Journey more than two decades to explore the outer planet

From the last few centuries, the existence of the or just the speculation.

But things began to change in 1955, when scientists first discovered an alien planet called 51 Pegasi, a giant gas-like planet of Jupiter, orbiting a star-like star. Sun.

Over 20 years later, more than 2000 exoplanets have been discovered and hundreds of billions of other alien planets are believed to exist in the universe.

It is difficult to see the direct image of an alien planet.

Astronomers discovered the first largest extrasolar planets because they were most easily detected. Next are the gas dwarfs (transitional planets) with an atmosphere of hydrogen and helium, followed by planets covered by oceans, lava or rocks . until the outer planets. size like Earth.

It is difficult to see the direct image of an alien planet, as they are often obscured by the much brighter host star.

The extraterrestrial planets are often detected indirectly by observing the gravitational effect that exoplanet affects the host star. Or by studying the decrease in the brightness of the host star, when a planet passes by.

The remarkable progress of technology has enabled astronomers to capture images of a number of exoplanets, helping to learn more about the origins of the Solar System and finding life outside of Earth.