With thousands of discovered exoplanets and new missions that will explore our Solar System, the search for life in the Universe has entered a new era. However, a reference database to enable the search for life on the surface of icy exoplanets and exomoons by using records from Earth’s icy biota is missing. To facilitate the search for extraterrestrial signs of life, Universidade de Lisboa astrobiologist Lígia Coelho and her colleagues developed a spectra catalog of life in ice.
As ground-based and space telescopes get larger and can probe the atmosphere of rocky exoplanets, astronomers need a color-coded guide to compare them and their moons to vibrant, tinted biological microbes on Earth, which may dominate frozen worlds that circle different stars.
But they need to know what microbes that live in frigid places on Earth look like before they can spot them elsewhere.
“On Earth, vibrant, biological colors in the Arctic represent signatures of life in small, frozen niches,” Coelho said.
“We grew and measured this frigid, colorful biota at the Carl Sagan Institute at Cornell University.”
In their study, Coelho and co-authors measured the reflection spectra of 80 microorganisms with a wide range of pigments.
They collected these organisms from ice and water at Kuujjuarapik in Quebec, Canada, working across the frozen Hudson Bay, obtaining ice cores and drilling holes in the ice to take water samples.
“When searching for life in the cosmos, microbes in these frozen plains of the Arctic give us crucial insight of what to look for on cold new worlds,” said Professor Lisa Kaltenegger, a senior author on the paper, director of the Carl Sagan Institute at Cornell University.
“This icy microbial life is well-adapted to the harsh radiation bombardment of space — which can be the norm on distant exoplanets under a red sun.”
“We are assembling the tools to search for life in the Universe, so as not to miss it, taking all of Earth’s vibrant biosphere into account — even those in the breathtaking chilled places of our Pale Blue Dot.”
The team’s paper appears in the journal Astrobiology.
Lígia F. Coelho et al. 2022. Color Catalogue of Life in Ice: Surface Biosignatures on Icy Worlds. Astrobiology 22 (3): 313-321; doi: 10.1089/ast.2021.0008
Source link: https://www.sci.news/astronomy/icy-world-surface-biosignatures-10623.html