Across
- 3. dwarfs a theoretical, hypothetical remnant of a white dwarf that has cooled down so much that it no longer emits any light or heat
- 4. a nuclear process where light atomic nuclei combine to form heavier nuclei, releasing a large amount of energy
- 8. dwarfs a small very dense star that is typically the size of a planet. A ..... dwarf is formed when a low-mass star has exhausted all its central nuclear fuel and lost its outer layers as a planetary nebula.
- 9. flat, thin, and circular like a disk.
- 11. a star of relatively great size and luminosity compared to ordinary stars of the main sequence, and 10–100 times the diameter of the sun.
- 12. reaction a change in the identity or characteristics of an atomic nucleus that results when it is bombarded with an energetic particle, as in fission, fusion, or radioactive decay
- 13. a spiral galaxy containing our solar system, including Earth and the Sun
- 14. diagram a graph that plots the luminosity (or absolute magnitude) of stars against their surface temperature (or spectral type)
- 15. class the group in which a star is classified according to its spectrum, especially using the Harvard classification.
Down
- 1. sequence a series of star types to which most stars belong, represented on a Hertzsprung–Russell diagram as a continuous band extending from the upper left (hot, bright stars) to the lower right (cool, dim stars).
- 2. the intrinsic brightness of a celestial object (as distinct from its apparent brightness diminished by distance).
- 5. The .... is everything. It includes all of space, and all the matter and energy that space contains
- 6. a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.
- 7. a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
- 10. giants a very large star that is even brighter than a giant, often despite being relatively cool.