What Does the Atmosphere Say About Earth?

To date, astronomers have discovered about 209 extrasolar planets; that is, planets outside our solar system. From Earth, it is quite difficult to even detect them, much less learn anything about them. We haven’t been able to determine much about these planets—usually only the mass—though we’ve been able to get glimpses of atmosphere in a couple cases.

Of course, we have no idea if there is life on other planets, or how we might detect it. One way to think about it is to imagine what other life forms might think of Earth if they were to stumble across it.

Some scientists at NASA put together a cool summary of what Earth might have been like during different periods in its history. Here’s an excerpt:

At Epoch 0 (3.9 billion years ago), the young Earth possessed a turbulent, steamy atmosphere composed mostly of nitrogen, carbon dioxide and hydrogen sulfide. The days were shorter and the Sun was dimmer, shining as a red orb through our orange brick-colored sky. The one ocean that covered our entire planet was a muddy brown that absorbed bombardment from incoming meteors and comets. Carbon dioxide helped warm our world since the infant Sun was a third less luminous than today. Although no fossils survived from this time period, isotopic signatures of life may have been left behind in Greenland rocks.

Read the rest at NASA’s web site.


7 thoughts on “What Does the Atmosphere Say About Earth?

  1. This is yet another reminder of how conditions on Earth as we know them are not merely transient; they’re fleeting.

  2. Well, in a million years we might not be gone (if we’re lucky, that is) but we’ll be different. I guess, technically, that means we _will_ be gone, having evolved into something else, but you know what I mean. Anyway, I’m willing to be that in a billion years we will be gone, period. And, of course, if I’m wrong, you won’t be around to collect. 🙂

  3. Even a million years is an awfully long time. Our species has only been around for at most, a fifth of that time, and civilization has only existed for 1% of that. So much has changed in that 1%—there is so much that could happen: nuclear war, climate change (human-induced or natural), asteroid strike, gamma ray burst, and so on. I hope humans or their descendants are around but who knows?

  4. Was it Fisher who wrote extensively about an advanced civilization inhabiting the Orion constellation? As the old argument goes, we’d be arrogant to think that we’re the only life form wigglin’ in this vaaaaaaaast space. Plus our ‘being’ is not limited to merely its meaty dimension … anyone tried Astral travel here 🙂 In a million years we’ll be inhabiting the astral fields 🙂 [Fluid deliberately puts wood on the fire, while Darmok pulls out his hair]

  5. I definitely agree that the chance that there is no other life in the universe is quite low, near zero I would think. I’m not familiar with the work you mention, and I’m not sure what it would mean to inhabit a constellation—Orion is only a constellation from our point of view, and there’d be no reason to expect others in space to group those stars together. I suppose, though, that “in the direction of Orion” it could be used as a directional term (sort of like “north-northeast”).

    I don’t quite know what an astral field is, but if you’re suggesting there are aspects to the universe (or other universes) we’re not aware of yet, I think that’s reasonable, and even likely. Numerous science fiction works have postulated such entities to use to help get around the speed-of-light restriction that the theory of relativity implies. Of course, there’s no evidence yet that any of this exists.

  6. In fact, the only statement of yours to which I really object is perhaps your implication that humans will still exist in a million years—while I hope this to be the case, I don’t believe it’s certain by any means.

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