Dr. Brian Keating

It was the 100th anniversary of Einstein's theory of general relativity. And we had a ceremony to honor the first person who ever came up with a theory of relativity, which is also Galileo. Galileo had the first notion that relative motion is indistinguishable. That if you and I are on a bike and I'm stationary, you can't tell if you're moving. I can't tell if I'm stationary.

That's called relativity of motion. Motion is not absolute. Einstein would later enhance that, put on steroids, and then come up with all sorts of cool stuff that we can get into.

That's called relativity of motion. Motion is not absolute. Einstein would later enhance that, put on steroids, and then come up with all sorts of cool stuff that we can get into.

That's called relativity of motion. Motion is not absolute. Einstein would later enhance that, put on steroids, and then come up with all sorts of cool stuff that we can get into.

But this notion that you could do observations, that you could use a scientific tool coupled with a hypothesis and then iterate on those hypotheses to make both the instrument better and your hypothesis better and then expose that to scientific peer review, which was not what we have today. That was done by Galileo. He was the first person to use the scientific method. What did he use it with?

But this notion that you could do observations, that you could use a scientific tool coupled with a hypothesis and then iterate on those hypotheses to make both the instrument better and your hypothesis better and then expose that to scientific peer review, which was not what we have today. That was done by Galileo. He was the first person to use the scientific method. What did he use it with?

But this notion that you could do observations, that you could use a scientific tool coupled with a hypothesis and then iterate on those hypotheses to make both the instrument better and your hypothesis better and then expose that to scientific peer review, which was not what we have today. That was done by Galileo. He was the first person to use the scientific method. What did he use it with?

A telescope. So a telescope that he used was a refracting telescope. Lenses like eyeglasses, two of them, one put at the far end called the objective. It's closer to the object. The other one, the eyepiece, close to your eye. And he was able to magnify things about three to 10 times pretty easily.

A telescope. So a telescope that he used was a refracting telescope. Lenses like eyeglasses, two of them, one put at the far end called the objective. It's closer to the object. The other one, the eyepiece, close to your eye. And he was able to magnify things about three to 10 times pretty easily.

A telescope. So a telescope that he used was a refracting telescope. Lenses like eyeglasses, two of them, one put at the far end called the objective. It's closer to the object. The other one, the eyepiece, close to your eye. And he was able to magnify things about three to 10 times pretty easily.

Light travels at the fastest speed of any entity. Photons travel at roughly 300,000 kilometers per second, except when they go into a medium. That's what they travel in the vacuum of space or in a vacuum in my laboratory or whatever. But when they go into a medium that's transparent or translucent, they slow down. You can think of it as the light waves themselves.

Light travels at the fastest speed of any entity. Photons travel at roughly 300,000 kilometers per second, except when they go into a medium. That's what they travel in the vacuum of space or in a vacuum in my laboratory or whatever. But when they go into a medium that's transparent or translucent, they slow down. You can think of it as the light waves themselves.

Light travels at the fastest speed of any entity. Photons travel at roughly 300,000 kilometers per second, except when they go into a medium. That's what they travel in the vacuum of space or in a vacuum in my laboratory or whatever. But when they go into a medium that's transparent or translucent, they slow down. You can think of it as the light waves themselves.

Imagine light waves as rows of soldiers marching together. And then imagine that they're walking an angle to the beach here in Los Angeles. They're marching at an angle. The ones that encounter the water first, they start to slow down. The other ones keep moving at a fast speed. And then the whole beam of light, the whole beam of soldiers gets bent. That process is called refraction.

Imagine light waves as rows of soldiers marching together. And then imagine that they're walking an angle to the beach here in Los Angeles. They're marching at an angle. The ones that encounter the water first, they start to slow down. The other ones keep moving at a fast speed. And then the whole beam of light, the whole beam of soldiers gets bent. That process is called refraction.

Imagine light waves as rows of soldiers marching together. And then imagine that they're walking an angle to the beach here in Los Angeles. They're marching at an angle. The ones that encounter the water first, they start to slow down. The other ones keep moving at a fast speed. And then the whole beam of light, the whole beam of soldiers gets bent. That process is called refraction.

We can do it – well, this yerba mate is so delicious. We can't do it because it's got a little bit of –

We can do it – well, this yerba mate is so delicious. We can't do it because it's got a little bit of –

We can do it – well, this yerba mate is so delicious. We can't do it because it's got a little bit of –

Put a pencil in a clear glass of water, same phenomenon will happen. That's refraction. It's the bending of light by what's called a dielectric or just a medium that's transparent or translucent. And you can do that in a way that you shape the wave of light coming in that will be magnified. And that's in fact what a telescope does. Tele means distance, scope means viewer.