NASA has reported the discovery of an Earth-size planet, named TOI 700 d, orbiting its star in the “habitable zone”.
- A habitable zone, also called the “Goldilocks zone”, is the area around a star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets.
- Our Earth is in the Sun’s Goldilocks zone. If Earth were where the dwarf planet Pluto is, all its water would freeze; on the other hand, if Earth were where Mercury is, all its water would boil off.
- Life on Earth started in water, and water is a necessary ingredient for life as we know it.
- So, when scientists search for the possibility of alien life, any rocky exoplanet in the habitable zone of its star is an exciting find.
- An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmation of detection of exoplanet occurred in 1992.
- Exoplanets are very hard to see directly with telescopes. They are hidden by the bright glare of the stars they orbit.
- So, astronomers use other ways to detect and study exoplanets such as looking at the effects these planets have on the stars they orbit.
- M dwarf or M-type star, also called Red Dwarf Star are the most numerous type of star in the universe and the smallest type of hydrogen-burning star.
- These have masses from about 0.08 to 0.6 times that of the Sun.
- In the Milky Way Galaxy, about 70% of the stars are red dwarfs.