Looking Directly at Extrasolar Planets

D2Deek writes "Science Daily is reporting on a new device called an Optical Vortex Coronagraph that's been invented to directly image planets orbiting other stars by using a special lens that "spins out" the light from the star leaving only the reflected light from the planet." I just can't imagine trying to clean a lens shaped like a giant corkscrew.

The light of a planet

[fembots]

Seeing the planet next to its bright star has been compared to trying to discern, from a hundred meters away, the light of a match held up next to the glare of an automobile's headlight.

I thought a planet must be illuminated by light from a star, and not emitting light itself?

Anyway, this technology might be useful for photography, so that one will never get an overexposed shot again.

Re:The light of a planet

[Bradee-oh!]

I tend to think it's quite appropriate. Granted, in the strictist of senses, yes a planet reflect the star's light while a match creates its own. But from a analogical sense, it works. The brightness of the light from the match is a fraction of the light coming out of the headlight, just as the light reflected towards us from the planet is many times dimmer than the starlight itself. When applied to very large planets, which are the only extra-solar ones we've discovered so far, the size comparison works as well. Plus who's to say the planet is not a dim-light emitting gas giant? ;)
 
The point is, the analogy does get across the difficulty of this acheivement quite well, even moreso when you don't knitpick it to oblivion.

The point

[oni]

You wont be able to see any surface details, but the point, for those who don't already know, is that if you can look at just the light that's reflected, then you can run that light through a spectroscope. If you see in the spectroscope that there is free oxygen in the atmosphere, then you've probably found life. See, free oxygen (O2) doesn't occur anywhere in nature - except where it's created by life. So, if you find lots of O2 in the atmosphere, you've found a living planet (and a reason to build daedelus [geocities.com])

Re:The problem...

[m0nstr42]

Can't image things until you can find them. Can't find them if the starlight is making it impossible to discern the planet.

Can this be done without vortex lens?

[mattr]

This is extremely cool. I was wondering if there would be any way to do this in software (at least that technical explanation page shows there is a simulator) but thoguht that if it is based on slowing down light of a certain color, you would have to have all the phase info stored. Or at least extremely high resolution/range to have any data left after subtracting the green. I could be way off here but does anyone know of a way this technique could be used on an amateur telescope computationally based on light captured by a ccd without actually physically building a vortex lens? Is it true that this is based on a single color? Also, if you worked on the spectra of the star would this not also include spectra of the planet, i.e. is this really based on a pure black body incandescense i.e. pure green for this star and not really the full spectra of the star? Thanks.