This dramatic cluster of young, hot, giant stars is named NGC 3603. Located about 20,000 light-years from Earth in the Carina spiral arm of the Milky Way, this nebula is one of the most massive star-forming regions in our galaxy. Astronomers suspect that clusters similar to NGC 3603 located in other galaxies are the source of at least some of the cosmic rays that regularly collide with Earth. While the exact birthplace of these highly energetic charged particles is still unknown, you can read more about efforts to pin down their origins in our recent AAS Nova highlight and in the corresponding research article in the Astrophysical Journal. [NASA, ESA, and the Hubble Heritage Collaboration]