Comments on: Water Worlds in Known Planetary Systems

By: Velcro City Tourist Board » Blog Archive » Links for 09-09-2006

Velcro City Tourist Board » Blog Archive » Links for 09-09-2006 — Sun, 10 Sep 2006 21:48:32 +0000

[...] 6 – Water Worlds in Known Planetary Systems “…according to a new study led by the University of Colorado at Boulder and Pennsylvania State, solar systems with hot Jupiters may well harbor Earth-like planets covered with deep oceans.” Intriguing stuff, and a boost for the SETI mob. (tags: cosmology astronomy alien life SETI Jupiter hot extrasolar planets Earth-like space) [...]

By: andy

andy — Sat, 09 Sep 2006 19:53:56 +0000

Oxygen formation by photodissociation of water would produce oxygen, though if the ocean’s in contact with the underlying rocks it’d probably end up oxidising the rocks rather than building up in the atmosphere.

On the other hand, if there’s an ice layer then you could get build up of oxygen produced in this way.

By: pfdietz

pfdietz — Sat, 09 Sep 2006 19:06:39 +0000

I wonder if planets like this could even accumulate oxygen in their atmospheres.

On Earth, net O2 production occurs because of the burial of organic matter in sediments. Photosynthesis alone is not enough, since the unburied biomass is reoxidized on a short time scale, consuming the O2 that was liberated when it was formed.

Wthout exposed continents being subject to erosion, there will be much less sedimentation, so the rate at which the redox gradient from the atmosphere to the crust is ‘pumped’ will be much lower. Granted, the rate at which O2 is consumed by reduced material exposed by erosion will also be lower, but the rate at which reduced gases are emitted by volcanoes should not be.

By: Kelly Parks

Kelly Parks — Sat, 09 Sep 2006 15:49:47 +0000

This seems overly optimistic. I think it would be more accurate to say the study shows there may be more Earth-sized planets than previously thought. Saying these planets are Earthlike, meaning with conditions like Earth today, is pretty speculative.

By: andy

andy — Sat, 09 Sep 2006 14:24:38 +0000

And then there’s the issue of whether there’s going to be enough stuff dissolved in those oceans to make life feasible. If the ocean gets too deep, an ice layer forms at the base, which would cut off the ocean from supplies of minerals from the silicate planet below.

By: philw

philw — Sat, 09 Sep 2006 13:11:55 +0000

I find it a little depressing. These allegedly myriad Oceania worlds might harbor rich ocean life (assuming life doesn’t form most readily in mineral rich shoreline tidal pools) but without the ability to harnes fire, a technological civilization is exceedingly improbable.

To me, “Earthlike” means seas of H2O, land and a rich all pervasive biosphere.