Brooke and Avery in Manhattan

From Chad Taylor

A Look Inside The Crazy Experiments Where Scientists Are Learning How Clouds Form : The research at CERN isn’t just about finding the God Particle. They’re also looking a little lower down in the heavens, trying to find out the origins of clouds, because right now we have very little idea. (Andrew Price, Co.Exist)

Clouds seem pretty straightforward, right? They’re just droplets of water hanging in the atmosphere. But scientists still don’t have a good understanding of how clouds form or what role they play in the Earth’s climate.

Figuring that out is the goal of the CLOUD project at CERN (that’s the same European research center where scientists are looking for the “God particle”). The project, led by British physicist Jasper Kirkby, is trying to understand how clouds form in the sky by recreating those conditions on Earth. To do that, Kirkby and his colleagues are using “a very, very high-tech metal bin” called the CLOUD chamber.

Scientists know that cloud formation happens when tiny particles in the atmosphere grow large enough (through condensation or coagulation) to become “seeds” for cloud droplets. But that seed-formation process isn’t well understood. Scientists don’t know what kinds of particles can become cloud seeds and, more importantly, they don’t know how cosmic rays streaming in from space affect the process. The CLOUD chamber helps them recreate high-altitude conditions and then add particles and cosmic rays to create clouds themsevles.

But particles are so sparse at high altitudes that doing controlled experiments requires a very sterile space. “That’s why doing the CLOUD experiment is very tough,” Kirkby explained in a recent interview with Yale e360. “It means that you have to suppress any contaminant vapors at the level of one in a million million molecules. It’s right at the limit of technology, but I think we’ve gotten there with CLOUD.”