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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Updated 25 mins ago - Politics & Policy

Coronavirus dashboard

Illustration: Aïda Amer/Axios

  1. Politics: Chris Christie: Wear a mask "or you may regret it — as I did" — Senate Democrats block vote on McConnell's targeted relief bill.
  2. Economy: Why the stimulus delay isn't a crisis (yet).
  3. Health: The pandemic is getting worse again New York reports most cases since MayMany U.S. coronavirus deaths were avoidable.
  4. Education: Boston and Chicago send students back home for online learning.
  5. World: Spain becomes first nation in Western Europe to exceed 1 million cases — France becomes the second.

Biden says he will appoint commission on Supreme Court reform

Photo: Chip Somodevilla/Getty Images

Joe Biden told CBS' "60 Minutes" this week that if elected, he would put together a bipartisan commission to study the federal court system and make recommendations for reform.

Why it matters: Biden has come under pressure to clarify his position on court packing after some Democrats suggested expanding the court if Senate Republicans confirm President Trump's Supreme Court nominee Amy Coney Barrett.

Dion Rabouin, author of Markets
56 mins ago - Economy & Business

Wall Street still prefers bonds

Illustration: Aïda Amer/Axios. Photo: Sunset Boulevard/Getty Contributor

Investors' return on U.S. corporate bonds has been falling since its August peak, but buying has only accelerated, especially in investment grade bonds that are offering historically low yields.

The state of play: Since hitting its 2020 high on Aug. 4, the benchmark Bloomberg Barclays U.S. bond aggregate has delivered a -2.2% return. (For comparison, the S&P 500 has gained 3.9% during the same time period.)