Exoplanets

Why was the Kepler mission not able to find planets smaller than Mars, even though it was in space (and had no Earth atmosphere to deal with)?

(got wrong on both tries) Possible answers: Such planets make dips in the light of the star that are too small for Kepler to detect Such planets are red in color, and Kepler's cameras could not see red objects

When astronomers carefully examine the planets found by Kepler and draw conclusions from the Kepler sample, what do they conclude about planets the size of Earth?

Earth-sized planets are common, but so are planets somewhat bigger than Earth

What can we conclude from the shown graph? (Planet radius x Planet mass)

Got wrong on both tries Possible answers: In general, larger planets are located farther away from their star In general, larger planets have lower average densities

Planets in the habitable zone of their stars:

are at a temperature where water can exist as a liquid

What technique did astronomers use to make the first confirmed discovery of a planet around another star like the Sun?

measure the Doppler shift of the lines in the star's spectrum and look for periodic changes in this shift due to the pull of the planet as it orbits the star

The big surprise about the first planet discovered around another regular star was that it

orbited so close to its star it took only 4 days to go around

The telescope that allowed astronomers to discover most of the planets found with the transit method was called

the Kepler mission

To measure how dense a planet is (to know whether it is made of rock or gas and liquid) they must be able to measure the planet's mass from the Doppler shift and

the planet's radius using the transit method