Earth sized planet found around Alpha Centauri B!

[Bonam]

Link:

http://spaceref.com/extrasolar-planets-1/alpha-centauri-b-has-an-earth-mass-planet.html

Alpha Centauri is our nearest neighboring star system, 4.3 light years away, and this is the first planet discovered in it. It is also the only Earth sized planet found so far orbiting a star similar to the Sun. Of course, it is way too close to Alpha Centauri B to be habitable, but the technique used is biased towards planets that are closest to their parent star, and there may be other planets in the Alpha Centauri system yet to be discovered.

Exciting times!

[Guest]

And I was looking for vacation ideas, too!

Edit> I don't want to give the impression by that comment that I am belittling the find. As an avid fan of Science Fiction and Fact I am also very excited when an Earth sized planet is detected.

Edited October 17, 2012 by bcsapper

[Moonlight Graham]

Amazing. Thanks to telescopes or comparable viewing technology, within my lifetime I hope we'll be able to find & observe E.T. life out there somewhere.

With simply a strong enough telescope and a fairly clear atmosphere of the other planet, imagine how much we could learn by just watching another habitable planet!

[Bonam]

Amazing. Thanks to telescopes or comparable viewing technology, within my lifetime I hope we'll be able to find & observe E.T. life out there somewhere.

With simply a strong enough telescope and a fairly clear atmosphere of the other planet, imagine how much we could learn by just watching another habitable planet!

Unfortunately, a telescope large enough to discern detailed surface features on planets in other solar systems would have to be truly gigantic. The formula for the angular resolution that a telescope can resolve is:

http://en.wikipedia....ingle_telescope

To be able to see, say, a 100m sized object (so you could start to see the lay of cities, terrain, etc) on a planet in the Alpha Centauri system (4.3 light years = 4*10^16m), you'd need an angular resolution of 100/4*10^16 = 2.5*10^-15

The wavelength of the visible spectrum is about 500 nm, applying the telescope formula, to get a resolving power of 2.5*10^-15, you would need:

D = lambda/R = 500*10^-9/(2.5*10^-15) = 200,000,000 m = 200,000 km.

So a telescope that could literally see the surfaces of other planets and the activities of alien civilizations that go on there would have to be about 15 times the diameter of the Earth. For reference, the largest telescope currently planned is 39m across, about 5 million times smaller than what would be necessary.

I think it is safe to say that we will not be building planet-sized telescopes in the foreseeable future.

To even resolve the recently found planet at all, in the visible spectrum, would require a 2km diameter telescope, also far beyond feasibility in the near future.

Now, some of the advantages of large telescopes can be achieved with a telescope array. For example, you could put two telescopes in orbit around the in the Earth-Sun Lagrange points, and effectively have a telescope with a resolving power equivalent to if it was a single telescope 150 million km across. To actually be effective in creating an image, though, you need not just 2 telescopes but a large two-dimensional array, or even better, spherical array, of such telescopes. This is much more realistic than a single large telescope, but due to the nature of orbital mechanics in the solar system, I don't think it would be possible to maintain a spherical or grid arrangement of telescopes stationary relative to each other for long periods. The only way they could be stationary relative to each other would be if they were all in the same orbit around the Sun, but the most you could get that way would be a circular ring, not enough to create a real visual reconstruction using any known algorithm in astronomical interferometry.

You can also build a telescope array on Earth, and such an array could be up to about 10,000km in diameter, however, any Earth-based system is limited in accuracy by Earth's atmospheric effects, and due to the associated optical distortions could never be used to see the surface of planets in other solar systems.

Perhaps the best bet for a telescope for resolving planets in another solar system may be to build it on an atmosphere-free body, like the Moon. On the dark side of the Moon, one could build a 1000 km size telescope array that could resolve 20 km sized features on planets in the Alpha Centauri system. That would be enough to generate rough maps of the surfaces of planets there, see if they have oceans, lakes, forests, craters, mountains, clouds, etc. And such an undertaking would probably only cost a few trillion dollars, so it is at least conceivable.

Anyway, while direct visual observation of the surfaces of other planets from Earth may not be feasible, there is much we can infer without such observations. For example, careful but feasible spectroscopy will allow us to determine the composition of the atmospheres and surfaces of other worlds, as well as their temperatures, and possibly even provide insights into any planetary magnetic fields (which are crucial for providing an environment that is shielded from the radiation generated by the star a planet orbits). Gravitational wobble observations, star brightnesses used in the transit method, and direct imaging will allow us to detect the presence of planets and ascertain their mass and distance from their star, allowing a good estimate of their surface conditions, especially in combination with spectroscopic information. And, lastly, by the end of the century it may well be within our capability to send interstellar probes that take only several decades to reach the nearest star systems, and then send back information, including detailed visual images.

Edited October 17, 2012 by Bonam

[DogOnPorch]

Triple star system with a planet. Now that would be a weird sky.

[Boges]

Triple star system with a planet. Now that would be a weird sky.

Perhaps the Navi live there.

Edited October 17, 2012 by Boges

[DogOnPorch]

Perhaps the Navi live there.

Heh...perhaps...perhaps. It might also be somewhat like Issac Asimov's 'Nightfall'.

http://www.astro.sunysb.edu/fwalter/AST389/TEXTS/Nightfall.htm

[Moonlight Graham]

You can also build a telescope array on Earth, and such an array could be up to about 10,000km in diameter, however, any Earth-based system is limited in accuracy by Earth's atmospheric effects, and due to the associated optical distortions could never be used to see the surface of planets in other solar systems.

Perhaps the best bet for a telescope for resolving planets in another solar system may be to build it on an atmosphere-free body, like the Moon. On the dark side of the Moon, one could build a 1000 km size telescope array that could resolve 20 km sized features on planets in the Alpha Centauri system. That would be enough to generate rough maps of the surfaces of planets there, see if they have oceans, lakes, forests, craters, mountains, clouds, etc. And such an undertaking would probably only cost a few trillion dollars, so it is at least conceivable.

And, lastly, by the end of the century it may well be within our capability to send interstellar probes that take only several decades to reach the nearest star systems, and then send back information, including detailed visual images.

I don't know if telescopes are the answer, or some other technology, but i hope something of the sort could be possible. The moon array scenario is interesting.

On a somewhat unrelated note, I want scientists to invent fast-than-light travel so we can send a telescope many light-years away so it can take pictures of the light images of the earth as it appeared in the past...almost like time travel. Imagine being able to take a picture of the earth when the Hiroshima nuke went off and witness that again? Then send those images back to earth via faster-than-light travel.