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Comet May Have Hit Earth 56 Million Years Ago, Triggered warm, ice-free period on Earth: Scientists

The researchers said they have not found the location of an impact crater linked to the collision

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A tiny sand-grain-size tektite, thought to be created when vaporized material from an impact solidified while flying through the air, is shown in this image released in New York, Oct. 13, 2016. VOA

October 14, 2016: Droplets of glass dug up in New Jersey and from the Atlantic seabed indicate a comet or some other extraterrestrial object may have smacked Earth 56 million years ago, roughly 10 million years after the asteroid impact that doomed the dinosaurs.

Scientists said on Thursday the collision may have triggered a particularly warm, ice-free period on Earth when important mammalian groups, including the primate lineage that led to humans, appeared for the first time.

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The findings, published in the journal Science, marked the latest evidence of the profound influence that past impacts by celestial bodies have had on life on Earth.

The tiny spherical bits of dark glass, called microtektites, represent strong evidence of a collision with a comet or asteroid, the researchers said. They form when a space rock hits Earth’s surface and vaporises the spot where it lands, ejecting into the air bits of molten rock that solidify into glass.

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The microtektites were excavated from a geological layer marking the start of the Eocene Epoch about 56 million years ago from three sites in southern New Jersey (Millville, Wilson Lake and Medford) and an underwater site east of Florida.

That coincided with the beginning of a warming event, called the Paleocene-Eocene Thermal Maximum, associated with an accumulation of atmospheric carbon dioxide. It lasted more than 100,000 years and drove up global temperatures about 9-14 degrees Fahrenheit (5-8 degrees Celsius).

The impact of an asteroid about six miles wide (10 km) off Mexico’s Yucatan Peninsula 10 million years earlier killed off many marine and terrestrial creatures including the dinosaurs, and enabled mammals to gain supremacy.

No such mass extinction was associated with the event 56 million years ago, although many single-celled ocean-bottom creatures disappeared. During the warming period, primates and two mammal groups — one that includes deer, antelope, sheep and goats and another that includes horses and rhinos — first appear in the fossil record.

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The researchers said they have not found the location of an impact crater linked to the collision. They said geological evidence suggested the object was a comet.

“We can’t really say where it was, or how big, at this point,” said geochemist Morgan Schaller of Rensselaer Polytechnic Institute, who led the study.

While the findings are not proof that the impact caused the warming period, they are “a rather dramatic finding in support of an impact trigger” for the climate changes, said planetary scientist Dennis Kent of Columbia University’s Lamont-Doherty Earth Observatory and Rutgers University. (VOA)

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Earth’s Twin? Scientists Discover Two Planets that Could Support Life

Scientists have been searching for planets close to nearby stars since 2016 using a 3.5-meter telescope

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The Doppler technique detected at least two signals, which have now been identified as planets Teegarden b and Teegarden c. Pixabay

Two exoplanets that have been discovered, which are warm similar to Earth and may have water, could be good candidates to support life, according to a study on Tuesday. Scientists have been searching for planets close to nearby stars since 2016 using a 3.5-meter telescope.

Images captured at the Calar Alto Observatory in Almeria, southern Spain, and two other Spanish telescopes allowed researchers to analyse, in great detail, the Teegarden star — a cold red dwarf only around 12.5 light years away from our solar system, Efe news reported.

“Teegarden only has eight per cent of our sun’s mass,” said Ignasi Ribas, co-author of the study. “It is much smaller and much less brighter than the Sun. In fact, despite being very close to the Earth it was not discovered until 2003,” Ribas said.

The temperature of the star is around 2,600C (the Sun’s temperature is 5,500C) and because it is 10 times smaller, it’s 1,500 times weaker and radiates mostly infrared waves.

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“In other words, they are much closer to their (parent) star than the Earth is to the Sun,” Ribas said. Pixabay

Once the star was found, scientists used the Doppler technique, also known as the wobble method, which uses radial-velocity measurements of the parent star to detect planets around it.

The Doppler technique detected at least two signals, which have now been identified as planets Teegarden b and Teegarden c. Teegarden b has the mass similar to Earth and orbits the star every 4.9 days. The second planet takes 11.4 days to complete the orbit, which is the length of its year. “In other words, they are much closer to their (parent) star than the Earth is to the Sun,” Ribas said.

“Teegarden, the more internal one, receives 10 per cent more light than we do from the Sun, that’s why we think it may be too hot and may not have water. But this is just speculation because there are elements of its climate that we don’t know and that could mean there could be liquid water,” he continued.

Teegarden hovers in the midst of a habitable zone, which means the temperature on its surface is between 0 degree Celcius and 100 degree Celcius, meaning it could very well have water on surface.

earth twins, life
Once the star was found, scientists used the Doppler technique, also known as the wobble method, which uses radial-velocity measurements of the parent star to detect planets around it. Wikimedia Commons

What scientists are excited about is that both exoplanets are excellent candidates to support life, alongside Proxima, which to date was the planet that presented the best conditions for habitability.

ALSO READ: NASA Selects Missions to Study Sun, its Effects on Space Weather

Experts believe between the closest star to our solar system — Proxima Centauri that is four light years away, and Teegarden (the 24th furthest away at 12 light years) — there are dozens of stars, some with planets orbiting them, but “apart from Proxima, none of them present ideal conditions (for life),” Ribas said.

Researchers have not ruled out the possibility of there being more planets orbiting Teegarden, but the system would have to be observed in more detail. “These planets are of great interest in order to search for life in the mid-term,” Ribas said. Without doubt, for the scientist, the forthcoming decade will be thrilling and key in space exploration and the search for suitable terrestrial exoplanets. (IANS)