It's dark, the stars are out, you're all alone. Suddenly an eerie light soars over the horizon. It glides noiselessly overhead--a spaceship! You dash inside and wake the family, but by the time you're outside again it's too late. The ship is long gone and nobody believes you anyway.

Don't you hate it when that happens?

This week could be different: A spaceship will appear, but even if you're the only one who sees it you can prove you're not crazy. That's because it'll be back again tomorrow.

We're talking about the space shuttle Columbia (STS-107).

Columbia left Earth on Jan. 16th for a 16-day mission dedicated to scientific research. Onboard are 80+ scientific experiments ranging from fundamental physics and biology to fire fighting and perfume research. Although Columbia has been circling Earth every 90 minutes since launch, it hasn't been easy to see from North America until now.

The space shuttle flying overhead at dawn is really a beautiful sight. You'll spot it first in the western sky not too far from Jupiter. The giant planet is brighter than the shuttle, but not much. Both are among the brightest "stars" in the morning sky. Columbia will glide slowly eastward toward Venus and the rising Sun. The shuttle takes about 6 minutes to travel from one horizon to the other. It only seems slow, however. Four hundred km above Earth, Columbia is moving 17,500 mph!

In recent years, most shuttle missions have been to the International Space Station (ISS) to deliver supplies, personnel and building materials to the growing outpost. (STS-107 is different. Columbia is nowhere near the ISS--it doesn't need to be to accomplish its research goals.) Sky watchers who have seen both spacecraft orbiting Earth in tandem have noticed something remarkable: although the shuttle is only 1/3 as big as the space station, the shuttle is much brighter.

Why?

Both spacecraft shine by means of reflected sunlight and both are good reflectors with plenty of light-colored surfaces. But while the ISS is a gangly structure that reflects light in all directions, the shuttle has a more regular shape like an airplane. Its smooth white top reflects sunlight exceptionally well.

We can see Columbia's white top because it circles Earth "upside down." The orbiter's tough black underside faces outward toward space to protect the crew and cargo from incoming meteoroids. In this position, astronauts and telescopes inside the open cargo bay get a good view of Earth, which is a key requirement for Earth science experiments. (There are two such experiments on STS-107: one to study Earth's ozone layer and another to monitor dust plumes over the Mediterranean Sea.)

Convincing your family and friends that you had seen a spaceship was hard enough ... but an upside down spaceship? This week they can see for themselves.