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THE BALTIMORE SUN

In ancient times, the brightening glare of ruddy Mars - the Roman god of war - might have been seen as a harbinger of bloody conflict.

This month, it's a signal for Marylanders and other earthlings to step outdoors for the best view of the Red Planet in their lifetimes. In fact, it's the best view in all of recorded history.

For weeks now, Mars has been growing steadily nearer and brighter in the late-night sky. It is now a red-orange beacon gleaming low in the southeast beginning after 9 p.m. or 10 p.m. It's the brightest object in the night sky except for the moon - unmistakable, even amid bright urban lighting.

"I've had a lot of questions from people asking, 'What's that bright red star out there?' People don't realize it's Mars," said Jerry Feldman, 39, of Parkville, an amateur astronomer who often shares his telescope with the public at the community's high school and library.

The summer's Martian climax comes on Aug. 27, when the Earth will pass less than 34.7 million miles from the planet. As nearly as computers can figure it, that's the closest the two planets have been since one evening 59,619 years ago, when Neanderthal man was competing with cave bears for living quarters.

Backyard stargazers have been watching for months as Mars has drawn closer, zooming in from a distance of nearly 250 million miles a year ago.

Even in a small (3.6-inch) reflector telescope, it has grown from a reddish dot to a pea-sized, pumpkin-colored disk, with dark surface features and a small, bright spot of south polar ice - frozen carbon dioxide.

Professionals, too, are seizing the opportunity to swing the orbiting Hubble Space Telescope and ground-based observatories toward Mars. Hubble images to be snapped next week are expected to be the sharpest ever taken from the vicinity of Earth.

James F. Bell, a planetary scientist at Cornell University working with others, is using the orbiting Hubble telescope to measure the chemical composition of Mars' atmosphere and its surface minerals in both ultraviolet and infrared wavelengths.

Thanks to Hubble's power and Mars' unusual proximity, he said, they're getting better resolution - finer detail - than the robotic spacecraft sent to Mars in the 1960s and 1970s. "It's really like having a space mission in a sense," Bell said.

Bell said a dust storm that sprang up on Mars several months ago has settled down, giving astronomers a clear view.

If bad weather spoils your view, don't fret. The spectacle won't change appreciably for several weeks. But if you miss it altogether, you'll have to wait 284 years before the view gets this good again - on Aug. 28, 2287.

Earth is the third planet from the sun. Mars is the fourth. "Close" approaches like this one occur when the Earth, circling the sun on an "inside" track, passes directly between the sun and slower-moving Mars.

Astronomers call it "opposition," and it happens with Mars every 2.2 years. But Mars' orbit is more elliptical, and lopsided, than Earth's, so its distance from Earth at opposition varies from less than 35 million miles this year, to as much as 63 million miles in other years.

"Every opposition would be good enough for us to see detail on the planet," Feldman said. "At other times of the year Mars is quite small and looks more like Uranus or Neptune - a colored circle. You do not see much detail on it at all."

This opposition is unusually close because Mars also happens to be within days (Aug. 30) of "perihelion" - the point in its orbit closest to the sun, and therefore also closer to the Earth's orbit. This sort of "perihelic opposition" with Mars occurs about every 17 years, and amateur astronomers around the world are taking advantage of it. They're snapping pictures of Mars through their telescopes and posting them to Internet archives. The images become valuable sources of scientific data.

"If there's dust storm activity, or clouds, those features can be traced over time by amateurs and professionals by putting all the images together in a database," Bell said. The view of Mars through amateur telescopes might not wow every one, Bell said. "But to people who have experience, who've looked in the past, it is a very impressive sight."

On the night of the 27th, Mars will appear to cover a breadth of sky 25.1 arcseconds wide, as astronomers measure it. For comparison, the full moon appears about 1,800 arcseconds across.

In 1988, the last time Mars' opposition and perihelion coincided, the planet appeared 23.8 arcseconds wide. Two years from now, at its next opposition, Mars will appear 20.2 arcseconds wide - almost 20 percent smaller than it will appear next week.

"The planet really has been growing in [apparent] size," said Feldman, who observes with a small, 4.5-inch Orion reflector. As the southern Martian summer approached, "the ice cap has definitely shrunk down."

"Then you can see different shades of the different land mass areas - a lot of lighter features, something to do with different rust and things in the soil," he said.

Even without a telescope, this celestial event is hard to miss. Mars is rising in the southeast every evening around 9 p.m. this week. By the 27th, it will rise at about the time the sun is setting in the west. After that, it will come up even earlier, a convenient evening object to observe.

But as summer turns to fall, Mars will begin to grow dimmer and smaller as Earth pulls ahead - like Seabiscuit on the rail, leaving War Admiral behind.

As close as Mars is now to amateur telescopes, the view can't compare to those being sent back daily by NASA's two Mars orbiters, now circling the planet.

Mars Global Surveyor, launched in 1996, and Mars Odyssey, launched in 2001, are orbiting just a few hundred miles above the surface. Many closeup images are available at www.msss.com/mars_images/moc/index.html

NASA has also taken advantage of Mars' close approach this year and launched two more spacecraft toward the planet, in June and July. The pair is racing to land rovers on Mars early next year.

Activities

Here are some Mars-related public events planned as opposition approaches.

Maryland Science Center, Light Street and Key Highway, Baltimore: Mars Opposition activities in the SpaceLink Update Center from 2 p.m. to 5 p.m. daily. Live telescope views, weather permitting, in the Crosby-Ramsey Observatory, Aug. 27-31, 8 p.m. until 11 p.m. Call: 410-685-5225

Anne Arundel Community College, Arnold: 6 p.m. Aug. 23 at the Pascal Center for Performing Arts. Astronomy Club will sponsor a Mars exhibit, speakers. An all-night "Mars Under the Stars" telescope viewing starts at 10 p.m., Astronomy Building. Information at 410-269-5315 or 410-798-6625 after 6 p.m.

Fells Point, Baltimore: 10 p.m., Aug. 29-31. Darryl Mason, sidewalk astronomer and president of the Baltimore Astronomical Society, will hold Mars viewings and raffle off children's telescopes "by the waterfront near the pretzel stand" in Mike C. Amiger Square. Call: 410-685-2370 or visit www.baltastro.org.

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