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EPOXI Team Develops New Method To Find Alien Ocean
Matt_dk writes "Astronomers have found more than 300 alien (extrasolar) worlds so far. Most of these are gas giants like Jupiter, and are either too hot (too close to their star) or too cold (too far away) to support life as we know it. Sometime in the near future, however, astronomers will probably find one that's just right — a planet with a solid surface that's the right distance for a temperature that allows liquid water — an essential ingredient in the recipe for life. Now scientists looking back at Earth with the Deep Impact/EPOXI mission have developed a method to indicate whether Earth-like extrasolar worlds have oceans."
why should water be essential for life? and how do you define life anyway?
As far as I know, most of the techniques used for detecting exoplanets depend on the planet being ~Jupiter mass and pretty close because then
-you get gravitational "wobble"
-you're more likely to be in line for a transit
-mass is enough for gravitational lensing
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Well, yes, but finding gases in the atmosphere by spectroscopy is a lot easier. Luckily, they can look for two things. High-5's all round
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Considering the likelihood of a gas giant to have many moons of significant size, why do we insist on a planet in the goldilocks zone? Here we are considering Europa and Callisto for possible subsurface oceans, and even life, and how would it be to have moons in that orbital slot?
If we're looking for planets that reflect a lot of blue light, we may end up finding ones covered with blue tarps.
Have gnu, will travel.
So if I got this right from TFA, they can tell there are oceans by how the amount of blue light changes? Doesn't it assume that the planet in question has large continents? I mean if the planet was pure ocean on the surface, then it'd always be a uniform display of blue. So basically what they do is detect different patches of colour, and if they find blue patches in the mix they'll assume they're oceans, am I right?
Also, using this technique of variation of light, couldn't they build a very crude longitudinal colour map of the planet? I mean, it would probably look like taking a map of Earth, squishing it to a height of 1 pixel in Photoshop and stretching it back, but they could get something like that, right?
You just got troll'd!
Yeah sure, or they could breathe lead and drink plutonium, I mean what do you know!
Or maybe possibly these guys have a better idea than you do about what seems even remotely plausible or even likely and they're taking their shot at it?
You just got troll'd!
What makes you think they haven't thought of that? You're stating the obvious.
The reason they focus on 'life as we know it', is that /know how/ to search for 'life as we know it'.
By very definition, 'life as we don't know it' is more difficult to search for. How to you try to find something you don't know the characteristics of?
'Broader horizons' is one thing, but in a case we're trying to find extrasolar life, let's not invent artificial difficulties - it's already damn hard as it is.
What are the alternatives? Carbon-sulfur might be a reasonable option. Silicon-oxygen is a little further out. There are only so many atoms available, and their prevalence is dictated by stars, so that puts a limit on what variations could be possible, and, well, there aren't that many.
I just wondered something. Generally, the presence of condensed phase liquid water is considered a marker that tells us "Look for life here." Unfortunately, given our current technology, most planets we find are gas giants that orbit too close to the star to be in the "habitable zone". But gas giants, by virtue of being huge, have hugely high atmospheric pressures in the lower atmosphere. Couldn't supercritical water (i.e. water at a sufficiently high temperature/pressure that there is no distinction between gas and liquid) support life? Or, for that matter, supercritical methane, or any other supercritical medium? After all, we can run useful chemistry in supercritical fluids such as supercritical CO2. And if it can support life, wouldn't the possibility of life in supercritical water significantly extend the habitable zone?
Even on earth, the study of lithotrophs ("rock eaters" that get energy by oxidizing inorganic materials) is a decades-old field. They are found in all sorts of settings, though not a significant part (by mass, not necessarily by importance) of the biosphere. Many lithotrophs even engage in carbon fixation from CO2 using the energy they derived from "rock eating", and thus can live completely independently of any need for photosynthesis (even by other organisms). As for lithotroph metabolisms, your imagination is the limit. Lithotrophs even have commercially viable applications. Anaerobic oxidation of ammonia by nitrite, a reaction performed by certain "anammox" bacteria, is useful for the treatment of fertilizer-contaminated waste water.