Astronomy questions (edit: questions answered Thanks guys!)

BiggusGeekus · Aug 2, 2006

Assuming you had the very best of modern computers available

Assuming you had orbital telescopes like the Hubble.

Assuming you knew you were going through a wormhole to another star system

How hard would it be to find your location in this galaxy? How hard would it be to find your location in another galaxy?

EDIT: new question - is there a star atlas that lists a nice, firiendly G2 star that's at least 5,000 light years but not more than 15,000 light years from Earth?

painandgreed · Aug 2, 2006

Probably not too hard in the same galaxy. They'd just look to the sky, see the new version of the Milky Way to get an idea of how they were positioned in the galactic disk. look for some other galaxies that should have the same appearance anywhere in this galaxy, and from their orientation, determine where they are in the same galaxy.

In a new galaxy, they'd be doing the same thing but the galaxies they are looking for may have different appearances. You may be looking at a glaxy from edge on where before you were not. There are other formations made up of galaxies and such that could be looked for and a best guess made. Although background radiation is fairly uniform, there are slight differences IIRC, and if not too far from the origin, and if conditions haven't changed too much, they might be able to orient themselves that way work similarly. They'd be using a variety of methods to get a good estimate and then confirming with ideas. A big issue, is if they are too far away from their origin, things won't look the same because they are viewing a different slice of time than they were. They may be farther away from a red giant so that it appears to them as a blue star in their new location. If they are beyond the Hubble limit, then there is very slim chance they could figure out where they are because they cannot even see the same things in the sky.

Jdvn1 · Aug 2, 2006

*Arrow pointing at self*
"You are here."

Assuming you had all the necessary knowledge and could were in the same part of the visible universe, you could find where you are at any time. Or, at least, get pretty close.

Say you're in a perfectly round room with a red column and a blue column close to the center. You can measure how far away each column is and calculate your location. If you're blind-folded and taken to any other part of the room, you can look at the two columns and think, "Okay, I was (x distance) away from that column and (y distance) away from that column... they were (z degrees) apart with that one closer to me than the other..." and you can figure out where you were, and then based on where you were and based on the location of the two columns, figure out where you are now.

If the room is infinitely large, you should be able to do that from anywhere in the room, assuming you can still see the columns.

The only quirk is that, in large spaces like the universe, light takes time to travel. Which means that a) We see the universe as it was hundreds or thousands or millions of years ago due to that light/information not getting to earth yet and b) from other locations, the universe looks like a different point in time.

Though, with computer modelling, you should be able to roughly model what the universe looked (and will look) like in a pretty wide range. Which turns time into another axis of measurement.

With a minimally rough model, you should be able to figure out where you are in the universe, or get pretty close.

BiggusGeekus · Aug 2, 2006

painandgreed said:
Probably not too hard in the same galaxy. They'd just look to the sky, see the new version of the Milky Way to get an idea of how they were positioned in the galactic disk. look for some other galaxies that should have the same appearance anywhere in this galaxy, and from their orientation, determine where they are in the same galaxy.

In a new galaxy, they'd be doing the same thing but the galaxies they are looking for may have different appearances. You may be looking at a glaxy from edge on where before you were not. There are other formations made up of galaxies and such that could be looked for and a best guess made. Although background radiation is fairly uniform, there are slight differences IIRC, and if not too far from the origin, and if conditions haven't changed too much, they might be able to orient themselves that way work similarly. They'd be using a variety of methods to get a good estimate and then confirming with ideas. A big issue, is if they are too far away from their origin, things won't look the same because they are viewing a different slice of time than they were. They may be farther away from a red giant so that it appears to them as a blue star in their new location. If they are beyond the Hubble limit, then there is very slim chance they could figure out where they are because they cannot even see the same things in the sky.

OK, so as long as they had some kind of reference point they could figure it out sooner or later? Thanks. I was hoping for something a little more disorienting while staying within the same galaxy, but you can't have everything and it isn't really that important that they be lost.

Thanks again.

Whizbang Dustyboots · Aug 2, 2006

Well, it could be made to be more confusing, even within the same galaxy.

If Sol was swapped with a star on the exact opposite side of the Milky Way, we'd be in the same galaxy, but it'd be a long time before we could spot any reference points, if we ever could, since everything that was familiar to us would be too far away to see through all the other crap in the way, or just too faint to see.

Our landmarks would be things near the galactic core, which is the densest portion of the galaxy and the area most likely to block landmarks, or they'd be outside the galaxy. It would likely take the computers quite a bit of time to figure out where we were now based on the new position of the Magellanic Clouds.

That said, I think astronomers would figure out we were within the same galaxy within the same year. Beyond that, it'd mostly be guesses for them, I think.

tzor · Aug 2, 2006

Intergalaxy might be hard but you can use outside galaxy references to get your general location within the galaxy.

Extragalaxy is harder because the farther you travel the more outdated the maps are of the other galaxies. You might be able to use a map of local galaxies to locate yourself in the proper galaxy. Anything more accurate would be useless because you would still need to do a complete local map of the area since the stars would have moved somewhat over the course of the years it would have taken for the light to reach the original destination where you first observed them (before the wormhole).

Pbartender · Aug 2, 2006

painandgreed said:
Probably not too hard in the same galaxy. They'd just look to the sky, see the new version of the Milky Way to get an idea of how they were positioned in the galactic disk. look for some other galaxies that should have the same appearance anywhere in this galaxy, and from their orientation, determine where they are in the same galaxy.

Of course, that all depends on well you know the specific coordinates of EVERY star, nebula and such in the galaxy... There's a lot of them, and currently we only have our immediate neighborhood charted with any great accuracy.

Determining whether or not you are in the same galaxy wouldn't be too tough... Other galaxies nearby should look roughly the same, no matter where you are in the milky way. Figuring out exactly where you are within the Milky Way would be much, much tougher.

In other words... What Whizbang said.

Umbran · Aug 2, 2006

Whizbang Dustyboots said:
If Sol was swapped with a star on the exact opposite side of the Milky Way, we'd be in the same galaxy, but it'd be a long time before we could spot any reference points, if we ever could, since everything that was familiar to us would be too far away to see through all the other crap in the way, or just too faint to see.

If you've got telescopes like Hubble, no. Hubble can quite clearly make out other nearby galaxies, and we can get a pretty good idea of relative position that way. Remember, if you can figure out what it is from just a point (like many quasars), you can get a decent estimate.

The real issue here is how much information you've got - do you know you're in the same galaxy or not? Same spiral arm? Exactly how quickly you can pin down your exact position depends largely on how quickly you can determine what reference points to look for - do you need to look for specific stars, specific galaxies, or specific quasars?

BiggusGeekus · Aug 2, 2006

Umbran said:
The real issue here is how much information you've got - do you know you're in the same galaxy or not? Same spiral arm? Exactly how quickly you can pin down your exact position depends largely on how quickly you can determine what reference points to look for - do you need to look for specific stars, specific galaxies, or specific quasars?

In this case they're outer space guys flying robots through a wormhole in space. So for my purposes, it sounds like barring something weird they know where they are.

Which is fine, because they don't have FTL. So if I make the wormhole go bye-bye it's a long walk home.