Aug 22, 2017

A blanket of soot from asteroid impact may have killed off dinosaurs


Scientists may have solved the mystery behind one of the five mass extinctions in Earth's history – a time 65 million years ago at the end of the Cretaceous period when a meteor struck the Earth and wiped out dinosaurs and nearly every living creature on the planet. The reason? A blanket of soot cast the Earth into darkness for up to two years, according to a new study.

What they found: Using a sophisticated climate supercomputer, researchers modeled what may have happened when a meteor hit the planet and found such an impact would likely create raging global wildfires and toss a blanket of soot into the atmosphere, thereby keeping more than 99% of sunlight from reaching the surface of the Earth for up to two years.

Why did the dinosaurs die?

  • With the Earth in darkness for that long, photosynthesis would stop; temperatures would plummet by more than 30 degrees Fahrenheit for several years; and the protective ozone layer would be depleted.
  • This creates a deadly combination that the researchers say could have led to mass extinctions and the end of the dinosaurs.
  • Geological evidence shows that the Cretaceous mass extinction event occurred at the same time that a very large asteroid hit Earth in what is now the Yucatan Peninsula.
  • What the new computer model shows is how such a collision would trigger other events in its wake that drastically altered Earth's climate.

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History's largest lockdown leaves Indian workers stranded, afraid

A migrant worker on the move with his child, in Gurugram, India. Photo: Parveen Kumar/Hindustan Times via Getty

Few moments better capture the world into which we've slipped than the decision of one man to order 1.4 billion into lockdown.

Why it matters: India’s three-week lockdown is the largest ever attempted, and it sparked South Asia's greatest migration since partition in 1947. While the economic effects could be devastating, the public health crisis it's intended to fend off could be more destructive still.

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Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 7 p.m. ET: 782,319 — Total deaths: 37,582 — Total recoveries: 164,565.
  2. U.S.: Leads the world in confirmed cases. Total confirmed cases as of 5 p.m. ET: 161,807 — Total deaths: 2,953 — Total recoveries: 5,595.
  3. Federal government latest: The White House will extend its social distancing guidelines until April 30.
  4. State updates: Rural-state governors say testing is still inadequate, contradicting Trump — Virginia, Maryland and D.C. issue stay-at-home orders to residents, joining 28 other states.
  5. Business latest: Ford and General Electric aim to make 50,000 ventilators in 100 days.
  6. In photos: Navy hospital ship arrives in Manhattan.
  7. What should I do? Answers about the virus from Axios expertsWhat to know about social distancingQ&A: Minimizing your coronavirus risk.
  8. Other resources: CDC on how to avoid the virus, what to do if you get it.

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First U.S. service member dies from coronavirus

Photo: Yasin Ozturk/Anadolu Agency/Getty Images.

The Pentagon on Monday announced the death of a member of the New Jersey National Guard who tested positive for the coronavirus.

Why it matters: It's the first U.S. service member — active, reserve or Guard — to die from the virus, according to the Pentagon. The guardsman passed away on Saturday after being hospitalized for the novel coronavirus on March 21.