3 ms·

What if it's something simple like a galactic lighthouse of sorts? Not sure why I'm being downvoted. Lighthouses use directional light and if you're stationary

What if it's something simple like a galactic lighthouse of sorts? Not sure why I'm being downvoted. Lighthouses use directional light and if you're stationary you'll see the light at certain increments of time. An advanced race might be saying "don't go here" or "be careful." Just like we do for ships here.

zatel 6y ago
I like this idea. Orienting people in the dark of the cosmos. Find your way home just follow the flash
- jacquesm 6y ago
  Or attract some moths to the flame for consumption...
imglorp 6y ago
There are lots of naturally occurring ones such as pulsars, enough to the point they could be used for 3D navigation, if you can find your distance to them. It's an old idea: Pioneer and later spacecraft have a plaque showing our location relative to distances to pulsars we can see from Earth. https://en.wikipedia.org/wiki/Pulsar https://en.wikipedia.org/wiki/Pulsar https://en.wikipedia.org/wiki/Pulsar#/media/File:Pioneer_plaque_sun.svg https://en.wikipedia.org/wiki/Pulsar#/media/File:Pioneer_pla... edit: I guess if you're a Type 3 civilization with nothing better to do, you wouldn't have to set up lighthouses but you could better direct your attention to moving galaxies around or whatever.
- privong 6y ago
  > There are lots of naturally occurring ones such as pulsars, enough to the point they could be used for 3D navigation, if you can find your distance to them. There's work towards this, from the X-ray emission of pulsars[0]. I don't think you'd need a precise distance to the pulsars to measure your own position, as long as you're measuring your own position relative to some other object (e.g., Solar System barycenter). If it's a relative measurement then you should be able to determine that by comparing the time-of-arrival (TOA) of the pulsed emission from multiple pulsars with the TOAs at Earth. [0] https://en.wikipedia.org/wiki/X-ray_pulsar-based_navigation https://en.wikipedia.org/wiki/X-ray_pulsar-based_navigation
  - kabdib 6y ago
    Pulsar glitches are a thing, here's a great resource: http://www.jb.man.ac.uk/pulsar/glitches.html http://www.jb.man.ac.uk/pulsar/glitches.html I'd worry about pulse identification over any significant period of time.
    - privong 6y ago
      And pulsars spin rates slowly change over time do to energy losses. But I don't think these things would cripple a pulsar-based navigation system. Presumably any network of pulsars used for this purpose would be regularly monitored and timing solutions would be updated regularly. The updated timing solutions could be transmitted as-needed. At any rate, a robust navigation network of pulsars would need a sufficient number of sources to guard against glitches breaking the navigation system.
      - TeMPOraL 6y ago
        Also, in context of an alien civilization finding our XX century probes a million years from now, I think they could reconstruct the location anyway - I'd assume there would be only one combination of pulsars you could pattern-match to what's on Voyager plaques, even if each of them shifted in frequency a bit.

zatel 6y ago

I like this idea. Orienting people in the dark of the cosmos. Find your way home just follow the flash

jacquesm 6y ago
Or attract some moths to the flame for consumption...

imglorp 6y ago

There are lots of naturally occurring ones such as pulsars, enough to the point they could be used for 3D navigation, if you can find your distance to them. It's an old idea: Pioneer and later spacecraft have a plaque showing our location relative to distances to pulsars we can see from Earth. https://en.wikipedia.org/wiki/Pulsar https://en.wikipedia.org/wiki/Pulsar https://en.wikipedia.org/wiki/Pulsar#/media/File:Pioneer_plaque_sun.svg https://en.wikipedia.org/wiki/Pulsar#/media/File:Pioneer_pla... edit: I guess if you're a Type 3 civilization with nothing better to do, you wouldn't have to set up lighthouses but you could better direct your attention to moving galaxies around or whatever.

privong 6y ago
> There are lots of naturally occurring ones such as pulsars, enough to the point they could be used for 3D navigation, if you can find your distance to them. There's work towards this, from the X-ray emission of pulsars[0]. I don't think you'd need a precise distance to the pulsars to measure your own position, as long as you're measuring your own position relative to some other object (e.g., Solar System barycenter). If it's a relative measurement then you should be able to determine that by comparing the time-of-arrival (TOA) of the pulsed emission from multiple pulsars with the TOAs at Earth. [0] https://en.wikipedia.org/wiki/X-ray_pulsar-based_navigation https://en.wikipedia.org/wiki/X-ray_pulsar-based_navigation
- kabdib 6y ago
  Pulsar glitches are a thing, here's a great resource: http://www.jb.man.ac.uk/pulsar/glitches.html http://www.jb.man.ac.uk/pulsar/glitches.html I'd worry about pulse identification over any significant period of time.
  - privong 6y ago
    And pulsars spin rates slowly change over time do to energy losses. But I don't think these things would cripple a pulsar-based navigation system. Presumably any network of pulsars used for this purpose would be regularly monitored and timing solutions would be updated regularly. The updated timing solutions could be transmitted as-needed. At any rate, a robust navigation network of pulsars would need a sufficient number of sources to guard against glitches breaking the navigation system.
    - TeMPOraL 6y ago
      Also, in context of an alien civilization finding our XX century probes a million years from now, I think they could reconstruct the location anyway - I'd assume there would be only one combination of pulsars you could pattern-match to what's on Voyager plaques, even if each of them shifted in frequency a bit.