Astronomers find first habitable Earth-like planet
Artist's impression of the planets in orbit around the red dwarf star Gliese 581. Their masses are 5 times, 8 times and 15 times Earth's mass. The five-Earth-mass planet makes a full orbit around the star in 13 days, the other two in 5 and 84 days. (European Southern Observatory image)
(April 24, 2007) An international team of astronomers has announced the discovery of what they are calling “the most Earth–like planet outside our solar system to date.”
This planet has a radius only 50% larger than that of Earth, they say. Its location within the habitable zone of its solar system indicates that any water on its surface may exist in liquid form.
A team of Swiss, French and Portuguese scientists discovered this planet – whose mass is about 5 times the mass of the Earth – in orbit around a red dwarf called Gliese 581. This star is among the 100 closest stars to us, located only 20.5 light–years away in the direction of the constellation Libra (“the Scales”). This star is already known to harbor a Neptune–mass planet. The astronomers have also strong evidence for the presence of a third planet with a mass about 8 Earth masses in the Gliese 581 system.
The discovery of the new Earth–like planet was made using the European Southern Observatory’s 3.6–meter telescope.
The Earth–like exoplanet – as astronomers call planets around a star other than the sun – is the smallest ever found up to now, according to these astronomers. It completes a full orbit in 13 days. It is 14 times closer to its star than the Earth is from the sun. However, given that its host star, the red dwarf Gliese 581, is smaller and colder than the sun – and thus less luminous – the planet nevertheless lies in the habitable zone, the region around a star where water could be liquid.
“We have estimated that the mean temperature of this super–Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid,” explained Stéphane Udry, from the Geneva Observatory (Switzerland) and lead–author of the paper reporting the result. “Moreover, its radius should be only 1.5 times the Earth’s radius, and models predict that the planet should be either rocky – like our Earth – or covered with oceans,” he added.
“Liquid water is critical to life as we know it,” said Xavier Delfosse, a member of the team from Grenoble University (France). “Because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extra–terrestrial life. On the treasure map of the universe, one would be tempted to mark this planet with an X.”
The host star, Gliese 581, has a mass of only one third the mass of our sun. Such red dwarfs are at least 50 times intrinsically fainter than the sun and are the most common stars in our Milky Way galaxy. Among the 100 closest stars to the sun, 80 are red dwarfs.
“Red dwarfs are ideal targets for the search for such planets because they emit less light, and the habitable zone is thus much closer to them than it is around the sun,” emphasized Xavier Bonfils, a co–worker from Lisbon University.
Two years ago, the same team of astronomers already found a planet around Gliese 581. With a mass of 15 Earth–masses, i.e. similar to that of Neptune, it orbits its host star in 5.4 days.
At the time, the astronomers had already seen hints of another
planet. They therefore obtained a new set of measurements and found the new super–Earth, but also clear indications for another one, an 8 Earth–mass planet completing an orbit in 84 days. The planetary system surrounding Gliese 581 contains thus no fewer than 3 planets of 15 Earth masses or less, and as such is “a quite remarkable system,” according to these astronomers.
The discovery was made thanks to HARPS (High Accuracy Radial Velocity for Planetary Searcher), which these astronomers say is “perhaps the most precise spectrograph in the world.” It is located on the ESO 3.6–m telescope at La Silla, Chile.
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You people are worse than the media at a disaster, your SPECULATION about there being a habital planet (which you can’t even give me a REAL picture of) is as stupid as being able to prevent Virgina Tech’s disaster.When you can really give something worth reading let me know.
Hello Bill,
Thanks for writing.
Astronomy is one of the most speculative of sciences. But this announcement isn’t any more speculative than anything else in astronomy. This system is 20 light-years away. Our fastest spacecraft are only the barest fraction of a light-year away … barely out of our own solar system. And even the Hubble Space Telescope, the best we have at seeing distant objects in space, would see Gliese 581 as just a star … with no planets visible. Any planets would be drowned in the light of this star, as seen by the Hubble Space Telescope, or any other telescope on Earth.
That’s why the search for planets is so intriguing! Astronomers have found clever ways to conduct it.
