Relativity and stuff

[Drbretto]

Note, this is cross posted from another place I frequent, but I wanted people's opinions from here as well. And this looks like the closest thing to an off-topic forum here, but mods, please feel free to move if I got that wrong!

Anyway, without further ado, please have a seat and get ready to have your mind blown.



I have been on a real kick lately starting with podcasts and documentaries on all the big questions but I've never even taken a physics class in my life, so I'm doing my best to understand these concepts. It's very likely I am ignorant of some stuff, so please by all means, take this as me attempting to understand as well as me sharing how I've understood some of these concepts, not like me trying to sound all smart-like or anything. I'm Joe Rogan-ing. I'm just trying to understand.

Also, this thread can feel free to evolve into any other kind of big think type of subjects if you wanna talk about, say, the Fermi Paradox or Simulation theory or whatever, too. Also, I'm sorry if any of this is boring, but please don't skip ahead even if you totally get this stuff, I need you to get what I think I get to get the last bit.

Anyway, I relayed this stuff to some friends last night and kinda blew their minds, so I figured I'd step up and present it to the smart people at SoSH. Now, I've long since totally accepted things like relativity and spacetime as fact already. This isn't trying to convince anyone. This is about "getting" it.

So, I'll start with spacetime because it leads to the next thing. Somewhere in my podcast binges, NDT put it out like this: Have you ever met someone at a place and not a time? How about a time and not a place? Ok, it's starting to click a little bit there. I can accept that time is intrinsically connected to space from that. But I still didn't get it until the other day, I imagined a scenario:

You're watching a ten second youtube video of the earth spinning on its axis, followed by 10 seconds watching the earth orbit the sun, followed by 10 seconds of watching the Milky Way spin. On each video, as you scale up the X,Y,Z to fit the new image, but you also have to scale up the time along with it in order to capture any motion, otherwise the galaxy would just look stationary. It actually makes perfect sense that if you're trying to scale something up in 3 dimensions, but are adding in the 4th dimension, time, by making it a video, of COURSE you'd have to scale up that dimension as well. That shit blew my mind the more I thought about it. It's still rattling around in there. We'll come back to this in a moment.

Next, relativity. And it was Lawrence Krauss (a phenomenal communicator, BTW, I'd recommend giving him a listen even if you disagree with anything he has to say) that helped me simplify this concept and I get it enough to accept it, and can kinda visualize it a little bit, but I'm taking his word for it that it's not just an illusion, that it's something we can actually measure every day. And, that it's the basic principle behind our GPS system. But, what I do totally get is the part about how all of the light that enters your eyes is coming from different points back in time at all times due to the speed of light being constant and things being different distances away from you. Not just stars and galaxies, but even your hand right in front of your face.

The part I'm accepting but not totally visualizing is the part where this isn't an illusion, but is actually your experience of time itself. And I accept that because they've measure the time experienced by astronauts in orbit and it was different in exactly the way it was predicted. So, an object moving at a different speed from another object actually experiences time differently from the other object at a calculable rate that is in relation to the speed traveled, thus time is relative.

SO....

In pondering these things, I began to wonder how we experience this concept of time if we're sitting down in front of a computer. I'm not moving relative to the earth and I'm not moving relative to you in any meaningful way, so what gives?

And it dawned on me. Expansion. The universe is expanding, and not just constantly, but it's accelerating. Just as our perception of time accelerates as we get older. Could the expansion of the universe be what drives our constant perception of time itself? Could "Dark Energy" basically BE time? Or am I way off here?

Please be gentle, lol.

 

[SolManX]

A couple of things - our perception of time passed is going to be independent of actual local time measured by any clock. And there are plenty of contenders for clocks - your heart, for one.

Also, when you say we're not moving whilst at our computer, we are of course, spinning on the earth's surface and literally hurtling around the sun!!

 

[Drbretto]

That's true that we're spinning on the earth, as well as rotating around the sun and rotating around the galaxy, and the galaxy itself is moving.

But, the perception of time is not independent of the local time measured by a clock. Time itself is relative, not just the perception. Edit: as long as that clock is with you

Edit 2: also, our perception of time accelerates as we age, and the earth's rotation, orbit arund the sun, and orbits around the supermassive black hole at the center of the Milky way are not accelerating.

 

[SolManX]

I really meant it the other way around - ie measured local time is independent of any subjective perception of it in the sense that we can't reliably perceive intervals without an accurate clock. Even so, we can still perceive time passing while we're stuck at our desk, not only because of external motion, but also because of the many internal clocks inside our body.

Also, just to say, related to your realisation, I remember doing an exercise to program a simple model of the solar system. Plugged in all the numbers, pressed go and of course, nothing happened. It would have taken a year for my earth 'pixel' to travel around the sun 'pixel'! Doh.

 

[Drbretto]

On that first part, we're talking about two different things, I promise. But I like that subject as well.

With relativity, you can carry that clock, heartbeat, whatever along with you as you travel faster or slower than someone else, and that other person is also carrying a clock, once you meet back at point A, according to some smart people out there, your clocks will be different. This isn't relating to perception of time, but time itself as a function of movement in relation to the speed of light.

