If an exoplanet happens to transit its star, we can often determine both its mass and its radius, and hence estimate its density and possibly even its composition. More than 200 transiting hot Jupiters have been measured in this way. But when astronomers calculate their densities the numbers they obtain are generally much lower than predicted by theory.
| Game | Time | WPM | Accuracy |
|---|---|---|---|
| 909 | 2017-05-26 04:19:39 | 41.51 | 87% |