Starship Asterisk*

Beyond wrote:So what is it that gets blown away as jets?

Beyond wrote:From what i gather about the conversations thus far... space doesn't move and doesn't enter a black hole. It's some of the matter that moves in space, that is not converted to energy at the event horizon, that is blown away, that eventually falls in, like in geckzilla's video.

Ron-Astro Pharmacist wrote:Thanks for the comments. It seems so inviting to think that a black hole could be the generation of a new universe if both space and matter are being drawn into one. Also seems like it opens the door to consider that the new universe would continually fed and not a one-time event such as the big band. A continuously expanding universe; where have I heard that one before

Chris Peterson wrote:

Beyond wrote:WOW! That coin thingy is neat! It's better than the marble ones.

Although they still depends upon "real" gravity to make them work, I do think those coin drains and dimpled rubber sheet models are much better analogies than the waterfall. They do a better job teaching the important concept of distorted space and geodesics (although most people using them don't do so properly).

A manifold is a portion of 3 (or more) dimensional space. It may be Euclidean, or it may be scrunched or expanded (what scientists generally call ‘curved’, but this term often confuses non-scientists because we can easily think of curves in 2D, but when transposed into 3D, scrunching/expanding is a more intuitive description of what really happens).

Chris Peterson wrote: (although most people using them don't do so properly).

Beyond wrote:WOW! That coin thingy is neat! It's better than the marble ones.

Beyond wrote:So the gravity of the black hole pulls on matter that flows along spacetime that doesn't move... just as gravity on earth pulls the water along an unmoving ground, to it's lowest point.

Beyond wrote:In the analogy of a waterfall, wouldn't the ground the water flows over represent the spacetime that is not moving?

Markus Schwarz wrote:

Beyond wrote:Just what the heck is "space", really??

This discussion goes back to the days of Newton an Leipniz. Newton argued for an absolute space, while Leipniz insisted the only thing you can measure are the positions of objects relative to each other. My quick answer is that you cannot measure space (or time for that matter) but only distances in space and the passage of time.

This was a major source of confusion for gravitational waves. A gravitational wave is a "wiggle in spacetime". But to truly detect a gravitational wave you need to measure the proper distances between particles, not "the space at which the particle sits". Similar, the spacetime around a static black hole is not sucked into it. But particles moving in this spacetime are sucked in.

The flowing water represents the pull the black hole exerts on a particle. But unlike the water, the spacetime is not moving. This is were the analogy to a waterfall breaks down.

Beyond wrote:Just what the heck is "space", really??

SsDd wrote:Here is the link to a slower paced version of the video I made a few months ago, using Dr.Nemiroff's simuation.

Click to play embedded YouTube video.

geckzilla wrote:How silly of me to suggest that the infallible Beyond could possibly be confused.

geckzilla wrote:Maybe the black hole is confounding you. Take away the black hole and you only take away the black hole. Space is still there just as it was before black hole formed, as it was while the black hole occupied it, and light can travel through it no problem now without the black hole.

Boomer12k wrote:...this "thing" is a nothingness as we perceive it...

Chris Peterson wrote:

Beyond wrote:That which you said does not move and does not fall into a black hole, which is understandable. IF it does not move, how could it fall. But what is it that does not move?

Basically, I'd say that spacetime is a mathematical construct that models what we observe. It doesn't move because the mathematics we use to manipulate it don't correspond to any concept like motion. Spacetime is the coordinate system of the Universe. Mass distorts the system locally, but there's nothing to move.