60-Second Science

Dwarf Galaxies Really Cooking with Gas

The smallest galaxies in the universe gave rise to an unexpectedly large proportion of stars. Karen Hopkin reports 


[Audio of Twinkle, Twinkle, Little Star] As kids, many of us pondered what stars are made of. [bars of twinkle twinkle?]. Some grown-up astronomers, on the other hand, wonder about where stars came from.

Now, a study serves up a surprise.  Because it seems that the smallest galaxies in the universe gave rise to an unexpectedly large proportion of stars. The findings are in the Astrophysical Journal. [Hakim Atek et al, Hubble Space Telescope Grism Spectroscopy Of Extreme Starbursts Across Cosmic Time: The Role Of Dwarf Galaxies In The Star Formation History Of The Universe]

Most of the stars we see in the sky were formed when the universe was young, just a few billion years after the Big Bang. So to study stellar origins, scientists use telescopes that allow them to see galaxies that are so far away, they’re essentially looking back in time.

Previous observations had focused on the star-forming powers of larger galaxies. But in this latest study, researchers used data collected by a powerful camera aboard the Hubble Space Telescope. With this instrument, they could eyeball smaller, dwarf galaxies. And they found that these diminutive dynamos churned out stars at a furious rate, fast enough to double their mass in only 150 million years. That reproductive feat would take most so-called “normal” galaxies one to three billion years.

Seems the universe has long known what Danny Devito, Michael J. Fox and Dustin Hoffmann later proved: You don't have to be big to have real star power.

—Karen Hopkin

[The above text is a transcript of this podcast.]

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