[ExI] 67p rosetta d/h

[BillK]

On Wed, Dec 10, 2014 at 5:49 AM, spike  wrote:
<snip>
> So, tomorrow we get a clue for where the Earth's water came from.  If 67P
> has a D/H ratio that matches Earth, well now isn't that interesting.  If it
> matches Mars, isn't that puzzling.  If it matches the Kuiper belt objects,
> now what do we think?
>
> Any guesses before the number comes out?  I think it will match Earth
> because I have long since bought into the argument that our water came from
> comets.
>


They already announced preliminary results last month.

<http://news.sciencemag.org/europe/2014/11/doomed-comet-lander-delivered-harvest-science>
Quote:
And ROSINA, a Rosetta instrument that uses spectrometers to measure
gas abundances, has obtained a highly sought after result: the
so-called deuterium-to-hydrogen ratio of water in the comet's thin
atmosphere, or coma. The measured value for 67P is much higher than
the ratio in Earth's oceans and higher than in other comets, says
ROSINA principal investigator Kathrin Altwegg, of the University of
Bern. Three years ago, the comet Hartley-2 was found to have a D-to-H
ratio near that of Earth's oceans--sparking interest in the notion that
comet impacts delivered much of Earth's water. Altwegg says the result
for 67P could make asteroids the primary suspect again.
--------

BillK