Comety Show: Oceans from Space

Finally, a comet has been found with a deuterium-to-hydrogen ratio that is close to that found in Earth’s oceans. That had not been true of many other comets. Astrobiologists claim this ration in Comet Hartley 2 as “proof” that our water came special delivery from water-balloon comets. But why do they believe that, what constitutes proof, and what new problems does the “proof” lead to?
All Posts by Date