Are infra red space based telescopes best for detecting objects that could collide with earth?
It seems the James Webb telescope concept is better for this. Objects in our system being likely heated by the Sun.
Of course it would be best to design them for this purpose. But is infra red a better range for detection of these objects?
Probably.
The Near Earth Orbit Surveyor (aka NEO Surveyor) space telescope that was approved by NASA last year is an infra-red telescope. It’s scheduled to launch in 2026.
Thanks. Quick and accurate.
If you’re trying to detect infrared that things are emitting as a result of “being heated by the Sun”, that’s going to be a far longer wavelength (lower frequency) than what Webb detects. It’d probably also be much, much dimmer than what the object reflects directly, which could be any wavelength band produced by the Sun.
And completely aside from wavelength, the Webb is completely the wrong sort of instrument to look for potential impactors. Its field of view is tiny; you have almost no chance of something that you didn’t already know about “just happening” to be in its field of view. In fact, even if you did know where to look, there’s a good chance you couldn’t: Because of the way its sun shield works, at any given moment, Webb can look at only a narrow ring across the sky (over the course of a full year, it can look at any given point, but most points you have to wait for).
What you’d want would be something with a large field of view, and which is very sensitive to changes in brightness. You could skimp a bit on the field of view by mostly looking in the ecliptic, because that’s where impactors are most likely to come from, but you’d want to be able to see as much of the ecliptic as possible at once.
The best telescope we have for spotting potentially dangerous asteroids and comets is the Gaia telescooe. Gaia is an all-sky survey telescope orbiting in L2 where JWST also operates.
Gaia is the least-talked about telescope in the public eye, because it doesn’t provide amazing high resolution images of distant objects that the press likes to publish. But it is doing amazing science work. For example, here’s a descriotion of what’s in its current data release:
Gaia data is so accurate that even though it is a wide-field scope it has measured the radial velocity of stars so well that we expect to find some 20,000 exoplanets by measuring the host star’s wobble. It has has precise measurements of the orbits and even spectra of every single Earth crossing asteroid known. And if new threats come down from the Kuiper Belt or Oort cloud, Gaia is the scooe that will likely find it.