What are Exoplanets?

Exoplanets (exoplanets for short; English: extrasolar planet or exoplanet) refer to planets outside the solar system. Astronomers in history generally believe that there are other planets outside the solar system, but their popularity and nature are a mystery. It was not until the 1990s that humans first confirmed the existence of exoplanets, and since 2002 more than 20 newly discovered exoplanets have been discovered each year. It is currently estimated that no less than 10% of stars similar to the sun have planets.

Exoplanet

Method 1: Astrometry

Astrometry, mainly by precisely tracking the changes in the trajectory of a star in the sky, determines the planets dragged by its gravity. This is similar to the principle of the radial velocity method, except that

Astronomers first took direct images of extrasolar planets in 2008, including a visible light snapshot of a single planetary system and infrared photos of a multi-planetary system. Earth-like planets may exist in this three-planet system, but they are too dark to take ordinary pictures.