One such moment was when space craft sent back images of the Earth for the first time. Another is the discovery of life on another world, a moment that has inched a little closer today with the news that signs of a gas, which on Earth is produced by simple marine organisms, has been found on a planet called K2-18b.

British researchers have found the "strongest evidence yet" of alien life beyond Earth with the discovery of an ocean-covered planet far beyond our solar system. While studying exoplanet K2-18b, which is 124 light years away, the team found signs of chemicals which are produced on Earth by simple organisms such as marine phytoplankton and bacteria.

The discovery was made on a massive exoplanet known as K2-18b that for years has captivated scientists searching for life outside of Earth.