I know you don’t have a catchy name like Voyager or Cassini, but I appreciate you all the same. Unlike your extrovert cousins, you are an introvert—inward-looking, focused on just one planet. But it’s an important one, the only planet we know of so far in the universe that is home to life: Earth.
As you orbit over the Poles, your role is to measure the “energy balance” that governs Earth’s temperature. With one eye looking down, you measure the outgoing heat escaping from the surface and atmosphere. With the other eye looking up, you measure the incoming solar radiation that heats Earth from above. Subtracting the former from the latter, you estimate the net heating of the