Clouds moving above the Curiosity rover on Mars. Gif: NASA/JPL-Caltech

A new study in the journal Nature Geoscience finds meteors may be responsible for helping to form clouds in Mars' middle atmosphere, about 18 miles above the ground.

Why it matters: Learning more about the red planet's current climate could help scientists piece together the world's past. The origins of the clouds in the middle atmosphere were a mystery until now.

Details: Meteors deliver about 2 to 3 tons of space debris to Mars each day. The new study suggests the "meteoric smoke" produced when these space rocks break up in the Martian atmosphere allow water molecules to coalesce around the bits of dust, forming clouds.

  • The study used computer simulations to piece together how these mysterious clouds form.
  • When the researchers added in material brought to Mars by meteors, the clouds in the middle atmosphere appeared in the model.
  • Other clouds on Mars, particularly in lower parts of the planet's atmosphere, form when dust is kicked up from the Martian surface.

What they found: The wispy clouds may play an important role in determining the temperature in the Martian atmosphere, which could vary by as much as 18°F, 10°C, depending on the cloud cover, the researchers say.

Be smart: Meteoric smoke also helps form clouds on Earth. One explanation for noctilucent clouds that form high in Earth's atmosphere centers around meteor dust.

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Updated 1 min ago - Politics & Policy

Coronavirus dashboard

Illustration: Annelise Capossela/Axios

  1. Global: Total confirmed cases as of noon ET: 20,391,697 — Total deaths: 744,211— Total recoveries: 12,625,076Map.
  2. U.S.: Total confirmed cases as of 11:30 a.m. ET: 5,161,612 — Total deaths: 164,690 — Total recoveries: 1,714,960 — Total tests: 63,252,257Map.
  3. Business: U.S. already feeling effects of ending unemployment benefits — U.S. producer prices rose last month by the most since October 2018.
  4. Public health: America is flying blind on its coronavirus response.
  5. Education: Gallup: America's confidence in public school system jumps to highest level since 2004.
  6. World: Lebanon reports coronavirus record, UN warns Beirut blast may drive cases higher
31 mins ago - World

U.S. threatens to veto UN peacekeeping in Lebanon over Hezbollah concerns

Peacekeepers with Lebanese troops in southern Lebanon. Photo: Jalaa Marey/AFP via Getty

The Trump administration is threatening to veto a resolution to extend the UN's long-standing peacekeeping mission in southern Lebanon if its mandate isn't changed, Israeli and U.S. officials tell me.

Why it matters: The U.S. is the main funder of the UN Interim Force in Lebanon (UNIFIL), which has an annual budget of $250 million. The veto threat is a tactical move, and part of a broader effort to put pressure on Iran and its proxy in Lebanon, Hezbollah.

Trump congratulates QAnon conspiracy theorist on GOP runoff win

Photo: Brendan Smialowski/AFP via Getty Images

President Trump on Wednesday tweeted congratulations to Marjorie Taylor Greene, a vocal QAnon conspiracy theorist who won the Republican nomination in Georgia's deep-red 14th Congressional District runoff.

Why it matters: The president's approval illustrates how the once-fringe conspiracy theory has gained ground within the GOP. Greene is among the at least 11 GOP candidates for Congress who have openly supported or defended the QAnon movement or some of its tenets, per Axios' Jacob Knutson.