natural and Cultural History.
“I realized that all of the artwork and all of the publicity materials and bumper stickers and buttons and T-shirts we had just made two months prior, for the new exhibit, were all out of date,” he says with a laugh.
Davis is co-author of the new study in the journal PLOS One, which renames the giant fish the “spike-toothed salmon.”
It says the salmon used the tusk-like spikes for building nests to spawn, and as defence mechanisms against predators and other salmon.
The salmon lived about five million years ago at a time when Earth was transitioning from warmer to relatively cooler conditions, Davis says.
It’s hard to know exactly why the relatives of today’s sockeye went extinct, but Davis says the cooler conditions would have affected the productivity of the Pacific Ocean and the amount of rain feeding rivers that served as their spawning areas.
Another co-author, Brian Sidlauskas, says a fish the size of the spike-toothed salmon must have been targeted by predators such as killer whales or sharks.
“I like to think … it’s almost like a sledgehammer, these salmon swinging their head back and forth in order to fend off things that might want to feast on them,” he says.
Sidlauskas says analysis by the lead author of the paper, Kerin Claeson, found both male and female salmon had the “multi-functional” spike-tooth feature.
“That’s part of our reason for hypothesizing that this tooth is multi-functional … It could easily be for digging out nests,” he says.
“Think about how big the (nest) would have to be for an animal of this size, and then carving it out in what’s probably pretty shallow water; and so having an extra digging tool attached to your head could be really useful.”
Sidlauskas says the giant salmon help researchers understand the boundaries of what’s possible with the evolution of salmon, but they also capture the human imagination and a sense of wonder about what’s possible on Earth.
“I think it helps us value a little more what we do still have, or I hope that it does. That animal is no longer with us, but it is a product of the same biosphere that sustains us.”
This report by The Canadian Press was first published April 24, 2024.
Science
Nasa's Hubble marks 34th anniversary with stunning view of Little Dumbbell Nebula – The Times of India
In celebration of its 34th anniversary, Nasa‘s Hubble Space Telescope has once again wowed astronomers and space enthusiasts alike by capturing an extraordinary image of the Little Dumbbell Nebula. This latest image offers a vivid glimpse into the complexities of a planetary nebula, demonstrating Hubble’s enduring capabilities in its extended mission.
The Little Dumbbell Nebula, also known as Messier 76, is one of the faintest objects in the Messier catalog and has intrigued astronomers for its intricate structure and dual-lobed shape. This planetary nebula, located approximately 2,500 light-years away in the constellation Perseus, represents a brief stage in the life cycle of a moderate-sized star like our sun.
Dr. Jennifer Wiseman, a senior scientist at Nasa’s Goddard Space Flight Center, expressed her admiration for the new imagery: “This beautiful nebula is what remains after a star like our own sun has exhausted the bulk of its nuclear fuel and shed its outer layers. The vibrant colors and intricate structures visible in the nebula are a telescope’s way of painting the portrait of the final stages of stellar evolution.”
The Little Dumbbell Nebula, despite its faintness, shines brightly in the detailed images provided by Hubble, allowing scientists to study aspects of the nebula that are rarely visible. The images highlight the dense, glowing gas and complex layers of material expelled from the dying star at the center of the nebula.
According to Dr. Wiseman, “Hubble’s high-resolution capabilities allow us to examine the fine details within the nebula, helping us understand how stars expel their material and the dynamics of this expulsion process. This image is more than just a picture; it’s a deep dive into the life of stars.”
Since its launch on April 24, 1990, Hubble has revolutionized our understanding of the universe, from the dynamics of galaxies to the atmospheres of exoplanets and the distribution of dark matter. Its contributions continue to support and complement data gathered by newer space observatories.
As Hubble continues its journey in space, the scientific community remains enthusiastic about the ongoing contributions it will bring to our understanding of the cosmos. Dr. Wiseman remarked, “Every image from Hubble is a new lesson in our cosmic curriculum.”
These observations not only contribute significantly to our knowledge of the life cycle of stars but also continue to highlight the critical role of Hubble in the exploration and understanding of our universe. As Hubble enters another year in orbit, its legacy of discoveries promises to keep inspiring both the scientific community and the public.
SpaceX sent up the 30th launch from the Space Coast for the year on the evening of April 23, a mission that also featured the company’s 300th successful booster recovery.
A Falcon 9 rocket carrying 23 of SpaceX’s Starlink internet satellites blasted off at 6:17 p.m. Eastern time from Cape Canaveral Space Force Station’s Space Launch Complex 40.
The first-stage booster set a milestone of the 300th time a Falcon 9 or Falcon Heavy booster made a successful recovery landing, and the 270th time SpaceX has reflown a booster.
This particular booster made its ninth trip to space, a resume that includes one human spaceflight, Crew-6. It made its latest recovery landing downrange on the droneship Just Read the Instructions in the Atlantic Ocean.
The company’s first successful booster recovery came in December 2015, and it has not had a failed booster landing since February 2021.
The current record holder for flights flew 11 days ago making its 20th trip off the launch pad.
SpaceX has been responsible for all but two of the launches this year from either Kennedy Space Center or Cape Canaveral with United Launch Alliance having launched the other two.
SpaceX could knock out more launches before the end of the month, putting the Space Coast on pace to hit more than 90 by the end of the year, but the rate of launches by SpaceX is also set to pick up for the remainder of the year with some turnaround times at the Cape’s SLC-40 coming in less than three days.
That could amp up frequency so the Space Coast could surpass 100 launches before the end of the year, with the majority coming from SpaceX. It hosted 72 launches in 2023.
More launches from ULA are on tap as well, though, including the May 6 launch atop an Atlas V rocket of the Boeing CST-100 Starliner with a pair of NASA astronauts to the International Space Station.
ULA is also preparing for the second launch ever of its new Vulcan Centaur rocket, which recently received its second Blue Origin BE-4 engine and is just waiting on the payload, Sierra Space’s Dream Chaser spacecraft, to make its way to the Space Coast.
Blue Origin has its own rocket it wants to launch this year as well, with New Glenn making its debut as early as September, according to SLD 45’s range manifest.
2024 Orlando Sentinel. Distributed by Tribune Content Agency, LLC.
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SpaceX launch marks 300th successful booster landing (2024, April 24)
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Giant prehistoric salmon had tusk-like teeth for defence, building nests: study – CP24
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