When it's young, a red dwarf star frequently erupts with strong ultraviolet flares as shown in this artist's conception. Some have argued that life would be impossible on any planet orbiting in the star's habitable zone as a result.
Image: David A. Aguilar (CfA)
An Earth-like alien planet may reside right in our solar system's backyard, just 13 light-years or so away, astronomers announced today (Feb. 6).
That number is just an estimate, though, and not based on an exoplanet discovery.
The researchers used data from NASA's prolific planet-hunting Kepler space telescope, which is staring at more than 150,000 stars simultaneously. Kepler detects planets by measuring the temporary brightness dips caused when the worlds pass in front of, or transit, their stars' faces from the instrument's perspective.
The team pulled out a sample of 3,897 red dwarfs — stars dimmer and smaller than our own sun — and determined that Kepler has identified 95 exoplanet candidates circling them. Three of these candidates are roughly Earth-size and orbit within their stars' "Goldilocks zone," where liquid water (and possibly life as we know it) can exist. ['Alien Earths' Should Orbit Nearby Stars (Video)]
Kepler isn't able to detect every planet circling every star that it's watching, researchers noted. Many worlds don't orbit in the right plane for Kepler to observe transits, and the signals of others may be masked by brightness variations inherent to red dwarfs.
Taking this into account, about 6 percent of red dwarfs in the Milky Way galaxy should host Earth-like planets, the astronomers said.
Since about 75 percent of the galaxy's 100 billion stars are red dwarfs, this translates to an estimated 4.5 billion "alien Earths" spread throughout the galaxy. The research team stressed, however, that this is a tentative figure because the distribution of stars varies widely.
Within 30 light-years of our sun, there are 248 red dwarfs, according to separate surveys conducted by the Research Consortium on Nearby Stars, an international astronomical group led by Georgia State University.
In the new study, the research team used this information to find out how far from Earth we need to go to find planets like our own.
"It should be, hopefully, within 13 light-years," lead author Courtney Dressing, of the Harvard-Smithsonian Center for Astrophysics, said during a press conference today.
If the Milky Way galaxy were the size of the United States, 13 light-years would be the equivalent of taking a stroll across New York City's Central Park, she added.
The estimated distance increases to 21 light-years when scientists apply the standard 95 percent confidence interval to their calculation.
The closest red dwarf to Earth is Proxima Centauri, which is 4.2 light-years away in the three-star Alpha Centauri system.
Last October, scientists announced the discovery of an Earth-size (though hellishly hot) planet orbiting Alpha Centauri Bb, another star in the system. No worlds have been detected around Proxima Centauri yet.
- Planets Large and Small Populate Our Galaxy (Infographic)
- Kepler Reveals Lots of Planets: Some Habitable?
- Gallery: First Earth-Size Alien Planets Discovered
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18 Comments
Add CommentAnd the closest alien life form as intelligent as us existing in the same overlapping timeline could be billions of light years away. We have only been intelligent enough to produce transmissions for the last 100 year or so out of 3.8 billion years since the first single celled organism arose to bring forth mankind. Assuming a similar fate of aliens then what is the chances of another life form overlapping our own 100 years? About 1 in 160,000,000 because since the big bang created this Universe 16 billion years ago. Not good odds.
Reply | Report Abuse | Link to thisIts worse than that.
Reply | Report Abuse | Link to thisMany great thinkers have shown that if there was Intelligent life in our galaxy anywhere near the estimates by overzealous seekers the entire galaxy would have probes littered in every solar system. Its not necessary to align our timelines---there is simply zero PAST evidence of life. Other people would have had billions of years of a head start to send signals and there is nothing.
This search is mathematically and logically absurd guided by atheists who feel that if they find one spec of life anywhere else it will fulfill their entire worldview when it would do no such thing. Abiogenesis has probabilities that are beyond all the atoms in the universe. There is no one else. Its abundantly clear that "We" should no be here at all--let alone anyone else.
