Let’s say that Proxima B, the nearest potentially habitable exoplanet to us, has a civilization of intelligent beings with exactly the same technology we have.
Would they see the same constellations we see? Would their equipment be able to pick up all eight planets in our solar system?
I was trying to find an app or website that showed the sky from other star systems, but no luck.
From Proxima B, you will see a first-magnitude star in Cassiopeia and that would be our Sun. Other nearby stars such as Sirius will move dramatically across the sky, distant stars will be in pretty much the same position as we see on Earth.
Just as to this:
No.
Our current equipment can’t pick up anything much smaller than overgrown Jupiters anywhere. They certainly could not “see” Sol’s rocky planets.
As to this:
@K364 pretty well covered it. But it also depends what you mean by “see”.
Someone staring up into their night sky with their naked eyes (on stalks) will find that constellations whose constituents are hundreds or thousands of lightyears away to be slightly different than what we humans see with our non-stalky eyes from our planet. But maybe not different enough for an ordinary citizen or even an astronomer with access to both planets to notice.
Now once they start aiming precision telescopes and taking detailed sky photos, if they could compare their detailed pix from Proxima with our detailed pix from Earth, the differences would be obvious.
And, just for completeness …
As @K364 said, any stars within, say, 25LY will appear to be in an obviously different place versus the rest of the more distant background stars.
There is whole section (View from this System) in the Wikipedia article on Alpha Centauri that might be close enough to satisfactorily answer this question. There’s even pictures:
The Astronomy software used is Celestia.
That used to be the case when exoplanets were first discovered, but under the right conditions much smaller planets can also be detected, though not directly “seen”. For example, all seven planets orbiting the red dwarf star Trappist-1 are believed to be about earth size, and that’s about 40 light-years away.
Closer to home, the planet Proxima Centauri b is also about earth size. But there’s uncertainty about several other planets orbiting that star, so if the aliens over there have the same equipment as we do, they might detect some of our planets – most likely the gas giants – but probably not all of them.
Actually, we could detect any of our system’s planets around another star… if we’re lucky. Exoplanets can also be detected when they transit in front of their star, causing (from our perspective) a periodic slight dip in the star’s brightness every planetary year. Of course, this only works if the alignment is right, which it is in around 1% of cases (and isn’t, in the case of our system as viewed from Proxima).
Cool. Thank you both. TIL some new stuff about exoplanet discovery.