Astronomy final Crossword
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Down:
1) extreme redshift of visible Balmer and UV Lyman hydrogen emission lines, indicating high recessional velocities and hence, by the Hubble law, very large distances |
Across:
1) Sa2) primarily old, metal-poor stars3) Spacetime is something real, with galaxies inside it; as spacetime expands, the galaxies (or superclusters of galaxies) are carried along by the expansion.4) can be formed in collisions of galaxies and thus can be young if the collision occurred recently5) expansion of space, stretching the photon’s wavelength while the photon is traveling toward Earth6) flocculent spiral 7) they contain no gas and dust clouds or young, hot stars.8) spiral galaxy classification9) relatively common. Over 10,000 have been identified so far10) small central bulge and loosely wound spiral arms.11) irregular galaxies12) Sb13) a background “glow” of microwaves, with blackbody temperature of about 3 K.14) Edwin Hubble 15) elliptical galaxy16) irregular galaxies17) have very bright, very hot starlike central cores with variable energy output18) size of the nuclear bulge19) infrared 20) the double image of a single source behind the galaxy produced by gravitational lensing by the galaxy.21) The Milky Way has at least four spiral arms, whereas most galaxies have only two.22) Albert Einstein 23) While the electromagnetic force of a charged particle has an infinite range, it is usually screened (and limited) by the existence of charges of the opposite sign. Ordinary matter has only one sign and therefore does not screen other gravitational forces.24) Sc 25) infinity26) The optical path through the gravitational lens producing one image is longer than that for the other image. |
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