Prior to 1957, everything you saw high in the night sky was untouched by human hands, assuming there aren't any other humans out there beyond our solar system. That all changed on Oct. 4, 1957, when Spunik was rushed into orbit by the Soviet Union to show up the United States.

The reaction in this country was frantic. The Russians had beaten us into space with a 184-pound satellite the size of a basketball and a steady beep beep beep signal. What was next? Would they be dropping hydrogen bombs on us from space platforms?

America had to get something up there, and quick. Our answer was Explorer One, launched on Jan. 31, 1958.

The early space race was an exciting time. One of my favorite movies, "October Skies," was a story of four high school boys growing up during that time in a dying West Virginia coal mining town. They were inspired to build rockets and eventually won first place at the state science fair. I'm no movie reviewer, but I'd give it a whole bunch of stars. Literally!

Since the late 1950s, thousands and thousands of satellites have been sent into orbit and beyond by many countries. Many of them have succumbed to the drag of Earth's atmosphere and have perished in flames, but many more are still up there, anywhere from 100 miles to over 20,000 miles over our world, watching the weather, studying the Earth's geology, aiding communications, spying, and so much more. Some are even occupied, like the International Space Station.

Anyone who has ever seriously stargazed has seen a satellite. It's hard to go more than 20 to 30 minutes without seeing at least one of them cross the sky. Most move from west to east like the Space Station, but some are in polar orbits.

The best time to see them is in the early evening for about an hour or so after evening twilight, or within the hour or so before the start of morning twilight. That's because, for satellites to be visible, they have to reflect sunlight. Even if they had huge spotlights mounted on their sides you'd never see them. They're just too high up.

Just before morning twilight and for a short time after evening twilight there is no direct sunlight available to us on the ground, but high above us in space there's enough sunlight to bathe the satellites, sending second-hand sunshine our way.

During the middle of the night, however, the sun is completely behind the Earth, so even the satellites passing high over us are in total darkness.

Two of my favorite man-made space objects are the aforementioned International Space Station and the Iridium satellites. When the station passes over, it can be as bright as the brightest star. One of the coolest things to see is the Space Shuttle approaching and docking with the station. It looks like two bright stars merging.

There are also more than 60 Iridium communications satellites orbiting the Earth. They are about the size of Volkswagen Beetles with enormous solar panels.

When the angle of one of its solar panels is just right it can reflect a bunch of sunlight our way, causing it to flare up for several seconds. After that the solar panel is turned away from us and disappears into the night. These are known to amateur astronomers like myself as Iridium Flares and can be a lot of fun, especially if you know one is on the way and the person or people you're with have no idea what they're about to see.

There are many good sites on the Internet to keep up with the comings and goings of bright satellites, but my favorite is

www.heavens-above.com

. You can set up the site for your location and get a complete schedule of when the space station is coming over your house, as well as times and locations of Iridium flares.

There's also other satellite tracking info available and other great backyard astronomy stuff. Quite frankly, there's a lot of traffic up there.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the new book, "Pennsylvania Starwatch," available at bookstores and at his Web site: www.lynchandthestars.com