Exoplanets

On December 17th, the European Space Agency’s CHEOPS telescope will blast into space to take a closer look at some of the potentially habitable planets we’ve found beyond our solar system. Ahead of its launch, Horizon takes an in-depth look at what we already know about such exoplanets and what’s still to learn. We speak to Dr Michaël Gillon, who in 2017 was instrumental in discovering a system of seven Earth-like planets outside our solar system, about the diversity of the thousands of exoplanets we’ve found so far and next steps for research. We talk to scientists who are trying to understand the structure of Super-Earths – planets up to 10 times the size of Earth – by recreating elements of planetary cores in their labs, and others who are trying to understand how different planetary systems formed in the first place. Finally, we delve into one of the most important conditions for life to exist on exoplanets – their atmospheres – and find out how scientists are trying detect the biosignature gases that indicate the presence of life.

Space, Frontier research

Probing exoplanet atmospheres could reveal telltale signatures of life

It may be that life is lurking out there on other planets. But stuck here on Earth, how can we ever know for sure? A good place to start is by looking for the compounds on other worlds that are known to be the key ingredients of life as we know it.

The way that a young exoplanet interacts with its star's disc of dust and gas determines the type of exoplanet that will ultimately form. Image credit - NASA/JPL-Caltech/D. Berry

Space, Frontier research

Zeroing in on baby exoplanets could reveal how they form

Twenty-four years ago, Swiss astronomers Michel Mayor and Didier Queloz discovered the first planet orbiting a sun-like star outside our solar system – a milestone recognised by this year’s Nobel prize in physics. Today we know of thousands more ‘exoplanets’, and researchers are now trying to understand when and how they form.

The habitability of a super-Earth could be related to its having a magnetic field. Image credit - ESA/Hubble, M. Kornmesser, licensed under CC BY 4.0. Artist’s impression of super-Earth K2-18 b

Space, Frontier research

Is there life on super-Earths? The answer could lie in their cores

Rocky planets larger than our own, so-called super-Earths, are surprisingly abundant in our Galaxy, and stand as the most likely planets to be habitable. Getting a better idea of their interior structures will help predict whether different planets are able to generate magnetic fields – thought to be conducive for life to survive.

One of the main goals of exoplanet research is to work out the frequency of potentially habitable planets, according to Dr Gillon. Image credit - ©ULiège / JLWertz

Interview, Space, Frontier research

'We've found dozens of potentially habitable planets - now we need to study them in detail'

From the first discoveries of planets beyond our solar system in the 1990s, we now know of thousands of alien worlds, some of which could even be habitable to life as we know it. Now we need to detect more of these exoplanets and study them in detail, says astronomer Dr Michaël Gillon from the University of Liège in Belgium, who was involved in one of the most important exoplanet discoveries to date.

Scientists are working out how cosmic dust turns into hard, spherical pebbles which can then develop into planets. Image credit - NASA/JPL-Caltech

Space, Frontier research

From dust to pebbles to planets – insight into the birth of a solar system

Detailed simulations of planetary formation are revealing how tiny grains of dust turn into giant planets and could shed light on where to find new Earth-like worlds.

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