How do we Describe and Understand Spacetime Curvature?

[@Ben942K]

Happy New Year Jason! Looking forward to enjoying the history and science you share with us.

[@jasonshapiro9469]

I wish you well for 2025! Thanks for the work you put into this!

[@JasonKendallAstronomer]

You’re welcome! More to come.

[@deltalima6703]

I like this series. It has no practical use to me, but it is interesting.

[@LiftPizzas]

Huh, before watching this video, the idea that spacetime might curve "into" anything never even occurred to me. It would be like asking "if this apple is redder than that apple, what does it red into?" Or what wavelength of red photon is a red quark? The "curvature" always felt more like a metaphor, a word for a local property like "density" or "stiffness." You know, something that doesn't have a size or shape, but a magnitude. I guess that might be helpful in getting the idea across, it's just a magnitude. Is it a common sticking point for people? (I suppose at least some of that is just a matter of being bothered by people being mistaken about something that's a special interest. I totally get that. LOL)

[@JasonKendallAstronomer]

Yeah, it is a common sticking point. Comments in various videos over time, in my classes, plus passionate tirades at my public talks, and at the subsequent beer chats at the pubs. But, you have a great idea there. It is "just a magnitude." It's like a scalar field that is a simple property of the space.

[@sneezebiscuits7239]

I love your work. I maybe understand a third if it because i'm dumb, but i hugely appreciate it :)

[@dexter8705]

Bravo that was amazing. Makes me feel like the way gravitational spacetime curvature works that the earths seasons shouldn't change and the axis shouldn't change relative to the sun.. weird. Yes I know earth spins and has a gyroscopic direction but I feel like even that and it's vectors should keep moving towards the sun. It's like this space-time curvature you speak of doesn't work for rotation but just for orbits and pathways and doesn't effect the rotation of the object in that orbit. Great presentation 👍

[@JasonKendallAstronomer]

Thanks!

[@noelstarchild]

I think it must be what mass does to specetime. It makes we wonder if we have ever seen a straight line?

[@DARARobot]

Jason, I have a science question not related to your videos, but maybe would go a great video if you create it. What would happen to a black hole traveling at the speed of light?

[@JasonKendallAstronomer]

Well, that's a Special Relativistic question. But, since a black hole is a "thing" it cannot travel at lightspeed, or be accelerated up to lightspeed relative to some rest frame. (unless we are talking about space expansion carrying it away, but then it's past the particle horizon, so it's unobservable.). Basically, anything that has mass cannot be accelerated to the speed of light. Only light, and massless particles, can travel along null geodesics.

[@YogSoth]

I think spacetime curvature is when curvature occurs in spacetime.

[@JasonKendallAstronomer]

lolz!

[@icantseethis]

Word to our old ladies

[@babynautilus]

silly question maybe did euclid ever talk about non euclidean spaces?

[@JasonKendallAstronomer]

Perhaps, but it's not in his extant writings...

[@kangoos2000]

GREAT

[@CLipka2373]

"All of physics relies on a concept called a metric space." There you have it. Not imperial space or freedom space. METRIC space. Good that this debate has finally been settled. (Thanks, I'll see myself out.)

[@JasonKendallAstronomer]

LOLZ

[@deltalima6703]

1:00:00 those cristoffel symbols etc are just begging to be put in a matrix.

[@JasonKendallAstronomer]

Yes indeed....

[@ShonMardani]

Imagine there is only earth and the moon and some of us were living on the moon. People on the earth will claim that moon is turning around the earth and the moon people will claim that the earth is turning around the moon, I say they are both correct, do you agree with me? Thank you for the video.

[@rezzer7918]

What he said

[@deltalima6703]

Lemaitre getting left out? Oh well, who cares about that guy? 😂

[@JasonKendallAstronomer]

Yeah, it's a common failing. I'll rectify in my next video...

[@billynomates920]

the lazy eight 😄

[@Me-hk8dd]

So 2d