Quiz your exoplanet knowledge

Not quite! An exoplanet is a planet beyond our solar system.The vast majority of exoplanets are found orbiting other stars, but there are a few that do not, which are called free-floating planets.

Exoplanets come in many different sizes, with a very wide range of temperatures, compositions, configurations and orbital periods. So far we have not found one that is exactly the same as the Earth, but we are looking…

Not quite! As of November 2022, more than 5000 exoplanets have been discovered using a variety of different techniques, telescopes and surveys. There are many more "candidate" exoplanets which have yet to be confirmed.

For more information take a look at exoplanet.eu.

Not quite! Exoplanets are found well beyond our Solar System. It takes light from even the closest exoplanet several years to reach the Earth.

Current spacecraft can travel at only a very small fraction of the speed of light, so travelling to the nearest exoplanet would take thousands of years with current technology.

Not quite! An exoplanet transit occurs when an exoplanet passes between the star it is orbiting and the telescope observing it, blocking a small portion of the starlight that the telescope would collect.

By monitoring the dip in the light from the star as the planet transits, we can study the planet itself. This technique is known as transit photometry, and is used by Cheops.

Almost correct! Cheops orbits the Earth approximately once every 100 minutes, at an altitude of 700 km above the Earth’s surface.This orbit is called sun-synchronous, with the satellite crossing the equator at the same local solar time every day and night.

Cheops passes over the equator at around 6am/6pm, riding the so-called day/night terminator – as a result the orbit is also known as a dawn/dusk orbit. The orbit was chosen to minimise the impact of sunlight and reflected stray light from Earth on Cheops observations.

For a visualisation of the CHEOPS orbit take a look at: esa.int/ESA_Multimedia/Videos/2018/11/The_orbit_of_Cheops.

To see where Cheops is right now take a look at: cheops.unibe.ch/.