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Time is a dimension, but not like space

(bigthink.com)
171 points belter | 7 comments | 17 Oct 24 15:29 UTC | HN request time: 0.002s | source | bottom
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nyc111 ◴[20 Oct 24 04:27 UTC] No.41892855[source]▶
"This is the underlying reason why, when you move at speeds that approach the speed of light, you start to experience phenomena such as time dilation and length contraction:"

This is not even possible in pulp science fiction. In order to be able to move with the speed of light you need to transform yourself into a photon. Only a photon can move with the speed of light. Saying "close to the speed of light" changes nothing. You need to be light to move with the speed close to the speed of light. Macroscopic objects cannot move with speeds approaching light speed.

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klodolph ◴[20 Oct 24 04:29 UTC] No.41892868[source]▶
“Close to the speed of light” means, like, 99% of the speed of light. You can even see the speeds listed on the graphs, which are given as a fraction of c.
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1. nyc111 ◴[20 Oct 24 05:14 UTC] No.41893040[source]▶
"'Close to the speed of light' means, like, 99% of the speed of light"

So, you are saying that it is possible to accelerate human body to 99% of speed of light without transforming the body into a massless particle?

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2. tsimionescu ◴[20 Oct 24 05:37 UTC] No.41893132[source]▶
Yes.

It will never be possible to get to 100%, but I principle anything below that is possible. Not just 99%, but 99.99999999% or however many you want.

Of course, it's not actually feasible, you would need galaxies worth of energy to do so.

But for something like 10% or even 50% of the speed of light, it's not even that implausible.

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3. icehawk ◴[20 Oct 24 06:35 UTC] No.41893385[source]▶
Yes.

Gven the average mass of a human body at 66kg: (((1/sqrt(1-((0.99c)^2/c^2)))--1) 66kg * c^2) = 50,000PJ

which is the amount of electrical energy the entire US produces in 0.287h???

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4. etcd ◴[20 Oct 24 07:34 UTC] No.41893639[source]▶
What is our current speed?
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5. ithkuil ◴[20 Oct 24 07:46 UTC] No.41893695{3}[source]▶
Our current speed is 99.999999% the speed of light, according to some frame of reference, 10% according to another frame of reference and 0% according to another.

A lot of work is done by the words "get to" which is colloquial for "accelerate".

6. rbanffy ◴[20 Oct 24 10:31 UTC] No.41894417[source]▶
I’d need about 40 minutes.
7. DHRicoF ◴[20 Oct 24 11:48 UTC] No.41894729[source]▶
> Not just 99%, but 99.99999999% or however many you want.

Badly enough, even that's not true.

We have a frame of reference given by the cosmic microwave background. When you move faster and faster at some limiting speed will create pions that will slow down the particle creating an effective slower max speed.

https://bigthink.com/starts-with-a-bang/speed-limit-below-sp...