How would you find your way back?

On all representations of the Galaxy i have seen, earth is on the right side, about 2/3 the way out so that narrows it down to about half the galaxy Your next best bet is too look for certain nublae or tell the aliens that its a nine planet system with 3 gas giants (jupiter, Uranus, Neptune). Maybe they have been by here, also the spectral class of earths star would be a big help since we know its a yellow star, and not a red giant etc.

Originally posted by Terapin
Err, the Zodiac constellations are totally useless once you get any distance from where we are. They just dont look the same from a different angle so it wouldn't help much. Better to have a solid knowledge TODAY of the heavens as we know it, and then to plot a course based on our location relative to, for example, the galactic core, the outer spiral arms, the crab nebula, the horsehead nebula, and other notable spatial phenomena. Our sun is remarkably common and not at all a feature one would notice from a distance. Radio emissions from Earth haven't traveled very far yet and would not help much until you are relatively close.

I would certainly agree it would be better to have a good working knowledge of the galaxy's layout to get back to Earth under these circumstances. Does anyone out there have such an intimate understanding of the Milky Way?

Given the conditions I listed in my earlier post about the zodiac, it is simply untrue to say these constellations would be totally useless.

Like I said, these constellations lie approximately in the galactic plane. If you looked at the galaxy from the perspective of a sidewise view, at least one of these constellations should be recognizeable (barring dust clouds or other obstructions), since they form a ring around our view of the universe from here on Earth. If only one was recognizeable, traveling in the direction of the one recognizeable constellation would put one on a path toward Earth. Stopping every few light years to recheck for other zodiac constellations that should be coming back into shape would ensure continued success. Once all the zodiac constellations are viewable (in a "ring" around the viewer), you are in the Earth's neighborhood. It is then that detection by other means should be employed (gas giants, radio waves, etc.)

Harte

Originally posted by EngineMan2145
If aliens took me across the galaxy, and then told me they'd take me back, considering it takes 100,000 years travelling at the speed of light to cross the galaxy, then it would probably take about 50,000 years at light speed to get to the center. Since modern physics says things made of matter can't travel that fast, I would first ask them if Earth was going to be about 100,000 years older when I got back.

Then I'd tell them, if they were acting serious about a map, to get real and get some real technology, after all, THEY BROUGHT ME ACROSS THE GALAXY, how in he** am I supposed to know where Earth is!?

Well some people

Like David Sereda have theories regarding changing mass to energy.

Here is a link to a thread discussing him :
www.abovetopsecret.com...'


And here is a link discussing how alien technologoy might allow for movement beyond the speed of light :

www.abovetopsecret.com...'

That's an interesting challenge...I know that Earth is on the tip of one of the Milky Way's arms, so if I had an automatic "you are here" map of the galaxy, a 2-D radar reaching out several light-years, unlimited fuel (zero point energy?) and wormhole travel, all of which an alien civilization would probably have, it wouldn't be too hard, especially because I could search out the constellations on the radar, and eventually the planets. Or I could just hitch a ride...

BUMP

I sent this question out to Phil Plait of badastronomy.com and got a response, and sharing it with the rest of you for some added insight

This is a pretty good question. If I had a good piece of software, I could get close, I bet.

1) The first thing to do would be to see what bright galaxy, as seen from Earth, is as close to opposite in the sky of the Galactic center as possible. Then I would head toward that Galaxy. If that proves impossible, I would find some bright pulsar or other rare object directly *between* the Earth and the core, and head toward *that*. That gets ne going in the right direction.

2) Go about 20,000 light years, and slow down. We're not sure exactly how far from the core we are.

3) Look for the Orion Nebula. We're 1500 ly from it on Earth, and it's easy to see. Even from 10,000 light years it would be easy to find. HEad toward it.

4) Once there, we're almost home! Check the software, and find something obvious in Earth's sky that is opposite the Orion Nebula (a globular cluster would be good). Head toward that, go 1400 or so ly (you'll pass Beteleguse, so you'll be gettiogn close, only 400 ly from Earth).

5) Now we're close, probably about 100 light years from home. I would look for some bright stars in our neighborhood, like Vega, or Arcturus. They are very close. Then look for Sirius, which has a white dwarf companion, making it easier to find.

6) At that point, you're only a few light years from home. Alpha Centauri should be an easy find, and it's only a short hike to Earth from there.

So the best weapon is probly a good starmap of the galaxy, and nearby galaxies. or even a good "Sky scanner" to find rare or significant objects. Might take a while but it could be done if you know some key bits of info

Originally posted by Jehosephat
BUMP

I sent this question out to Phil Plait of badastronomy.com and got a response, and sharing it with the rest of you for some added insight

This is a pretty good question. If I had a good piece of software, I could get close, I bet.

3) Look for the Orion Nebula. We're 1500 ly from it on Earth, and it's easy to see. Even from 10,000 light years it would be easy to find. HEad toward it...


5) Now we're close, probably about 100 light years from home. I would look for some bright stars in our neighborhood, like Vega, or Arcturus. They are very close. Then look for Sirius, which has a white dwarf companion, making it easier to find.

6) At that point, you're only a few light years from home. Alpha Centauri should be an easy find, and it's only a short hike to Earth from there.

So the best weapon is probly a good starmap of the galaxy, and nearby galaxies. or even a good "Sky scanner" to find rare or significant objects. Might take a while but it could be done if you know some key bits of info

I bolded part of the above quote of this post to illustrate the steps recommended that would be immensely aided by a knowledge of constellations.

Of course a good starmap would be better, but it would also include Sol, would it not? What's the point of going through all the steps you posted above if you have such a map?

Harte

A knowledge of constellations could still help. If the aliens had a database of all the stars in the galaxy with approximate luminosities, you could enter your knowledge of the constellation locations (as seen from earth) into a software program. Only from our solar system would we have the correct view of the constellations. So, have the software calculate which point within the galaxy would produce a view of the stars that is similar to what you entered for the constellations.

This would be tricky because your constellation data entered from memory would not be perfect, but well-written software is capable of dealing with this and outputting what point in the galaxy is statistically the closest match.

SIrius is probly one of the better stars to keep and eye out for since it is so brite, and even has a companion dwarf to make it more unique.

But to start out with it would be a good idea to know where the LMG SMG and the nearby galaxies of our local group are to get you withen a few 1000 light years of earth. after that most anyone with some basic knowledge of nearby stars and constilations could find thier way... even with an earth based star map

I'd look for the bar and hang a right.

The bar

Seriously this is the first "landmark" that I have heard of. It might just work.

Yes I jsut saw that recently myself, mainly I ma thrill because it was discovered by an astronomer that wors no more then 20 minutes from my house (UW-Madison)

here is a link to the most accurate picture of our galaxy yet
you are here