What is an Exoplanet?
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Since the discovery of the first planet orbiting another Sun-like star in 1995, thousands of exoplanets have been found. Our Solar System is no longer unique.
Extrasolar planets — or exoplanets for short — are planets orbiting around stars other than our own Sun. Astronomers have speculated about their existence for centuries. However, the first exoplanet orbiting a Sun-like star was not found until 1995. Since then, an amazing variety of exoplanets has been discovered, mainly through indirect detection methods; only a few have been directly observed. It turns out that over 50% of all stars are accompanied by at least one planet, sometimes more. Whether or not they resemble our home planet is another question.
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Eight planets orbit the Sun. Earth is one of them. The Sun is just one star among billions and many other stars have planets too. These are called exoplanets.