Yo, I think I know a guy from that planet. His name is Crum Rooni. Pretty smart dude. He came here to the US in 2008 to teach his language and share his exotic alien culture with us, but they locked him away... understandably, I guess, he's pretty nutty, and no one believed he travelled across interstellar space to get here. He says his planet is called Shrilp (that's the closest we can come to transcribing it in Latin script... he says it's closer in Cyrillic, Шрилп. When he wrote it out for me one evening in Groodge script and in his native language, Chop, the insane tangle of scribbles came to resemble what looked to me like a series of ampersands, lemniscates, and pounds sterling symbols). Could anyone tell me how to do this email thing? I would like to send him this article, but have never been able to figure out this dingus internet.
Reply | Report Abuse | Link to thisYou make unwarranted assumptions in that you assume the nearest civilization is "billions of light years away" and that you assume their technological progress mirrors our own. As such, the odds you calculate are worthless.
Reply | Report Abuse | Link to thisWe have no way of knowing (right now) how many civilizations exist in this galaxy, let alone other galaxies, but a perfunctory use of logic will show you that where one exists, others are almost certain to. We have no scientific reason to think we are unique.
"This search is mathematically and logically absurd guided by atheists who feel that if they find one spec of life anywhere else it will fulfill their entire worldview when it would do no such thing. Abiogenesis has probabilities that are beyond all the atoms in the universe. There is no one else. Its abundantly clear that "We" should not be here at all--let alone anyone else."
Reply | Report Abuse | Link to thisBullcrap. Cite your *source for your belief that abiogenesis has such a stupendously small probability. It's already happened once, here, on Earth. Prove that it has not.
@Brain1 "Many great thinkers have shown that if there was Intelligent life in our galaxy anywhere near the estimates by overzealous seekers the entire galaxy would have probes littered in every solar system." Who are the great thinkers who have made such preposterous claims?
Reply | Report Abuse | Link to thisAlso, it may not fit into your worldview, but you should know that a great many "non-atheists" also believe that it is entirely possible for life to exist elsewhere in the universe.
Regardless of any other assumptions, in simple non-relativistic terms we will not receive any extraplanetary signal that was not being transmitted at the moment when that emission source was at the distance from us equaling its propagation delay. In other words a planet 100 light years away would have had to have been transmitting a signal right about 100 years ago for us to receive it now. If they transmitted a burst signal 200 or more years ago we've already missed - it's passed us by.
Reply | Report Abuse | Link to thisLikewise, if they were located in the MW at the opposite end of the disk, about as far from galactic center as we are, they'd have to have transmitted a signal right around 80,000 years ago. If they were transmitting much before that time, we missed it.
If their technological society persisted for ~200 years (like ours if we're lucky enough to survive the next ~90 years), they'd only have a short window to transmit to us before their and/or our demise...
Who knows how many technological societies have or will exist just in our galaxy, but the chances of our running into them are pretty slim.
Full disclosure: I’m an atheist, but in this comment I won’t try to bring you over to my side on religion. You argue that other civilizations would have billions of years of head start on us. This needs some perspective, because biology as we know it needs chemical elements that were exceedingly rare during the Universe’s early age, and that became gradually more abundant as stellar evolution took its course.
Reply | Report Abuse | Link to thisWhat this means is that the biology of Earth may well be among the first to evolve into complex life forms, which would entail that, by and large, the “head start” advantage might not exist or be significant enough to allow routine, long-range space travel .
You can find a more detailed explanation concerning stellar chemical element synthesis here: http://en.wikipedia.org/wiki/Metallicity .
Isn't the view that "the Earth is among the first planets to evolve life" undermining the extraterrestial life theories?
Reply | Report Abuse | Link to this(1) Why should we ever be so lucky to be among the first? (2) The conditions have already been favourable for quite a few billion years. (3) That way, the extraterrestial life theories are escaping toward unprovability. (4) Can the future be considered in probabilistic terms if affected by conscious actions, such as spreading or hampering life? Which brings us back to the uniqueness or brevity of complex life...
read "Where is Everybody" by Stephen Webb - after giving many theories as to why there has been no contact from aliens (probes and signals), he talks about all the factors which led to Homo Sapiens developing the technology to attempt to detect communications from said aliens. He finally presents his explanation of no contact, which in short, says that the large number of factors which had to work out just right to lead to us (Earth in right orbit, Jupiter in right orbit, moon, steady sun, plate tectonics, multi-cellular life, mathematics, technology, etc.) pretty much guarantees that we are alone in our galaxy, and probably the whole universe. He does believe that bacterial and single cell life occurs frequently, but since it took 3,000,000,000 years to move from single to multi celled life, that step alone pretty well says we are alone. :(
Reply | Report Abuse | Link to thisYou said, "Many great thinkers have shown that if there was Intelligent life in our galaxy anywhere near the estimates by overzealous seekers the entire galaxy would have probes littered in every solar system."
