Astronomy / Space Stars movement and lightspeed in Elite: Dangerous

[Voyager_NL]

Heya Folks,

It just occured to me that when we look at the stars in our MilkyWay at any given point in time those stars are not there at that exact point anymore.

They move according to their individual rotation around the center of the MilkyWay. Stars in our MilkyWay can be up to 100.000 - 120.000 light years away. That is 120.000 years of motion... a lot can change in that time.

Still... in Elite: Dangerous we can visit those stars... Will frontier take into account this movement? I think they can't! Because if you want to jump back and forth from one end to the other they'd have to make that the state of the MilkyWay shows old data from wherever you are. I think this will be impossible for a multiplayer environment. It would be easier to keep a static galaxy with everything in one place.

What's your take on this?

 

[Darren Grey]

On the astronomical scale would they really move that much? Especially when you consider that almost all gameplay will take place in a 100 light year bubble (getting further takes a long long time even with hyperdrives).

 

[JohnStabler]

I believe Darren is correct; although stars move *through* space, it is not that fast, so there shouldn't be a huge difference between what you see from earth, say, and where it is when you get there.

I think that the *expansion* of space which is fast enough to account for the red-shift happens in such a way that all parts of the universe *appear* to be at the centre, so there should not be any difference in the sky over time due to that. Apart from the fact that as the expansion rate increases the shifting of light may leave the visible spectrum; making stars disappear!

 

[JKF]

It's an interesting point but it may be that the only significant change you would see would be that between stars separated by many thousands of light years.

If you were to travel to a system 10,000 light years from Earth and look back at Earth's system and neighbouring stars, what would be different?

In 10,000 years how much has changed in the distance between Earth's system and that of Alpha Centauri? Even the distance between Betelgeuse and Earth's system may not have changed enough to be noticed.

When it comes to traveling to distant systems it seems we will do that in a series of short hops, perhaps no greater than 30ly, so physical/apparent position should be of very little significance.

 

[Dr Wookie]

I don't think that a static model will be a problem for two reasons:

1) the Galaxy moves pretty slowly (in space terms... 500 km/s is actually pretty fast ). So the actual position of a star 100,000 lightyears away would only be about 1 lightyear from its "apparent" position (multiplying by 2 because we are going in opposite directions).

2) This doesn't matter, cos we can't see stars that far away in our own galaxy, due to a host of other crap in the way. I.e., there is no "apparent position" to differ from

Stars in the halo or bulge might be more of a problem, but hey- most of them don't have names anyway, so who care which is which !

In the 100 ly bubble, positions will be accurate to ~0.0005 ly I guess

 

[Voyager_NL]

I don't think that a static model will be a problem for two reasons:

1) the Galaxy moves pretty slowly (in space terms... 500 km/s is actually pretty fast ). So the actual position of a star 100,000 lightyears away would only be about 1 lightyear from its "apparent" position (multiplying by 2 because we are going in opposite directions).

2) This doesn't matter, cos we can't see stars that far away in our own galaxy, due to a host of other crap in the way. I.e., there is no "apparent position" to differ from

Stars in the halo or bulge might be more of a problem, but hey- most of them don't have names anyway, so who care which is which !

In the 100 ly bubble, positions will be accurate to ~0.0005 ly I guess

Thanks DR. Wookie and the rest, I can now go to sleep resting assured that the stars will not move that much Great to have a real astrophysics guy amongst us!

 

[Bungarus]

I can now go to sleep resting assured that the stars will not move that much

True for a human lifetime, but I was quite surprised when I learned recently that since Homo sapiens appeared on Earth, our sun has (roughly) moved two hundred light years, and during it's own lifespan it has probably completed more than 20 entire galactic orbits.

Some scientists think this movement has influenced the evolution of life on Earth because about every 60 million years the Solar System moves away from the galactic plane which shields us against cosmic radiation, causing a stress on the biosphere and increasing the mutation rate.

Stars in the halo

Planets of stars in the halo or in star streams that are located at the zenith of the galactic plane must be spectacular at night with that glowing spiral across the sky.

 

[Novastar]

i asked a similar question in the DDF and actualy got an answer
i was thinking in terms of a suns lifespan and how it changes over that time and that by definition we see distance stars as the were in the distant past.
I asked if they were going to model this aspect of astrophysics.
They gave a very blunt "no".

Then I did the math and figured it didn't matter.
Space is BIG but stars are really really really OLD.
They might be able to do a scripted event where everyone sees a distant star that's about to change in a dramatic way but we cannot know for sure it had happened or not until we actually travel there.
Which could be a tad dangerous.

 

[Splendour]

The only real downside I see to the static model is it means we won't be able to go off to distant systems and watch historical novas / supernovas. That would have been really cool...