Scientists solve 3.5 billion-year-old mystery of life and its link to meteorites

[Vikrant]

It seems life may have received a boost from asteroids smashing into the surface of Earth early in its life.

According to a newly published report produced by researchers at the University of South Florida (USF) and the University of Washington, life-producing phosphorus may have landed on Earth 3.5 billion years ago, providing a boost to early life forms.

USF professor Matthew Pasek, who led the study, says the phosphorus, when released in water, may have over time incorporated themselves into prebiotic molecules. The phosphorus, which has been found in asteroids, was likely carried to Earth via comets and meteorites, which released the element when impacted Earth.

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Scientists solve 3.5 billion-year-old mystery of life and its link to meteorites | The Space Reporter

 

[waltky]

New Kind of Meteorite Discovered in Sweden...

New Kind of Meteorite Unearthed in Sweden
June 16, 2016 - Scientists say they’ve discovered a new kind of meteorite that was unearthed in a Swedish quarry.

Writing in the journal Nature Communications, researchers from the University of California, Davis say the meteorite, which is called Ost 65, is “chemically distinct from all known meteorite types.” "In our entire civilization, we have collected over 50,000 meteorites, and no one has seen anything like this one before," said study co-author Qing-zhu Yin, Professor of geochemistry and planetary sciences at UC Davis. "Discovering a new type of meteorite is very, very exciting." Ost 65, researchers say, is likely to have come from the “missing partner” of a huge asteroid collision that took place 470 million years ago that caused debris to shower Earth for over a million years. The other asteroid involved in the collision was the L-chondrites, the most common type of meteorites.

A meteorite discovered in a Swedish quarry is unique and distinct from other meteorites. It appears to be a relic of a massive collision in the asteroid belt 470 million years ago that send debris raining to Earth during the Ordovician Period​

The rain of meteors — which fell at 100 times the rate they do now — could have led to a blossoming of new life on Earth during the Ordovician Period, which began 488 million years ago and lasted for 45 million years. "I think this shows the interconnectedness of the entire solar system in space and time, that a random collision 470 million years ago in the asteroid belt could dictate the evolutionary path of species here on Earth," Yin said. Discovered in the Thorsberg quarry, Ost 65 is considered a fossil meteor. It measures just over 10 centimeters in diameter and “looks like a gray cow patty plopped into a pristine layer of fossil-rich pink limestone,” researchers say.

It’s called a fossil because much of the original material is “completely altered,” except for spinels and chromite, two minerals. A chemical analysis, however, revealed that Ost 65 was different. Researchers were able to ascertain the age of the meteorite by measuring how long it was exposed to cosmic rays.They believe it floated through space for about a million years before finally falling to Earth. This matches with the age of the other L-chondrite meteorites found in the same quarry.

New Kind of Meteorite Unearthed in Sweden

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‘Quasi’ Moon Discovered Orbiting Earth
June 16, 2016 - Astronomers have discovered a new “quasi” moon orbiting Earth.

2016 HO3, as the asteroid is called, is at least 40 meters across and could be larger, up to 100 meters, researchers say, but it’s too far from Earth to qualify as a true satellite or mini-moon. "Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the sun, we refer to it as a quasi-satellite of Earth," said Paul Chodas, manager of NASA's Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California.

"One other asteroid -- 2003 YN107 -- followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth's companion for centuries to come."

NASA says there is a previously undiscovered "quasi" moon orbiting the Earth and sun.​

The asteroid, NASA says, “spends about half of the time closer to the sun than Earth and passes ahead of our planet, and about half of the time farther away, causing it to fall behind.” "The asteroid's loops around Earth drift a little ahead or behind from year to year, but when they drift too far forward or backward, Earth's gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the moon," said Chodas. "The same effect also prevents the asteroid from approaching much closer than about 38 times the distance of the moon. In effect, this small asteroid is caught in a little dance with Earth." 2016 HO3 was first observed in April by the Pan-STARRS 1 asteroid survey telescope on Haleakala, Hawaii.

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Scientists Discover Building Blocks of Life Around Forming Planets
June 15, 2016 - The ingredients of life are scattered throughout the universe. New stars are born from the remains of their ancestors, and whatever material doesn't go into the star swirls around it in a disk, building up into planets, dwarf planets, asteroids and comets.

This is how our solar system formed. Scientists understand the mechanism, but they don't know all the ingredients. Carbon, which is the foundation of life on Earth, is formed in the interior of stars and dispersed at the end of their lives. It has an uncanny ability to combine with other atoms to form complex organic molecules, and amino acids — another essential building block of life. These links of life are found in the dusty shroud that envelops a forming star, as well as in comets and, recently, on the surface of Pluto. Where they haven't been found is the stage in between, in the disks around young, newly-formed stars where planets form.

Some questions answered

Scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile have detected, for the first time, methanol in the planet-forming disk around a very young star. The star, named TW Hya, is only slightly smaller than the Earth’s sun, so researchers believe this system looks similar to how our solar system looked when it formed planets. "Because we now detect [methanol] in disks, we have that missing link between … stars that we don't yet see a disk around and ... comets," explained Catherine Walsh, principal investigator of the study. This detection shows that methanol can make the transition from star creation into the planet-forming disk, where it can be incorporated into comets and planets. The methanol was detected in the region that is equivalent to where Pluto and comets are found in our own solar system. However, the TW Hya system is only beginning to form its planets and comets.

Radio telescope antennas of the ALMA (Atacama Large Millimeter/submillimeter Array) project, in the Atacama desert, some 1500 km north of Santiago, Chile, March 12, 2013. Scientists using the ALMA have detected, for the first time, methanol in the planet-forming disk around a very young star.​

NASA's New Horizons mission to Pluto detected organic molecules on the surface and in the atmosphere of the dwarf planet. William McKinnon, a member of the New Horizons team and professor of Earth and Planetary Sciences at the California Institute of Technology, tells VOA they also have evidence for methanol on Pluto's surface. The team announced those results at the Lunar and Planetary Science Conference in March. "The detection of methanol in the disk of TW Hya is an important step in understanding how icy worlds ... form around stars," McKinnon said. Finding these molecules during the formation of the planets coincides with their detection in the pristine, icy worlds of our outer solar system.

More questions remain

Methanol must be in a gaseous form to be detected. But the disks around these newly formed stars are so cold, their chemicals are expected to be trapped in ice, explains Walsh. "There is some other chemical process which is releasing methanol from the icy grains into the gas phase," she said. Her team needs higher resolution data from the ALMA telescope in order to confirm the chemical origin of the methanol.

NASA's New Horizons team says there is evidence of methanol on Pluto's surface.​

Also, the amount of methanol detected is lower and closer to the star than predicted by models run by Walsh. The researchers are now using the observed data to modify the chemical ingredients of their models to match what they see in space. Using ALMA, astronomers have now shown that methanol is present at all stages of planet formation. This leads them to conclude that other complex organic molecules must be present in these planet-forming disks as well, meaning life has all it needs to get started.

Carbon left over from star formation migrates to forming planets