Looking For Another Earth? Here Are 300 Million, Maybe (baltimoresun.com) 42
Long-time Slashdot reader fahrbot-bot shared this report from the New York Times:
A decade ago, a band of astronomers set out to investigate one of the oldest questions taunting philosophers, scientists, priests, astronomers, mystics and the rest of the human race: How many more Earths are out there, if any? How many far-flung planets exist that could harbor life as we know it?
Their tool was the Kepler spacecraft, which was launched in March 2009 on a three-and-a-half year mission to monitor 150,000 stars in a patch of sky in the Milky Way. It looked for tiny dips in starlight caused by an exoplanet passing in front of its home star. "It's not E.T., but it's E.T.'s home," said William Borucki when the mission was launched in March 2009. It was Dr. Borucki, an astronomer now retired from NASA's Ames Research Center, who dreamed up the project and spent two decades convincing NASA to do it. Before the spacecraft finally gave out in 2018, it had discovered more than 4,000 candidate worlds among those stars. So far, none have shown any sign of life or habitation. (Granted, they are very far away and hard to study.) Extrapolated, that figure suggests that there are billions of exoplanets in the Milky Way galaxy. But how many of those are potentially habitable?
After crunching Kepler's data for two years, a team of 44 astronomers led by Steve Bryson of NASA Ames has landed on what they say is the definitive answer, at least for now. Their paper has been accepted for publication in the Astronomical Journal... The team calculated that at least one-third, and perhaps as many as 90 percent, of stars similar in mass and brightness to our sun have rocks like Earth in their habitable zones, with the range reflecting the researchers' confidence in their various methods and assumptions. That is no small bonanza, however you look at it.
According to NASA estimates there are at least 100 billion stars in the Milky Way, of which about 4 billion are sunlike. If only 7 percent of those stars have habitable planets — a seriously conservative estimate — there could be as many as 300 million potentially habitable Earths out there in the whole Milky Way alone.
On average, the astronomers calculated, the nearest such planet should be about 20 light-years away, and there should be four of them within 30 light-years or so of the sun...
"The new result means that the galaxy is at least twice as fertile as estimated in one of the first analyses of Kepler data, in 2013."
Their tool was the Kepler spacecraft, which was launched in March 2009 on a three-and-a-half year mission to monitor 150,000 stars in a patch of sky in the Milky Way. It looked for tiny dips in starlight caused by an exoplanet passing in front of its home star. "It's not E.T., but it's E.T.'s home," said William Borucki when the mission was launched in March 2009. It was Dr. Borucki, an astronomer now retired from NASA's Ames Research Center, who dreamed up the project and spent two decades convincing NASA to do it. Before the spacecraft finally gave out in 2018, it had discovered more than 4,000 candidate worlds among those stars. So far, none have shown any sign of life or habitation. (Granted, they are very far away and hard to study.) Extrapolated, that figure suggests that there are billions of exoplanets in the Milky Way galaxy. But how many of those are potentially habitable?
After crunching Kepler's data for two years, a team of 44 astronomers led by Steve Bryson of NASA Ames has landed on what they say is the definitive answer, at least for now. Their paper has been accepted for publication in the Astronomical Journal... The team calculated that at least one-third, and perhaps as many as 90 percent, of stars similar in mass and brightness to our sun have rocks like Earth in their habitable zones, with the range reflecting the researchers' confidence in their various methods and assumptions. That is no small bonanza, however you look at it.
According to NASA estimates there are at least 100 billion stars in the Milky Way, of which about 4 billion are sunlike. If only 7 percent of those stars have habitable planets — a seriously conservative estimate — there could be as many as 300 million potentially habitable Earths out there in the whole Milky Way alone.
On average, the astronomers calculated, the nearest such planet should be about 20 light-years away, and there should be four of them within 30 light-years or so of the sun...
"The new result means that the galaxy is at least twice as fertile as estimated in one of the first analyses of Kepler data, in 2013."
Obligatory Arthur Clarke quote (Score:3, Insightful)
"Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying” Arthur C. Clarke
I don't know if I would use the word terrifying. The possibility that life on this planet is a huge (near impossible) statistical outlier should be a humbling moment and underscore our obligation to preserve and extend life and "cherish the pale blue dot". On the other hand, if there are other civilizations just beyond our sensing capability what a wild crazy thought... all we have to do keep looking and reaching.
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Life and civilization are two very different things. Earth for most its history had unicellular life, about 3 billion years worth. There is very good reason to believe that is the norm and what all those planets have.
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Sounds like a typical college dorm room.
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Not if I were unicellular.
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It is entirely possible that several tool-using dinosaur civilisations evolved, then became extinct leaving no trace, and we'll never know.
100 million years is a long time.
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Sorry, but brain and EQ of dinosaurs is mostly like reptiles with some being more bird-like. They were kind of dumb.
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A tiny percentage of species leave fossils behind, maybe a low as 1%. We know very little about the world of the dinosaurs really.
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we do know a lot, because dinos are still here. They didn't and don't have magic brains. Low EQ animals, sorry. No Dino Atlantis for U!
