Glossary N

Neutron Star: An extremely dense compact star. Typically with Nebula: A cloud of gas and dust in interstellar space.

a diameter of around 6 miles but having the same mass as the Sun.

New General Catalogue (NGC): A catalogue of nebulae, clusters and galaxies that was published in 1888.

Nova: A star that suddenly brightens by a factor of thousands or more and then fades back to its original brightness over a period of weeks or months.