151–160 of 234 posts
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Einstein can help: https://books.google.com/books/download/Relativity.pdf?id=3H... His book was intended to help people understand these exact questions, without getting into any complex math. Regarding "how is this possible?": This was experimentally verified in the 70s in the Hafele–Keating Experiment. Read more here: https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experim...
That Google link doesn't work. https://www.gutenberg.org/ebooks/5001
I think a lot of people assume that this means you couldn't go more than a few (~100) light-years in your lifetime... But this is not actually correct. Counter-intuitively you can theorically go any number of light-years (essentially) in your lifetime, as long as you are able to approach the speed of light because when you do so the distance is dilated and hence you're covering far more ground within your reference f…
Also, it doesn’t take too much acceleration to make that trip. Comfortable earthlike 1g (~ 10m/s/s) is enough to build up a decent speed in a very reasonable time. Energy is the issue though.
I think a lot of people assume that this means you couldn't go more than a few (~100) light-years in your lifetime... But this is not actually correct. Counter-intuitively you can theorically go any number of light-years (essentially) in your lifetime, as long as you are able to approach the speed of light because when you do so the distance is dilated and hence you're covering far more ground within your reference f…
You can even do so without going near the speed of light if you build a very massive ship and utilize time dilation of gravity. Arvin Ash has a cool video on this that is probably too complicated to describe in a HN comment: https://www.youtube.com/watch?v=PA66ah9b0U4
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And the reason for this, as we all know, is because the universe runs on distributed computers with no global state, where each computer simulates its own local physics and connects only to other nearby computers, and thus the so-called speed of light is simply the emergent rate that data may travel across the network.
It's funny, as a programmer i had similar interpretations. Universe is like a processor and the c is the frequency limit. There was a talk with lawrence krauss I think, where he explained that at galaxy scales, everything is distributed, there's not one reality but an infinity since no point in space can be aware of far points in the universe. I also wonder if there would be ways to tweak C.
(I also highly recommend their book "There Is No Antimemetics Division" if you're at all interested in SCP Foundation)
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> So if a photon is emitted from the sun, it's passing earth immediately? Then why does sunlight need 7 or 8 minutes to get to earth? From the photon's perspective, it passes earth immediately. From our perspective, it takes 7 or 8 minutes. > And let's say, i travel one light-year at the speed of light, that should be instantaneous, right? The odometer would show 1 light-year, my watch would should 0 seconds and some…
just curious... does "time" have a "speed" ? Is travelling at the speed of light, actually travelling a a fraction of the speed of time?
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> If you were watching their lives out the window of your spaceship you’d see them in fast forward vv. they’d see you in slow motion. Everything is relative. Both observers, looking at one another, would see the other moving near c. Neither would know who was ‘actually’ moving. Yet, you assume there would not be a symmetry in their respective views of the other’s passage of time. Explain why. In simpler terms, a twin…
I asked this in physics when I first heard the twin experiment. The answer comes from more complicated relativity based on acceleration and depends entirely on which reference frame you meet in. If you travel back to earth you age slower, if the twin catches up to you they aged slower.... It's not intuitive but time actually warps and there is no true concept of "simultaneous" in a special relativity world.
This did my head in. Wikipedia has a great explanation.
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Why do you feel the need to say somebody is a troll? Here: https://phys.org/news/2017-01-violations-energy-early-univer... Here: https://phys.org/news/2015-02-space-faster.html - we are trying hard to reconcile this and categorize universe expanding as something else (e.g. not a movement that has speed because time itself is a dimension or something). But this is still up for debate, tbh. Another example was one wher…
Apologies, I wasn’t trying to call you a troll, more that your first comment seemed to me like it might have been made in jest, clearly it wasn’t. The articles you’ve linked to are interesting and there are clearly many scientific discoveries to be made by studying the early formation of the universe which will test our current models. However I don’t feel like convention is the right word for laws like the conservat…
You're wrong. The Thermodynamic laws are sort of axiomatic, meaning you really can't explain why energy is conserved. It's just experimentally shown to be maybe true, but no one knows why energy is conserved or has actually proved it to be true. It is totally "convention" as you defined it.
The caveat here is that entropy is not axiomatic. Entropy occurs as a consequence of probability. Probability is the real axiomatic assumption of the universe and entropy is a byproduct.
The thermodynamic laws were established before people fully understood the true nature of what was going on with entropy so these laws are sort of a hodge podge of axioms and derived theorems. From a temperature perspective these assumptions work so the laws still have their use. But the laws of thermodynamics aren't some elegant grouping of fundamental laws of the universe. It is a set of rules that are grouped arbitrarily.
>But we’re verging on pedantry now so no point going down that route any further.
I find this attitude rude. You called him a troll than apologized then gave your final answer and dismissed any further discussion as "pedantry." Like wow, you get the last word and shut down anything else he has to say? You were rude to assume he was in jest and you're being rude again by saying any further discussion after your final statement is pedantry.
Either way I disagree with you. It's not pedantry. This discussion is about convention and the conservation of energy. Your statement is wrong.
I think a lot of people assume that this means you couldn't go more than a few (~100) light-years in your lifetime... But this is not actually correct. Counter-intuitively you can theorically go any number of light-years (essentially) in your lifetime, as long as you are able to approach the speed of light because when you do so the distance is dilated and hence you're covering far more ground within your reference f…
You can even do so without going near the speed of light if you build a very massive ship and utilize time dilation of gravity. Arvin Ash has a cool video on this that is probably too complicated to describe in a HN comment: https://www.youtube.com/watch?v=PA66ah9b0U4
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I know this is true, but I never got my head around this, maybe someone can help. So if a photon is emitted from the sun, it's passing earth immediately? Then why does sunlight need 7 or 8 minutes to get to earth? And let's say, i travel one light-year at the speed of light, that should be instantaneous, right? The odometer would show 1 light-year, my watch would should 0 seconds and some decimals. How much would I h…
> So if a photon is emitted from the sun, it's passing earth immediately? Then why does sunlight need 7 or 8 minutes to get to earth? From the photon's perspective, it passes earth immediately. From our perspective, it takes 7 or 8 minutes. > And let's say, i travel one light-year at the speed of light, that should be instantaneous, right? The odometer would show 1 light-year, my watch would should 0 seconds and some…
Earlier quoted context omitted.
> So if a photon is emitted from the sun, it's passing earth immediately? Then why does sunlight need 7 or 8 minutes to get to earth? From the photon's perspective, it passes earth immediately. From our perspective, it takes 7 or 8 minutes. > And let's say, i travel one light-year at the speed of light, that should be instantaneous, right? The odometer would show 1 light-year, my watch would should 0 seconds and some…
So it sounds like they did a decent job sticking to the science on the Interstellar movie?
Even the 5-dimension tesseract was a decent representation as well.
Matthew Mcconaughey using love to navigate through the 5-dimension is classic hollywood.