Jeremy Darling – TRANSCRIPT
OK, so I’m going to tell you about water in the universe, and the charge to you tonight is to think big, very, very big. So, why do we care about water in the universe? It’s because water is essential for life.
Where we find water, we find one of the key ingredients where we can find life. What we’re going to do tonight is a tour of the universe through the prism of water. At the top of the screen, I have a little meter for you to keep track of where we are in the universe. We’re going to start at the Earth and move out to the very early universe. So let’s start our tour, here we go.
We’re going to start here and now – here we are on the Earth – and we live in an amazing place in terms of water. You can see in this pressure-temperature diagram that there are three phases of water: solid, liquid, and gas. Every day, especially here in Colorado, we can see all three phases at once. So we see ice, we see liquid water, and we see clouds. But you can imagine if we leave the atmosphere of the Earth, the pressure drops and we can no longer have liquid water, we can only have ice or vapor.
Likewise, if we go out in the cold, cold, cold space, the pressure drops, the temperature drops as well, and we only have ice; all the water freezes out. Let’s take the next step on our tour, and we’re going to find water in a really extreme environment. You may be surprised to learn that there is water on the surface of our Sun. We can see these dark spots on the surface of the Sun; these are sunspots. They look dark because they’re slightly cooler than the rest of the Sun.
They are still very hot, about 5,000 degrees Fahrenheit, but if you look in the centers of these sunspots, it turns out that water is spontaneously forming; there is a chemistry there forming water on the surface of the Sun. It’s a gas, but it’s still water. Very hot water. We’ll see water in very extreme environments later on in our tour; this is the first spot. So let’s move further out in the solar system, let’s look at the moon of Jupiter called Europa.