In this case, they are using a technique called “radial velocity.” As we said in the article, this discovery was made using the HARPS (High Accuracy Radial Velocity for Planetary Searcher) instrument on the ESO 3.6-meter telescope in Chile.
Radial velocity is about things moving toward us and away from us. In this case, it’s about planets moving in orbit around this star, Gliese 581. As the planets move in orbit, they are sometimes moving toward us and other times moving away from us … assuming this system is more edge-on to us than perpendicular which, presumably, it is … or astronomers wouldn’t be able to take this measurement.
In other words, they’re not seeing the planets themselves. Again, that’s not possible. They’re seeing minute variations in the overall light from the system. I’ll try to write more about that soon on the EarthSky website. Or you might try looking at skytonight.com or cosmicvariance.com in the coming days. Both of those sites are geared more to people who want the details about astronomical subjects. I’m sure the writers there are preparing longer articles about this subject.
Thank you for your comment. Again, we’d love to show you a picture if one were available! But the lack of a picture doesn’t mean this object doesn’t exist.
All the best,
Deborah
http://paranormalvision.com/images/mulder_sofficepic.jpg
Hi green! Thanks!
That’s a cool link you suggested. I want to believe, too.
Deborah
It was briefly reported on TV, as I watched tonight April 25 GMT+8. Not sure how to detect if water exists there. If intelligence exists, can they just dial a simple Morse code to us :) Anyway, such discovery is encouraging. Keep working you great scientents.
Keep in mind that reporters are … well, they aren’t scientists and often aren’t very discriminating in what they report. Here in Denver we had a reporter on this story this morning giving speculation as if it were proven fact.
Truth is, much of this is speculation based on relatively little actual data. I think it is strong and reasonable speculation, but it should not be reported as if it is an observed fact. That is, reporters should not say that the planet has oceans or earth-like conditions specifically. They should report that the data suggests it — not that it has been directly observed as such.
LS
Please note that my comments above are in reference to the general media, and NOT to Deborah’s report on the newly discovered planet.
In regard to Bill’s comments above, I have to say that while we have no actual image of the planet, the evidence is strong if indirect. We don’t have pictures of black holes either, but we have lots of evidence — through gravity and various radiations of objects falling into black holes, to know they exist. It’s kind of like air or radio waves — I can’t see them per se, but I’m as sure that they exist as I am that the Sun will rise tomorrow.
LS
this is great news !!! but just for thought, if there was intelligent life on this new earth planet whats to say that they are intrested in us as from the out side our planet is pretty messed up both enviromentaly and socially.if they are intelligent they would turn blind eye and hope we go away.
Yes, they would probably want us to go away and leave them alone because we are sooo messed up!! Maybe we should send them some porn and bourbon so they can fully understand that no matter how messed up we look from 20 lys away, we still know how to party.
Don’t forget … we’ve only had the technology to see their planet for a short time. We’ve just now discovered this planet. If indeed it is inhabited, they would have to have technology matching ours … or exceeding ours … in order to know we exist.
I just watched the news on BBC yesterday, it is a very interesting discovery. Hope our researcher could find more about the mistery of our universe
Sweet a new planet! Do they have cable yet? I did a search, but I cant find their Marriot! Jeez- get with the PROGRAM already!
no, really-
Come ON people, were lookin into the stars here. Give the guys that hunt this stuff down some credit.
Nice work guys, keep it up!
awsome news, i am obsessed with this. Any idea how long will it take to find any kind of life or water on this earth like planet?
this is the science that fires the imagination and gives hope to mankind. i love the idea if not the fact. its wonderful thanks
God, yes. Let’s GO there asap! And if the planet has life, we can teach the inhabitants how to torture, rap, pollute, steal, lie, cheat, enslave, hate, demean, rape, murder, plunder, and all the other behaviors that have ruined life here. Scientists, please: Let’s keep the virus of “humanity” under quarantine until we evolve to a point where we are no longer a danger to ourselves or others.
Assuming the discovery is confirmed the real excitement is that ‘we’ have found a planet in a habitable zone within our own neighbourhood.
It is either an amazing co-incidence or odds of finding many more habitable planets has just increased dramatically. The universe could be teeming with life.
