500 Coolest Things About Space

[Jim Colyer]

The March, 2015 issue of Astronomy Magazine was its 500th, so the editors included a section called the "500 Coolest Things About Space." I touched on 30 of them.

19 Cygnus X-1 in 1972 was the first X-ray source recognized as a black hole.

23 Sunlight is 40% visible light, 50% infrared light and 10 percent ultraviolet light.

51 The Hyades in Taurus is the nearest star cluster at 153 light-years away.

89 A spacecraft must travel 25,000 mph to Escape Earth's gravity.

111 Earth is 3 million miles closer to the sun in January than it is in July.

115 Penzias and Wilson discovered the cosmic microwave background in 1965.

121 The Doppler effect is a change in wavelength caused by the motion of the source.

124 Astronomers think there are 125 billion galaxies in the universe.

156 Light demonstrates characteristics of both particles and waves.

192 We live in the Orion spur of the Milky Way.

196 The New General Catalog was compiled in 1888.

198 The sky is blue because air molecules scatter blue light more than red or yellow light.

259 Edwin Hubble determined the universe was expanding in 1929.

263 The earth orbits the sun at 67,000 mph.

266 Einstein showed that Earth warps local space-time.

291 Elements are made by fusion in stars or by the explosions of supernovas.

322 A pulsar, or spinning neutron star, lies at the center of the Crab Nebula.

328 The moon rotates once for each orbit it makes.

349 Earth's axis tilts 23 1/2 degrees to the plane of its orbit.

365 Einstein published his General Theory Of Relativity in 1915, showing that gravity is caused by the warping of space-time.

387 The Milky Way has rotated 60 times.

413 Short-period comets come from the Kuiper Belt. Long-period comets come from the Oort Cloud further out.

426 The Milky Way and the Andromeda Galaxy will merge to form Milkomeda.

435 Sigma Octanis is the South Pole star at magnitude 5.4.

438 The sun and moon appear to be the same size because the sun is 400 times larger than the moon but 400 times further away.

440 A "galactic year" is between 225 and 250 million years.

454 Stars twinkle when their light passes through Earth's atmosphere.

490 1854 exoplanets were confirmed as of December 15, 2014.

496 The Spitzer Space Telescope showed the Milky Way to be a barred spiral galaxy.

500 Carl Sagan is quoted in reference to his "pale blue dot," the picture taken by Voyager four billion miles from us.

"That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam."