科学美国人60秒:Little Galaxy Keeps Churning Out Stars

Our galactic home, the Milky Way, is big. Most galaxies are far smaller. And it’s not easy being one of those little galaxies—a big galaxy’s gravity can rob their gas. And gas creates new stars, so losing gas spells the end of star-making. That's what happened to nearly all the small galaxies orbiting the Milky Way.

But a small galaxy can still succeed. Take the example of Leo P. Discovered in 2005, the galaxy Leo P lies some 5.3 million light-years from Earth. And it contains only about a hundred-thousandths as many stars as the Milky Way. But it’s thriving nevertheless.

So what’s Leo P's secret for success? Pretty simple: steer clear of gas-grabbing big galaxies. Leo P still has lots of gas. In fact, Leo P's gas outweighs its stars. Astronomers used the Hubble Space Telescope to study the small galaxy and published their findings recently in The Astrophysical Journal. [Kristen B. McQuinn et al, Leo P: An Unquenched Very Low-mass Galaxy]

All that gas means that Leo P can keep making new stars. So the diminutive galaxy has a bright future, as long as it keeps obeying the number one rule of survival: don’t let any behemoths siphon off your gas.

—written by Ken Croswell, voiced by Steve Mirsky

(The above text is a transcript of this podcast)