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Comment by pedalpete | Hacker News Reader

I may be super naive here, but are we really defining "close" or is it that the object is close enough that it makes sense to point our objects that are close to Jupiter at the new object?

It is passing between two point in our night sky. I believe from a plane view, if you look at our universe from the perspective of it laying flat, it is my understanding the spin of our universe means that everything ends up within a flat plane, so in a 3 dimensional space, we have a limited Y axis. The other planets are spaced out across the X and Y axis, this is passing between or across two points.

Am I thinking of this right? I know very little about astronomy.

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There’s no evidence that the universe is spinning. The observable universe is not a flat plane - we see galaxies in all directions and at all distances.

You may be thinking of our galaxy (the Milky Way) or even our solar system, which both rotate and as such are both somewhat flattened (the solar system much more so than the galaxy.)

But what’s happening here has little to do with that. If you imagine the closest distance that Earth gets to Mars as a yardstick, 3I/Atlas is about half that yardstick’s distance from Mars right now - much closer than Earth ever gets. It’s practically in Mars’ back yard.

Thanks for clarifying that. And you're right, I was referring to our solar system, not the universe.

It's in Mars' backyard, but was it, or will it also be in Jupiter's backyard? I couldn't understand that from the original post.

It seemed to me that it was just that our telescopes/cameras near Jupiter would be pointed in that direction.

It's Juice (Jupiter Icy Moons Explorer) and it's not yet anywhere near Jupiter. Its trajectory has a few slingshot loops around Venus and Earth, and it's just coming off the Venus encounter.

It's about 0.43 AU from the comet at its nearest, whereas Earth will be pretty much on the opposite side of the Sun, making observations difficult from here.

Edit: Earth, Mars and Jupiter are in roughly 120 degrees from each other as seen from the Sun, with the Earth-Sun-Jupiter angle closing up fast and the E-S-M angle growing slightly slower. In about two months the E-S-M angle will be 180.

> There’s no evidence that the universe is spinning.

True, but if it were that would solve some problems in observations:

https://academic.oup.com/mnras/article/538/4/3038/8090496?lo...

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