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"You take a million, billion tonnes of flaming inferno and turn it into 'twinkle, twinkle little star' ..."

Tue, 18 Nov 2008

Hubble open for Business

Just as life was getting frantically busy, and as catdynamics predicted, Hubble is back open for business with a Supplemental Call for Observing Proposals.

So an idea I bounced off my supervisor has rebounded with a deadline attached. Fun predicted.

Fri, 02 May 2008

CO2 reconsidered

Just up on arxiv.org this week appeared Warming the early Earth - CO2 considered, by von Paris et al.. Just a preprint, and i'm working through its 53 pages now, put its likely to put the cat among the pidgeons:

Abstract: Despite a fainter Sun, the surface of the early Earth was mostly ice-free. Proposed solutions to this so-called "faint young Sun problem" have usually involved higher amounts of greenhouse gases than present in the modern-day atmosphere. However, geological evidence seemed to indicate that the atmospheric CO2 concentrations during the Archaean and Proterozoic were far too low to keep the surface from freezing. With a radiative-convective model including new, updated thermal absorption coefficients, we found that the amount of CO2 necessary to obtain 273 K at the surface is reduced up to an order of magnitude compared to previous studies. For the late Archaean and early Proterozoic period of the Earth, we calculate that CO2 partial pressures of only about 2.9 mb are required to keep its surface from freezing which is compatible with the amount inferred from sediment studies. This conclusion was not significantly changed when we varied model parameters such as relative humidity or surface albedo, obtaining CO2 partial pressures for the late Archaean between 1.5 and 5.5 mb. Thus, the contradiction between sediment data and model results disappears.

The suspected composition of the eary Earth (the Archean, when life is believed to have started, 3.8 to 2.5 billion years ago), has alternated between CO2 and other reducing gases, such as methane.

Originally CO2 was thought to be the main greenhouse gas, making life possible. However the high CO2 levels required were a problem; high CO2 levels would have created siderite (FeCO3) in the top layers of soil as iron interacted with CO2 in the oxygen-free air. Since then methane has top billing as the greenhouse gas responsible, with significant hydrogen levels a possibility. Over time, methane has come out on top. And thats what I wrote when I did my literature review for my PhD. Now I'm tidying it up a bit, and that section may be in for a rewrite.

But what does it mean for our Climate change models of today?

Thu, 13 Dec 2007

CoRoT: Reporting on the 20th

So, SpaEurope blog reports, with independent confirmation at Dynamics of Cats, that the CoRoT team is ready to do a press release and conference on the 20th December.

Now to go convince my PhD Supervisor to hold off 'til after christmas for the Lit. Review. I suspect he will be devasated to have a hole open in his calendar right in the middle of a week when (undergrad) students are away, and all he has on his Todo list is his own research ...

Wed, 12 Dec 2007

Waiting for CoRoT

So, the CoRoT team apparently had a meeting in Paris on Monday. I've been waiting with baited breath (and intermittent internet access, for assorted reasons) for the results of a "Press Conference", that according to the blogosphere rumour mill, and a (started by a breathless interim report) was going to rewrite the sciences of exoplanets and stellar seismology. There were rumours of special editions of Nature (or Science, or A & A), Earth-mass planets (possible according to the apparent spec. of CoRoT).

This mattered to me as I'm finishing up a literature review for a PhD and the work is on exoplanets, and depends a lot on stellar variation. CoRoT could rewrite large sections of my conclusions. So, it looks like I finish my review and just have to be patient while they release their results in the proper peer-reviewed manner.

But it would probably be a good idea for the CoRoT team to set up a blog, as Rumour Central, to respond to mentions and rumours about their project that appear on the 'net. Kudos, for example, to Wesley Traub for taking the time to answer my questions aboout Darwin/TPF in this manner.