John (j2469)

Race #170

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Official speed 40.59 wpm (104.95 seconds elapsed during race)
Race Start September 20, 2019 6:59:07am UTC
Race Finish September 20, 2019 7:00:52am UTC
Outcome No win (4 of 5)
Accuracy 98.0%
Points 39.23
Text #3622418 (Length: 355 characters)

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.