Clouds grossly affect the greenhouse effect on the planet. So they play a very profound role in weather and climate. Yet taken altogether they are one of the most poorly understood aspects of the climate change problem.

It was kind of frustrating, but everyone's relieved and really very happy this morning. It was a flawless launch.

It's been a long journey. And the science community is absolutely excited about this, naturally, because of the new nature of these observations.

It provides a look at clouds somewhat analogous to a CAT Scan. It provides a kind of in-depth profile through the clouds and we can see the processes in clouds - where fresh water is created and the rain processes occur.

It provides an in-depth profile through the clouds where we can see processes in clouds which fresh water is created in.

We've not been able to place these brush strokes into the context of a wider canvas.

We can't tell you, for example today, what fraction of the water in the sky falls as rain and snow at any instant in time.

Today we can't even tell how much of a cloud is making precipitation.

We haven't seen Earth before like this, and we're going to discover new things about Earth and clouds that we've not experienced before.

We've been waiting so long . . . I'm just kind of numb at this point. The excitement will come when the data starts flowing, in May, and we see the Earth like we've never seen it before.