Recent Rosetta data shows water on Earth did not originate from comets as it appears that water from comets is different from the water found on Earth. These findings could start a debate about the origin of water on Earth.
Among the major hypotheses about the formation of Earth is the one that claims the planet was so hot 4.6 billion years ago when it formed that any water on it should have disappeared because of boiling. Clearly, there is water present at this time, which means the water must have come from somewhere. Numerous researchers believe that this water got here by asteroids and comets colliding with Earth’s surface.
However, the recent discoveries bring some conflict in the theory. In the month after the spacecraft landed on Comet 67P/Churyumov-Gerasimenko, Rosetta started taking measurements. Particularly, Rosetta analyzed deuterium and hydrogen proportions. Deuterium is a form of hydrogen that has an additional neutron.
It’s believed the comet formed beyond Neptune, in the Kuiper Belt. Sometimes, the bodies are disturbed from that location and sent in the inner solar system. For example, Rosetta’s comet travels now between the orbits of Mars and Earth, around the sun.
Asteroids contain water that is very similar if not exactly the same as the water found on Earth. The issue is that there is much too little water on asteroids when compared to comets. In order to form the oceans on Earth, tons of asteroids should have crashed on the planet. However, asteroids cannot be ignored when it comes to the origin of water on Earth as the water found on them is very similar to the one on our planet.
The discoveries shocked researchers at the European Space Agency (ESA) who thought the proportions of deuterium to hydrogen would be a lot more alike with proportions on Comet Hartley 2. But in fact, the deuterium to hydrogen ratio on Rosetta’s comet was greater by three times than on Hartley 2.
It’s quite intriguing that scientists have not been able to discover many comets containing water that is similar as the one on Earth but only about a dozen comets and asteroids were studied so far.