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A Galactic Block Party for Mars

August 02, 2003|Allison M. Heinrichs | Times Staff Writer

In the wee hours of Aug. 27, Californians will be able to witness the closest approach of Mars to Earth in almost 60,000 years.

The Red Planet will be a little more than 34.6 million miles away, shining like a ruddy orange sparkle in the southern sky.

At that distance, even modest telescopes and binoculars will reveal many Martian features -- from the white south polar cap and light orange highlands to deep brown basins and perhaps a smudgy dust storm or two.

Because only half of Earth is dark at any given time, Mars' closest position will be visible mainly to people in North and South America, and many Pacific islands. Tahiti will be roughly the closest spot to Mars during the event, said Bruce Betts, a scientist with the Pasadena-based Planetary Society.

But people in other parts of the world will be able to see Mars just as well in the days before and after the planet's closest approach.

In anticipation of the historic occasion, the Griffith Observatory is launching the first of a series of Mars parties this evening, with plenty of telescopes for the public to look through.

The parties will begin at 8 p.m. every Saturday in August -- with a special party the night of Aug. 26 -- at the observatory's satellite facility adjacent to the Los Angeles Zoo.

"The closest approach in all of recorded history," said Griffith astronomical observer Tony Cook. "Kind of sounds like the sort of thing you don't want to miss."

The close passing of Earth and Mars is the result of the elliptical orbits of both planets, and the different speeds with which they orbit the sun. Every 26 months the Earth laps its neighbor Mars, although their closest point can vary by about 30 million miles.

At 2:51 a.m. Pacific time Aug. 27, the two planets will swing right by each other, with the Earth near its farthest point from the sun and Mars at its closest.

Although this is the closest Mars has come to Earth since the time of Neanderthals, nearly 60,000 years ago, the planet will really be only between 1 million and 2 million miles closer to Earth than it was in 1988 -- a difference unobservable to the naked eye and small change in astronomical terms.

There will be about half a dozen slightly closer approaches between 2003 and 3000, with the closest -- 34.58 million miles -- occurring in 2729.

The Griffith Observatory celebrations will have several Mars-related activities, including informal planetarium presentations by the observatory staff and planet-watching workshops hosted by Timothy Robertson of the Assn. of Lunar and Planetary Observers.

Los Angeles Astronomical Society president Jim Strogen said there will be "at least 15, maybe 25, people and the Sidewalk Astronomers will have eight to 10 folks, all with telescopes," at the parties.

The Riverside Astronomical Society and Griffith Observatory also will provide several telescopes to the public, including a relatively powerful 11-inch refractor.

Because of Mars' rotation, observers with telescopes will see a different view of the planet's surface each night in August.

A telescope isn't necessary to see Mars, however. Even from light-polluted Los Angeles, the planet will be clearly visible as a brilliant orange gem any night after about 10 p.m. throughout August and into autumn.

To get the best view of Mars, Griffith Observatory telescope, demonstrator Mary Brown suggested that viewers position themselves away from bright street and building lights, and stand outside for at least 15 minutes to let their eyes adjust to the dark.

There is a chance that seasonal Martian dust storms could obscure views of the planet's surface this month.

The storms are caused by extra solar heating when the planet gets close to the sun. As the planet warms, fine surface dust particles are stirred into the thin Martian atmosphere, making the planet appear hazy.

"It has happened before and if there is a big dust storm ... it can seriously affect your ability to see details on the Red Planet," said amateur astronomer Tim Thompson.

More information on Mars activities is available on the Internet at www.griffithobs.org/mars2003.html and www.planetary.org/marswatch2003.

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