False positive: Exoplanets could have lots of oxygen but no life

Oxygen is thought to be a biomarker for extraterrestrial life, but there are at least three different ways that a lifeless planet can produce it.

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  • If an exoplanet houses life, it almost certainly will have gaseous oxygen.
  • But a new study modeling the development of rocky planets identifies three scenarios in which oxygen can form abiotically.
  • The notion that oxygenated exoplanets are all candidates to host life should be treated with skepticism.
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Less-advanced alien civilizations may be nearby — but we're not looking for them

Humans are more likely to have "first contact" with an advanced alien civilization, according to a recent NASA-funded paper.

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  • A new paper outlines some of the most promising ways scientists and space agencies can search for evidence of extraterrestrial civilizations.
  • Because of a concept called "contact inequality," the researchers suggested it's relatively unlikely humans will discover evidence of alien civilizations that have similar levels of technology to us.
  • However, near-future technology could soon allow scientists to search for both highly advanced and less advanced alien civilizations.
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Lightning may have provided a key mineral for early life on Earth

How do you get usable phosphorus into a system? A new study suggests lightning can do the trick.

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  • A chance discovery in suburban Illinois may change how we understand the dawn of life.
  • Among other things, life needs water-soluble phosphorus, which was hard to come by 3.5 billion years back.
  • This finding may imply that life has more opportunities to begin on other worlds than previously supposed.
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NASA's Perseverance records first-ever sounds of rover driving on Mars

Sound waves behave quite differently on Mars than on Earth.

Credit: NASA
  • NASA's Perseverance rover landed on Mars on February 18, and is currently preparing to begin its main mission of searching for signs of ancient life.
  • The rover contains two microphone systems, one of which was recently used to capture sounds of the rover traveling at speeds below .01 mph.
  • NASA hopes to return Perseverance's rock collection to Earth by 2031.
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If we do find alien life, what kind will it be?

Three lines of evidence point to the idea of complex, multicellular alien life being a wild goose chase. But are we clever enough to know?

Credit: "Mars Attacks!" / Warner Bros
  • Everyone wants to know if there is alien life in the universe, but Earth may give us clues that if it exists it may not be the civilization-building kind.
  • Most of Earth's history shows life that is single-celled. That doesn't mean it was simple, though. Stunning molecular machines were being evolved by those tiny critters.
  • What's in a planet's atmosphere may also determine what evolution can produce. Is there a habitable zone for complex life that's much smaller than what's allowed for microbes?
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