Jun 18, 2019

Meteors may help seed clouds on Mars

Miriam Kramer, author of Space

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.

Go deeper

Trump threatens to deploy military amid national unrest

President Trump announced from the White House Rose Garden Monday evening that he is "mobilizing all available federal resources, civilian and military" to stop violent protests across the country, decrying "professional anarchists, looters, criminals, antifa and others" whose actions have "gripped" the nation.

The backdrop: Trump's announcement came as police clashed with protesters just outside of the White House, using tear gas and rubber bullets to disperse crowds chanting, "Hands up, don't shoot," and other slogans. Flash bangs used outside the White House could be heard from the Rose Garden.

Updated 1 hour ago - Politics & Policy

Autopsies say George Floyd's death was homicide

Police watch as demonstrators block a roadway while protesting the death of George Floyd in Miami. Photo: Joe Raedle/Getty Images

Preliminary results from an independent autopsy commissioned by George Floyd's family found that his death in the custody of Minneapolis police officer Derek Chauvin was "homicide caused by asphyxia due to neck and back compression that led to a lack of blood flow to the brain," according to a statement from the family's attorney.

The latest: An updated official autopsy released by the Hennepin County medical examiner also determined that the manner of Floyd's death was "homicide," ruling it was caused by "cardiopulmonary arrest complicating law enforcement subdued, restraint, and neck compression."

The Biden-Trump split screen

Photos via Getty Images: Jim Watson/AFP (L); Yasin Ozturk/Anadolu Agency (R)

The differences between former Vice President Joe Biden and President Trump are plain as day as the two respond to recent protests.

Why it matters: Americans are seeing firsthand how each presidential nominee responds to a national crisis happening during a global pandemic.