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What is physically stopping us from actually seeing this planet with visible light? Is it that we can't build a big enough telescope? Also would it be possibl

What is physically stopping us from actually seeing this planet with visible light? Is it that we can't build a big enough telescope? Also would it be possible start broadcasting radio waves or maybe some kind of laser towards this planet incase there's something there that can respond to us a thousand years from now?

windsurfer 12y ago
Yes. We haven't build a large enough telescope to pick up the faint reflection of it's star's light on the surface.
dredmorbius 12y ago
Resolving power. There are limits to the angular separation a telescope can detect. Even the very largest telescopes on Earth (or more often: arrays of several telescopes, effectively creating multi-thousand-kilometer baselines) can resolve the disks of even the largest stars. It turns out that Betelguese is roughly the same distance as Kepler 186f -- 643 light years (plus or minus 146), and its disk can be resolved, even to the point of detecting surface features. But Betleguese is roughly 1000 times the radius of our Sun, and 4x wider than Earth's own orbit: "If Betelgeuse were at the center of the Solar System, its surface would extend past the asteroid belt, possibly to the orbit of Jupiter and beyond, wholly engulfing Mercury, Venus, Earth and Mars." (Wikipedia) http://en.wikipedia.org/wiki/Betelgeuse http://en.wikipedia.org/wiki/Betelgeuse http://www.space.com/7771-spots-sun-revealed-giant-star.html http://www.space.com/7771-spots-sun-revealed-giant-star.html For planets, we're limited to detecting brightness fluctuations in the parent star (how Kepler detects planets), and possibly spectral absorption lines. That last would be hugely exciting, as it allows knowledge of the composition of the atmosphere of a planet. And there's one molecule whose presence would be an almost absolute certain tell-tale of life: oxygen. Ordinarily, free oxygen reacts with other substances in its presence to create oxides. Only if new oxygen is being released will an atmosphere be high in oxygen. So a planet with an oxygen-rich atmosphere should almost certainly have light. As for beaming radio signals, the challenge is in creating signals which would be strong enough to detect at 500 light years' distance. Signal strength for most broadcast sources would be undetectable even at the nearest star, 100x closer: http://zidbits.com/2011/07/how-far-have-radio-signals-traveled-from-earth/ http://zidbits.com/2011/07/how-far-have-radio-signals-travel...
- welterde 12y ago
  > There are limits to the angular separation a telescope can detect. Even the very largest telescopes on Earth (or more often: arrays of several telescopes, effectively creating multi-thousand-kilometer baselines) can resolve the disks of even the largest stars. Just to clarify: In radio-bands we can easily achieve sub-mas angular resolution using VLBI (the mentioned multi-thousand-kilometer baselines) or large arrays (ALMA, VLA, etc.) In the optical/NIR bands your baselines are typically limited to a few hundred meters, where you can go down to mas, but it's much more difficult than in the radio bands. And direct imaging of the disks of the largest stars is possible in the optical/NIR.
3rd3 12y ago
There is a very cool project for new space telescopes in the works. Here is a 6 minute TED talk about it, also explaining why it's difficult to detect planets directly within the visible spectrum: http://youtube.com/watch?v=XYNUpQrZISc http://youtube.com/watch?v=XYNUpQrZISc

windsurfer 12y ago

Yes. We haven't build a large enough telescope to pick up the faint reflection of it's star's light on the surface.

dredmorbius 12y ago

Resolving power. There are limits to the angular separation a telescope can detect. Even the very largest telescopes on Earth (or more often: arrays of several telescopes, effectively creating multi-thousand-kilometer baselines) can resolve the disks of even the largest stars. It turns out that Betelguese is roughly the same distance as Kepler 186f -- 643 light years (plus or minus 146), and its disk can be resolved, even to the point of detecting surface features. But Betleguese is roughly 1000 times the radius of our Sun, and 4x wider than Earth's own orbit: "If Betelgeuse were at the center of the Solar System, its surface would extend past the asteroid belt, possibly to the orbit of Jupiter and beyond, wholly engulfing Mercury, Venus, Earth and Mars." (Wikipedia) http://en.wikipedia.org/wiki/Betelgeuse http://en.wikipedia.org/wiki/Betelgeuse http://www.space.com/7771-spots-sun-revealed-giant-star.html http://www.space.com/7771-spots-sun-revealed-giant-star.html For planets, we're limited to detecting brightness fluctuations in the parent star (how Kepler detects planets), and possibly spectral absorption lines. That last would be hugely exciting, as it allows knowledge of the composition of the atmosphere of a planet. And there's one molecule whose presence would be an almost absolute certain tell-tale of life: oxygen. Ordinarily, free oxygen reacts with other substances in its presence to create oxides. Only if new oxygen is being released will an atmosphere be high in oxygen. So a planet with an oxygen-rich atmosphere should almost certainly have light. As for beaming radio signals, the challenge is in creating signals which would be strong enough to detect at 500 light years' distance. Signal strength for most broadcast sources would be undetectable even at the nearest star, 100x closer: http://zidbits.com/2011/07/how-far-have-radio-signals-traveled-from-earth/ http://zidbits.com/2011/07/how-far-have-radio-signals-travel...

welterde 12y ago
> There are limits to the angular separation a telescope can detect. Even the very largest telescopes on Earth (or more often: arrays of several telescopes, effectively creating multi-thousand-kilometer baselines) can resolve the disks of even the largest stars. Just to clarify: In radio-bands we can easily achieve sub-mas angular resolution using VLBI (the mentioned multi-thousand-kilometer baselines) or large arrays (ALMA, VLA, etc.) In the optical/NIR bands your baselines are typically limited to a few hundred meters, where you can go down to mas, but it's much more difficult than in the radio bands. And direct imaging of the disks of the largest stars is possible in the optical/NIR.

3rd3 12y ago

There is a very cool project for new space telescopes in the works. Here is a 6 minute TED talk about it, also explaining why it's difficult to detect planets directly within the visible spectrum: http://youtube.com/watch?v=XYNUpQrZISc http://youtube.com/watch?v=XYNUpQrZISc