2019 September 17
Explanation:
Where else might life exist?
One of humanity's great outstanding questions, locating planets where
extrasolar life might survive took a step forward recently with the
discovery of a significant amount of water vapor in the atmosphere of
distant exoplanet
K2-18b.
The planet and it parent star,
K2-18,
lie about 124 light years away toward the constellation of the
Lion
(Leo).
The
exoplanet is significantly larger and more massive than our Earth, but orbits in the
habitable zone of its home star.
K2-18, although more red than our Sun, shines in
K2-18b's
sky with a brightness similar to the
Sun in Earth's sky.
The
discovery
was made in data from three space telescopes:
Hubble,
Spitzer, and
Kepler, by noting the absorption of water-vapor colors when the
planet moved in front of the star.
The
featured illustration imagines exoplanet K2-18b on the right, its parent
red dwarf star
K2-18 on the left, and an unconfirmed sister planet between them.