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.

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...

How likely is it that a random alien object does a wellness check on a barren planet in the same decade the humans happen to turn on the big survey telescope array?

Shuffle a deck of cards, and statistically no one has ever shuffled the same sequence in all of human history.

It is extraordinarily unlikely you will shuffle one particular order of cards. It is 100% likely you will result in a sequence of cards.

Space is full of trillions and trillions and trillions of these. Given the rate of detection, we’ll probably see them come through regularly.

That's my point. If you turn on several telescopes particularly good at seeing these things and see three objects in fairly quick succession, the implication is probably (not certainly) that there are lots of interstellar objects hammering in all the time, not that the first ones you see are particularly special, even if one of them seems to be making a statistically unlikely near approach to Mars.

Yeah, like exoplanets. When I was in middle school there were none. Now there’s 6,000 confirmed ones.

Surely no one was actually thinking there weren't exoplanets though. We didn't need experimental proof that they exist to be reasonably sure that they do.

The existence of exoplanets was an open question still in the 80s. They were pretty sure that they existed, but no one had any evidence of it. It fell kind of in the same category of whether the Riemann conjecture is true. Mathematicians are pretty sure it is, but they don’t know for sure.

I’m curious how unlikely it is. Seems very, very unlikely to pass by 2 major planets.

Any path it could possibly take is equally unlikely.

It is. It’s similarly unlikely that I win the lottery. But someone always does!

The situations are in no way analogous.

Sure they are. There are likely trillions of these things. We are likely gonna see them everywhere. Like scratch-off lottery cards.

We have seen 3.

Yes. In very quick succession, right after we put the tech in place to find them.

In the mid 1990s we’d only seen a handful of exoplanets. That they were basically everywhere we looked early on clued us in to their prevalence.

We have seen 3 and one of them makes a very close pass to 2 major planets. Seems very unlikely.

If you are unaware of gravity, sure. It is accelerating towards the sun, which also happens to be where the planets are.

I urge you to take a look at how much empty space there is around the Sun.

Pretty likely if there are a lot of them!

Then I guess we'll see another one soon (unless we freak them out by noticing them and broadcasting about it!).

Once more survey telescopes like Nancy Grace Roman and Xuntian come online we'll increasingly find out how many there really are and I suppose if they seem to like buzzing the proverbial tower.

In fact, we already have; that's why there's a 3 in its name.

The other two didn't make a planetary close pass. As we see more of them, the statistical strangeness of the third one getting so close to Mars will fade. (Or, I suppose, they keep doing it and then we really will have a puzzle on our hands!)

Aliens have been doing this every few years for 250,000 years but we've just only managed to build barely decent telescopes ;)

Any object not doing so is very unlikely to be seen by us.

Why so?

There is a lot of darkness, and we can only look in so many places. We tend to look along the plane of our elliptic because that is where everything in our solar system is. Looking elsewhere is possible, but increasingly lonely/low odds.

I don’t know if that applies to the sky surveys.

1) they are new 2) they are still limited in coverage area (https://irsa.ipac.caltech.edu/applications/FinderChart/docs/...)

I wonder if we are going through a debris cloud and these are just the first small objects.

We have only recently been able to detect them at scale, so we should not confuse first ones detected with first ones to arrive in the solar system. It’s just as likely they are the tail end of a debris cloud, but our detection tech wasn’t up to spotting all the previous ones.

I find this to be an interesting thought.

Earth is currently traveling through the Local Interstellar Cloud, a region of gas, dust, and plasma, and a recent study suggests that the solar system may have recently passed through a dense cloud of supernova debris. Evidence for this supernova event includes the presence of the radioactive isotope iron-60.

This one is anything but small.

zero. It must be the Borg after the time jump.