The Best Test of General Relativity The Science of Six Degrees of Separation 2 days ago   11:52

A launch mishap led to the best experimental confirmation of gravitational redshift. Get a free audiobook with a 30-day trial of Audible: or text VERITASIUM to 500500

Huge thanks to
Dr. Pacome Delva:
Dr. Sven Herrmann:
Gravitational Redshift Test Using Eccentric Galileo Satellites:

Disclaimer: It is arguable what is THE best test of general relativity because there are different ways to test the theory. This is the best confirmation of gravitational redshift, which is one of the three original tests proposed by Einstein.

Special thanks to Patreon supporters:
Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd

Animations and editing by Alan Chamberlain

Music from "Subtle Substitutes 2" "A sound Foundation 1" "Cell Research 1" "Particle Attraction 1"

Comments 1590 Comments

I’d be interested to know your thoughts on this format. Would you like to see more ‘Talking to scientists about their recent publications on Skype’? Maybe not on this channel but on Sciencium perhaps?
But we agree that Earth is still flat right ? :)
Kaneki Uzumaki
So that means in black hole the time is stopped????
acid junkie
2:23 Luckily, you French lower form of life.
That's one way to get money for research :D
Thank you for interesting subjects and good and concise storytelling.
Abhishek ml
Can't we measure the difference with Earth's elliptical orbit..???
Understand the Quantum GR dimensions, hmmm? Scientist will never, until they look bigger to what’s right inside.

Hurray, determined time, they did. Big discovery, might show them the way, hmmm maaaahahahha!

Think bigger, think as big as one can see! Show you the way, it will!
Bogdan Gabriel
if the gravitation make the time past harder , then .... negative gravitation will make the time past backwards ?
Sriram Srinivasan
If i watch a 5-min video (say, on a mobile phone) at earth and in space, will I observe any difference in the length of the footage or rise/drop in the frame-rate?
General relativity is true. Great respect to You and Einstein. You have made great experiments by yourself, and I trust You. Don't ask me to trust ESA, NASA, etc, if you want to keep that respect. They are proven liars.
freethinker modern
then why things float inbetween earth and moon.i mean moon rotate around earth because earth bends the space time around it..if we put an object in between earth and moon it is not going around either moon or same time earths gravity pulls moon .why is that??(sorry about my english if any mistakes)
I love how so many things in science follow this format:

"Well, we set out to do this one thing... and it broke. Badly. So badly, in fact, that we can no longer do the thing we spent so much effort trying to do.



BUT there's this OTHER really cool thing that we can TOTALLY do with the broken first experiment now, and it's completely by accident!!"

So much stuff in science was discovered accidentally because of things like that, and it's fantastic.
i think this thing is wrong and im pretty sure this will be debunked in few years just saying .
The Savior
but i want to know the findings
Arda Özcan
Accident huh? Just at the right time, yeeeaah suuure.
nandu gangu
@veritasium, What happened to the second satellite??
Hareece Thorogood
Scientific experiment successful:

Religious people who were wrong: this is unfortunate
Scientists who were right: this is unfortunate
John Nicholson
How about a video on: "Why is big G (the gravitational constant) not more accurate?"
Graham Cartwright
the orbit and the earth kinda look like a avocado don't they
Add Reply

The Science of Six Degrees of Separation The Best Test of General Relativity 2 days ago   09:23

Are all people on Earth really connected through just six steps?
There's much more science in this than I initially expected. It turns out ordered networks with a small degree of randomness become small-work networks. This is why your acquaintances turn out to be more important in job searches and finding new opportunities than close friends.

1. Do not send it directly to me unless you know me.
2. Send the email to someone you have met IN PERSON and know on a first name basis AND THEY KNOW YOU.
3. Make the subject line 'Six Degrees of Veritasium'
4. Explain that you're trying to get this email to me and ask them to forward it on to me (only if they know me IRL) or someone they know who might know me.
5. If your email reaches me by Sept. 1, 2015 I will email you back and ask for your address so I can send you a postcard.

Animations in this video by The Lyosacks:

There are some great books on this topic:
Duncan Watts, Six Degrees: The Science of a Connected Age
Albert-Laszlo Barabasi, Linkds: How Everything is Connected to Everything Else

And here are articles I referred to:
Milgram's small world experiment:

Granovetter, Strength of Weak Ties: