Exoplanets are planets out of the Solar System. What are the mysteries of them and are there any life on them?
Categories of Exoplanets
There are many kinds of exoplanets, each having different properties. For example, Proxima Centauri b, Barnard’s Star b and CoRoT-7b are rocky planets larger than Earth, which are called Super-Earths. Also, there are some planets like 61 Virginis b-d and Kepler-11c-g are planets with similar size and mass with Neptune. These are Neptunian planets. Kepler-7b, Kepler-6b, Kepler-435b are huge and massive planets. They are Gas Giants or Jovian planets. Moreover, there are some planets smaller than Earth, these are called sub-Earths.
How to determine different types? Well, by determining its mass and size. If it is smaller than Earth, it would be classified as a sub-Earth. If it has 100 Earth masses and is huge, it is a gas giant.
Well, talking about alien life, scientists still haven’t found any yet. That is because they are still not sure whether planets found are habitable. To define a potentially habitable exoplanet, it must be a rocky exoplanet in the host star’s habitable zone. But there are a lot more here. For example, they must also be Earth-sized to develop an appropriate gravitational force.
Scientists are still finding alien life, even on our Solar System. There might be some sort of organisms right on Europa, which has an ocean of liquid water underground. Moreover, we don’t know whether the planet even has a single drop of water or an atmosphere.
Highlights of exoplanets
Other than alien life, there is still so much to learn about exoplanets. They might be even sources of the knowledge of how can we exist. Weird planets can also help scientists learn about exceptional conditions. Just like……
55 Cancri e, 40 light years away, is a totally uninhabitable lava planet It orbits its star at a distance of a mere 0.015 AU, making its temperature about 2,000 K. Also, its sky sparkles because of the condensed silicates.
WASP-12b which races in a 1.1-day orbit is egg-shaped due to the star’s gravity. It belongs to a type of planet called hot Jupiters, which are short-period, large planets.
The Kepler-11 system, which has 6 planets crammed into an area 0.7 AU in radius. It is made of 1 Super-Earth and 5 Neptunian planets.
The TRAPPIST-1 system, which has a crowded 7 planets in a space between Sun and Mercury. 3 of the planets are potentially habitable.
TRES-2b is the darkest planet known. It’s so dark that it absorbs 99% of the light it received. It is also a hot Jupiter, racing in a 2.5-day orbit.