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John C. Mather: “There is no first moment of time” (2017)

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Re: John C. Mather: “There is no first moment of time” (2017)

#51

Post by TedDoesntTalk »

russellbeattie wrote: post #45

There is no time, only movement. No movement == no time. You can't measure time without movement. If everything in the universe stopped moving, no time would pass. The first moment happened when space was created and something in it changed its position. (Of course, that something is matter, which is just a wave, and a wave by definition is movement... So really, time started when reality started wobbling.)

> So really, time started when reality started wobbling

“It’s all wiggles” —- Alan Watts

Re: John C. Mather: “There is no first moment of time” (2017)

#52

Post by nyc111 »

Does anyone know how the validity of a linear extrapolation is determined? I mean is there a standard way of measuring an extrapolation, like sigma? The only way I can think of is to take the ratio of the sample with the population. For instance, if sample = 24 and population = 200 billion, their ratio is 0.00000012. How do we know if this is a valid linear extrapolation? In this case, sample is the number of galaxies Hubble observed in 1929 for his famous paper and the population is the number of known galaxies. Is there a rigorous way to evaluate an extrapolation in statistics?

Re: John C. Mather: “There is no first moment of time” (2017)

#54

Post by kadoban »

idealmedtech wrote: post #39
kadoban wrote: post #30

Earlier quoted context omitted.

One thing I've always wondered is if there's any _interesting_ statements that can't be proved or if they're all kind of self-referential nonsense statements.

There's whole _fields_ of inquiry that either take or leave the axiom of choice; so yes, absolutely.

Is that the kind of statement Godel was talking about? Seems to me to be somehow different. It's not really true or false, it's an arbitrary choice, so it's just something you either decide is part of your system or not, not a true statement that's unprovable.

Maybe I'm missing something?

Re: John C. Mather: “There is no first moment of time” (2017)

#55

Post by TedDoesntTalk »

xwdv wrote: post #20

Not only might there not be a first moment, there might be no time at all. Every possible instant of time could be randomly distributed with some very small but not infinitely small probability of occurring. On an infinite timeline, everything should occur, forever. When a moment occurs, a structure of your brain exists coded with memories of past events that feel real but never happened. Since each moment is pure an…

> you do not perceive the trillions of years that could pass in between two moments occurring, nor do you have any way to realize you are perceiving moments out of order or that other possibilities of realities exist

This is intriguing. But how does cause and effect work? If there is no “external state”, say I burn my hand by spilling hot coffee on it. There’s a burn in my skin. Trillions of years pass and I experience the next moment… with burned skin?

Re: John C. Mather: “There is no first moment of time” (2017)

#56

Post by TedDoesntTalk »

fallingfrog wrote: post #36
xwdv wrote: post #20

Not only might there not be a first moment, there might be no time at all. Every possible instant of time could be randomly distributed with some very small but not infinitely small probability of occurring. On an infinite timeline, everything should occur, forever. When a moment occurs, a structure of your brain exists coded with memories of past events that feel real but never happened. Since each moment is pure an…

“On an infinite timeline, everything should occur, forever.” I can imagine scenarios where that isn’t true- maybe the universe cycles through a long loop of states and just repeats that infinitely for example.

Isn’t that saying the same thing but a little differently? In your scenario, everything is re-occurring, forever (obviously beyond our perception)

Re: John C. Mather: “There is no first moment of time” (2017)

#57

Post by [deleted] »

TedDoesntTalk wrote: post #48
anonymousiam wrote: post #43

Earlier quoted context omitted.

"We don't know that." Yes we do: https://www.britannica.com/science/space-time > it's difficult for most people to grasp. "Oh come on…" Q.E.D.

> Yes we do: https://www.britannica.com/science/space-time I don’t see anything in that article mentioning that time did not exist before the universe existed. Did I miss it?

[deleted]

Re: John C. Mather: “There is no first moment of time” (2017)

#58

Post by Natsu »

zibby8 wrote: post #3

> There’s another way in which the giant firecracker idea misleads us, because even scientists often talk about the “universe springing into existence.” Well, it didn’t, as far as we can tell. The opposite is true. There is no first moment of time, just as there is no smallest positive number. In physics we have equations and laws of nature that describe how one situation changes into another, but we have no equation…

I know the models treat time as a real number that we can do funky things with (see also Banach-Tarski), but I really wonder if time isn't quantized like so much else in QM.

Re: John C. Mather: “There is no first moment of time” (2017)

#59

Post by sounds »

aasasd wrote: post #22

> there is no sign of an edge of the universe How is this determined? I would think that the observable universe puts a limit on our view anyway. Is it the redshift receding into infinite wavelengths? Can the instruments even detect this?

I'm going to skip the more philosophical part of your question. Or in other words, if you're asking, "is there any observable evidence of something outside the observable universe?" My answer is: no comment at this time.

If you're asking, "what did John C. Mather mean in talking about the edge of the universe?" I'm not John C. Mather, but here's my guess --

The curvature of the universe [1] has been computed from distortion of the Cosmic Micrwave Background and independently using other measurements.

The current consensus is that the universe is indistinguishable from a flat universe. [2]

A curved universe would have an edge, meaning there's a limit to how much could be observed. If it's x light-years until you wrap around the universe, then plant an observer into this universe at a time greater than x years and that observer (if lucky) could observe the same things in two directions by seeing "all the way around the universe."

A curved universe might lead to a "big crunch" since the curvature of space-time is caused by the quantity of matter, or not. Depends on if the matter is tightly packed enough.

A flat universe has no limit -- no matter how far in the future you plant an observer, the speed of light is not fast enough for them to observe the entire observable universe.

There's a relationship between the curvature of the universe, how dense the universe is (how densely packed the matter is), and how fast the universe is expanding (the Hubble Constant). It's likely the universe is flat, implying that the Hubble Constant is on the high end of possible values.

[1] http://background.uchicago.edu/~whu/beginners/curvature.html

[2] https://astrobites.org/2020/12/03/cosmic-clocks/

Re: John C. Mather: “There is no first moment of time” (2017)

#60

Post by paulrouget »

anonymousiam wrote: post #43
paulrouget wrote: post #35

Earlier quoted context omitted.

> Before the existence of our universe, there was no time We don't know that. > Time was created along with the space, matter, and energy when the thing "sprang into existence." These are just speculations. Some theories indeed mention that, but they are not part of our standard models. For now, we just don't know. > it's difficult for most people to grasp. Oh come on…

"We don't know that." Yes we do: https://www.britannica.com/science/space-time > it's difficult for most people to grasp. "Oh come on…" Q.E.D.

> Yes we do: https://www.britannica.com/science/space-time

We have an accepted standard model. 2 in fact. QM and Lambda CDM say very little about how things were working very close the t=0, and say absolutely nothing about how the conditions were a t=0 or "before".

As I said in my comment, people suggest ideas of how things could be. But nothing tangible, nothing ever included in ΛCDM, nothing predicted by QM… we are missing data, solid math, and solid physic to postulate anything about t> Q.E.D.

I would classify your previous comment as pseudo science, and saying "it's difficult for most people to grasp" as lack of humility.

If you do understand how space and time were structured "before the existence of our universe", you should go claim a Nobel price.

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