I don’t think we’ll ever need traffic reports for satellites, but since 1957 — the dawn of the space age — more than 23,000 satellites have been launched into orbit around the Earth and about a third of them are still up there.

In fact, Vanguard One, launched on St. Patrick’s Day in 1958, is still in orbit 56 years later. It’s made well over 200,000 orbits around our world and has traveled more than six billion miles. Move over Energizer Bunny! Vanguard really keeps going and going and going.

Some satellites, like the International Space Station, even have people in them.

Along with useful functioning satellites, there’s also a lot of junk up there: useless out of commission and out of control satellites, spent rocket stages, and other random space garbage. It’s like a floating junkyard up above the atmosphere, in what some refer to as the “junkosphere.”

Don’t get me wrong, though. If you were ever lucky enough to grab an extra seat on some future space ship and orbit the Earth once every 90 minutes, chances are you wouldn’t see any garbage. There’s a lot of space in space.

Just about any time you stargaze you’ll see starlike objects march across the heavens at a steady but sane pace. They’re either seen in the early evening a little after twilight or just before morning twilight.

You’re just about guaranteed to see at least one satellite zipping among the stars as you study the constellations. Satellites are seen mostly at those times because they’re better able to reflect sunlight then. That’s the only light they’ve got. You could have the biggest floodlight ever created mounted on a satellite and have it shine back to the Earth and we’d still never see it.

These satellites are at least 110 miles high but most of the healthy ones are a lot higher. In fact, just by observing and comparing satellite speeds you can estimate how high they are.

Most military reconnaissance and communications satellites are high flyers, at altitudes of 250 to 600 miles high. They traverse the sky in two to three minutes, looking like brighter stars moving against the backdrop of actual distant stars.

Faster paced satellites are in much lower orbits, and in a lot of cases are not long for the orbital world. Lower trajectory satellites skim through the upper drag of the upper atmosphere which slowly pulls them down, leaving them more vulnerable to being sucked in by the atmosphere and incinerated because of air friction.

That was the fate of Sputnik One, the first USSR satellite, and Explorer One, the first U.S. orbiter.

Sputnik, to everyone’s dismay, was launched in October 1957 and burnt up in the atmosphere just four months later. Explorer One launched in February 1958 and stayed in orbit until March 1970. We built them to last back then!

What powers these satellites as they circle our world? They’re certainly not propelling themselves. The answer is good, old- fashioned Newtonian physics.

Satellites are always falling toward the Earth in a curving path, much like a thrown baseball curves down toward the ground. However, satellites are traveling at a fast enough speed after their launch that the curve of their fall matches the curvature of the Earth. They never hit the ground, provided they’re high enough above the dragging atmosphere.

Most satellites travel from west to east across the sky, taking advantage of Earth’s east to west rotation, which is faster toward the equator. That’s why just about all U.S. space launches are at Cape Canaveral, Fla., as opposed to Fairbanks, Alaska.

Some satellites travel in polar orbits south to north or vice versa. A lot of those are spy satellites so wave when you see ’em. There are also satellites that are geostationary and sit in one place above the Earth with their orbits in perfect sync with Earth’s rotation.

The brightest satellite is the space station. It is almost as bright as high flying aircraft, sometimes more so. It can even be brighter than the very dazzling planet Jupiter now in the southeastern evening sky. In fact, if conditions are right, it’s even possible to spot the space station during the day. It’s gotten that big over the years

Another really fun group of satellites to watch are the 60 plus Iridium satellites that provide worldwide cell phone service. About the size of an old Volkswagen Bug, they track across our heavens and rotate. As they do, they dramatically flare-up for a few seconds at a time when the angle of one of the solar panels is just right between you on the ground and the distant sun.

Sometimes Iridium flares are more than 100 times brighter than the brightest stars.

Presently there are nearly four dozen satellites you can easily see with the naked eye, even in areas of city and suburban light pollution.

There are some absolutely wonderful websites for keeping track of them and many more fainter satellites. Of course they’ll also help you track the space station.

One of them is Heaven’s Above and you can reach it at www.heavens-above.com.

After you set it up for your location, you can keep track of every major spacecraft and satellites.

If something is coming over, the website will tell you where and when to look for it. It also tracks the times of Iridium flares.

There’s another arguably even better website called Real Time Satellite Tracking. I love this site because it automatically reads your location from the IP address on your computer.

It’ll give five day predictions for the visibility of the space station and many other satellites, help you make a viewing log and even show you a map of the satellite orbit and where it’s at in that orbit. You can literally “watch” it orbit different parts of the world. I think it’s so cool. You can even track Vanguard One, but actually spotting it in the sky requires a large telescope and a lot of skill.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications and available at bookstores and at www.adventurepublications.net.