Origin of life

Our solar system formed from a molecular cloud that was ejected by a supernova explosion. Within a few million years, this cloud gave rise to the precursors of the Sun and the planets. However, there were also many smaller bodies that repeatedly collided with the planets. It’s possible that life first emerged more than once, only to be extinguished again by such collisions.

The building blocks for the molecules that living cells use were already pre-formed in interstellar space. Through purely chemical processes on the early Earth, these formed a mixture of dissolved molecules in water, often referred to as primordial soup. These processes can now be easily replicated in the lab.

However, how the first living cell originated remains unknown. While there are numerous theories and ideas about this, clarity is still lacking. It is also possible that life originated on another planet and was brought to Earth by rock fragments ejected by meteorite impacts. However, since the earliest biochemical traces of life on Earth are detectable shortly after the last major impact, it seems most likely that life originated directly on Earth.

In recent years, astronomers have increasingly succeeded in discovering solar systems with planets where life might have also emerged. New telescopes are expected to explore the chemical signatures of these planets in the coming years. We will likely soon know how many other planets with signs of life exist in our cosmic neighborhood. In our own solar system, it is suspected that there could have been, or even still be, life on Mars and on some of Jupiter's moons.