Looking for Life in Light

Gearoid_Murphy writes "Earth-like planets around distant stars may be too far away to be reached by spacecraft but scientists could still investigate whether they harbour life. Telescope technologies are being developed that will probe the very faint light from these objects for tell-tale signs of biology. These are the same "life markers" known to be present in light reflected off the Earth - so-called "earthshine"."

Comments

By the sound of it, they will be using optics

[El Cubano]

Telescope technologies are being developed that will probe the very faint light from these objects for tell-tale signs of biology.

I am guessing that they are talking about optical observations, since it appears to be an extra-atmospheric telescope they are designing. However, at those distances, how can they discern the difference between the shine from a planet and the light given off by the star(s) near the planet? I would think that we observe the earthshine from small enough distances that we can see it in spite of the Sun. I am curious how this would work for distant bodies.

Re:Seems primitive. (Resolution v. Lightgathering)

[ookabooka]

Are you sure about the capabilities of such an array? There are two main properties to a radio telescope (or any telescope for that matter) and that is Resolution and Lightgathering. By increasing the diameter of the collecting dish you increase both the resolution and lightgathering capacity. By creating an array using interferometry you can increase resolution to create a "virtual" dish with a diameter equal to the distance from one end of the array to the other. This doesn't, however, increase lightgathering capacity the same way. Let me propose a crude analogy: think of dishes as buckets, you can put two buckets 50ft apart and infer how much rain fell between them by adding them and dividing by two, but if it was just a drizzle, your data wont be so hot. If however, you have a 50ft bucket, you're gonna collect a lot of water.

So an array of a bunch of teeny TV sattelite dishes wont have as much surface area as a dish a kilometer wide. So yes we could resolve a planet, but it would have to be bright enough to be seen.