Question: what is a dwarf galaxie?

David Whitworth answered on 5 Mar 2019:

Hi Daisy,
A dwarf galaxy is a smaller, less heavy galaxy. The Milky Way, our home galaxy has a mass of around 1×10^11 solar masses, thats 1 trillion times the size of our sun, or 1×10^42kg. Dwarf galaxies are much small and can have a mass of around 1×10^7 to 1×10^8 solar masses (1×10^37kg to 1×10^38kg). They are also much smaller in diameter, the Milky Way is between 45-60 kilo parsecs (roughly 106,000 light years or 6.2x 10^17 miles) where as a dwarf galaxy can be as small as 2kilo parsecs (7000 light years or 4.1×10^16 miles), like the Large and Small Magellanic Clouds, 2 dwarf galaxies connected to the Milk Way. The chemistry inside the dwarf galaxy is also very different, and they tend to have much fewer elements bigger than helium compared to the larger galaxies.
Some are thought to be young galaxies that will eventually turn into larger ones like our own Milky Way, and because they are young they have a lot of star formation activity. This means we can study how stars form much easier than in larger galaxies. Hope that helps?

David