Can a Lost Spaceship Navigate Back to Earth in the Milky Way?

[Vanadium 50]

No. Many of them are in poorly known places outside a deep sky object. The rest are in deep sky objects, but in poorly known places within.

That's simply false. I'm through with this conversation.

 

[Nugatory]

So how do you get there from Earth before that light arrives - wormhole?

Yes - that's part of the premise in the starting post.

That also means that this problem (arbitrary location in the galaxy right now) is interestingly different than the Pioneer problem (somewhere that Pioneer might slowly crawl its way to). It's plausible that pulsars can solve the latter problem but not the former; Pioneer isn't going anywhere that light from the Crab supernova hasn't.

 

[D H]

Yes - that's part of the premise in the starting post.

The starting post doesn't specify.

A suggestion for getting this thread outside the realm of magic: Suppose the spacecraft is automated; it either has no crew or the crew is in suspended animation. Next, suppose the spacecraft 's navigation computers do a hard reboot. (This has happened multiple times with existing spacecraft .) When the reboot is complete, the spacecraft is in a random location as far as the computers are concerned. No wormholes are needed. Computers courtesy of Cheapest Electronics, Inc. is all that's needed. The spacecraft is lost in known space.

In this case, Chronos' suggestion of using pulsars is exactly what is needed. The spacecraft doesn't need a big dish (unlike finding Sagittarius A). A few handfuls of small X-ray telescopes on the surface of the spacecraft is all that is needed.

 

[jim mcnamara]

@DH

Let's say a spaceship from Earth (via a wormhole or something) suddenly found itself in a random place in the Milky Way galaxy. Assuming the crew possesses all of our current knowledge of the galaxy, and time was not a factor, would they be able to locate where our Sun is, and travel back to it?

However, I agree it is totally more magic than reality. Which is why I find the whole debate kind of odd.

 

[Draygoes]

I would count this as an extremely difficult task. If you say "lost", then the members of the expedition have not been keeping track. (That being the case, they should have never been there to begin with.)

You would need support from the Earth for this one. I say that for a reason... even if you could find your way back to our star, you would be stuck around a large number of planets, moons, and anything else that chooses to get in your pathway. Are you asking based on the fact that we have unlimited energy (impossible, but this looks like a syfi thread)? If so, then you can wait for the correct math to be done at home.

Also, you can be spotted by several probes we already have in "deep space" and compensate for that. With the right equipment, you could navigate your way into the solar system, but it would still require help once you get there.

 

[nikkkom]

You would need support from the Earth for this one. I say that for a reason... even if you could find your way back to our star, you would be stuck around a large number of planets, moons, and anything else that chooses to get in your pathway.

Yeah, it's a miracle Voyager managed to wiggle its way out of Solar System without hitting your "planets, moons, and anything else".

Yesterday, I was barely able to see the Sun, moons were repeatedly obscuring it. ;)

 

[.Scott]

Assuming the crew possesses all of our current knowledge of the galaxy, and time was not a factor, would they be able to locate where our Sun is, and travel back to it?

I think the "travel back to it" is a lot more challenging than locating where you are. Even if "time was not a factor", propulsing yourself back to sol with current technology would be daunting. Your random place in the galaxy is likely to be over 40,000 light years away. If time is not a factor, then we are not worrying about aging the crew, aging the ship, or aging our solar system and its civilizations. But you still have a current-technology craft that will need to be fueled and perhaps refueled.

Also, you not only need to know where you are, but what kind of a trajectory (gravity-assisted) you will need to get back, and where the solar system will be when you finally reach it (in some number of tens of millions of years - that are not a factor). I would guess you would set up roots in whatever neighborhood you found yourself in and spend a few decades planning you journey back.

I think my first thought would be reverse engineering that worm hole.