How Many Stars are in our Milky Way Galaxy? According to Jos de Bruijne, a scientist at the European Space Agency (ESA) who works on the galaxy-mapping Gaia mission, the current estimate is between 100 to 400 billion stars. How Many Galaxies are there in the Universe? In 2020, it was estimated that there are around 2 trillion galaxies in the observable Universe. Each galaxy is unique, ranging in size from 10,000 light-years to hundreds of light-years.