Small Galaxies Show Influence of Dark Matter

Astronomers at the University of California at Irvine (UCI), looking at dwarf galaxies orbiting our own Milky Way, have found that most of them display characteristics suggesting they were formed by the effect of dark matter.

A news report in National Geographic informs us that the scientists, using the relative speeds of stars, determined that 18 of the 23 known satellite galaxies have a common central mass of about ten million times that of the sun.

Prior to their findings, the nearby dwarf galaxies were thought to be much less massive at their cores.

The astronomers have theorized that this points to the presence of the mysterious force exhibited by so-called dark matter, which physicists think comprises the bulk of the mass of the universe and enables galaxies to coalesce, even though it can not be directly observed.

The current model of the universe, as put forth by leading scientists, theorizes that galaxies form as dark matter's gravity attracts normal matter (or atoms), producing the starry cosmos we see at night.

"We've gone down to the smallest galaxies we can see," said Manoj Kaplinghat, a UCI astrophysicist who worked on the research. "What's surprising is there's so much dark matter, even though these guys are little. They barely have a few thousand stars."

It's something to think about the next time you take a stroll on a clear summer night and gaze up at the heavens.