We all travel at exactly the speed of light c through spacetime.
The faster we move through space, the slower we move through time.
Only massless particles like photons travel at the speed of light through space.
The faster we move through space, the slower we move through time.
Only massless particles like photons travel at the speed of light through space.
I have to admit I haven't finished the Space/Time book yet:
https://en.wikipedia.org/wiki/Time_Reborn
But am certainly liking it more than String Theory:
What we, in the Physics and Mathematics Community call "Preliminary Results". 🙂
https://en.wikipedia.org/wiki/Time_Reborn
But am certainly liking it more than String Theory:
What we, in the Physics and Mathematics Community call "Preliminary Results". 🙂
That must have been the royal we from Steve! 
Lee Smolin thinks that understanding the nature of time is central to the success of attempts to understand reality itself.
Smolin's hypothesis is based on a kind of cosmic version of Darwinian natural selection. He is suggesting that our very existence may be evidence for cosmic evolution. And since evolution can only happen over time, that in turn suggests time is real.
If he's right, our Universe as just the latest in an endless series. Over time, over successive universes, the laws of physics have been evolving to the point where the conditions are just right to form not just black holes – the birthplaces of new universes – but also the building blocks of life, including us. In other words, time explains the apparent fluke that our Universe has just the right combination of conditions to allow our existence.
Read the full story on Science Focus (the home of BBC Science Focus magazine): https://www.sciencefocus.com/the-human-body/the-incredible-truth-about-time/

Lee Smolin thinks that understanding the nature of time is central to the success of attempts to understand reality itself.
Smolin's hypothesis is based on a kind of cosmic version of Darwinian natural selection. He is suggesting that our very existence may be evidence for cosmic evolution. And since evolution can only happen over time, that in turn suggests time is real.
If he's right, our Universe as just the latest in an endless series. Over time, over successive universes, the laws of physics have been evolving to the point where the conditions are just right to form not just black holes – the birthplaces of new universes – but also the building blocks of life, including us. In other words, time explains the apparent fluke that our Universe has just the right combination of conditions to allow our existence.
Read the full story on Science Focus (the home of BBC Science Focus magazine): https://www.sciencefocus.com/the-human-body/the-incredible-truth-about-time/
I have to admit I haven't finished the Space/Time book yet:
https://en.wikipedia.org/wiki/Time_Reborn
But am certainly liking it more than String Theory:
What we, in the Physics and Mathematics Community call "Preliminary Results". 🙂
I’ve ordered a copy of his book. To paraphrase Smolin ‘there ain’t going to be any unified theory of the universe until the paradox of time is solved’
Separately, if time is an illusion, what does that say about entropy?
Separately, if time is an illusion, what does that say about entropy?
It can be argued that time is an illusion which emerges only in a thermodynamic context. The only law which suggests that there is some kind of a distinction between the past and the future is the law of entropy, the irreversible progress of heat.
However, Carlo Rovelli argues that our perception of time’s flow depends entirely on our inability to see the Universe in all its detail.
Quantum uncertainty means we cannot know the positions and speeds of all the particles in the Universe.
If we could, says Rovelli, there would be no entropy, and no time as well.
https://blog.12min.com/the-order-of-time-pdf-summary/
Attachments
I would imagine with Rovelli ultimately it must lead to questioning the concept of space time and therefore aspects of GR. I Look forward to reading Smolin’s book and the idea that time and space are essentially the same thing.
So existence itself can be reduced to "time and space"?I would imagine with Rovelli ultimately it must lead to questioning the concept of space time and therefore aspects of GR. I Look forward to reading Smolin’s book and the idea that time and space are essentially the same thing.
There are many views as to what time and space and even space-time are - you can see that from the Lee Smolin video. Its still a struggle to grasp Einstein's 'space time' paradigm - seems very few really understand it. Maybe one way of thinking about it is time and space are interchangeable. You cannot have one without the other because as soon as you have some distance between objects you have a relative time difference and vice a versa. As the Smolin video says space time is 'lumpy' and affected by local mass and the relative velocity between observers.
But if there is no distance between objects there is no space and hence no time and therefore no existence...except the singularity.
it's so simple! 🙄
it's so simple! 🙄
This is a fascinating presentation by Jurgen Renn on how Einstein's work on relativity https://hifisonix.com/wordpress/wp-content/uploads/2022/06/Einsteins-path-to-Relativity.pdf
(80+ page presentation so its quite big)
(80+ page presentation so its quite big)
Its still a struggle to grasp Einstein's 'space time' paradigm - seems very few really understand it.
In science, a paradigm is a distinct set of concepts or thought patterns, including theories, research methods, postulates, and standards for what constitute legitimate contributions to a field.
Understanding the basic concepts of spacetime is difficult enough, but the underlying mathematics is impenetrable to a geek like me! 🤓
Relativity tells us that all observers can't agree on distance and time in space as they change due to length contraction and time dilation.
Minkowski spacetime allows all observers to agree on the distance between events in spacetime because time as treated as separate from the three spatial dimensions.
the best specialist for such questions is here:I was referring to the first link, not the second. The whole dark matter question is really complex (translation: requires more general relativity and high energy background than I have 😀).
https://www.usm.uni-muenchen.de/people/lesch/lesch.html
- Status
- Not open for further replies.
- Home
- Member Areas
- The Lounge
- What is the Universe expanding into..