On 19/05/2013 2:38 PM, John Curtis wrote:
> On May 18, 1:58 am, Yousuf Khan <
bbb...@spammenot.yahoo.com> wrote:
>> But the article up above doesn't mention anything about tholeites being
>> the cause of the low D/H ratios. They do mention that carbonaceous
>> chondrite meteorites having the same ratio as the Earth and the Moon,
>> thus implying that the Earth and Moon came from the same source.
>>
> Low D/H is also present in the Sun, which makes the Sun a potential
> source.
> Trapping of solar hydrogen in tholeitic basalt, suggest a reservoir
> of solar
> hydrogen in Earth's interior. Similar process in the Moon may have
> contributed
> to low D/H water in mare basalts.
My understanding is that deuterium is low on the gas giant planets and
The Sun, simply because deuterium is heavier than hydrogen so it sinks
down to the center, where it's not detectable as a surface gas. Since we
only analyze the surface spectra of these bodies, we don't see much D.
This is also what I stated previously below in this quote:
>>>>
http://www.sciencedirect.com/science/article/pii/0012821X7690118
>>>> Lowest D/H ratios in the solar system are found in the Sun,Jupiter
>>>> and Saturn:
>>>>
http://www.lpi.usra.edu/books/MESSII/9038.pdf
>>>
>>> Well, that might make sense as in those high gravitation bodies, much of
>>> the D would likely sink to the centers of those bodies, making their
>>> surface detection less likely.
>>>
>>> Yousuf Khan
>>> primordial helium-3 and primordial neon-20, which point to primordial
>>> origin of hydrogen.
>>
>> How are those things related to D/H ratios? I'm not doubting you, just
>> wondering what the relationship is?
>>
> Helium-3 and neon-20 are solar gases. Their association with low D/H
> hydrogen implicate a solar origin for this hydrogen.
Well, apart from the obvious fact that all of H & D originated from the
same gas cloud that coalesced to form this solar system, I don't see how
the Sun could possibly supply enough of either H or D to supply the
inner planets and asteroids?
The solar wind does provide a steady stream of hydrogen isotopes into
the Earth's atmosphere, as it gets trapped in our magnetic field, but
it's not enough to provide all of this water. How much solar hydrogen
comes into our atmosphere each year, via the magnetic field entrapment?
I'm guessing at most it can be counted in the kilograms, maybe even
single-digit tons. Yes, over billions of years it'll add up, but then
that would mean we've just recently gotten enough hydrogen to form the
oceans to start evolving single-cell organisms, certainly not sentient
beings already. Also the Solar wind was much weaker in the past than
now, the Sun is much more powerful now and thus able to supply even more
particles in its solar wind. Thus it would've been slow to start.
Yousuf Khan