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posted by martyb on Friday May 03 2019, @04:35AM   Printer-friendly
from the Drake-Equation dept.

Which of Earth's features were essential for the origin and sustenance of life? And how do scientists identify those features on other worlds?

A team of Carnegie investigators with array of expertise ranging from geochemistry to planetary science to astronomy published this week an essay in Science urging the research community to recognize the vital importance of a planet's interior dynamics in creating an environment that's hospitable for life.

With our existing capabilities, observing an exoplanet's atmospheric composition will be the first way to search for signatures of life elsewhere. However, Carnegie's Anat Shahar, Peter Driscoll, Alycia Weinberger, and George Cody argue that a true picture of planetary habitability must consider how a planet's atmosphere is linked to and shaped by what's happening in its interior.

For example, on Earth, plate tectonics are crucial for maintaining a surface climate where life can thrive. What's more, without the cycling of material between its surface and interior, the convection that drives the Earth's magnetic field would not be possible and without a magnetic field, we would be bombarded by cosmic radiation.

Source: WHEN IT COMES TO PLANETARY HABITABILITY, IT'S WHAT'S INSIDE THAT COUNTS

Also Covered By: What makes a planet habitable

Basically, it is what is inside that counts — I've heard this numerous times from various teachers in school. This seems to be true for planets as well.

[See also: the Drake Equation, abiogenesis, anthropic bias, and the Fermi Paradox. --Ed.]


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  • (Score: 3, Interesting) by takyon on Friday May 03 2019, @07:53AM

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday May 03 2019, @07:53AM (#838341) Journal

    I think we overestimate the extent to which the planet is being made unlivable. We may see a correction, i.e. a catastrophic or gradual loss of human life and/or reduction of industrial activity. Regardless of that we are probably trending towards being more sustainable, although if the population doesn't level off at 10-12 billion, or if developing countries decide to have their moment as the top polluters, then things could get worse. You could also predict that Jevons paradox will come into effect even if we have stuff like cheap solar and fusion.

    The threat of nuclear war still scares some people but doesn't seem likely to happen. Cold War 2 (U.S. and friends vs. China and friends) will probably be economic with a lot of behind-the-scenes cyber harassment and physical espionage. Most large asteroids are well-tracked in advance of potential close approaches and detection will get much better in the coming decades, see LSST results very soon. I don't think we'll have a supervolcano catastrophe and we may have ways to mitigate it.

    Considering all of that, we could have several decades or centuries to kick off efforts to back up humanity, making it interplanetary. I don't think there needs to be urgency to get it started by the 2020s-2030s. As long as we see fully reusable rockets come onto the scene, humanity should naturally spread out over the next century.

    Initial colony sizes don't have to be huge. They just need to be relatively self-sustaining and capable of sending some people back to Earth after the dust settles if shit hits the fan here. Mars, Titan, the Moon, Ceres, Callisto, Mercury, and Venus all have potential as colony/base targets. All of them are crappy compared to Earth for various reasons, but they don't have to be perfect. Von Braun wheels in Earth orbit or elsewhere could also be considered.

    It doesn't benefit the overwhelming majority of people to have this stuff, but it shouldn't detract from ecological efforts here. We've already seen that nations are not willing to pursue expensive manned spaceflight programs in lieu of domestic concerns. But if you can slash the costs with fully reusable rockets, you can get more done with less. If you give people the ability to exploit the solar system's resources, you may see a lot of private funding put into it. And we have seen assertions from the likes of Jeff Bezos that industrial activities could be moved into orbit (in the long run), helping to preserve Earth. That idea at least deserves some consideration even if it seems absurd right now.

    They also had continual supply lines, and a means to trade with their mother country, making some trips a worthwhile investment.

    We are developing new technologies that should help colonies to be set up in advance using robots and hopefully become entirely self-sufficient. The approach will be tested on Mars long before we try it in another star system (doing it on the Moon is not so important since it is so close to Earth). It appears likely that there are exoplanets within a 25 light year radius that will be more friendly to humans than Mars (some combo of better temperature, breathable atmosphere, liquid water, similar gravity, etc.). If we send people to Mars or some exoplanet, we should be thinking of initial costs that result in a self-sustaining colony. Eventually we will be able to quantify it and determine that each colonist sent needs to pay or be funded $1 million for Mars, $100 million for a particular exoplanet, etc. Then see if enough people bite to actually make it happen. Although this life is almost certainly like hell compared to living on Earth, at least initially, if you can lower the price enough you will find some people willing to suffer the journey and the destination. Century+ travel times to exoplanets could be addressed using life extension or possibly the deep freeze or other sci-fi means.

    We have a hard limit of about 1 billion years before Earth is unlivable due to the Sun's activity. The actual number could end up being 100 million years. We could buy more time with some massive geoengineering projects.

    This rant is badly organized so if you want me to address something let me know.

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