Four new satellite galaxies of the Milky Way have been discovered, bringing the total known to about 20. The pace of new discoveries suggests that many more such satellites remain unknown, which would present a serious challenge to models of dark matter as "warm", fast-moving particles.

The satellites are dwarf galaxies a few hundred to a few thousand light years across. The tiny galaxies are thought to be the building blocks of large galaxies, such as our own Milky Way ? which is about 100,000 light years wide.

So astronomers try to study them to understand more about how this merger process took place. Their exact numbers could also tell astronomers how easily dark matter forms clumps, which might offer clues about the nature of this mysterious substance, whose presence is detected only by its gravitational effect on ordinary matter and light (see Cosmic smash-up provides proof of dark matter).

For more:
http://www.newscientistspace.com/article/dn9844-sky-survey-nabs-four-new-milky-way-satellites.html

maybe they should name the next one froto or baggins . interesting.