Across
- 3. the group of stars that on a graph of spectrum versus luminosity forms a band comprising 90 percent of stellar types and that includes stars representative of the stages a normal star passes through during most of its lifetime.
- 4. the stellar core left behind after a dying star has exhausted its nuclear fuel and expelled its outer layers to form a planetary nebula.
- 5. Newton's law that says that every particle attracts every other particle in the universe with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
- 6. the science that deals with the material universe beyond the earth's atmosphere.
- 8. a theory that deduces a cataclysmic birth of the universe (big bang ) from the observed expansion of the universe, cosmic background radiation, abundance of the elements, and the laws of physics.
- 9. a shift toward longer wavelengths of the spectral lines emitted by a celestial object that is caused by the object moving away from the earth.
- 10. a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space.
- 11. an enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars.
Down
- 1. an optical instrument for making distant objects appear larger and therefore nearer.
- 2. a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
- 7. A group of stars seen as forming a figure or design in the sky,
- 12. an area of such immense gravity that nothing—not even light—can escape from it.