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I'm just speculating.
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https://www.scientificamerican... [scientificamerican.com]
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Life and civilization are two very different things. Earth for most its history had unicellular life, about 3 billion years worth. There is very good reason to believe that is the norm and what all those planets have.
There isn't really a very good to believe that this is the norm... we have a sample size of one planet with life so far. While I don't believe we are alone - and I certainly don't believe we're here because we are created - I do think that any calculations, statistical analysis (even something as simple as "good reason to believe") etc are inherently flawed.
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"Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying." -- Arthur C. Clarke
I don't know if I would use the word terrifying.
Wait until they show up wearing Make the Galaxy Great Again hats ...
Who rulz? (Score:2)
Red dwarfs are where it's at (Score:1)
Re:Red dwarfs are where it's at (Score:4, Interesting)
Quite possibly. Red dwarfs probably aren't a great place for life to evolve - they tend to be unstable with occasional severe radiation storms that would tend to sterilize planets and possibly strip atmospheres. Not to mention the high chance of tidal locking of planets within the habitable zone - though "eyeball worlds" might be more resistant to solar storms.
However, there's so many of them, that the sheer number of chances might overcome the probable long odds.
The real boost to their odds might be as colonization targets for interstellar civilizations. Assuming civilizations master living in space before going interstellar, the problems of planets don't really apply to them anymore. And if you're going to all the trouble of interstellar colonization, there's much to be said for a new home that will outlast pretty much everything else in the universe.
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Are either of those states relevant to Earth though, for comparison? My impression ifs that our sun is of a very mild and even-tempered breed - as massive raging fusion-infernos go.
Saying death-trap 1 is more hospitable than death-trap 2 is kinda overlooking the whole death trap thing.
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I agree that the popular concept of of habitable zone is far too restrictive. Though it's worth noting that large gas giants are much less common around red dwarfs, and without those you have no huge tidal heating engines operating out in the cold reaches of a solar system, which is what creates most of the potential life-bearing environments within our own solar system.
Our sun is bright, at least for a dwarf star, but it's not particularly violent.
The problem with violence is that your planet has to be a
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*Potential* abodes for life, let's not get too enthusiastic. We've found some tantalizing hints, but haven't actually found life anywhere else yet. Which means we only have assumptions and guesses guiding us in evaluating what conditions are necessary, And while "solvent and an energy gradient" is looking increasingly plausible, the only conditions we're sure can nurture life, and probably generate it, are the relatively narrow range where it's happened on Earth.
But yeah, it seems like there's lots of p
Here we go again (Score:3)
We can estimate how many earth-like worlds may exist in our galaxy - but we have no flippin' idea what the odds are that life exists on any of them. You can't extrapolate from one datapoint, regardless of how strongly you're hoping for tenure.
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Which is why so many people are so eager to examine the other worlds in our solar system. Mars, Venus, all four Galilean moons of Jupiter, and Titan are all promising places to find life. Not to mention Pluto, which defied all expectations by showing evidence of liquid water below the surface, presumably kept warm by a radioactive core.
On Earth life seems to have appeared almost as soon as liquid water did - and while that's only one data point, the lack of delay offers a tantalizing suggestion that life
All we need to do is figure out how to get there (Score:2)
Now we have somewhere to visit, we just need to figure out how to get there ...
wrong question . (Score:1)
"one of the oldest questions taunting philosophers, scientists, priests, astronomers, mystics and the rest of the human race: How many more Earths are out there, if any?"
The correct question is: Is there intelligent life in the universe?
Considering the leadership tolerated by the various disparate and desperate fiefdoms on this planet, we will have to keep looking elsewhere.
More worlds to infect with humans! (Score:2)
We may not improve but we can metastasize....
Why don't we search all those close sun-like stars (Score:3)
Re:Why don't we search all those close sun-like st (Score:4, Informative)
Why are you assuming we aren't studying the exoplanets we've found?
TESS [wikipedia.org] is a follow-on mission to Kepler. ESA's CHEOPS [wikipedia.org] will study the exoplanets found be Kepler in more detail, and so will JWST.
The classic ... (Score:2)
... how many angels can dance on the head of a pin calculation.
We get it; you want there to be ETs.
Earth is aairly odd (Score:4, Insightful)
Earth is a double planet, alongside the Moon, created by a massive planetary impact. It's ocean is broken up by landmasses. Other worlds with liquid water, like Europa, are covered entir4ely with water.. In europa's case, there is also a thick ice coating. Those make crafts and technologies that rely on high energy concentrations, such as metallurgy, very difficult. That may make technology veyr difficult, even for species that become sentient.
Those events are not common, and they may have been critical to our development as a species wielding technology.
More subtle than that? (Score:1)
New model to update a Master of Orion remake (Score:1)
Thank you. (Score:1)
I was just on my way to the store, and I realized I need to find another earth. Unfortunately, google failed to find a decent route to it.
Packing my bags, BRB (Score:1)
What do you mean "we can't go now?!"