 

[Drbretto]

So, I googled "is dark energy time" just to see how crazy my theory here is, and, well, apparently, I'm at the very least not alone:

https://www.sciencealert.com/physicists-just-found-a-link-between-dark-energy-and-the-arrow-of-time

 

[SolManX]

On that first part, we're talking about two different things, I promise. But I like that subject as well

I was only responding to your 'Just as our perception of time accelerates as we get older.' I'm pretty well-versed in relativity

There's a couple of good lectures online by Leonard Susskind on the arrow of time. They're a few years old (2013) but very good ... here's one:

 

[Drbretto]

ok, gotcha.

I will add that to my podcast/lecture list and listen to it in the car sometime this week. Thanks!

 

[Drbretto]

The other board I frequent has a couple of actual scientists and I drew the attention of one that is actually giving a lecture on relativity soon, and he will comment on all this and then some in the next day or two. I will re-post his thoughts here. Unless he disagrees with me (kidding!)

As most of my understanding of physics has been to some degree entertainment science, it will be really great to get to hear the opinion of a real scientist. I can't wait to how how utterly wrong and crazy I am, lol

 

[Pyure]

Sometimes I feel like Dark Energy is the "aether" of our time. My personal stupid theory is that the universe is expanding more quickly because the "universe" is simply falling into "non-universe", and accelerating in a similar matter by which objects accelerate towards objects of mass via gravity.

 

[Drbretto]

Point of clarification on my end. My idea here says nothing about the forces that cause it. It merely pontificates on what it's actually doing. I haven't watched that video above yet, btw, so I'm the same level of ignorant now as I was when I started the thread and that idea may change.

What you're talking about is different. That's more like something like Simulation "Theory", where science goes out the door and you can fill in your blanks however you see fit. Or, more accurately however the weed is hitting you. That can be fun, don't get me wrong. But that's a little bit different from what I'm getting at.

Theoretically, this should be something that someone with more scientific knowledge could actually test and measure to see if it has merit. It's not philosophy or religion. I'm very aware of those pitfalls. I have to be to keep myself from floating off into space.

 

[Pyure]

Point of clarification on my end. My idea here says nothing about the forces that cause it. It merely pontificates on what it's actually doing. I haven't watched that video above yet, btw, so I'm the same level of ignorant now as I was when I started the thread and that idea may change.

What you're talking about is different. That's more like something like Simulation "Theory", where science goes out the door and you can fill in your blanks however you see fit. Or, more accurately however the weed is hitting you. That can be fun, don't get me wrong. But that's a little bit different from what I'm getting at.

Theoretically, this should be something that someone with more scientific knowledge could actually test and measure to see if it has merit. It's not philosophy or religion. I'm very aware of those pitfalls. I have to be to keep myself from floating off into space.

Is this a reply to me specifically?

 

[Drbretto]

Is this a reply to me specifically?

Yes, but I may have misunderstood your post. Are you interested in expanding on why that's your theory?

I was just clarifying my position. I wasn't out to give an explanation for dark energy or time. I was just thinking about both around the same time and that idea came to me. Which is fundamentally different than what I thought you were doing, which was taking that unknown and trying to fit a theory into it.

If I misunderstood though, I totally apologize!

 

[Drbretto]

BTW, that's not a judgement of that kind of thinking. I will sit here and talk simulation theory all day.

I am curious about your thoughts though. I just read it again. I think it is missing something that I think I can fill in, but I'm not 100% sure.

 

[Pyure]

Yes, but I may have misunderstood your post. Are you interested in expanding on why that's your theory?

I was just clarifying my position. I wasn't out to give an explanation for dark energy or time. I was just thinking about both around the same time and that idea came to me. Which is fundamentally different than what I thought you were doing, which was taking that unknown and trying to fit a theory into it.

If I misunderstood though, I totally apologize!

Certainly dude. I just get bummed out when I read papers on "dark energy", because it reminds me of dark-age "science" where we assert something based on a gap of knowledge.

My understanding iirc is that some very substantial portion of the universe is supposedly composed of dark energy. This is probably valid, but it also reeks of aether. From a common-sense perspective, it feels like we would have encountered this energy by now if its that's prevalent. (again, there's perfectly good reasons why we wouldn't, for instance if it simply tends to orbit galactical centers or some such). But sometimes the simplest answer fits.

I wasn't actually discussing your idea at all. I was sidetracking in order to express sadness at the commonly popular "dark energy" notion.

 

[Drbretto]

Certainly dude. I just get bummed out when I read papers on "dark energy", because it reminds me of dark-age "science" where we assert something based on a gap of knowledge.

My understanding iirc is that some very substantial portion of the universe is supposedly composed of dark energy. This is probably valid, but it also reeks of aether. From a common-sense perspective, it feels like we would have encountered this energy by now if its that's prevalent. (again, there's perfectly good reasons why we wouldn't, for instance if it simply tends to orbit galactical centers or some such). But sometimes the simplest answer fits.

I wasn't actually discussing your idea at all. I was sidetracking in order to express sadness at the commonly popular "dark energy" notion.

Gotcha gotcha!

