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exoplanets have already been directly imaged orbiting the stars Fomalhaut and Beta pictoris, as well as three exoplanets orbiting hr 8799. these planets are large Jupiter-sized bodies orbiting far from their host star and are observed with special instruments called coronagraphs that are used to block the starlight while leaving the planets visible.
in order to get a clear image of a possible habitable exoplanet, such as an earth-analogue, the observation would need to be able to resolve the star from the planet and deal with the very large contrast in light between the two. to get a feel for these two difficult tasks, get a bright torch (flashlight) and a small marble. have a friend stand across a room from you, hold the marble against the torch and shine the light directly into your eyes. can you see the marble? Small, close-in exoplanets orbit very near in angle to their stars and shine very dimly by reflected light. Just building a big telescope alone will not allow the observation. astronomers are working to make special telescopes such as the James Webb Space telescope (JWSt) and special instruments (star shades and vortex coronagraphs) that can be placed in space, above the disrupting effects of our atmosphere, in hopes of obtaining a direct image and measurement of an earth-like
planet, perhaps revealing signatures of life. Dr Steve Howell is a senior research scientist at NASA’s Ames Research Center