4 ms·

Wouldn’t it still be passing in front of something, or is it likely to be comparatively ‘stationary’ against a similarly stationary backdrop of stars and other

Wouldn’t it still be passing in front of something, or is it likely to be comparatively ‘stationary’ against a similarly stationary backdrop of stars and other objects?

bastawhiz 3y ago
When a star is occluded by a planet, it'll dip in brightness at a pretty regular interval (because of the orbit). So you can look look for a series of dips, which gives you a candidate. That's then looked at more closely. Since a planet 9 wouldn't transit a star at any regular interval, it wouldn't show up as a candidate for that search technique.
- catlifeonmars 3y ago
  So we would need to potentially deliver the telescope far outside of our solar system and have it look back at us, kind of like a very expensive selfie stick?
  - bastawhiz 3y ago
    That's not possible. The furthest things we've ever sent out are the voyager probes, and they're 135 and 162au away, each. We'd have to get twice that distance to even be at the distance that we expect a planet 9 to be. Even if we managed to get many multiples of the distance planet 9 is from the sun to take pictures backward and send them home to earth, it's _so far_ from the sun that a) the amount it would occlude the sun is ridiculously small, if it ever even lined up. At that distance, the sun just looks like another star in the sky. That's like waiting for one particular asteroid to block out the North Star. And b) the orbit period would still need to be short enough that you could see it transit a few times to use the technique that scientists use to detect planets elsewhere. Just seeing something block the sun doesn't tell you what it was that blocked it, especially at 400-800au distance. Plus, then you're talking about latencies of about a light month, which makes it super hard to even know to look for the thing you saw (a month ago).

4 ms·

Wouldn’t it still be passing in front of something, or is it likely to be comparatively ‘stationary’ against a similarly stationary backdrop of stars and other

by greggsy 3y ago

Wouldn’t it still be passing in front of something, or is it likely to be comparatively ‘stationary’ against a similarly stationary backdrop of stars and other objects?

bastawhiz 3y ago
When a star is occluded by a planet, it'll dip in brightness at a pretty regular interval (because of the orbit). So you can look look for a series of dips, which gives you a candidate. That's then looked at more closely. Since a planet 9 wouldn't transit a star at any regular interval, it wouldn't show up as a candidate for that search technique.
- catlifeonmars 3y ago
  So we would need to potentially deliver the telescope far outside of our solar system and have it look back at us, kind of like a very expensive selfie stick?
  - bastawhiz 3y ago
    That's not possible. The furthest things we've ever sent out are the voyager probes, and they're 135 and 162au away, each. We'd have to get twice that distance to even be at the distance that we expect a planet 9 to be. Even if we managed to get many multiples of the distance planet 9 is from the sun to take pictures backward and send them home to earth, it's _so far_ from the sun that a) the amount it would occlude the sun is ridiculously small, if it ever even lined up. At that distance, the sun just looks like another star in the sky. That's like waiting for one particular asteroid to block out the North Star. And b) the orbit period would still need to be short enough that you could see it transit a few times to use the technique that scientists use to detect planets elsewhere. Just seeing something block the sun doesn't tell you what it was that blocked it, especially at 400-800au distance. Plus, then you're talking about latencies of about a light month, which makes it super hard to even know to look for the thing you saw (a month ago).