According to the astronomers of the University of Cambridge, life outside our solar system could be found within a few years, thanks to the discovery of a new class of planets superheats similar to the Earth, the Hyceans.
Cambridge researchers have identified a new class of exoplanets, called Hycean planets, which, just like Earth, are covered by oceans and have hydrogen-rich atmospheres, an essential element to create life, at least according to our “standards”.
Many of the newly discovered planets are “bigger and warmer than Earth”, reaching size up to 2.6 times larger than our planet and atmospheric temperatures reaching almost 200 degrees Celsius, or 392 degrees Fahrenheit.
The Hyceans are further classified into two groups: i “dark” worlds and those “Cold”. As for dark worlds, these have habitable conditions only on their permanent night sides, while cold worlds receive only a little radiation from the stars in which they orbit.
Despite this, researchers believe they could support microbial life forms similar to those found in Earth’s extreme aquatic environments and that Hycean planets are probably common throughout space.
“It is exciting that habitable conditions can exist on planets so different from Earth”
said in a note there co-author of the Anjali Piette study.
Researchers claim that their findings, published last Wednesday in the The Astrophysical Journal, indicate that it is possible to discover life outside our solar system within the next few years.
“The Hycean planets open a whole new path in our search for life elsewhere”
he said Nikku Madhusudhan, lead researcher at the Cambridge Institute of Astronomy.
The history of the exoplanets up to the discovery of the Hyceans
The exoplanets –Planets orbiting a star other than the sun in our solar system–, were first identified nearly 30 years ago and, since then, thousands of these planets have been discovered, most of which are the size of Earth and Neptune.
Planets that resemble Earth or Neptune are often referred to as “Super-Earth” or “mini-Neptune” and they are distinguished in varieties that I tend to be mostly rocky to ice covered, or some middle ground between these two variants.
Most mini-Neptunes are more than 1.6 times the size of Earth – smaller than Neptune but too large to have rocky interiors like Earth. Previous studies on such planets have found that the pressure and temperature below their hydrogen-rich atmospheres would be too high to sustain life.
However, a recent study on the mini-Neptune K2-18b of Madhusudhan’s team, found that under certain conditions these planets, and other similar planets, they could support life.
The result led to a detailed investigation of the full range of planetary and stellar properties for which these conditions are possible, which known exoplanets can satisfy those conditions, and whether their biosignatures can be observable.
“Essentially, when we looked for these various molecular signatures, we focused on Earth-like planets, which is a reasonable starting point, but we think that the Hycean planets offer a better chance of finding different traces of biosignatures. “
Madhusudhan said, later adding:
“A bio-signature detection would transform our understanding of life in the universe. We need to be open about where we expect to find life and what form it might take, as nature continues to surprise us in ways that are often unimaginable ”.
Madhusudhan and his team found that a series of traces of terrestrial biomarkers that are expected to be present in Hycean’s atmospheres would be easily detectable with spectroscopic observations in the near future.
The larger size, higher temperatures, and hydrogen-rich atmospheres of the Hycean planets make their atmospheric signatures much more detectable than Earth-like planets.
The Cambridge team identified a sizable sample of potential Hycean worlds which are the first candidates for detailed study with next generation telescopes, as the James Webb Space Telescope (JWST), which is expected to be launched later this year.
These planets all orbit red dwarfs at a distance of 35-150 light years – close by astronomical standards. The already planned JWST observations of the most promising candidate, K2-18b, could lead to the detection of one or more bio-signature molecules, but for now we just have to wait and see how everything will develop.
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