How long will it be until a telescope is made which can see planets in detail in other solar systems?

Question

How long will it be until a telescope is made which can see planets in detail in other solar systems?

Answer 1

Hi. We could probably see gross detail with two telescopes set up using interferometry. But it is difficult through the atmosphere.

Answer 2

Not to long I would imagine. The problem has already been solved by placing the cameras and telescopes aboard satellites and sending them on deep space missions to observe other planets. So far, however, our primary missions have been to planets within our own Solar System.

Two problems confront us when we consider sending a photographic mission to a distant solar system to photograph distant planets orbiting stars far away.

First: The distance to the nearest star (other than our Sun) is 4 1/2 Light Years. Other stars within our Galaxy are as much as 800 Light Years away from Earth. Each Light Year is equal to 6 Trillion Miles. So, any mission would take a very long time to approach the distant star's planets and begin its photographic mission...like maybe 5,000 to 7,000 Years.

Second: Radio signals become weaker and weaker the farther away a satelite probe gets from Earth. Signals from the current Cassini Probe destined to orbit Saturn and its moons will send back the weakest immaginable radio signals containing photographic and scientific telemetry information. A satellite destined to travel 1000 times to 10,000 times that distance or more would be just that much harder to hear by Earth receiving stations. Even worse for the mission project managers, any corrective command transmissions from Earth to the distant satellite would take years to get there, and the digital photos along with scientific telemetry signals would also take "years" to reach us. So, while this technical possibility is not far off, the constraints I just mentioned suggest that the possible information we might obtain will arrive years and years in the future.

Answer 3

Yep. It will be a while. The main problem is not the capacity of telescopes (Cirric has talked about interferometry which will soon provide sufficient resolution, and eri has already named the upcoming missions). The main problem is seeing the planets so close to their stars.

Our Sun puts out 3.85x10^26 Watts (3.86e26 W) which, at a distance of 10 parsecs (32 light years, very close in astronomical terms) would give it a magnitude of 4.8 (invisible from most North American cities and towns).

The Earth intercepts 1370 W per square metre of this power, and reflects 37% of it back into space. That is approximately 1.5e11 W.

That makes the Earth appear only 0.000000000000005 times as bright as the Sun (The absolute Magnitude of Earth would be +43, as seen from 10 parsecs). That, we can't achieve yet.

The Earth would appear to be at most 0.1" from the Sun (which is resolvable with modern technology); however, when it is at its greatest elongation, it is not full: observers 10 parsecs away would only see a "half-Earth" which, of course, would be even fainter than the "full-Earth" whose brilliance was calculated above.

It will be done. It will just take a while longer.

Answer 4

Today we can see other planerts in the solar system. But it will take so much of time to invent a telescope that we can see so much of planets in detail.

Answer 5

The distances and sizes are extraodinary. To see something the size of our moon orbiting Proxima Centuri (4.2 light years), with the same detail that we can detect on our moon with the naked eye, would require something with a magnification of around 8 million x; something Earth-size might require 3-4 milion x; a Jupiter sized planet perhaps 350 thousand x. This is a whole different order of equipment then what we have today, even if we focus on our nearest neighboring star.

Answer 6

I think that will be a while; the telescope needed for that would have to have a huge mirror, and a clear vantage point - excluding all Earth-bound sites. Probably even the moon's gravity would distort a mirror of the size needed for that as well, which means you'd need a space-based scope. I would say 50-70 years.

Answer 7

There's the Kepler telescope and the Terrestrial Planet Finder, both upcoming missions. They are supposed to be able to detect Earth-like planets, but probably not in much detail.

Answer 8

The Rayleigh criterion might show this to be a problem.