The CMBR is the ancient light that the universe emitted 380,000 years after the big bang. The picture above shows what all of the ionized gas looked like before it condensed into super clusters and formed stars, galaxies, and planets. The CMBR was discovered completely by accident. This also provides solid evidence for the Big Bang Theory.
Dark matter is a theoretical concept that is said to make up about 27% of the universe. Dark matter is completely invisible to the naked eye and instruments. It is theorized that it holds the universe together. Dark energy is what is expanding the universe at its rapid speed. Eventually we wont be able to see as many stars because of the universe expanding.
Neutron stars are formed when a massive supergiant star dies and collapses in on itself. They emit these pulses because they are rotating around 60-700 times in a single second and release large energy pulses from their poles. If a black hole were to come in contact with a neutron star then they would likely orbit around each other until the black hole swallows it.
Everything in the universe is heading towards the Great Attractor. It is not a supermassive black hole in the center but rather a volume of space that embodies the center of all attraction. We would never reach the center of the Great Attractor because of the acceleration of the dark energy is expanding the universe. Even the Great Attractor is being pulled towards something even bigger.
Gamma rays are the smallest wavelength in the electromagnetic spectrum. They are also the most powerful wave lengths and are produced by only the most powerful and hottest celestial objects in the universe. The objects that produce them are neutron stars, pulsars, supernovas, and areas around black holes. If a gamma ray from a supernova were to wash over the earth then all life that we know would be extinct in a moment.
Black holes are one of the mysteries of the universe. There could be millions of black holes in our galaxy but we would never know because you can't directly see black holes. At the center of every galaxy is a super massive black hole. The more massive a black hole is, then the colder it is. The gravitational pull of a black hole is so strong that once you pass its event horizon nothing can escape its pull, even light.