Do you really understand Einstein’s theory of relativity? – BBC News

Do you really understand Einstein’s theory of relativity? – BBC News


Albert Einstein’s theory of general relativity
completely changed the notion of the Universe. It shed light on the birth of the universe,
planetary orbits and black holes. It also has very practical uses, like in GPS
navigation. But what exactly is this theory and why was
it so revolutionary? Until the early 20th Century, physics was
mostly explained in terms of Isaac Newton’s laws.
For Newton, gravity was a force generated by the mass of an object causing them to attract
each other, heavier objects pulling others more intensely.
This is why we stand on the ground on Earth, said Newton…
it attracts us to its centre. And it’s why planets move around the Sun.
But imagine if the Sun disappeared completely. According to Newton’s theory, the planets
of the Solar System would instantly abandon their orbits, as there would be no
gravity attracting them to the Sun. For Newton, gravity is a force with immediate
action regardless of the distance between the bodies.
But according to Einstein’s calculations, light was the fastest thing in the Universe.
Nothing could travel faster than light, not even gravity.
Light takes about eight minutes to cover the nearly 150 million kilometres
that separate the Sun from the Earth. So, if the Sun disappeared, how could the
Earth go off its orbit before us Earthlings stopped seeing
sunlight? Problems like that suggested to Einstein
that gravity could have a different explanation than Newton thought.
Between 1905 and 1915, Einstein developed the theory of general relativity.
He imagined the three dimensions of space and the dimension of time together
as a kind of fabric surrounding us, shaped by the presence of celestial bodies.
He called it space-time. Imagine the Sun as a heavy bowling ball placed
in the middle of a trampoline. The ball makes the surface of the trampoline
dip, right? This curvature is what we feel as gravity.
So for Einstein, the Earth and the other planets remain in orbit not because the Sun attracts
them but because the Sun is such a massive star
that other celestial bodies follow the curve it generates in the space-time
fabric. Now gravity is no longer considered a force
of attraction between two bodies, as Newton thought.
It is an effect of the space-time curvature on bodies.
So according to Einstein, what would happen if the Sun disappeared?
His theory says this disturbance in space-time would form a gravitational wave
that would travel to the planets at exactly the speed of light.
That means we would see the Sun go dark at the same time
as the Earth changes its orbit. In other words, what Einstein demonstrated
is that until then we had been seeing the Universe in the wrong
way. The general relativity theory turned Einstein
into a world celebrity. Because of him, science (and our imagination)
could fly higher and higher. General relativity not only surprises scientists
it fascinates us all.

100 thoughts on “Do you really understand Einstein’s theory of relativity? – BBC News

  1. Can some one explain how space time affect orbits horizontally. Things are still attracted towards the center of mass not beneath curved space. I think more explanations are needed than just fabric of space time, cos it does not explain orbital objects in all directions, how does the space bend diagonally? Or the effect of fabric of space time is always perpendicular to the direction of the incoming object?

  2. There's nothing like fabric of time and space or whatever!!! Scam. The earth is not rotating on any fabric. Gravity is a pull, not a push!

  3. Relativity? I could claim that the world is flat if I could invent an equation that proved it so.

  4. of course I do I wake up I go to work , pay my bills pay my taxes , eat , shit , sex , having fun , than die , nothing special

  5. Well, this is copy-paste of other youtube videos, just a tiny little piece of Einstein's theory. This happens when journalists try to explain smth.

  6. Albert was very well educated ,thanks to his parents, but was since childhood possessed by spirits, Albert as Albert had no knowledge, and Bcoz of lack of true knowledge much of his recorded material lacks vision, but ones from spirits were quite accurate…..and that's the reality of Albert which our fellow westerners will never approve inspite of knowing the truth…..

  7. Einstein was a wife beating, plagiarising, cross dressing, exam failing, patent clerk.
    Total contribution to mankind = 0.

  8. Well:
    (Takes deep breath)
    Albert Einstein says that space-time is a four dimensional Hausdorff differential manifold on which a metric tensor is imposed that solves the Einstein field equations, and that metric tensor gives rise to geodesics, and objects that are not experiencing any other force will move along the geodesics described by that metric!

  9. My results on the buzzfeed iq test was 200. I should be able to understand this thank you very much.

  10. They always make an example of space-time fabric, but I have hard time imagining it, HOW?!?!?!?! I can fly into space from earth all the way south and all the way north and encounter stars, WHY DO YOU ALWAYS MAKE A FABRIC GRAPHIC WITHOUT EXPLAINING THIS QUESTION/PARADOX

  11. Well explained in short time.. If still people don't get it after watching this then he Is a Dummer… #noofference
    😀

  12. I don’t think that will happen if the sun disappears surly they will follow There original path spiralling rapidly into the “sun” and all planets will collide creating a mass of meteorites and a black hole big enough to wipe out the 2 closest galaxies around the Milky Way

  13. In simple words, einstein was clown who stole other peoples work and turned it into his own. E=mc2 was first proposed by Olinto De Pretto. it's hard to imagine where he would get the equation of relativity from 🙂

  14. I was shocked relativity is surprises science and facinate us all. Thats relativity. hahaha. Plus the wave.

  15. Is there any doubt that the Light is the fastest moving things in the Universe ? Einstein's thought was his ●Imagination● .There are many thoughts about the Universe including Religious Imagination.
    Then What they found in Switzerland?

  16. Lol, this is so stupid, all theoretical and they consider him a genius, lol… Pure fantasy, like a lil kid reading a super hero comic book…

  17. Yes, I do. At least well enough not to say that spacetime is like a bowling ball on a sheet of rubber…

  18. This is the first time somebody explained it in an understandable way. Don’t know why nobody else could explain it in a normal way.

  19. The assumption Science makes, is that the sun exists. What if it did not, would Scientists accept God as creator?

  20. What is that makes one a Scientist🤔
    Long hair sure does help. We had one go on to become the President of India.
    Budding scientists please take note😉

  21. The only fact in this video is that your imagination could fly higher and higher.
    Time isn't real it's made up. All time is is our measuring of how long it takes earth to orbit.

  22. A pic is a frame of a moment
    ..it was nice..
    I skip some sort of boring stuff…whle want watch the credits..
    Id like to made friendships and talk about universe…id like to do sport and vactations with motor bicycle and i like myself the most..dont like humans…had meet alot selfish people and wanna leave this shit hole planet…ma wife calls me…

  23. The thing is, Newton isn't wrong. His formula is still used nowadays. Newton's law is his *theory* of gravity. Theories cannot be wrong. They can be incomplete. Newton's theory was incomplete in its explanations about what gravity is, in the first place. Scientific theories cannot be not debunked or proven wrong, they are incomplete by their very constraint of being falsifiable. Only better theories can take their place. Einstein's theory is now the current theory about gravitation. Maybe we can have a better theory about gravity (quantum gravity?) in the future, because I have found many physicists who hypothesize and strongly claim that GR has some massive flaws in its implications, particularly in the case of singularities and event horizon areas.

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