Close look at Mars? It's still not too late

THE BALTIMORE SUN

Neanderthal man went extinct waiting for Mars to be this close again. Modern man waited 59,619 years and got ... rained out?

Showers, thunderstorms and clouds canceled evening Mars parties across the Baltimore area last night, dousing plans for crowds of people to see the planet looming closer than it has been since woolly mammoths roamed the country.

But experts say it's not too late. "The good news is that Mars will be almost as close to the Earth, and therefore almost as bright, for many weeks," said Kelly Beatty, executive editor of Sky & Telescope magazine. "Just go out whenever it's clear."

Partly cloudy skies and good viewing conditions were forecast for tonight. But the threat of rain returns tomorrow and continues into next week.

Earth actually made its closest approach to Mars yesterday before most Marylanders were awake. At 5:51 a.m., the centers of the two planets were "only" 34,646,418 miles apart.

It was the closest such pass in all of recorded history - since the year 57,617 B.C. And there won't be a closer one until Aug. 28, 2287.

Such a rarity is guaranteed to capture the public's attention. But in truth, Beatty said, Mars was only about 300,000 miles closer to Earth (and appeared less than 1 percent wider) this week than during a similar event in 1971.

Now, Earth is racing ahead on its orbit. Mars is falling behind, and it will appear smaller and dimmer each night.

But Mars will recede only about 6 million miles by Sept. 28 - still very close for a planet that can be 250 million miles away when it's on the opposite side of the solar system. And in some ways, Mars is getting even easier to see.

"As August turns to September," Beatty said, "Mars will be up a little higher each night once it gets dark. It will be easier to spot and easier to take in," especially for children with early bedtimes.

You can't miss it.

"It is unambiguously, breathtakingly, dazzlingly the brightest star in the sky, although it's not a star," Beatty said.

Look after sunset for an extraordinarily bright object in the southeastern sky. It is visible all night, even under urban lighting. Its steady, yellow-orange color is the result of iron oxides - rust - in its soil.

Opposition, perihelion

The reasons for Mars' spectacular apparition this summer are twofold:

The planet is at both "opposition" - the point in its orbit where it is nearest to Earth - and "perihelion," its nearest approach to the sun.

The two events coincide in a "perihelic opposition" every 15 to 17 years, bringing Mars unusually close to Earth and attracting plenty of media attention. This is just the best in 59 millennia.

Mars has been visible to the naked eye for months. Hundreds of people enjoyed telescopic views last weekend from the University of Maryland's observatory in College Park. And still more have stopped to peep through amateurs' telescopes wherever they find them.

"I had lines of 20 to 25 people, solid, for two or three hours," said Herman Heyn, Baltimore's original "street-corner astronomer." He set up his telescope at Harborplace when the skies cleared over the weekend.

People asked whether they could really see Mars through his telescope, he said. He turned them around and pointed to the brilliant planet hanging over the city's southeastern skyline.

"They're really surprised and startled they can see it with their own eyes," he said.

Through his telescope, they could spot Mars' south polar cap, a bright button of frozen carbon dioxide -"dry ice" - that has been shrinking for months as the Martian summer approached.

"Most of us have never seen our polar caps here on Earth, and here we are looking at ice and snow on the south pole of Mars. People like that," Heyn said.

Lots of late lookers

After rain clouds cleared in Baltimore at 11 p.m. Tuesday, more than 100 people paused to look through Darryl Mason's street-corner telescope at Liberty Heights Avenue and Garrison Boulevard.

"Even the police stopped by," Mason said. "They said, 'We didn't think it [Mars] looked like this.'"

Mason stayed out until 2 a.m. and plans more Mars-gazing at Fells Point tomorrow evening, if skies are clear.

Clear nights for astronomy have been especially scarce in this summer of rain, haze and Maryland humidity.

"It's been really awful," said George Varros, an amateur astronomer and astrophotographer in Mount Airy. For weeks, "there was so much moisture that you'd have a halo around Mars, or dew problems within minutes of putting your equipment up."

Mathematically at least, the best view of Mars yesterday was in the South Pacific. At the moment when Mars and Earth were closest, Mars stood almost directly over French Polynesia. That means Tahitians were closer to Mars than anyone in nearly 60,000 years.

The best pictures from Earth's vicinity were shot by the Hubble Space Telescope, which was also pointed toward Mars yesterday.

View from the ground

But the view from the ground has impressed even scientists accustomed to observing from the very best seats in the house.

Maria T. Zuber, a geophysicist at the Massachusetts Institute of Technology, leads a scientific team working with NASA's Mars Global Surveyor spacecraft, now orbiting a few hundred miles above the red planet.

They've used the satellite's laser altimeter to measure the depth of the Martian icecap. But this week they're seeing the ice through amateur telescopes they've lugged to a scientific meeting in Montana.

"We go up on the mountain and look at Mars the way other Earthlings look at Mars," Zuber said. And "it's been remarkable. ... The southern frost cap is still visible at very low magnification."

With spacecraft orbiting Mars, and surface rovers due to land there early next year, this week's apparition might not seem very significant. But Beatty insists it is.

"The significance is just that it gets people out to look at the night sky," he said. "What with light pollution, and the demands of everyday life, we've kind of lost touch with our celestial heritage."

There will be more to see this fall, if it doesn't rain. Look for a lunar eclipse Nov. 8 and good views of Venus and Saturn in December.

Look at Mars

Free public Mars viewings are planned for the following dates and locations, weather permitting:

Maryland Science Center's Crosby Ramsey Memorial Observatory, Baltimore: 8 p.m. to 11 p.m. today through Sunday. Call: 410 545-2999 after 5 p.m.

University of Maryland Observatory, College Park: 9 p.m. to 11 p.m. today through Saturday. Call: 301 405-6555 or visit www.astro.umd.edu.

Johns Hopkins University Maryland Space Grant Observatory, Homeland campus: Tomorrow. Call 410-516-6525 after 7 p.m. tomorrow.

University of Maryland, Baltimore County Observatory, Catonsville: nightfall on the first Thursday of each month. Visit http://jca.umbc.edu.

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