You probably recognize this image. You see something like it whenever you look up at the sky. Some days are clearer than others—some, you might even see a completely blue sky—but regardless, you know that this is an image of our atmosphere.
But do you know just how much your atmosphere does for you?
We’ll talk about how it protects you from space rocks later on. For now, consider the energy from our own sun. The sun doesn’t just send visible light our way—it operates in all wavelengths of the electromagnetic spectrum.
Some of those wavelengths are harmful, like gamma rays, X-rays, and ultraviolet radiation. Others, like infrared radiation, microwaves, and radio waves, are perfectly fine.
The atmosphere doesn’t really pick and choose which wavelengths get through to the surface. It blocks out some radiation it doesn’t need to. At least it protects us from the harmful wavelengths.
But that’s bad news for astronomers, because those wavelengths still contain useful information about the universe.
So how to we capture and analyze them? Continue reading