Can distant planets support life? This fridge-sized telescope hopes to find out
TORONTO -- As theatre-goers travel to galaxies far, far away this month with the cast of Star Wars, a high-tech satellite off the big screen will be cruising through space on a galactic journey of its own: to learn more about distant planets.
Earlier this week, a European Space Agency (ESA) satellite was borne up into the night sky by a Russian rocket in the launch of a mission called Cheops.
Unlike other missions investigating extra-solar planets -- also known as exoplanets -- Cheops is not a discovery only mission, scientists say.
“Cheops is the first instrument that is really dedicated to the follow-up of exoplanets that are known to exist," said Matthias Beck, Cheops ground segment manager.
The mission will examine exoplanets whose location has already been pinpointed and try to categorize them further by looking at their size and mass in hopes of understanding more about the exoplanets’ composition.
Cheops -- pronounced “KAY-ops” -- gets its name from a mashup of “Characterizing ExOPlanet Satellite,” according to ESA’s website. The telescope on board is roughly the size of a refrigerator, and it’s going to focus its gaze on bright star systems that house planets larger than Earth, but smaller than Neptune.
Cheops will also try to create a shortlist of exoplanets that could be worth even closer inspection in the future – potentially for their capacity to support life.
According to the ESA, one of the open questions that Cheops will address is whether planets that are larger than Earth but have a similar composition “could bear habitable conditions.”
"This is one of the steps towards perhaps the ultimate question that we ask ourselves as a civilization,” said Kate Isaak, an ESA Cheops project scientist. “And that is ‘Are we alone?’"
The Cheops mission builds on previous space missions that identified these far-flung planets. TESS, CoRoT, Kepler and K2 are all NASA or ESA affiliated satellite missions that launched between 2006 and 2018 that have assisted in the goal of creating a list of exoplanets, according to ESA.
Between the three missions, they have discovered almost 2,500 confirmed planets so far. TESS is still searching outer space and has identified over 1,500 potential targets at the moment.
Including exoplanets discovered using ground telescopes and other methods, ESA says that 4,143 planets have been found orbiting stars other than the Sun.
One of the most common ways of discovering exoplanets is by observing when the light emanating from a far-off star dims as something passes in front of it, a method called transit photometry. By studying those patterns, scientists can roughly discern the size of a planet orbiting a star.
The very first exoplanet was discovered in 1995 using a ground telescope, a feat which won Swiss astronomers Didier Queloz and Michel Mayor the Nobel Prize in Physics this year.
Now, Queloz is chair of the Cheops science team, still helping to unravel the continuing mysteries of exoplanets.
Willy Benz, Cheops’s principal investigator, said one of the exciting things about Cheops getting a more accurate read of the size of an exoplanet is that once they have the size and the mass of a planet, “we can derive the mean density, and from then we (can deduce) a little bit what the planet is made of.”
Cheops may be able to identify whether an exoplanet is a gas giant, has a rocky or icy core, has a tiny or thick atmosphere, or even whether it has moons or rings.
We may not be ready yet to jump to lightspeed and zip on over to these planets, but missions such as this one provide an important step forward in “understanding these alien worlds,” ESA says.
According to David Ehrenreich, a Cheops Mission Scientist, they “hope to publish the first results -- the first discoveries of Cheops -- just shortly before next summer.”