Dr. David Sing

So on this particular planet, the clouds are actually even confined to the morning side of the planet.

So the morning side is completely cloudy and the evening side is actually completely clear.

It's much hotter and those clouds can't form.

And so I kind of imagine it sort of like you're in San Francisco and in the morning it's all cloudy and you can't see anything anymore.

And then by the afternoon, they've all boiled off and you can see the clear sky.

Yeah, well, we've been studying exoplanets through the transit technique for nearly 25 years, and we've been mainly using the Hubble Space Telescope during that time.

But now we have the powerful JWST telescope, and that's given us actually two important advances to be able to make this measurement.

The one is...

Hubble is in low Earth orbit.

It's orbiting around the Earth about every 90 minutes.

And so it spends half of its time on the day side of our planet and half of it on the night side.

Well, when we look at these transit events of these exoplanets, you know, we're looking at it over the course of several hours.

But that means the Hubble is actually spending half of its time on the wrong side of our planet.

And so actually, you can't even observe the full transit event continuously, which kind of prevents this measurement from being made.

But JWST is out beyond the Earth and the Moon, and it can stare continuously for hours or even days.

So...

That's one key aspect of JWST that's important.

And the other is that the telescope, JWST, is just so much bigger.

It has seven times the light collecting ability.

So that means what took Hubble more than an hour to make a measurement, now JWST can do in, say, 10 minutes.