Scientists Find Water on Extra-solar Planet

amigoro writes "Scientists have, for the first time, conclusively discovered the presence of water vapour in the atmosphere of a planet beyond our Solar System, according to an article appearing in Nature. They made the discovery by analysing the transit of the gas giant HD 189733b across its star, in the Infrared using data from NASA's Spitzer Space Telescope. HD 189733b is a 'hot jupiter', a gas giant that is roughly the size and mass of Jupiter but orbits very close to the star, so no chance of life there."

While a great discovery, Is this surprising?

[Anonymous Coward]

Hydrogen is the most common element in the universe and oxygen is the third most common (helium, the second, is inert).

The most common heteroatomic molecule is likely to be water...

Re:While a great discovery, Is this surprising?

[Le Marteau]

No, it's not surprising. No one is saying it is a 'surprise'. It's just that water has never been detected outside of our planet, scientifically, and that's kind of cool.

Re:"no chance of life there"

[CastrTroy]

Which brings up the question, "what is life?". For millenium we've considered ourselves chosen by god, or at least special among all the animals on earth. However, what if we found another form of life that was as intelligent as we are? What if we found one that was more intelligent. How are we even sure that what we're looking for is going to be anything like us. Who says there won't be a race the size of Smurfs on some other planet. Who says there's no way you could have animals that think and act like humans yet get their energy from the sun and breath carbon dioxide like plants do.

"conclusively"?

[irtza]

First, let me state that I am not a chemist, so if there is someone who can do a better job of putting this into laymens term, I would be happy. with that said, how can we be sure its not the interaction of multiple molecules causing this or that this isn't a yet undiscovered molecule leading to this effect? I'm a bit wary of any indirrect measurement, so if someone with the proper background wishes to do some enlightenment, I'd be more than happy to read (even references would be nice).

Re:"no chance of life there"

[robgig1088]

Why stop there? Who claimed that said beings would even need to be cellular organisms? Perhaps there is some sort of alternative form of existence that we simply haven't considered that would enable life (in some form or another) in even the most severe conditions. Life will find a way.

Re:No Chance Of Life?!?! WTF?

[Mousit]

> I am sure that there are more but I can't think of any.

Hell, there are microbes that live and thrive in the heart of nuclear reactors, surviving both the heat and the radiation with ease. They'd be just the type to find a hot planet ultra-close to the sun a paradise..

Re:"no chance of life there"

[WastedMeat]

Something that gets its energy directly from the sun has less benefit conveyed to it by mobility and manipulation of the environment. Intelligence is not just gifted to arbitrary organisms by some kind of designer (how stupid is that?), it has to provide a benefit. A smart tree will not get much more sun than a dumb one.

Compare that to the advantages of intelligence to an organism that must actively search for its food, distinguish useful items from the background, and compete with other mobile animals for limited resources.

And the sizes of biological life are not arbitrary. The surface tension of water sets the surface area to volume ratio of structures that can rely on passive transport of nutrients,as well as those of active transport structures, and the surface to volume ratio of course does not scale linearly. It is logical to assume that any cellular based life that needs water would evolve a familiar relationship between function and size.

Given a similar planet and concept of life, I do not think extraterrestrial life would really be that dissimilar.

Re:Hrrmph!

[Smauler]

Ok... if hydrogen is common in the universe, and oxygen is expected near stars, why is this unexpected? It's a big planet close to a star!

It's the magnetic field

[Moraelin]

Well, you're right about Earth being a statistic improbability of many factors being just right, but methinks you're slightly wrong about Venus. Which is somewhat of a pity, since Venus is the perfect illustration of how many factors must be just right to get an Earth instead of a Venus.

On Venus too, it was the magnetic field -- or rather, lack thereof -- that did it. It's not just that some water gets split into hydrogen and oxygen, in which case it would just recombine sooner or later. It's that on Venus the lack of magnetic field allowed the solar winds to gradually wipe away the hydrogen. Venus is heavy enough to hold on th the slightly heavier elements, like Oxygen and Carbon anyway, even without a magnetic field. Hydrogen is a different story.

Outgassing CO2, well:

1. Earth spewed enough of that too, which is how it thawed back when cyanobacteria turned the atmosphere to O2 and the whole planet got deep frozen. (The Sun started a lot "cooler" and gradually warmed up. _Now_ it's warm enough to support life without a greenhouse effect, but in the beginning it wasn't.) I don't think there is any evidence that Venus spewed much more CO2 than Earth. On Earth just a lot of it got, well, buried right back. Say, in the Carboniferous era coal deposits.

The somewhat interesting corolary is that if we had too _little_ outgassing, then we'd have been really screwed. It took, IIRC, some 30% CO2 in the air to thaw that snowball Earth. Too little of it, and the deep freeze might just have continued long enough to be a total extinction event. Or at the very least a 1 billion year (or maybe more) pause in life evolution until the sun output went up some more.

2. Earth's original atmosphere was _methane_, which is a greenhouse gas about 200 times more potent than CO2. So if Venus would have been screwed by its outgassed CO2 atmosphere, the Earth should have been screwed 200 times harder (or close enough. Well over 100 times anyway.) In practice, that atmosphere on Earth just helped keep it warm enough at a time when the Sun was a lot weaker. If Venus had had a CO2 atmosphere at the time, well, it would have been a frozen snowball, quite the opposite of boiling off its water. In practice, it's a lot more likely that Venus started with a mostly Methane atmosphere too, only the hydrogen was swept away whenever some of it got broken up.

Pretty much if you start with water, methane and CO2, and continuously lose hydrogen, you end up with just the oxygen and carbon left, which means a lot of CO2. That's likely the short story of what happened on Venus.

3. There's an interesting extra factor there, which could have doomed Earth anyway, and that is: timing. If life or photosynthesis had started any later, for example, that methane and CO2 atmosphere would have sealed its fate. As I was saying methane is an _extremely_ potent greenhouse gas, so given enough extra time of gradually increasing solar output, it would have just boiled off the oceans. No liquid water, no life, game over.

At the risk of starting a flamewar...

[benhocking]

I find the similarities between belief in extraterrestrial life and God to be ... interesting, and I say this as an atheist who does believe that extraterrestrial life probably exists out there.