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The Celestial Map
" ...Joy and amazement at the beauty and grandeur of this world of which man can just form a faint notion..."
-- Albert Einstein
We live on a planet that orbits a star, our Sun. The Sun is one of two hundred billion stars that make up our Galaxy, the Milky Way. When you look up at the sky at night, all the stars you see belong to our Galaxy; all are orbiting about a very distant center. The stars in the Galaxy are not distributed at random; most are located in a flattened dist. The Sun too is in the disk, far from the center. It takes the Sun, moving at 500,000 miles per hour, about 200 million years to orbit once around the center of the Galaxy.
Without a telescope, we can see in the night sky only the nearest and brightest stars of our Galaxy, numbering just a few thousand. During the day, blinded by the Sun, we fail to see the stars in the daytime sky.
The celestial map at Einstein's feet plots the position of the stars at noon, April 22, 1979, the time of the dedication of this statue. But the map includes more than stars visible to the "naked eye." It plots the position of the Sun (a one inch brass disk), and our planetary neighbors Mercury, Venus, and Mars -- in their appropriate phases, plus four asteroids or minor planets, Ceres, Pallas, Juno, and Vesta.
Objects of particular interest in our Galaxy are added: variable stars, which vary in brightness; double stars, pairs that appear to be very close together; spectroscopic binaries, two stars orbiting one another so closely that they appear as a single star and can be differentiated only by study of their spectra; globular clusters, dense spheroids of hundreds of thousands of stars populating the halo of our Galaxy, each cluster orbiting the center on a plunging orbit; open clusters, irregular groups located in the dusty disk of the Galaxy, whose brightest stars have been newly formed from the surrounding gas and dust; and pulsars, aging, collapsed stars that emit beacons of radio pulses at regular intervals. Together, these objects comprise the celestial objects astronomers study at the end of the 20th Century.
Faintly etched across the map is the region we call the Milky Way -- actually the combined light of all the stars along the line-of-sight viewed through the disk of our Galaxy. You will have to search carefully to find it at Einstein's feet, as you must look hard, away from the city lights, to find it in the sky.
Astronomers have known for almost 100 years that our Galaxy is just one of billions and billions of galaxies in the universe, each containing vast numbers of stars. We see our closest large spiral galaxy neighbor in the constellation of Andromeda, thus we have named it the Andromeda galaxy (also M31). At a very dark site, away from city lights, you can see it as a faint "fuzz" in the Fall sky. Use this map to try to find it on the map at Einstein's feet, where it is also faint. five other galaxies are included in the map; one, M33, is near M31. Can you find the others?
Also indicated on the map are ten Quasars. These are enormously bright nuclei of very distant galaxies. Astronomers speculate they may be exotic massive nuclear black holes caught in the process of swallowing some of the stars in their galaxies.
The Einstein map identifies more than 2,700 stars, marked by stainless steel studs, which range in size from 1/4 to 5/8 of an inch, from faintest to brightest. Each stud is beveled so that its is visible from any angle. Lines of right ascension similar to lines of longitude on earth maps, radiate from the North Pole at 15 degree intervals. Concentric circles of declination, similar to parallels of latitude on earth, ring the pole at 30-degree intervals. These lines form a grid on which can be fixed the sky position of celestial objects.
The map, 28 feet in diameter, depicts 55 percent of the entire sky. It was prepared with the assistance of P. Kenneth Seidelmann and Richard E. Schmidt, astronomers at the United States Naval Observatory in Washington, DC. |