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How to go home?

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17 replies to this topic

#1 lada.dvorak

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Posted 24 July 2020 - 04:06 AM

If someone drops you in a random place in the Milky Way, leaves a binoculars and a rocket that violates the laws of physics and flies at super-light speeds, how do you get home while minimizing the trajectory in search of planet Earth?



#2 goodricke1

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Posted 24 July 2020 - 05:44 AM

There are a number of pulsars which act as galactic beacons and you could use them to triangulate your way back to Earth. Need a pretty powerful pair of binoculars though.



#3 FloridaFocus

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Posted 24 July 2020 - 11:02 AM

I believe you just turn left at Orion, then straight on till morning. Not sure, but sounds about right.


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#4 epee

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Posted 24 July 2020 - 12:19 PM

Look for M42 and the Veil; aim between the two...


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#5 Keith Rivich

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Posted 24 July 2020 - 01:51 PM

I suppose if one could use globular clusters as reference points. Wouldn't be easy but it could be done. 

 

Similar to "If you were blindfolded and dropped off somewhere on earth could you find your way home?".  I'm pretty sure I could, it would just take a while. 



#6 Kevin Thurman

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Posted 25 July 2020 - 10:33 PM

Well you could probably see M31 and M33 and that'll at least tell you which way you're currently pointed!



#7 llanitedave

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Posted 26 July 2020 - 12:23 AM

I suppose if one could use globular clusters as reference points. Wouldn't be easy but it could be done. 

 

Similar to "If you were blindfolded and dropped off somewhere on earth could you find your way home?".  I'm pretty sure I could, it would just take a while. 

If Lassie could do it, you can too!



#8 freestar8n

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Posted 26 July 2020 - 02:54 AM

If you did know where you are and where Earth is - there's still a separate question of what the best path is to take - if you wanted to optimize energy required and time somehow.

 

You could slingshot off stars on the way.

 

If you specify exactly how the thrust and total power available works - it's a reasonable question to ask what the best way to get from A to B would be - and I don't know what it is.

 

It's a lot different from a simple solar system with only a few planets as slingshot options - and no dark matter playing a role.

 

Frank


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#9 llanitedave

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Posted 26 July 2020 - 11:36 AM

Wasn't this the entire premise of Star Trek Voyager?



#10 Linwood

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Posted 26 July 2020 - 11:50 AM

At least for a little while, and assuming that physics-violating ship has plenty of fuel, I'd probably just roam around looking.  Earth would be boring in comparison.  cool.gif

 

And I'd certainly give a try to "Hey google, directions to home".  Who knows. 



#11 cuzimthedad

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Posted 26 July 2020 - 12:27 PM

It's simple really. Just join AAA. Free maps and stuff.



#12 Chuck Conner

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Posted 26 July 2020 - 04:28 PM

Easy, Everything in the sky is up, so home is always down...Be sure it's night time, easier to find the north star  (in case it's daytime on the planet. They say, it's in the same spot in day time too) , drop something out of the car (rocket ship) window, then follow it down to home !


Edited by Chuck Conner, 26 July 2020 - 05:15 PM.


#13 ColoHank

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Posted 26 July 2020 - 05:21 PM

I suppose if one could use globular clusters as reference points. Wouldn't be easy but it could be done. 

 

Similar to "If you were blindfolded and dropped off somewhere on earth could you find your way home?".  I'm pretty sure I could, it would just take a while. 

Oh, how I wish I had the wherewithal to put you to the test.  I can think of plenty of places where you wouldn't get very far, even if you knew where you were and which way to go.  Many of them are within a few miles of civilization.



#14 freestar8n

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Posted 27 July 2020 - 04:05 AM

It's just strange to me that I never thought of how to get from A to B in a galaxy with so many star slingshots possible.

 

You would need to specify just how close you can get to a star and what your thrust capability is - but a basic question is if you would stay in the plane of the galaxy and use lots of stars - or go out of the plane and come back in.

 

You can go ahead and assume you know exactly how the stars are laid out and their motions - and no concerns about collisions with stuff.

 

And you can even ignore dark matter for now since it's already a complex question.

 

The show Voyager et al. included wormholes and so forth - but even if you have an N-body galaxy and just Kepler involved - I'm not sure how you would choose to get from A to B.

 

Maybe slingshots around planets of those stars are important?

 

Frank


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#15 lada.dvorak

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Posted 27 July 2020 - 04:31 AM

Basic idea from Czech forum is to use M31 and Magellanic clouds to determine aproximate position in the Galaxy disk. This position will be very inaccurate. Then bubble of light from supernova 1987 from Magellanic cloud be used to refine location, if we follow the bubble trajectory then we know that the position of Sun is 33ly in the directon to Magellanic cloud. We could use the 1054 supernovae as well (if we find it), but 1987 is better. But there is still problem of "last mile", that seems difficult. May be M4+Antares could be use, or Mellote 111...



#16 Mister T

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Posted 27 July 2020 - 04:37 AM

If your space ship is advanced enough to have FTL travel, then you would be able to just ask the navigational AI to plot a course to Earth and say "Engage"borg.gif



#17 freestar8n

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Posted 27 July 2020 - 04:59 AM

Basic idea from Czech forum is to use M31 and Magellanic clouds to determine aproximate position in the Galaxy disk. This position will be very inaccurate. Then bubble of light from supernova 1987 from Magellanic cloud be used to refine location, if we follow the bubble trajectory then we know that the position of Sun is 33ly in the directon to Magellanic cloud. We could use the 1054 supernovae as well (if we find it), but 1987 is better. But there is still problem of "last mile", that seems difficult. May be M4+Antares could be use, or Mellote 111...

Yes I think there is an interesting question from the OP regarding using binoculars to figure out where you are in relation to home - and that would involve our nearby neighbors and the brighter farther galaxies.  That amounts to fairly simple 3D geometry.

 

But the separate question, which may be off topic from this thread, is once you know where you are, how many stars should you slingshot off to get home?  Even in a simple Keplerian model and knowing all the stars and their motions - I'm not sure what the answer looks like.

 

Frank



#18 Keith Rivich

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Posted 27 July 2020 - 02:20 PM

Oh, how I wish I had the wherewithal to put you to the test.  I can think of plenty of places where you wouldn't get very far, even if you knew where you were and which way to go.  Many of them are within a few miles of civilization.

smile.gif I was assuming no physical barriers. Like oceans or Wal-Marts




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