Meg Urry : The Two-WayA new study finds that the number of people who are obese in America has doubled since 1980. Urry : There is enough mass in the wind to carry away a lot of gas in the galaxy . She says this suggests an answer to why galaxies today do not have more stars . Urry : It 's because cold gas , which forms stars , is being blown out of galaxies .
Meg Urry : New data have mapped a `` superwind '' flowing out of a nearby galaxy . Urry : There is enough mass in the wind to carry away a lot of gas in the galaxy . She says this suggests an answer to why galaxies today do not have more stars . Urry : It 's because cold gas , which forms stars , is being blown out of galaxies .