• Announcements

    • Robin

      Welcome!   03/05/2016

      Welcome, everyone, to the new 910CMX Community Forums. I'm still working on getting them running, so things may change.  If you're a 910 Comic creator and need your forum recreated, let me know and I'll get on it right away.  I'll do my best to make this new place as fun as the last one!
Sign in to follow this  
Tom Sewell

Friday, November 29, 2019

Recommended Posts

1 hour ago, Don Edwards said:

You say I'm doing push-ups; I've defined that my back is stationary and I'm bench-pressing the planet.

I hope you remember to clean up your workout equipment when you're done

I hate it when the guy in front of me leaves the 13,170,000,000,000,000,000,000,000 pound weight as a sweaty mess

Edited by Pharaoh RutinTutin
Spelling

Share this post


Link to post
Share on other sites
7 hours ago, ChronosCat said:
8 hours ago, hkmaly said:

Universe expanding would not matter: nothing is actually MOVING due to it - it just gets farther apart.

So you're saying there is a difference between objects getting further apart and "moving away from one another"? I was under the impression that any change in distance between two objects could be considered "movement".

Yes. The proper term is metric expansion. There is interesting detail that while nothing can move faster than light, there is no such limit on metric expansion, and there are whole galaxies currently "getting away" from us with speed faster than light.

5 hours ago, Don Edwards said:
On 12/3/2019 at 1:47 AM, hkmaly said:

In our universe, you can measure relative speed between two objects but don't know if one of them is stationary or if both are moving.

In fact, in our universe the concept of "stationary" is meaningless and what object we assign it to is completely arbitrary.

You say I'm doing push-ups; I've defined that my back is stationary and I'm bench-pressing the planet.

Yes. Assuming, again, that there is no faster-than-light travel OR that it's equivalent to time machine.

 

Share this post


Link to post
Share on other sites
2 hours ago, hkmaly said:

Yes. The proper term is metric expansion. There is interesting detail that while nothing can move faster than light, there is no such limit on metric expansion, and there are whole galaxies currently "getting away" from us with speed faster than light.

So I get that if you compared a map of the universe at two different points in time, any change in position of galaxies between them would be unrelated to the expansion of the universe, only the scale would change; so from that point of view the expansion is not causing the galaxies to move.

However, if you pick a specific galaxy (or some planet in that galaxy) as your reference point, the distance to most other galaxies (or at least galaxies in other galactic clusters) is increasing over time, and I still don't quite get why that increase in distance shouldn't be called "movement".

Share this post


Link to post
Share on other sites
32 minutes ago, ChronosCat said:
3 hours ago, hkmaly said:

Yes. The proper term is metric expansion. There is interesting detail that while nothing can move faster than light, there is no such limit on metric expansion, and there are whole galaxies currently "getting away" from us with speed faster than light.

So I get that if you compared a map of the universe at two different points in time, any change in position of galaxies between them would be unrelated to the expansion of the universe, only the scale would change; so from that point of view the expansion is not causing the galaxies to move.

Mostly. Gravitation-bound objects like galaxies (galaxy clusters?) are expected to "shrunk" - gravitation will force them to keep fixed distances between their parts instead of expand with the scale. (I'm not entirely sure I understand how exactly that works when the speed of metric expansion change ... and I'm not sure physicists do.)

32 minutes ago, ChronosCat said:

However, if you pick a specific galaxy (or some planet in that galaxy) as your reference point, the distance to most other galaxies (or at least galaxies in other galactic clusters) is increasing over time,

Yes.

32 minutes ago, ChronosCat said:

and I still don't quite get why that increase in distance shouldn't be called "movement".

Because "movement" has specific physical properties: kinetic energy, limit at speed of light, inertia ... metric expansion doesn't. There were several points where the speed metric expansion changed ... without any inertia involved.

You can also look at it like this: movement is from point A to point B. Metric expansion will get you further away from A, but not a bit closer to B - in fact, it will get you further away from B as well.

Share this post


Link to post
Share on other sites
On 11/30/2019 at 10:55 PM, ijuin said:

More like the opposite—e.g. the size spell is supposed to be limited to half/double size, but Ashley manages to break that limit.

... or Sarah broke the limit, or Tedd was wrong. It would be interesting if this was a side effect of Sarah practicing.

Share this post


Link to post
Share on other sites
On 12/3/2019 at 0:06 AM, The Old Hack said:

Maybe they used Star Trek: Voyager physics for it. That crap is awesome. I still marvel at how they escaped from a black hole's gravitational field by flying through a crack in the event horizon.

Most black holes should be escapeable. What is generally portrayed in Sci Fi is a non-rotating black hole with an event horizon. Real objects will tend to have some angular momentum. When they then shrink to a point, they will be a rotating black hole, which has an ergosphere, distinct from the event horizon, which can be escaped from. This is what would normally be encountered if we were capable of flying to them, and this is what was encountered in the movie, Interstellar.

OTOH, the tidal forces would likely have torn your ship and you apart, apart, and the intense accretion radiation would have fried the remains, so maybe not.

Share this post


Link to post
Share on other sites
6 hours ago, hkmaly said:

Yes. The proper term is metric expansion. There is interesting detail that while nothing can move faster than light, there is no such limit on metric expansion, and there are whole galaxies currently "getting away" from us with speed faster than light.

We don't know that a rule change, fundamental laws shifting to a different state, would be constrained. I have a hunch it would be, but that's all it is, a hunch. Entanglement might totally sidestep the issue, as the change breaks out all over the place.

 

Share this post


Link to post
Share on other sites
12 minutes ago, The Old Hack said:

Unfortunately there is no escape from the bad science of Voyager.

The even worse thing is that they didn't need to do it. According to already-established Star Trek physics, since they're inside the event horizon (defined as the limit beyond which light is too slow to escape), they only need to engage their warp engines at a sufficiently high factor in order to escape, provided that they're not right on top of the singularity already. Since Voyager's top speed (warp 9.975 or whatever) comes out to around ten thousand times lightspeed, as long as they aren't more than a hundred times closer to the singularity than the event horizon, they should be able to escape via warp drive.

Share this post


Link to post
Share on other sites
2 minutes ago, The Old Hack said:

Don't you mean Imperial expansion?

I mean, it's fairly normal for empires to be expansionistic.

Yes, Imperial. I suppose it's not really English anymore what with them no longer using it.

 

Share this post


Link to post
Share on other sites
16 hours ago, ijuin said:
16 hours ago, The Old Hack said:

Unfortunately there is no escape from the bad science of Voyager.

The even worse thing is that they didn't need to do it. According to already-established Star Trek physics, since they're inside the event horizon (defined as the limit beyond which light is too slow to escape), they only need to engage their warp engines at a sufficiently high factor in order to escape, provided that they're not right on top of the singularity already. Since Voyager's top speed (warp 9.975 or whatever) comes out to around ten thousand times lightspeed, as long as they aren't more than a hundred times closer to the singularity than the event horizon, they should be able to escape via warp drive.

I wouldn't be so sure how warp engines interacts with singularity ... Enterprise wasn't able to escape black hole even at maximum warp.

Warp 9.975 is about how much you warp the space, it's ten thousand times lightspeed just in "normal" cases.

15 hours ago, The Old Hack said:
15 hours ago, Darth Fluffy said:

You raise a good point. We should be using the Rebellion units.

<plays March of the Resistance by John Williams>

Isn't that one futile?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this