One hundred years ago, Albert Einstein changed physics with four pages of text. Off those pages leapt his general theory of relativity, published in December of 1915. It would go on to describe the universe at its largest and fastest. Gravity is warped space-time, and both time and space will bend according to the mass and energy peppering the universe. This brilliant insight is now one of the pillars of modern physics, born from the musings of a lone German physicist. As confusing as warped space-time may sound, you don’t need superpowers to understand it.
In the latest special issue from Science, Einstein’s insights come alive in a delightful interactive comic aptly called “General Relativity.” It begins with Einstein contemplating the shoulders he stood on: Netwon’s laws of motion:
That’s all fine and good, but the physicist realized that an object can feel no force act on it yet still accelerate. That’s what would happen if you walked straight off a roof, and this scenario happens to be the exact same thought experiment Einstein envisioned.
So how can you explain the fact that an object in free-fall accelerates without a force acting on it? If gravity was warping space-time, then time might run slower at the Earth’s surface (it has more mass and therefore more gravity) than on the roof where he hypothetically stood. If that was the case, an object in free-fall could accelerate without being acted on by an outside force:
Of course, thought experiments only got Einstein so far. He needed to prove it. That took a lot of math and years of work.
But the central idea of gravity itself being warped space-time is easy enough to understand, at least explained this simply. As Einstein supposedly said, make everything as simple as possible, but not simpler. I wish my physics class had a comic like this.
Make sure to scroll through the whole comic at Science/AAAS here.