Many scientists believe that all the water on the Earth was brought by comets.
However, some scientists now think that the data from Rosetta, which shows that the comet’s water is not like Earth’s water, proves that the water came from asteroids.
Water on Earth is distinctive because for every 10,000 water molecules, three deuterium atoms can be found. When compared to the water samples from 67/P, it was discovered that there was far more heavy water than on Earth.
I’m not saying that the article’s authors have jumped to a conclusion, but we only ever have landed on one comet, and have only analyzed the water on two comets. There are billions of comets in the Ort cloud, and the comets (and asteroids) that struck the earth in the past to deposit water here may have endured some physical changes during the journey and eventual impact.
While the water on 67P is different than the water on Earth, the water on comet Hartley 2 appears to be exactly the same as the water in our planet’s oceans.
It just seems a little early to me to make a broad conclusion about the origin of water on Earth based on two observations…for events that happened millions of years ago.
– Ex astris, scientia –
I am and avid amateur astronomer and intellectual property attorney in Pasadena, California and I am a Rising Star as rated by Super Lawyers Magazine. As a former Chief Petty Officer in the U.S. Navy, I am a proud member of the Armed Service Committee of the Los Angeles County Bar Association working to aid all active duty and veterans in our communities. Connect with me on Google +, or by email.