236: Are there rainbows on other planets? (Part II)

I talked about it again with Dr. Matthew Kenworthy, who is an associate professor at Leiden Observatory.

Oh, that's a great question there.

Well, we certainly think that there can be rainbows on other planets if they've got liquid water.

So one of the ways we see rainbows on our planet is because we have raindrops in the sky, and then you need sunlight as well to shine on the raindrops, and those raindrops then bounce the light and split it up into the rainbow that we see.

So if you look at the other planets in our solar system, there are two possible places to see rainbows.

One of them would be on Titan, which is a moon of Saturn.

But unfortunately they've got lots of thick, hazy cloud in their atmosphere, and also it wouldn't be water droplets, but it might be some other chemical instead.

So if the atmosphere was clear on Titan, they could possibly have, not rainbows, but maybe methane bows, liquid methane.

But in our solar system, there is actually one other place where we know that rainbows can exist, and this is on the next closest planet to the sun, which is Venus.

But Venus is kind of weird.

It's thought of as a sister planet to the Earth, but it's very, very, very different because it has a very, very thick atmosphere of carbon dioxide, and so the surface of the planet is very, very, very hot indeed.

In fact, it's the hottest surface of the planet in our solar system.

Way above the tops of the clouds at the top of the atmosphere of Venus, there is a chemical called sulfuric acid, and it turns out that you can form rainbows if it's any kind of droplet, so long as it's translucent.

In other words, if light can bounce around inside the droplets to make the rainbow, then that works just as well.

And so for Venus, it's really weird.

One of the special things of rainbows is that they are something called polarized.

So this is a special thing.

If you have a pair of sunglasses and you look at a rainbow on Earth, you can spin the sunglasses around and the rainbow disappears.

And this is because the light, when it bounces around, not only does it split into different colors of the rainbow, it becomes this thing called polarized.

And so using telescopes on Earth, people looked at Venus over the past 100 years, and we could see that the light bouncing from the top of the clouds of Venus were polarized as well.

And that means that there must be not rainbows, but sulfuric acid bows instead.

And because the rainbow was in a different position when you look at it, so basically the size of the rainbow, how big and wide the rainbow is, tells you what the droplets of water have inside them as well.

So this is a special way where we can look at other planets and see rainbows or at least liquid droplets with rainbows in them.