The ball in a sheet cloth is a nice two dimensional model.

But I like this example as a three dimensional model.

Imagine a 3 dimensional grid of bungie cords so you have bungie cords going up and down, left and right, towards you and away, such that the bungie cords are connected at equal segments and the space between the bungie cords forms a cube.

Now grab several bungie cords close to each other and pull them close and tie them together. The bungie segments closest to those segments get warped and stretched out of position while bungie segments further away are relatively unaffected.

In space the spots where the bungies are tied together represent massive objects like stars and planets. And the amount of warping/stretching represents the gravity well around that object.

[removed]

It is an emotional experience.

Time is relative, and passing through space at different velocities warps time. Peering deeper into space is also peering further into time. Every physics equation and observation must account for all four dimensions. Since they are so intricately tied together, and dependent upon each other, astro-physicists speak of Space-Time.

All we know, all we can ever know, the entire universe is contained within Space-Time. Anything speculatively beyond that is outside of our existence.

Im no scientitian, but think of it like if you're standing somewhere. You are at a certain point of space at certain point of time.

The Earth is moving through space at 390kilometers per second.

If they Earth stopped moving through space (and ignoring all other issues that would cause) we would be moving through time quicker? Do we have the length of time to exist because of the earth travelling 1.2million miles per hour?

They have to offset geosatellite by millisecond every so often whist for going slight fast then us on the surface.

>Wouldn’t there be a measurable current of sorts in our path of movement?

"Current" feels like the wrong word here. In the sense of a river, "current" feels like the drag you would experience from molecules of water moving past you. You aren't gravitationally bound or dragged by the water, it's simply the inertia of heavy water molecules pushing against things as it moves downhill.

​

>Or is there a way to counter the trajectory of our galaxy traveling through the universe/ solar system traveling through galaxy ~roughly 490,000 mph/ earth traveling around sun ~roughly 67,000….

Absolutely. How do you stop a car from driving down the road? You apply a force that counteracts the force causing it to move forward (you apply the brakes). In space you do this by ejecting mass in an opposing direction. If you've ever seen Wall-E and remember that little robot buddy using a fire extinguisher to move and spin (space dancing scene) then you know what I'm talking about.

The fire extinguisher has mass and that mass is being ejected, which causes the body to move in an opposing direction. So if we wanted to slow earth down, we would just keep pushing things off of Earth, away from it's current trajectory. Unfortunately as we slow down, our orbit would also begin to decay, causing us to get closer to the sun.

So lets try to slow sun down, we just need to uhh, eject mass from the sun, thats all. Yeah that seems a bit trickier.

So technically possible, but not really within our current technological capabilities.

Last time I saw this was about 11-12 years ago, when it was flying over my house in Ireland..

I even managed to make out the outline of it, sitting on the booster, with my telescope. It was one of the coolest things I've ever seen. The plume from it was absolutely huge, about 10 times wider than the booster and the shuttle..

Best explanation for OP. Most were needlessly complicated.

The research linked seems to focus on the gases surrounding galaxies. The article seems to want to refine what the edge of a galaxy actually is to make the claim they are already merging to get the clicks. I'm not sure exactly how the edge of a galaxy is defined, but if you screw with the definition enough you can claim the entire observable universe is merging.

Happy Cake day btw!

[removed]

[removed]

photo doesn't do it justice. it's an absolutely beautiful exhibit in person

I just had a wild thought after watching those awesome videos. Does spacetime only change when one spacetime field of influence references another? Or is there a way to counter the trajectory of our galaxy traveling through the universe/ solar system traveling through galaxy ~roughly 490,000 mph/ earth traveling around sun ~roughly 67,000…. And travel with or against said force to gain compounding spacetime? Wouldn’t there be a measurable current of sorts in our path of movement? Or would we need an equal spacetime field of influence to travel towards in order to go against our collective spacetime trajectory? Not sure if any of that makes sense to anyone.

[removed]

Probably just strap some Starships together.

[removed]

Bro I was straight up crying and then this giant as space ship is right in front of me

Einstein's General Theory of Relativity shows that time is a physical thing. It is part of space-tme. Space-time manifests itself as a gravitational field created by the mass of objects. The presence of mass will warp, or deform, space-time. As a consequence, time passes more slowly near to a massive object such as a planet. This has been demonstrated to be true by comparing super-accurate clocks in orbit to clocks on the surface of the Earth. The clocks on the surface run just a little bit slower. (This is a paraphrase from other people's explanations)

[removed]

Exactly like that!!! Only the one I saw was animated. But it is a great example.

Love Brian Cox's videos

>Can someone explain what spacetime is?

Honestly? No. No one can. We can model it very accurately, but we don't really know what it is.

>Also does "one dimension of time" imply that there are multiple dimensions of time?

An easy explanation is, imagine I ask you "Meet me in the conference room on the 3rd floor of the building at 1st street and Main Street."

That room has three coordinates in space, X Y and Z, that you must traverse from your current position to arrive at. However, if we want to meet there, you also need a time coordinate. We also traverse from our current time to subsequent times, or at least, that's what we experience. Thus, we'd arrange our meeting with four coordinates, X Y Z and t.

Time is just how we measure changes in the spacial dimensions we observe. No time? No change. Hence, Spacetime. Without time, space would never have changed state to begin with, and everything would still be at a singular infinitely small point without space, as we theorize a pre-big bang universe would be. At that point all I can imagine is quantum indeterminacy spontaneously manifesting a universe from nothing.

In my opinion (assuming the variables eventually add up) the net total energy of our universe is zero. What that really means is the cosmos and all the spacetime therein, is zero energy. From the outside looking in (if there were such a thing) there's absolutely nothing here. There isn't even a here at all. It's something the photons emitted at the beginning of our universe that will get absorbed at the end of our universe experience. Time doesn't pass for a photon, so from its perspective, nothing is here, nothing has happened, is happening, or ever will happen. The beginning and the end are the same instant.

Maybe I went a bit too existential with this question, but the honest answer is we have not the faintest idea what spacetime actually is. Functionally, it's just the name we've given the model we use. I'm good with that. It's a solid model, that only breaks down under such extreme mass conditions, you'd need to observe the inside of a super massive black hole to figure out a better model.

Something similar to this? https://www.youtube.com/watch?v=-O8lBIcHre0&t=3s

[removed]

[removed]