Sky & Telescope - May 2021 - 34
LOOKING FOR LIFE
by Arwen Rimmer
Building a Better
Biosignature
Finding signs of alien life requires
more prep work than you might think.
E
very genre has its tropes, and science fiction is
no exception. Stories set in space often center
around the discovery of strange new worlds,
and the narrative tradition in these situations usually demands that someone " scan for signs of life. "
It's quite simple, really: An order is given, a touchscreen touched, and an answer promptly received.
If you've ever wondered at this fictive sleightof-hand, and whether such remote sensing is even
possible, you're in good company. Astrobiologists all
across the world are laboring to transform this pretend practice into a real science. We are a long way
from, " Alexa, check for life signs on Kepler-186f. "
But someday, we may know enough about the clues
life creates to estimate what portion of our galaxy's
terrestrial worlds, if any, are life-bearing.
The key for remote sensing is biosignatures. A
biosignature is something - whether a substance, a
pattern, or even an object - that (probably) had to
be made by life in order to exist. It is not life itself,
but something made by life, a kind of fingerprint.
34
M AY 2 0 2 1 * S K Y & T E L E S C O P E
Sky & Telescope - May 2021
Table of Contents for the Digital Edition of Sky & Telescope - May 2021
Contents
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