So, I think we're closer to the same page than I thought. You are absolutely correct about "Dark Energy" being the aether. Dark matter and dark energy aren't necessarily matter OR energy. They may not even *BE* anything.

Dark Matter is nothing more than measured gravity that we can't explain. No one has any real clue what it is. There are all kinds of things I can think of that might fit the bill like matter that's just shifted into a 5th+ dimension that we can see but still has a pull. It could be that there's something missing factor that we need to plug into the equations we rely on to measure gravity. It could be lots of stuff. Dark Energy is even more mysterious. Nothing more than an inability to explain why expansion is not only not being overcome by gravity, but is actually accelerating.

Calling either of them matter or energy is actually kind of painting them into something more than they are. They're just placeholders for "I don't know".

I did think you were saying that my thing was my attempt to explain what those forces are, and that's totally not the case. I was trying to come up with some ways to illustrate the concepts of relativity at the same time I was thinking about expansion itself, and the connection suddenly made some sense and I have been thinking about it ever since. Now that I get your meaning, I am 150% in agreement.

 

[Drbretto]

So, I boiled this down to a question. That could easily dispel any illusions of being "onto something" if I'm wrong.

If space and time are intrinsically connected, and space is expanding exponentially, wouldn't that mean that both space and time are accelerating?

And, if that's not already bunk, if time is accelerating, what would that look like?

 

[Pyure]

So, I boiled this down to a question. That could easily dispel any illusions of being "onto something" if I'm wrong.

If space and time are intrinsically connected, and space is expanding exponentially, wouldn't that mean that both space and time are accelerating?

And, if that's not already bunk, if time is accelerating, what would that look like?

My thinking was that the expansion and/or acceleration of space actually "generates" time. I don't think time as we understand it was actually a thing prior to the detonation of the singularity.

 

[Drbretto]

My thinking was that the expansion and/or acceleration of space actually "generates" time. I don't think time as we understand it was actually a thing prior to the detonation of the singularity.

Correct. The big bang was the origin of space and time. Our laws of physics were frozen at the moment of the big bang.

As I understand it, those concepts were meaningless "before" that. I have a picture in my head of it, kind of like an infinite sheet of glass, only the glass is nothing. Nothing but the scrambled potential for laws of physics, in a way that people way smarter than me can understand. This was covered on a talk about the science of nothing again with Krauss and Niel Degrasse Tyson and others. It's one of three kinds of nothing: empty space, like literally since, that still has volume. The "nothing" like what you see if you out your hand behind your head, like literally nothing, and the nothing that is this theoretical, potentially infinite empty canvass. That our universe, and the laws of physics that government it, formed in a pattern like ice freezing in a random pattern on the window. We're here in this universe because this just so happens to be the one configuration required to create matter in the way we experience it. If it didn't, we wouldn't be there to complain about it. The same theory explains why with all that crazy space out there, my avatar is still the most beautiful thing in it, and is about the only way we could exist.


So, sorry for rambling. Lol. I need to go to sleep.

 

[GamerwithnoGame]

Gotcha gotcha!

So, I think we're closer to the same page than I thought. You are absolutely correct about "Dark Energy" being the aether. Dark matter and dark energy aren't necessarily matter OR energy. They may not even *BE* anything.

Dark Matter is nothing more than measured gravity that we can't explain. No one has any real clue what it is. There are all kinds of things I can think of that might fit the bill like matter that's just shifted into a 5th+ dimension that we can see but still has a pull. It could be that there's something missing factor that we need to plug into the equations we rely on to measure gravity. It could be lots of stuff. Dark Energy is even more mysterious. Nothing more than an inability to explain why expansion is not only not being overcome by gravity, but is actually accelerating.

Calling either of them matter or energy is actually kind of painting them into something more than they are. They're just placeholders for "I don't know".

I did think you were saying that my thing was my attempt to explain what those forces are, and that's totally not the case. I was trying to come up with some ways to illustrate the concepts of relativity at the same time I was thinking about expansion itself, and the connection suddenly made some sense and I have been thinking about it ever since. Now that I get your meaning, I am 150% in agreement.

That's basically my understanding of dark matter and dark energy as well - they are names given to properties of the universe that we have observed or deduced from observation, but we have not yet identified. They could be the product of an incomplete understanding of existing physics, or an actual "stuff" with exotic properties. Dark Energy in particular is directly related to the accelerating expansion of the universe; dark matter is distinct from that, and related to other puzzling astronomical observations and gravitational behaviours.

OK, real talk for a sec:

When I found out about dark energy (or more particularly the accelerating expansion of the universe), I was devastated. I'd grown up hearing about the different models of what might happen in the future, and I completely believed that what we'd have was a Big Crunch. The idea that the universe is in a constant Bang-Crunch-Bang-Crunch cycle felt "right" in my child-brain - it had a wonderful symmetry to it, and I felt like I could almost imagine eternity when put like that. So to find out that, as we understand it right now, we're heading in the end for an eternal darkness and that this universe is truly a once-in-existence event, so that when it's over its OVER... yeah, that kind of bummed me out. But that feeling definitely falls into that weird category of my love of science where it comes closer to belief than true science.