Across
- 4. two light nuclei merge to form a single heavier nucleus
- 5. The measurement of the angle shift of a nearby star due to Earth's motion.
- 8. the science of the origin and development of the universe
- 9. when an object is moving towards us, the light from the object is known as _________
- 10. the distance light travels in one year
- 12. a hypothetical form of matter thought to account for approximately 85% of the matter in the universe
- 14. vast space between filaments, which contain very few or no galaxies.
Down
- 1. a region of space having a gravitational field so intense that no matter or radiation can escape
- 2. the idea that the universe began as just a single point, then expanded
- 3. the average density of matter required for the Universe to just halt its expansion
- 6. a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity
- 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
- 11. the wavelength of the light is stretched, so the light is seen as 'shifted' towards the red part of the spectrum
- 13. a branch of physics which deals with the energy and work of a system