The Alpha Centauri system, our closest interstellar neighbor and long the stuff of science fiction lore, harbors a planet about the size of the Earth. It whips around its star, Alpha Centauri B, every 3.2 days and is too close and hot to have any water. But it's both the lightest world to orbit a sun-like star, and the closest exoplanet ever found to date--by a long shot.
Alpha Centauri is actually a binary system, with Cen A and Cen B each pretty close in size to our own star. There's a third star, Proxima Centauri, which is associated with this system. Astronomers at the European Southern Observatory set their sights on the system because it's likely to harbor planets, and because it would be very tricky to spot a planet there. They did it with a special spectrograph installed on the La Silla Observatory in Chile, and used the so-called wobble method, which measures tiny changes in a star's radial velocity that are caused by planetary perturbations.
The planet is much closer to Alpha Centauri B than Earth is to the sun, so it's not Earth-like, because it's not habitable. Foundation Alpha it is not. Writing in Nature, the astronomers say their method could lead to plenty of other habitable-planet discoveries, however: "We are confident that we are on the right path to the discovery of Earth analogues," they write. The paper will be published this week. [It was initially embargoed until Wednesday, but Nature allowed publication after a European news outlet broke the news early.]
It's an important addition to the exoplanetary pantheon, but let's be honest--this is amazing because this is Alpha Centauri. It's so close to us at just four light-years away, and it figures so prominently in science fiction--that alone makes it an incredible discovery.
Fun....Alpha Centauri was one of my favorite games in the civilization series.
so, is it a Mercury type planet, or an out-&-out Lavaworld?
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At this stage it's actually pretty hard to say as it's dependent on the atmosphere ( or lack thereof ). This can provide a very wide range of temperatures thanks to green-house effects, and there are plenty of compounds that have the opposite effect, including good ol' O2.
Something else that has to be considered is the orientation and rotation of the planet. How fast does it spin and what is its tilt. Finally, is the orbit more circular or elliptical?
If the planet was tidally locked at a 1:1 with its star, and had very little to no water ( steam rather ) on the sun facing side, and a lot on the opposite side it could still be habitable if it had a very thick Oxygen ( and other such anti-greenhouse gas compounds ) atmosphere.
However, this would require quite the perfect series of events. If we're going to go that far, we might as well add a large moon that also rotates in a 1:1 remaining geo-stationary, keeping the planet partially shaded. ( At a guess I would say this system would be highly unstable though. Not good enough for life to grow there, but perhaps enough for us to survive there for now. )
I always like hearing about discoveries about Alpha Centauri. Its an entirely different solar system that could potentially be reached in our lifetime(s).
@Blarg_King: Sorry, but it's almost surely not going to happen.
I just did some rough math, and the numbers were not good. New Horizons is the fastest craft launched to date, and is currently cruising at approx. 15.14km/s, and slowing ( due to the suns gravity which it is still a very long ways from escaping. Voyager 2 is actually going a bit faster atm though thanks to its multiple gravity assists, which will be a long time before the planets line up so nicely again. ) Even at 100 times this speed, it would take just shy of 200 years to reach Alpha Centauri B. ( Proxima Centauri on the other hand would be a little sooner...but not a lot. )
Unfortunately, we would need a number of massive technological advances to make it there in our life times. Both in medical ( to keep us alive ), and in spacecraft propulsion. NTM we would have to actually choose to send a craft there. It's hard enough to get politicians to do something that we won't see a return on for 5-10 years. Imagine trying to convince them to send a probe that won't reach its destination for 2 centuries!
Hopefully some day we do indeed make it, but that's likely something for the distant future. Perhaps the next generation ( those born about 20 years from now ) will be alive when the first probe arrives.
@zechio blah. If only people were as motivated as they were before. In 60 years we went from the first airplane to landing on the moon. Its been 40 ish years since then and we haven't come close to anything like that in terms of aviation/space travel though. Also I wasn't talking about humans reaching there just an un manned probe. You never know though. People always say we'll need some big technological breakthrough to do something and then a few decades later it happens. If you told a 20 year old person back in the 1930's that in their lifetime (assuming they live to the average of around 80 years) that man would go from tiny 4 seater planes that had the most basic instruments to landing on the moon in a computer aided, 300 foot tall rocket, would they believe you? My grandmother was around in the 1940's and she never thought it would happen.
Home sweet home! I so look forward to 21St December 2012, when our alien overlord GODS return and they show us the way back to the home planet. ...... happy sigh! ;)
Regarding getting there in our lifetimes - it's money that's the issue. We're beginning to realize that the Alcubierre Drive is a legitimate probability: NASA is even planning experiments into warp at atomic levels, where even lasers provide enough energy to create the desired effect.
Yes, within our lifetimes is a possibility.
Brilliant news! Finally a planet around our closest star system! And the size of earth (although not likely to support life with it`s location). Congratulations to the European astronomers and their ESO agency. Their HARP is an incredible instrument. Alpha Centauri people! These are the kind of legendary discoveries we can only dream about.
200 years could be shortened, but the current prevailing philosophy is that anything that takes more than 40 years isn't worth doing.
Not because the goal is unattainable, but because it will be cheaper and faster to wait for technology to cut the overall time due to increased innovation.
Think of it like this - traveling 292200 miles on horseback (20 miles a day) would take 40 years in 1820 - finishing in 1860. A train going 35mph 24/7 in 1859 would finish the journey before the horse.
Why shoot a probe to Alpha Centari that would be passed by a better probe 20, 30, or 40 years from now? The first probe would be obsolete before it ever did anything, and would not even be the first one there.
Of course, at some point we might hit a ceiling on space-speed travel (speed of light, 1/2 sol, 1/4 sol, etc). There might be some wasted time because we won't know tht ceiling is reached until it has been there for some time.
It also isn't as simple as shooting something out as fast as we can, we would need a way to direct it in flight and slow it back down (requiring near equal energy to acceleration). We would also need to be able to do this with a four year delay on any communication sent (which is a lot of lag).
From you: "If only people were as motivated as they were before. In 60 years we went from the first airplane to landing on the moon. Its been 40 ish years since then and we haven't come close to anything like that in terms of aviation/space travel though"
How can you suggest such blatantly incorrect statement? Did you not pay any attention to the recent probe we landed on Mars? Talk about technologically advanced and quite the accomplishments in aviation/space! Or how about the probe we managed to land on an asteroid? We are far more advanced and equally motivated(from a scientific point of view, not political) to achieve great things. Just because a man has not been placed on Mars does not mean we are falling behind the curve, in fact we are ramping up in technological advancement exponentially. I realize how hard it is to try to live up to such a pivitol expedition as the first moon landing but in reality we make just as many significant acheivements all the time in science. The older generation has the hardest time noticing these advancements.
If Earth truly wants to find a planet we can all exist on, other than Earth itself, why not just build a gigantic space ship, this is 100% self-sufficient. There is more likeliness of achieving this goal, than actually find a human compatible planet we can actually visit.
Otherwise with our Earth technology, we will just continue to look to these cosmic bodies from a far.
Once this space ship is built, then let’s venture forth out to the cosmic heavens and yes EXPLORE!
Why does the article say, Alpha Centauri is the closest star to us, when google says that Proxima Centauri is marginally closer? I mean the name "Proxima" must have been given in the first place, because it is close.
Why is this light years away is getting closer to us? Four light years away is not that far if they are moving towards us with a speed of light .