Can we see exoplanets?
Stars are bright; planets are faint. Seeing exoplanets against the glare of their parent stars is as difficult as hearing a cricket during a rock concert. But in some cases, exoplanets have been captured in images.
An exoplanet can be more than a billion times fainter than its parent star. At infrared wavelengths, a young, hot planet is easier to spot – but only if you succeed in blocking the starlight. Even then, the star has to be relatively close to us, and the planet has to be big and orbiting far from its star. In 2004, ESO obtained the first ever image of an exoplanet. Since then, there have been photos of exoplanets in a handful of other solar systems. Future instruments may be able to actually image Earth- sized exoplanets.
Look at the image above. The light of the star has been blocked. As a result, faint planets orbiting the star become visible – if you’re lucky. How many planets can you see?