Mercury rising

During the last week of February and on through the middle of March, the sky will showcase Mercury like no other time in 2012.

The planet will be far enough from the sun's glare to be seen shortly after sunset, peaking at a relatively bright magnitude of about -1 a month from today.

Because of its tight orbit around the sun, Mercury will only be visible for less than an hour each evening, from about 6 to 7 p.m. as the sun sinks below the horizon. This is a convenient observation option - no 5 a.m. alarms or midnight viewings to deal with here.

Now, a little about the tiny, brownish-orange planet you'll see dancing with the sun later this month.

Although it has no moons of its own, Mercury is actually a lot like our moon. They're about the same size, and they're both cratered from millions of years of impacts since neither has an atmosphere to turn meteors and other approaching debris from solid threat to disintegrating fireball. The largest crater on Mercury is called the Caloris Basin and is about 800 miles wide.

Also like the moon, Mercury goes through "phases" (first quarter, last quarter, full) from our perspective, depending on which part of its sunlit side is visible from Earth. Unlike our moon, you would need a telescope to see them.

The moon and Mercury both reflect about 6 percent of the sunlight that hits their surfaces. The sun appears almost three times bigger in Mercury's sky than it does from Earth because Mercury is only about a third of the distance Earth is are from the sun.

Mercury holds the distinction of being the fastest-moving planet in our solar system, traveling through space along its orbital path at about 30 miles per second, which may be why the Romans called it Hermes, or messenger of the gods, when it came as an evening star. Mercury was called Apollo by the Romans when it appeared as a morning star.

The planet has an elliptical, or oval-shaped, orbit. Its closest approach to the sun brings it within 28.5 million miles, while its farthest distance from the sun is 43 million miles away.

And talk about global warming: the temperature on Mercury can reach 840 degrees F during the day and plummet all the way down to -275 below at night.

In March, NASA's Messenger spacecraft is scheduled to enter Mercury's orbit to begin a year-long study of the planet's composition, geological structure, magnetic field, poles - which contain ice - and other elements.

localuniverse@msn.com