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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.]
(Score: 4, Interesting) by redneckmother on Friday May 03 2019, @05:06AM (5 children)
I think what most of those here are concerned with, is "Is it inhabitable to "us"?'
That's hard to face, but I think that's what most everyone thinks.
Personally, I think that all the interest in "other worlds" takes away from thinking about preserving where we are now.
Of course, "humans" and our present existence are, in the grand scheme of things, but a minor blip. Still, here we are, and perhaps we should be concerned about preserving what we have, as best we can.
The universe doesn't give a rat's ass about humanity.
Mas cerveza por favor.
(Score: 3, Interesting) by pipedwho on Friday May 03 2019, @06:48AM (1 child)
Pretty much this.
Lets say we find a guaranteed mostly habitable world 25 light years away (which is extremely close in the grand scheme of things). And let's say we come up with some unknown technology that can power a generational ship to accelerate to an average of 25% light speed and decelerate at the other end. Let's also assume that space is vast, and that the odds of a collision is low enough to ignore. So, it takes 100 years to get there, and another 25 to send a message back to say "hi mom, we've arrived safely".
Awesome. Now we have a few hundred people on another planet 25 years (50 years round trip) communications distance away. Think how far away people seem when they live half way across the world in another country. This is so much further, that a typical conversation instead of a few minutes would take multiple lifetimes across such a vast distance.
Population of earth dropped by a few hundred. Which will be made up within a minute or two.
So what have we achieved here in this incredibly unlikely circumstance? For the average person, nothing. For everyone else, still nothing. For the people that have left the earth - a life in interstellar space, and for their offspring that might be lucky enough to survive, a chance to live in a world most likely as hospitable as some of the harshest places on earth.
Maybe you could say, we have started to seed the galaxy. Meanwhile, our planet becomes less and less liveable as resources are squandered and the population drops as people die of war/malnutrition/etc. The thought that maybe you or I will be able to head off to another planet is absurd at best. The only people conceivably going anywhere are a lucky few that would already be living well above the mean on Earth.
There is no 'greater good', where we pillage our planet but somehow manage to seed the galaxy with 'our' species. There is no 'urge to reproduce' beyond direct progeny for the common man. Maybe a megalomaniac wants to have a bigger army than the megalomaniac next door. But, again that doesn't help you or I.
Colonisation of the 'new world (ie. America) was based on people moving for their own reasons. They came for a better life, they came out of curiosity and the desire for a change, or maybe they were brought here as slaves. They didn't have a huge outfit bankrolling their journey to an empty land. They also had continual supply lines, and a means to trade with their mother country, making some trips a worthwhile investment. Some places were set up as penal colonies once local infrastructure had been put in place. Much colonisation was in the name of countries expanding their reach before other countries could get there - primarily to avoid being locked out of resource acquisition (mining, etc), strategic military locales, and maybe just to stop another country from getting too close. None of these things exist when it comes to a planet light years away. No one wants Antarctica, and that is likely far more hospitable (for humans) than any planet we are likely to find within a lifetime's communication distance.
If we end up with interstellar travel at some point in the future, great. But, to focus on it as an excuse to ignore the welfare of the planet where we live is not logical.
That being said, finding a planet that has the potential to evolve (or have evolved) some form of life may help us understand ourselves better. Not with the expectation of travel, but there may still be worthwhile outcomes in the study of exoplanets.
(Score: 3, Interesting) by takyon on Friday May 03 2019, @07:53AM
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.
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.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by urza9814 on Friday May 03 2019, @01:56PM
I don't think I agree. I think the most interesting option would be to find a habitable planet that is NOT habitable to us.
It's not like we're anywhere near ready to start launching interstellar voyages, so it doesn't really matter right now if we could live there one day. Nobody alive is likely to be making that journey anyway, and we've got plenty of time to find other candidates.
But how can we say a world is habitable if it isn't habitable to the one and only form of life that we currently know? As far as I can tell, the only way to say such a planet is habitable would be for it to be inhabited. So that means finding life -- life that is not like us. That would be a hell of an achievement, which could bring some fascinating scientific advancements.
Of course, a world that is inhabited by life that IS like us would be pretty crazy too. At that point we'd seriously have to start questioning if any other life is possible or at least recognizable as such. But we can find a world that is habitable to us without it being inhabited. We know what that looks like. So life isn't necessarily part of that discovery.
(Score: 3, Interesting) by HiThere on Friday May 03 2019, @04:01PM
In that case you don't need to look. It's not habitable by us.
It could not sustain an atmosphere that we could breathe without a native live, but if there is a native life the atmosphere will be full of allergens that we can't deal with.
Searching of worlds that may harbor life is interesting because of what it can tell us about the likelihood of other life. But that doesn't say we can live there.
OTOH, any civilization that could send a group of people to another solar system at below light-speed would find out that by the time they got there they'd prefer to live in their ships. Just because you would find that unnatural, doesn't mean that someone who has grown up in a ship wouldn't prefer it. So plan things that way anyway. There's plenty of space and materials, it's just spread a bit thin most places. With a nearly closed ecology and fusion power this would be reasonably simple. With a nearly closed ecology and fission power this would be probably doable. But the catch is you need the nearly closed ecology. And that includes the sociology required to keep things stable. (I expect that virtual reality will play a big part in enabling stability, because outside virtual reality actions are going to need to be rather strictly monitored and controlled.)
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Saturday May 04 2019, @08:17AM
phrased comically: https://www.schlockmercenary.com/2019-05-04 [schlockmercenary.com]