[TML] Alien ecologies

[Greg Kettler]

On Fri, Aug 29, 2008 at 3:56 PM, Bruce Johnson
<johnson at pharmacy.arizona.edu> wrote:

>>
>> Remember that the height of the solar spectrum has been squished by
>> a factor
>> of 10.55, so differences are way more then this makes clear.  Note
>> the the
>> blue peak of chlorophyll a (the most common form, considered
>> "universal") is
>> well down from the peak of sunlight, by about 30-38%.
>
> That's because the absorbtion peak does not depend on the protein
> (which can change via evolution) but the captive metal atoms chemistry
> (which cannot)

The peak can and does change. Chlorophyll b has a different peak, but
the same metal ion.