Rosetta discovers water on comet 67p like nothing on Earth
Measurements from Rosetta’s Rosina instrument found that water on comet 67P /Churyumov-Gerasimenko contains about three times more deuterium – a heavy form of hydrogen – than water on Earth.
The discovery seems to overturn the theory that Earth got its water, and so its ability to harbour life, from water-bearing comets that slammed into the planet during its early history.
Kathrin Altwegg at the University of Bern said that rather than comets ferrying water to Earth, it may have arrived onboard asteroids instead. Details of the discovery are reported in the journal, Science.
“Today asteroids have very limited water, that’s clear. But that was probably not always the case, said Altwegg. In the earliest period of the solar system, 3.8bn years ago, asteroids are thought to have crashed into Earth regularly in what is called the late heavy bombardment. “At that time, asteroids could well have had much more water than they have today,” Altwegg said.
Humbling discovery that even what we thought we knew about water is incomplete.