The smallest possible piece of an element.
These double stars are held together by gravity.
Blue giants are very massive, large and bright stars. They shine a bluish-white light. Blue giants are mostly at least 2 times hotter than our Sun and some put out thousands of times more energy than our Sun. Because they are so hot, they live short lives. If our Sun were a blue giant it would be so big, it would go past Mercury.
Groups of stars forming imaginary figures, like Orion, the Hunter. By international agreement, astronomers recognize 88 constellations.
A substance made of the same kinds of atoms.
A collection of stars, gas, and dust held together by gravity. There are four types of galaxies: spiral galaxies, barred spiral galaxies, elliptical galaxies, and irregular galaxies. Our galaxy, The Milky Way Galaxy, is a spiral galaxy. It has a few hundred billion stars in it. The galaxies called the Clouds of Magellan (one of these is known as LMC: the one where Ian Shelton found SN 1987A) are both irregular galaxies.
The amount of matter in an object.
Clouds of dust and gases in space.
An electrically neutral particle in the center of all atoms except hydrogen. Protons are particles with a positive charge, and electrons are particles with a negative charge.
A star made of neutrons, particles with no electrical charge. These stars are extremely dense since there is no positive or negative charge to their mass. A star even more dense than a neutron star is a black hole.
A neutron star that rotates very fast, sending out "pulses" of radiation.
These are huge stars that shine a red light because of their low temperature. They can look bright, but that is because they are so very big.
A giant star that explodes and becomes very, very bright. In one second a supernova puts out as much energy as our Sun does in about 60 years.
White dwarf stars have a tightly packed core of hydrogen and helium. They are .4 times the mass of our sun, about the size of the Earth. These stars are both dim and hot. They are very hot, but dim because they are so small. They look bluish-white.