How does Mercury's orbit prove General Relativity?

When Einstein proposed his new theory of gravity in 1915 - his theory of General Relativity that massive objects curve space - he came up with three ways of testing his theory. One of those ways was whether it could properly predict the orbit of Mercury, which up until then, no theory of gravity had been able to do. So why is Mercury's orbit so odd?

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👩🏽‍💻 Dr Becky Smethurst is an astrophysicist researching galaxies and supermassive black holes at Christ Church at the University of Oxford.

[DrBecky]

Whoops! Seems like I misspoke about how GPS works towards the end of this video. Your phone doesn’t send a signal to satellites, it only receives them. Thanks to everyone who pointed this out in the comments already 👍

Also to those who pointed out perihelion is Greek not Latin - but we’ve always known language isn’t my forte 🤪

[thestonewall]

Einstein just drop the mic on the end of that paper

[chrisray]

Science history is my favorite kind of history. Thanks for taking the time to make these types of videos. I love them!

[carrickrichards]

I've heard this put as "Einstein destroyed the planet 'Vulcan' with just the power of his mind. Le Verrier found Neptune with just the power of his!". I do love how the film 'Einstein and Eddington' shows how the proofs were worked out. It gives Planck his proper credit too. Thank you for bringing this to life

[murasaki]

16:21 For the younger viewers, the song she's singing is "Where You Lead" by Carole King, from her Tapestry album (1971). Carole King was an awesome songwriter, and that album won 4 Grammys including Album of the Year, as well as going 14x platinum by selling 30 million copies and having covers done by other singers such as James Taylor ("You've Got a Friend") that also charted, some that were released previously but Carole King co-wrote (Shirelles "Will You Still Love Me Tomorrow").

[Fenristhegreat]

Nothing could have prepared me for the Avril Lavigne smash cut.

[GameChanger-qiuo]

As much as I love learning from you, your out takes at the end and your singing makes the whole video seem like a perfect circle. Complete!

[BillMSmith]

Science science science science science SPIROGRAPH! science science science science science science science science MARSHMALLOWS! science science science...
This is why Dr Becky is a great communicator. There's always going to be some fun thrown in.

[amasaro]

Dr. Becky is one of those rare astrophysists who are very good at explaining abstract concepts. As a keen follower of astronomy, I find I can almost anticipate her next sentence. For this, I love her.

[craigfowler]

Shows what a genius Einstein was.

Very interesting and detailed overview of his theory and first proof.

[steveokay]

This is the first time I feel I've gotten a complete walkthrough of what the whole problem with Mercury and how it was resolved esp. WRT the speed of light.
Lots of other pop-science books, videos, TV episodes, etc. always wash over some bit of it and are just like "Oh, there was an error and it couldn't be resolved because Newton was wrong and then along came Einstein and fixed it..."
So, thanks for getting in those minor but very important details.

[sethsims]

GPS receivers only listen. The satellites are screaming out what time their extremely accurate clocks say it is. The receiver compares all the times it's hearing to get the distance. It actually needs a minimum of 4 satellite locks, it's solving for x, y, z and the actual time where it is. That's why GPS receivers are some of the best clocks an average person can use. They are listening to atomic clocks orbiting above our heads.

[davidtoddhoward]

Excellent video on Mercury's importance in proving General Relativity.. Really cleared up some details for me. So glad I found your channel.. Thanks so much! 😀

[YouTuber-mcel]

I understood all that you said...every word with complete clarity. I enjoyed the depth at which you took the subject. The presentation you put forth was exceptional without fault. No stumbling, no uhhs, no noticeable tripping of any kind. Very well Done. Then you had to include the edits and burst my bubble LOL.Thank you very much.

[creativelylily]

Dr. Becky, thanks for this video. I've only just started getting into astronomy/physics and I was reading this one book that dove into Einstein's theory of general relativity and the author briefly brought up how Einstein used Mercury's orbit and the 43 arcseconds to prove his theory, but it was quite vague and my new-to-physics mind didn't understand what it meant so I had to turn to trusty YouTube. Your video was the first to pop up and it was honestly so helpful. I'm now a subscriber, thank you! :)

[danieloneal]

I do love the old-timey headlines ... “Men of science more or less agog”

[clemstevenson]

Thanks to Albert Einstein, you now know what time it is when Cambridge arrives at your train.

[TheFeltbegone]

For as many times that I've heard Mercury's orbit mentioned in relation to relativity, this is the first time I have seen that extra term mentioned.
Also, I have heard of gravity and speed affecting GPS, but had not heard it explained as a gravitational red shift.
Super clear and interesting.
Thank you for that.

[toddarmstrong]

I have told you before how much I love your videos and your singing. Can't wait for the album.

[mikesnyder]

I have read several accounts of Einstein and his Mercury fixation and, now, finally, I kinda sorta understand! Thanks, Dr. Becky for yet another clear explanation on a complicated point of physics. Love your work!!!