Let us hope this discovery helps to focus minds on developing the technology to travel outside of the solar system as opposed to a revamped Apollo missions and space tourism.
Well…I for one am intrigued by the idea that life exists in our universe. It is fairly inexpensive to “explore” with telescopes and the images can be quite informative. I hope that we continue to poke around…As for the grumps who want conclusive evidence, sorry, we must make an additional commitment to advancing technologies. Humans are hard wired to explore. Our history is filled with tales of exploration. Isn’t space the ultimate challenge?
How can they say that we can go there? My husband and I were just talking about the actual distance that 20.5 light years represents: The speed of light is 186,000 miles per second. Since there are 60 seconds per minute, 60 minutes per hour, 24 hours per day, 365 days per year, there are 60*60*24*365*20.5 seconds in 20.5 years: 646,488,000 seconds in 20.5 years. Now 646,488,000 seconds*186,000 miles per second equals 120,246,768,000,000 miles. Over 120 TRILLION miles away!
I’ve been looking everywhere for a discussion of this discovery, excluding the forums I go to.
First of all, like the person above me has said, it’s too far to get there. Unfortunately, the most we can do is use our most sensitive instraments to study the planet’s atmosphere. It’s definately a rocky planet. It’s mass is 5 times than Earth, and the radius is 1.5 times as large, meaning that the density is greater than our planet, meaning rocky. The sun is a red dwarf, which live longer than our sun, but are much smaller and cooler than the sun. Since the planet is closer to its sun, it will be seen in the sky as maybe five times larger than our sun. It would be a sight to behold.
If anyone claims that this story is rubbish, I will tempted to post a link to the National Geographic article.
sir (no 15) says its too far. Its always been too far throughout our history. I live in Australia. Too far for most (- but well worth if you make the effort :)). The moon was too far, the outer planets were too far.
There are systems under development and on the drawing board that are well in advance of the chemical propulsion systems currently in use. What they all lack is funding. Maybe now there is a target this may change.
Throughout our history we have amazed ourselves at what we can achieve. The real mystery is we still think that we can’t – we can, if we dare to try.
Traveling at the speed of light (not possible, according to modern physics), the trip to the planet would take 20 years. Even if it were possible to travel that fast, relativistic effects would come into play. The people in the spaceship would age 20 years, but all left behind on Earth would age ... not sure how much ... thousands of years? ... during the same time. The space travelers would be leaving behind everything and everyone they knew …
It doesn’t have to be people..
My (admittedly limited) understanding of relativity suggests that if a spacecraft could be despatched at near-light velocity (with respect to us on Earth), it would take something in excess of 20 of OUR years to make the journey. If we were monitoring its progress from here I suppose we would detect its arrival approximately 20 years after it actually got there (as it would take the communication signal 20 years to reach us). Thus, we are talking of the order of 40+ years from launch before we could know it was safely there.
On the other hand, the occupants’ perception of the time taken would be very different. If (hypothetically) the ship COULD travel at the speed of light their journey would seem to be instantaneous. As it can’t, it will merely seem shorter than it would to us left behind. At any rate, we are not necessarily talking about mind-boggling time-scales!
Grounds for optimism then. Of course, reaching even “near-light” velocity would be a tremendous technological feat. But let’s stay positive – this is a most extraordinary and exciting discovery; even if we don’t know as much about this planet as we’d like … YET.
I’m looking up the calculation procedure for relativistic effects in Exploring the Cosmos by Louis Berman.
Let’s say the space travelers are going at 4/5 the speed of light. According to clocks on Earth, the 40 light-year round trip should take 50 years (40 divided by 4/5).
The space travelers’ clock runs slow relative to the Earthly clock by this contraction factor formula: square root of 1 – (4/5) squared. Thus, 1 – (4/5) squared = 1 – 16/25 = 9/25.
The square root of 9/25 = 3/5. From the space travelers’ perspective, the time period for the 40 light-year round trip would be 30 years (3/5 × 50 = 30). (This calculation presumes extremely brief periods of acceleration and deceleration.)
I think I have this right, but if anyone out there can verify or correct me, please do!
Bruce McClure
Hi Bruce,
I think I would agree with that. Maybe my understanding is better than I thought it was!
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