History of the Universe
Across
- 2. the height of a wave
- 5. the number of waves that pass a fixed point in a unit of time
- 7. lowest point of a wave
- 9. tiny atomic particle with little mass and a negative electric charge;an atom's electrons are equal in number to its protons and are located in a cloudlike region surrounding the nucleus
- 11. rhythmic movement that carries energy through matter or space and, in oceans, is generated mainly by wind moving over the surface of the water
- 13. the displacement of spectral lines toward longer wavelengths in radiation from distant galaxies and celestial objects
- 17. weak radiation that is left over from the early, hot stages of the Big Bang expansion of the universe
- 21. the distance between two identical points on consecutive waves
- 22. an instrument for forming and examining spectra especially in the visible region of the electromagnetic spectrum
- 23. large cloud of interstellar gas and dust that collapses on itself, due to its own gravity, and forms a hot, condensed object that will become a new star
Down
- 1. all types of electromagnetic radiation arranged according to wavelength and frequency
- 3. highest point of a wave
- 4. massive explosion that occurs when the outer layers of a star are blown off
- 6. natural or artificial substance that cannot be broken down into simpler substances by physical or chemical means
- 8. a table of chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure appear in vertical columns
- 10. collapsed, dense core of a star that forms quickly while its outer layers are falling inward, has a radius of about 10km, a mass 1.4 to 3 times that of the Sun, and contains mostly neutrons
- 12. theory that proposes that the universe began as a single point and has been expanding ever since
- 14. the combining of lightweight nuclei into heavier nuclei; occurs in the core of the Sunn where temperatures and pressure are extremely high
- 15. tiny atomic particle that has mass and a positive electric charge
- 16. change in the wave frequency that occurs due to the relative motion of the wave as it moves toward or away from an observer
- 18. tiny atomic particle that is electrically neutral and has about the same mass as a proton
- 19. number of protons contained in an atom's nucleus
- 20. small, extremely dense remnant of a star whose gravity is so immense that not even light can escape its gravitational field