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.
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 vaporizes the spot where it lands, ejecting into the air bits of molten rock that solidify into glass.
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.
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.
(Reporting by Will Dunham; Editing by Sandra Maler)
Two impeachment articles expected against President Trump: reports
Democrats are expected to announce on Tuesday two articles of impeachment against Donald Trump, US media reported Monday evening, after laying out their case at a hearing against a president they branded a "clear and present danger" to national security.
The articles will focus on abuse of power and obstruction of Congress, The Washington Post said, citing three official familiar with the matter.
It added that the full House of Representatives would vote on the articles next week, ahead of a trial in the Senate.
CNN said a third article on obstruction of justice was still being debated, and the network's sources cautioned that plans were still being finalized.
Ambassador McFaul ‘shocked’ Trump invited Sergey Lavrov back to the Oval Office: ‘What are they thinking?’
Former Ambassador to Russia Michael McFaul repeatedly said he was shocked that President Donald Trump will meet with Russian Foreign Minister Sergey Lavrov on Tuesday.
McFaul was interviewed Monday evening by Lawrence O'Donnell on MSNBC "The Last Word," where he contrasted how Trump is treating the Russian government of President Vladimir Putin to the Ukrainian government of President Volodymyr Zelensky.
"Ambassador McFaul, I want to get your reaction to the Russian foreign minister meeting tomorrow at the White House, in the Oval Office, with President Trump," O'Donnell said. "That's his second time. President Zelinsky still hasn't gotten that meeting and Donald trump apparently, apparently may be voted articles of impeachment in committee this week because of his interactions with President Zelensky."
House Judiciary to vote on Thursday to impeach Donald Trump: report
Democrats are moving ahead with the impeachment of President Donald Trump following another day of testimony on Monday.
"House Democrats plan to unveil at least two articles of impeachment Tuesday, charging President Donald Trump with abuse of power and obstruction of Congress, according to multiple lawmakers and aides. The Judiciary Committee plans to vote on the articles on Thursday, setting up a vote on the House floor next week to make Trump the third president in history to be impeached," Politico reported Monday evening.
"Democratic leaders plan to formally announce the articles at a press conference Tuesday morning. Judiciary Committee Democrats intend to meet ahead of the announcement and review the articles," Politico reported. "The decision to move forward with specific impeachment charges is the most significant move yet for the year-old Democratic House majority, a legacy-defining moment for Speaker Nancy Pelosi that sets up a Senate trial for Trump in early 2020."