May 12, 2020 - Science

Brines on Mars may not be habitable

Mars seen by the Hubble Space Telescope. Photo: NASA/ESA/STScI

Seasonal flows of extremely salty water on Mars could be longer-lasting and more frequent than initially thought, though they likely aren't suitable to life as we know it, according to a study in the journal Nature Astronomy this week.

Why it matters: If these brines on the Red Planet are not habitable for microbes as we understand them, then scientists may not need to worry about potentially contaminating these regions during future missions, opening up new avenues of exploration on Mars.

What they found: Seasonal brines on Mars don't get warmer than about -55°F, a much colder temperature than life is known to thrive in.

  • Those liquids can form on about 40% of the Martian surface for as long as six hours, according to the study.

Yes, but: While the study shows it's unlikely that Earth-originating microbes could find safe purchase in Martian brines, that doesn't mean space agencies should send rovers to explore these parts of Mars from very close range.

  • It's still possible that some type of yet-to-be-discovered life on Earth could find a way to live in even this extreme environment on Mars.
  • "My hope is that our work motivates such further research into extremophiles on Earth," Edgard G. Rivera-Valentín, an author of the new study, told Axios via email.

Go deeper: Where to hunt for life on Mars

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Mark Zuckerberg: Social networks should not be "the arbiter of truth"

Photo: Drew Angerer/Getty Images

Facebook CEO Mark Zuckerberg argued on CNBC's "Squawk Box" Thursday that social media platforms should not police political speech, and that "people should be able to see what politicians say.”

Why it matters: Zuckerberg was responding to Twitter's decision this week to fact-check a pair of President Trump's tweets that claimed that mail-in ballots are "substantially fraudulent." Twitter's label, which directs users to "get the facts" about mail-in voting, does not censor Trump's tweets.

House Democrats pull FISA reauthorization bill

Speaker Nancy Pelosi. Photo: Saul Loeb/AFP via Getty Images

House Democrats pulled legislation Thursday that would have renewed expired domestic surveillance laws and strengthened transparency and privacy protections amid broad opposition from President Trump, House GOP leadership and progressive Democrats.

Why it matters: The failure to reauthorize the Foreign Intelligence Surveillance Act (FISA) comes as Trump continues to attack the intelligence community, which he claims abused the law to surveil his 2016 campaign and Trump administration officials.

U.S. GDP drop revised lower to 5% in the first quarter

Data: Bureau of Economic Analysis; Chart: Axios Visuals

The U.S. economy shrunk by an annualized 5% in the first quarter — worse than the initially estimated 4.8% contraction — according to revised figures released by the government on Thursday.

Why it matters: It's the worst quarterly decline since 2008 and shows a huge hit as the economy was just beginning to shut down because of the coronavirus. Economists are bracing for the second quarter's figures to be the worst ever — with some projecting an annualized decline of around 40%.

2 hours ago - Economy & Business