Alien-hunting astronomers rallied to find life in space with ‘ET cheat sheet’ – and they’re looking for a mint-green planet

Alien-hunting astronomers rallied to find life in space with 'ET cheat sheet' – and they're looking for a mint-green planet

ASTRONOMERS have created a ‘cosmic cheat sheet’ which could help both experts and amateur stargazers search for alien life.
The scientists used natures colour palette to create a comparison chart of shades to look for when observing exoplanets because this may be able to determine how far along that planet is in its evolutionary spectrum.
2 The chart shows that dark green colours spotted on a planet outside our solar system could suggest land vegetation and aqua blue could suggest bacteriaCredit: Illustration by Wendy Kenigsberg/Cornell Brand Communications
An exoplanet is a planet that is outside of our solar system and lots of scientists are hunting for one that might contain life.
The exoplanet ‘cheat sheet’ was created by astronomers from Cornell University in the US and has been published in the Astrophysical Journal.
Co-author Jack O’Malley-James said: “In our search to understand exoplanets, we’re using the early Earth and its biological milestones in history as a Rosetta stone.
“Scientists can observe surface biosignatures beyond vegetation on Earth-like exoplanets by using our own planet as the key for what to look for.”
2 Kepler-62e is a super-Earth exoplanet, which may be a terrestrial or water planetCredit: NASA/JPL-Caltech/T. Pyle
Co-author Lisa Kaltenegger added: “Astronomers had concentrated only on vegetation before, but with a better colour palette, researchers can now look beyond a half-billion years and up to 2.5 billion years back on Earth’s history to match like periods on exoplanets.
“If an alien had used colour to observe if our Earth had life, that alien would see very different colours throughout our planet’s history – going back billions of years – when different life forms dominated Earth’s surface.”
On the graph, dark green represents land vegetation, light green represents ferns, grey/mint green represents lichens and aqua represents cyanobacteria.
So if you’re an astronomer and you’ve spotted a light blue planet outside the solar system, you might be on to something.
This colour coding is all made possible by chlorophyll – present in many forms of bacteria and plant life – that leaves telltale signs of life on a planets surface.
Around 1.2 billion years ago the Earth would have looked a greyish mint green thanks to lichens all over the surface.
Kaltenegger concluded: “When we discover an exoplanet, this research gives us a much wider range to look back in time.
“We extend the time that we can find surface biota from 500 million years (widespread land vegetation) to about 1 billion years ago with lichen and up to 2 or 3 billion years ago with cyanobacteria.”
What is an exo-planet?Here’s what you need to know…

An exoplanet is a planet that is located outside of our Solar System and one that is orbitting its own star, like how Earth orbits the Sun
They are very hard to see with telescopes because they are often hidden by the brightness of their star
Nasa sent the Kepler space telescope into orbit with the purpose of finding Earth sized exoplanets that might support life
Over 4,000 exoplanets have been discovered so far and more missions to find even more exoplanets are planned
A good way to spot an exoplanet is to look for “wobbly” stars because a disruption to star light can indicate that a planet is orbitting it and therefore blocking out light on occasion
Expoplanets are very common in the Universe and the more we find that look like Earth the closer we get to knowing if we’re not alone out there

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Do you think there is alien life out there? Let us know in the comments…

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