Across
- 3. An immense cloud of interstellar gas and dust. Nebulas may glow, reflect light, or form dark regions that are seen against a brighter background of stars.
- 4. A hot, dense collection of matter deep within a nebula that secular cosmologists believe will eventually form a star when nuclear fusion begins.
- 6. A huge, loose mass of billions of stars, other astronomical objects, and dust held together by gravity. Exist as spiral, barred spiral, elliptical, or in irregular forms.
- 8. A body of knowledge that attempts to explain how the universe began and how it has changed over time. More than any other area of science, cosmology depends on a scientist’s worldview and his presuppositions about the way the universe works.
- 10. A violent nuclear explosion that occurs when a white dwarf draws in hydrogen from a larger companion star, begins an unstable fusion reaction, blows off the outer shell of matter
- 12. The change of the observed spectrum of a star to longer wavelengths due either to the distance to the star or to its speed away from Earth. Cosmological red shift is a reddening of the star’s light with increased distance. This condition was predicted by the Big Bang theory. Red shift, or more properly, Doppler shift, occurs if a star is moving away from Earth.
- 14. A hot, dense core of a dead star. No nuclear fusion exists, there is no containing source of heat. Slowly cools and eventually becomes a black dwarf
- 16. Unusual stars that regularly change brightness as they expand and contract in size
- 17. The violent end of stars of greater than about 8 solar masses; a brilliant explosion that leaves behind a dead core such as a white dwarf, neutron star, or black hole. Very large stars are usually completely destroyed.
- 19. An immense star; mass can be up to 70 solar masses; size can be from 30 to 500 solar diameters or morelocated at the top of the HR diagram
- 20. stands for quasi-stellar object.
- 22. One of a pair of gravitationally connected stars that revolve around each other. Astronomers believe that a majority of stars in our galaxy may be members of binary star systems.
- 23. A city sized, dense object that is the remnant of a supernova or collapsed white dwarf. Matter is so condensed that it is made of only neutrons. Some spinning neutron stars produce beams of radio waves and are detected as pulsars.
Down
- 1. The distance light travels in a year; a useful unit of interstellar distance; about 9.7 trillion_km (6 trillion_mi)
- 2. A group of stars close enough to be held together by gravity. Stars in clusters have the same proper
- 5. In secular cosmology, the change of a star over time, starting with its birth, and continuing through its aging and final death, that takes place over millions or billions of years.
- 7. A star’s brightness as it would appear at a standard distance from the star
- 8. (CMBR) (606) Electromagnetic energy in the microwave band of the radio spectrum that appears to come from all directions in space; predicted by the Big Bang theory as stretched out electromagnetic waves from the light of the original big bang.
- 9. A strange astronomical object so massive and dense that its intense gravity prevents even light from escaping. It can result from the collapse of a supernova remnant, but extremely massive black holes may be the gravitational centers of most galaxies.
- 11. A star’s relative brightness as viewed from Earth
- 13. The apparent change in position of a distant object as one’s viewing position changes
- 15. One of 88 groups or patterns of stars used to subdivide the heavens in order to locate and name individual stars
- 18. (An unusual celestial object that is as bright as a galaxy but is compact and looks like a distant star in a telescope.
- 21. Invisible matter that secular cosmologists say must exist in the universe to create enough gravity to make their cosmological model work. Its existence is inferred from the arrangement of stars and galaxies, which are visible. If it exists, dark matter should make up more than 83% of the matter in the universe.