Slashdot Mirror
'Mirage Earth' Exoplanets May Have Burned Away Chances For Life
vinces99 writes: Planets orbiting close to low-mass stars — easily the most common stars in the universe — are prime targets in the search for extraterrestrial life. But new research led by an astronomy graduate student at the University of Washington indicates some such planets may have long since lost their chance at hosting life because of intense heat during their formative years. Low-mass stars, also called M dwarfs, are smaller than the sun, and also much less luminous, so their habitable zone tends to be fairly close in. The habitable zone is that swath of space that is just right to allow liquid water on an orbiting planet's surface, thus giving life a chance. [Researchers found] through computer simulations that some planets close to low-mass stars likely had their water and atmospheres burned away when they were still forming because they were exposed to high temperatures from their parent stars.
And left something behind... and another... Just because it was once hot doesn't exclude the chance of life ever forming. the Earth was once very hot... and look at us now lol
"Computers are a lot like Air Conditioners" "They both work great until you start opening Windows"
Our water and atmosphere were burned away when the Earth was still forming. We got them back from comet impact.
It seems every week that we get a story about habitability of planets - one saying that life could be in more places than we thought, two saying it's unlikely in areas we previously thought it was.
I'm just sad because the equations seem to be shaping up to quite a distance* between intelligent complex tool using species.
*If you assume they're more or less randomly scattered, the lower the odds per solar system, the longer the median distance between such races/civilizations.
I don't read AC A human right
Assuming there is life elsewhere in the universe, and there's a good chance, it takes many right circumstances to happen.
What's more, to be relevant to us it must also coincide with our time frame. We've only been capable over interacting with extra-terrestrials for about 150 years of 2+B years of the Earth's existence. Another civilization would have to be both advanced (more than we are) and at the right time for us to meet.
Could comets have come along later and re-added water?
[Researchers found] through computer simulations that some planets close to low-mass stars likely had their water and atmospheres burned away
That's a large assumption they had any atmosphere or water in the first place.
Given that we have a sample size of one: The earth
I think it's a tad ridiculous that we assume we have any idea what kind of environment can support life at all. There is no environment that we've explored that we can rule out the existence of life on. Yes, I understand that's because we haven't really explored any of them... but that's kind of the point.
The odds of Earth being the only host for 'selfconcious beings' in the universe might be bigger than we thought
If the oxygen content of Earth's atmosphere is unusual, perhaps our form of life is also unusual. Life could well be as plentiful as we could hope throughout the Universe - but life we can recognize evolved to exist in a Nitrogen/Oxygen atmosphere like ours may prove considerably less common.
Caveat, I'm not an astrophysicist or anyone who would know anything about this. I couldn't even play one on TV. However:
> some planets close to low-mass stars likely had their water and atmospheres burned away when they were still forming because they were exposed to high temperatures from their parent stars.
Ok, I understand that, but isn't it possible for an ice bearing comet (or several) to impact the planet at some later time when the sun was cooler? Surely those planetary systems have their own equivalent of oort clouds?
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
There's a missing asterisk right next to every mention of the word "life" to qualify it as "earth like". Who knows what other life forms might exist without requiring water?!
I guess the parent stars were too overbearing and self centered to let the solar systems have life. Sad but true.
We really don't have much idea how much migration goes on in early planetary systems, but it looks like there is a lot. So, a "mirage Earth" won't be a mirage if it sent its formative years further out from its star.
It is known that some planets migrate closer to their stars during the early stages of star-system formation. So, a planet that forms outside the habitable zone, but migrate into the habitable zone after the intense-heat period, could still be a good prospect for life.
Presumptuous maybe, but TFA is flawed as hell; planets move after they have formed, and generally inwards. They make no mention of this fact anywhere.
In our case, we had the Jupiter - Saturn duo that stabilized things, and prevented Jupiter from crashing into the Sun, taking the inner 4 planets with it.
It's entirely plausible that decent planets with atmospheres exist within the habitable zones of small stars, with crazy shit like 50 day years, and the dark side of the moon melts a little when it swings close to the sun. Heh.
But, a planet that formed close in to a star early on, and has remained there the whole time the system has cooled down, is likely to be a barren rock. Agreed. And a bit obvious...
It seems that earth size planets with moons formed by impact have nil chance to support life due to boiling of the atmosphere and water as a result of the impact by a Mars size object
oh well, another promising candidate off the list
Ok, I understand that, but isn't it possible for an ice bearing comet (or several) to impact the planet at some later time when the sun was cooler? Surely those planetary systems have their own equivalent of oort clouds?
The whole reason that a red dwarf is so dangerous to live around is its low gravity. It can hurl flares from its surface that ascend far out into space and reach its tight little "habitable zone", and its planets will occasionally orbit through a flare and get zapped. The flares are channeled and accelerated by electromagnetic turbulence that originates from deep inside the star. Even after the surface temperature of its photosphere finally declines, the star will continue to flare until it shrinks down to a white dwarf (which has no habitable zone at all, since its starlight is extreme ultraviolet radiation that can easily blast water molecules apart). Since M-class stars typically have expected lifetimes of trillions of years, you'd have to wait a long time to see it happen.
> [Researchers found] through computer simulations
Simulations are not science. I could produce my own simulation that would show exactly the opposite of what his simulation showed. It's all a matter of your assumptions. No simulation can sufficiently mimic the complexity of the real world. This is guessing and nothing more. That simulations have somehow become 'science' is just sad. Simulations, if anything, are the opposite of science.
Quite an experience to live in fear, isn't it? That's what it is to be a slave.
Comets could bring back an atmosphere and water. They may have done that for Earth, although the deuterium ratio is wrong...
If all life is based is based on DNA/RNA then a magnetosphere must exist to protect it. Or.. perhaps life was formed before a harmful burst of radiation penetrated the exoplanet and some form of protective bond formed over the DNA. radiation will cause DNA to mutate and eventually break apart. If life does exist on a planet without a magnetosphere then it would be much different than what is here on earth.
We consider how improbable life on Earth is given the odds of multiple events occurring at just the right time. But its possible that numerous different paths can be taken, each with their own likelihood, that lead to the same point. Its possible that the conditions for life involve nothing more than a planet settling into some 'sweet spot' of biochemical stability, where processes act to stabilize the environment around that point for a time sufficient for life to evolve. Whetever does evolve will be suited for that particular stable point.
Have gnu, will travel.