Heavenly sights there for the taking

Skywatch: Look, up in the sky, it's a planet, it's a star, it's the space station.

May 19, 1999|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

SCENE 1: A brutally cold, red-desert planet rises to our left. The camera pans right, to another world set deep within a suffocating shroud of hot, poisonous clouds.

Overhead, an ancient space station drifts across a starry sky. Its three nearly forgotten crewmen struggle to keep their decrepit outpost alive.

Suddenly, a laser-like beam of light streaks toward us from a fleet of robot moons that patrol our own turbulent home in the galaxy.

Sounds cool, huh? And you don't even have to buy a ticket to "Star Wars: Episode I -- The Phantom Menace."

It's all there, up in the sky -- the real sky. If you're waiting on line for the movies, headed back to your car, or just hanging out in the back yard this week, all you have to do is look up. The show is free and it changes every night.

If the night skies are clear, you should easily find frigid Mars and steamy Venus. The Russian space station Mir and its three cosmonauts will fly over tonight. Tomorrow, we should see an "Iridium flare" -- a brilliant glint of sunlight off one of the 66 new Iridium telephone-system satellites. And just after midnight on Saturday, the moon will eclipse the bright star Regulus in the last occultation visible here until 2005.

Here's a preview. First, the easy stuff.

Venus:

If you're on a movie line -- or just outdoors -- in the three hours after sunset, look toward the west, above where the sun went down. That bright, white "star" is actually Venus, the second planet from the sun.

Sunlight reflected off Venus' thick cover of hydrochloric acid clouds helps make it the brightest object in the night sky, not counting the sun and moon. Far below those clouds, on the barren Venusian surface, temperatures soar to 900 degrees Fahrenheit -- hot enough to melt lead.

The moon: A crescent moon that stood beside Venus last night will move farther toward the east each night this week. But if it's dark enough where you are tonight, you may be able to see the dark portion of the moon's disk glowing very faintly. It is dimly illuminated by Earthshine -- sunlight bounced back onto the moon from the daylight side of the Earth.

Mars: Turn around now and look toward the east. Rising well above the horizon during the evening hours (and arcing high overhead after midnight), should be a yellow-orange "star," easily the brightest in that part of the sky. That's Mars, the fourth planet from the sun.

Mars is about half Earth's size, and it's now about 60 million miles away from us. It's cold and barren except for a handful of derelict robot landers sent from Earth in 1976 and 1997.

NASA's Mars Global Surveyor spacecraft is still circling the planet, sending back scientific data and photos. Two more robot missions will arrive there later this year. One will land.

(Bonus: The star just to Mars' right is Spica, 260 light years from Earth. A light year is the distance light travels in a year, about 5.9 trillion miles.)

Now it gets trickier.

Mir: For a few minutes tonight, beginning at 9: 41 p.m., Mir and its three crewmen will soar across the Maryland sky. Mir will look like a bright, moving star. It will appear just above the western horizon and move toward the north-northeast.

It's only visible because we're in the dark, and the giant station and its vast solar panels are still in sunlight, 236 miles up.

Get outside a few minutes early. Mir will only be visible briefly. If you spot something moving with a red light, or a flashing strobe, it's an airplane. Mir's reflected light is steady and white.

If clouds interfere, go to the Web (www2.gsoc.dlr.de/satvis) to find out when and where Mir, the International Space Station and other satellites can next be seen from your location.

Iridium: Iridium is actually a fleet of 66 telephone communications satellites flying in north-south orbits, 485 miles high.

Each one has a set of antennas with mirror-like surfaces. When the angles are right between the sun and an Iridium satellite, the antennas bounce brilliant flares of reflected sunlight onto the ground.

Astronomers can forecast where and when these flares will be visible. Tomorrow at 11: 26 p.m., they say, a flash of sunlight will bounce off an antenna on Iridium 19, and fall across central Maryland.

In Baltimore, the flare will appear as bright as Venus, and even brighter 20 miles west of the city. Look for it 20 degrees above the west-southwest horizon -- about a quarter of the way up between the horizon and straight overhead.

Lunar occultation: This one is advertised as a naked-eye event, but binoculars will be a big help.

Just after midnight, at 12: 18 a.m. on Saturday in Baltimore, the moon -- by then half-illuminated by the sun -- will pass in front of the bright star Regulus, 85 light years away and shining above the southwestern horizon.

Regulus will appear to wink out as the dark, left-hand edge of the moon's disk passes in front of it. It's a kind of eclipse, but astronomers call it an occultation. This will be the last visible here until 2005.

At 1: 17 a.m., Regulus will reappear from behind the moon's opposite, sunlit edge. But it will be hard to see in the moon's glare.

Astronomers invite video camera owners to help them with their observation of such occultations. For information on how to participate, go to the Internet (www. lunar-occultations.com/iota).

For make-believe space spectaculars, go to the movies.

Pub Date: 5/19/99

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