Science

2. a region of spacetime where gravity is so strong that nothing, including light or other electromagnetic waves, has enough energy to escape it
7. is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency rang
8. the distance light travels in one year
11. vast space between filaments, which contain very few or no galaxies.
12. the wavelength of the light is stretched, so the light is seen as 'shifted' towards the red part of the spectrum
13. the science of the origin and development of the universe
14. two light nuclei merge to form a single heavier nucleus
15. the average density of matter required for the Universe to just halt its expansion

1. instruments that measure electromagnetic radiation, from ultraviolet to infrared, including the visible spectrum
3. when an object is moving towards us, the light from the object is known as _________
4. The measurement of the angle shift of a nearby star due to Earth's motion.
5. the idea that the universe began as just a single point, then expanded
6. a branch of physics which deals with the energy and work of a system
9. a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity
10. a hypothetical form of matter thought to account for approximately 85% of the matter in the universe