[ExI] Milky Way is on the outskirts of 'immeasurable heaven' supercluster

[BillK]

On Fri, Sep 5, 2014 at 9:21 AM, Anders Sandberg wrote:
> Imagine building a Dyson-Shkadov stellar thruster around each star, and
> start adding the same momentum to every star. That will set things in
> motion.
>
> In order to get anywhere at a decent clip you likely will need to use more
> dramatic engines, but the above can also rearrange the structure of the
> galaxy within a few rotations. Most likely you can then start ejecting
> hyperrelativistic stars as reaction mass using the central black hole to
> slingshot them, and then use the hole as the "anchor" for the galaxy.
> Gravity plus a bit of steering can do a lot.
>

The stellar thrust would have to be small otherwise you risk leaving
the planetary system behind. But over millions of years the speed does
build up.

Moving the black hole at the centre of the galaxy could present some
difficulties. Especially as there is a lot of mass concentrated there.
And approaching it could get a bit tricky.

I see another problem also. Building a thruster around every star in
the galaxy means you run into relativity problems. The Milky way is
about 100,000 light years across. First, you have to get a
construction system to every star in the galaxy. Then wait until every
star has built a thruster system and reported back to central control.
Now how do you synchronize all the thrusters when you have huge light
speed communication delays? With such huge time delays how can you
tell what is happening at every star system? Have they built a better
thruster? Have they gone extinct? Do they still want to obey Galactic
Central Control orders?
Waiting 100,000 years for a reply might make Galactic Central wonder
whether this was a good idea in the first place.

I think trying to move a galaxy might be a bridge too far. Getting our
own star system to tour the galaxy and perhaps cross interstellar
space to another galaxy might be sufficiently amusing.


BillK