When you look up at the twinkling stars in the sky, you might expect that they’re not so different from our own Sun. In some ways they are: they burn through the nuclear fuel in their core and give off tremendous amounts of light and heat, which make their way across many light years to our eyes. But another expectation of ours — that they’d have planets and a Solar System not so different from our own — takes a lot more work to verify.
Stars are the easy prey for astronomers: they’re bright, their light can be broken up into its individual wavelengths, and we can determine their speed, mass, size and even their age relatively easily. But planets are another story entirely. Except for the closest, largest and most widely-separated worlds from their stars, our current technology is completely insufficient for imaging planets directly. Instead, we’re forced to rely on indirect techniques, which is how the Kepler spacecraft works.
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