Do we travel through time at the speed of light?

In this video I explain why it is correct to say that we all travel through time at the speed of light and just what this means.

#physics #science #education

[michaelcornish]

Great explanation. I am a school teacher and I keep telling my students that we move through spacetime at the speed of light but they are not often convinced and it is nice to have an expert explanation to show them, thanks.

[nagualdesign]

There's an old adage that popular science authors will lose half their readers for every equation they include, and so libraries are full of books that deliberately exclude vital information despite the fact that their readers are making a concerted effort to glean precisely that information.

Thank you, Sabine, for flying in the face of that and daring to include and discuss these vital equations. Assuming that you're just as bold in your publications, you're doing a great service to anyone who's interested in self-education. Bravo!

[LarsPallesen]

"And you would end up with the arguably correct but rather lame insight that we travel through time at one second per second". I love the dry deadpan humour.

[GumbyTheGreen]

It’s true that you move at c through time from within your own reference frame (like she alluded to), but from the frame of someone moving relative to you, you move through space as well, so your speed through time slows down, hence time dilation. Your overall speed through spacetime is always c from every reference frame.

[nbridge]

During lockdown I have read "Lost In Math" I'm taking it into work next week (secondary schools open again) because I want some of my colleagues to read it, they are stuck in their ways and won't budge, Lee Smolin and yourself Sabine speak volumes about science being stuck in a trance seeing no way out.
Hopefully they will read it and have a clearer mind.
Thanks for writing such an excellent book.

[thedom]

Talking about time and not a single infantile reference
You are one excelent science communicator. Thank you Sabine

[Zamicol]

This was one of the best videos you've made. Thanks for always being so math minded as well as presenting simply.

I was just working on this this week. It's a stream of serendipity watching your videos.

[richardfrenette]

Thanks a lot Sabine for sharing your insights in GR and QM. Becoming an expert and still keeping an understanding of the perspective of non-experts is precious. Bravo and thanks again for you enlightenment.

[DANGJOS]

Best transition to a sponsorship ever! That was...well...brilliant! Haha

[fupopanda]

A physics video that I actually understood the equations presented. A miracle. The videos by PBS Spacetime are cool but always fly way over my head. I'm a data scientist, so my knowledge of physics is whatever I learned in a first year undergrad course and YouTube videos. Impeccable explanation in this video.

[benjaminweston]

I find it easier to think of it like this;
Take a right angle triangle, where the hypotenuse represents an invariant spacetime interval, one side is time and the other side represents the 3 dimensions of space.
The length of the space interval would be the square root of the spacetime interval squared MINUS the time interval squared.
Likewise, the length of the time interval would be the square root of the spacetime interval squared MINUS the space interval squared.

You can immediatelly see from this that if you are not moving in space, the time interval is the same magnitude as the spacetime interval, and that as your velocity in space increases the time interval decreases, to the point where the space interval is the same magnitude as the spacetime interval, and the time interval is zero.

[tarmaque]

I don't understand the math (dyslexia sucks) but I'm comforted by the fact that there are people out there like Sabine who do.

[danielhmorgan]

thought I was seeing a Feynmann diagram on her dress

[Matt]

I absolutely love the way you explain physics in your videos. Physics is awesome.

[aquamanGR]

What a great video! I love how you manage to explain x+c*t and the -1 for space vs 1 for time in the Minkowski metric by bringing in speed invariance. I have studied relativity way back when, and thought your video was a nice way to explain it to my non-physicist students.

[jonathaneves]

Fascinating. Sabine, that was a beautifully explained, easy to follow answer. I love your channel. ✌️🐝

[kebsis]

The first time I heard this explanation was in Brian Greene's book 'The Elegant Universe' and I had never heard it before. I searched around on the internet and all I could find were forum posts about having read it in the same book, asking if it made sense (the forum posters seemed to agree that it was a novel but not incorrect interpretation). That was probably around 2012 or so, and since then it has become a more commonly mentioned physics trivia. Interesting to see it explained properly here.

[jflopezfernandez]

Thank you so much for giving a formal answer and then giving an equivalent but more insightful answer as well, it really helps

[erenkad]

Sabine: Yes, that guy again.
* Einstein winks

[gordianknot]

If you don't believe this, wait till you are older. You'll find out just how fast you are traveling thru life, i.e. time.