Scientists investigated how cosmic rays might influence the habitability of distant alien worlds. The hundreds of exoplanets astronomers have discovered in the past two decades using ground and space telescopes have raised the possibility that some might be home to extraterrestrial life. Interest is especially focused on worlds in so-called habitable or Goldilocks zones, which receive enough heat to possess surfaces that can keep water liquid rather than freeze — on Earth, there is life virtually wherever there is liquid water.
The investigators reasoned the level of radiation a planet receives helps control its habitability. While a planet might see much fewer galactic cosmic rays compared to the radiation from its star, the average energy of cosmic rays is far higher than photons and protons from the star, making them critical to focus on.
"If the radiation dose is too high, then life as we know it cannot exist," said study author Dimitra Atri, a physicist at the Blue Marble Space Institute of Science, a nonprofit institute with a network of scientists across the world.
The researchers concentrated on two factors that might influence the cosmic ray dose a planet gets — the strength of its magnetic field, and the depth of its atmosphere.
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