Reply | Report Abuse | Link to thisYou need to work on your perspective of just how BIG our (or any) solar system is. I'm not saying they exist, but you could quite literally hide millions of probes in our system and we might not know they are there. If there are just a few alien probes, large or small, passing through, or parked in a Lagrange Point, it is unlikely that we would know.
Let's not forget that the search for intelligent life among the stars is only a part of a much larger search for extra-terrestrial life in general. Sure, it would be convenient if someone else out there were sending out a "hello" beacon for us to decipher out of all the other interstellar noise. To me this search is like spending a dollar a week on a lottery ticket; unlikely to yield any results but not enough to make a difference in the budget so why not?
Reply | Report Abuse | Link to thisIf there is or was any "ET" we'll most likely find it closer to home. Even if it exists no where else in our solar system we may one day be able to detect life, albeit not necessarily intelligent life, around planets of other stars.
From my perspective the fact that I can even ponder the existence of other life and the circumstances of my life itself means that I've "won the lottery" about 50 thousand times already. Perhaps we are the first "developed" form of life that can even ask these questions in our galaxy? Perhaps not. Finding even the simplest of life somewhere else would go a long way in answering these questions. No result is a result too. If we don't even try to find out we will never know one way or another.
Let's home mankind never exports it's species there or anywhere. It's not fit to inherit the Earth and certainly not fit to inherit other planets either. Man is too violent and revengeful a species for the Universe.
Reply | Report Abuse | Link to thisWe tend to view single cell life as 'simple' and that it was readily formed out of the conditions existing on this planet. However, a single cell organism is far from simple. It contains DNA and RNA etc like all living creatures. When one considers the complexity of this (a molecule containing billions of atoms in a precise sequence) it is very obvious that much more than chance was involved in its creation. If this is so then it is not unlikely that the founder of the Universe (whoever he or it is) planted this seed hither and thither. One must ask the question 'what is the purpose of the Universe if there is no intelligent life to observe it?'. This argument, to me, suggests that life in many forms is abundant through-out the galaxy and Universe. To prove it will be very difficult however.
Reply | Report Abuse | Link to thisAlthough I am pretty sure this comment thread has run its course, I have one more to add:
Reply | Report Abuse | Link to thisThe title says-
"Closest "Alien Earth" May Be 13 Light-Years Away",
however the scientists say-
"It should be, hopefully, within 13 light-years,"
Definitely not the same thing.
Yes well. He is very obviously a very frightened person.
Reply | Report Abuse | Link to thisThen again our lives are so uncertain that it is indeed frightening.
But think about this God / belief thing. and realize that everything in our little electromagnetic bubble of a Universe is scaleable.
There are levels upon levels.
Any creator that is responsible for us is very, very impersonable and probably has very different priorities from us.
Our brief life spans, make us less than the ant under foot.
Right!
Reply | Report Abuse | Link to thisThe Grey Aliens that visit us in UFO's as observers. With very big eyes probably come from a red dwarf with similar gravity.
That is why they have very big eyes.
Their technology has found out how to manipulate 'Space/time' by manipulating the EMF which is 'space/time'
I think you misunderstand me. I do not think we'll ever make contact with intelligent life from another world. I'm just adding some additional constraints that reduce any possibility. IMO, people too often envision that a relatively nearby Earth-like planet is very likely to have developed intelligent life we could contact but, as far as any otherworldly intelligent life could tell, Earth only developed remotely detectable intelligent life <150 years ago - and we may not be around much longer.
Reply | Report Abuse | Link to thisThe big eyes hypothesis seems promising, though...