Anonymous

I can't comment on what NASA knows or doesn't know. Alpha Centauri is actually three stars orbiting each other. But it certainly is possible for a planet to be orbiting one of those stars, in fact several have been discovered already, see below. It's not possible to detect if they are earth like or not.

Anonymous

NASA is not the astronomical authority you seem to think they are. There are thousands of astronomers and observatories around the world who study the universe. I doubt that any one of them would make such an absolute statement, either way, about that system.

Anonymous

One such Exoplanet has been found But as all three of the Stars in the Alpha System orbit each other.the planet planet's own orbit could well be chaotic Thought to be closest to Proxima. but being affected by the gravity of Alpha and Beta, its orbit would put Pluto and Mercury to shams Very Extreme and not very conducive to life giving conditions

Anonymous

1) I have no idea what NASA knows or not. NASA is one of many space agencies. There are hundreds of thousands astronomers in the world and very few of them work for NASA. Most astronomers don't even work in the USA nor for the USA. 2) Astronomers send their discovery papers to independant scientific publications where the papers are "peer reviewed" (other astronomers look at them to see if they make sense AND try to replicate the discovery with the information contained in the paper). None - as in zero - of these scientific papers is run by NASA. 3) There is an international group (not run by NASA) that compiles all the available information on exoplanets and publishes this information on a Web site accessible by everyone (not just astronomers), including you and me. http://www.exoplanet.eu/ They use ALL information, including any information from NASA. Using the site does take a bit of getting used to. But if you play around with that site, you will quickly learn how it works. It is a catalogue, listing all the known exoplanets (it may be a few days behind in the updates). As of today (July 20), there are 3,807 known exoplanets. There is a search box (if you know part of the name of the star) but the filter box requires you to follow very strict instructions (I avoid the filter and use only the "search"). The names of exoplanets is "easy" to understand. The name of the star is followed by a lower-case letter identifying the planet, starting at "b" (the letter "a" is reserved for the star itself in cases where you may need to talk about both the star and the planet, separately). In multiple star systems (like Alfa Centauri)**, the individual stars are identified by capital letters (A, B and C, for example). Proxima Centauri is also known as Alfa Centauri C But, because the star does have a proper name (Proxima) this is the name used. The planet around it is Proxima Cen b There is a planet around one of the two main stars of Alf Cen. It is around the star Alf Cen B. Since it is the first confirmed star, it gets the letter "b" Alf Cen Bb http://exoplanet.eu/catalog/alf_cen_b_b/ Careful, the site shows the mass of planets relative to Jupiter (M_J) 0.0036 M_J = 1.14 M(Earth). In other words, this planet is almost exactly the same mass as Earth. The star itself (alpha Cen B) is very similar to the Sun (93% of the Sun's mass, and a surface temperature around 5200 K, while our Sun is around 5700 K). HOWEVER, the orbital distance (from its star to the planet) is only 0.04 AU (Earth is, by definition, 1 AU.). The amount of radiation received by this planet is (1/0.04)^2 * (5200/5700)^4 = 433 times what Earth receives. The fourth root of 433 is approx. 4.5. Earth's average temperature is close to 0 C = 273 K, therefore that planet would have an average temperature of 4.5 * 273 K = 1200 K = 950 C = 1700 F Is it Earth-like? In mass, it is. In the quality of its "sun", it is. In terms of its temperature, it is not. The system of stars: The distance between A and B (the two main stars, both are similar to our Sun... almost) is equal to the orbital distance of Neptune in our system. The distance to C (Proxima) is so large that it would not interfere with any planets around A or B. If you imagine yourself on an Earth-like planet around A (which is a bit bigger than B), at a suitable distance to make it the right temperature, you have to ask yourself if its orbit would be stable if, in our system, you replaced Neptune with another Sun. The answer is "probably not". That second "sun" would be too close. Is it "impossible" to have such an Earth-like planet? Difficult to prove. Is it "possible"? Yes, but how long would such an orbit remain stable ("only" millions of years?) and how probable is it that a planet would have formed there in the first place = not very probable (but not impossible). All we know, for now, is that it is possible to detect "Earth-size" planets in that star system, but we have not detected one at the right distance... yet. --- **The exoplanet web site uses the "f" and not the "ph" to make things easier for all astronomers. There are so many languages where "ph" does not give the "f" sound.

Anonymous

As I recall, Doppler spectral analysis has ruled out any Jupiter-like gas giants, so the movie "Avatar" has been ruled out also. But most experts agree that Earth-like planets are still possible, but none have been observed yet.

Anonymous

A planet was found orbiting Proxima Centuri. That is the smallest of the triple star system. No one knows if it is earthlike or not.

Anonymous

NASA doesn't know. It doesn't do that kind of research. It only exists to launch things and keep track of them. Unless the research involves spacecraft, it's nothing to do with NASA.

Anonymous

https://www.youtube.com/watch?v=zDMwyGYM... It doesn't answer whether or not Alpha Centauri has a habitable planet, but it says how it is possible to detect the planet.

Anonymous

While *possible*.... none have been found.

Anonymous

I heard such a planet DOES exist.---but we don't know how Earth like it really is YET---new technology is needed.