Stargazers To See Red

2003 offers a unique terrestrial vantage point for observing some of our nearest skyward neighbors, particularly to those looking for brighter reddish spots in the night sky.

Mars makes its closest approach this year in the last 50 millenia
Credit: NASA/JPL Viking

Mars, the Red Planet, will be making its closest approach to Earth in at least 50,000 years this summer. Even without a big telescope, Mars will stand out for stargazers with a reddish light– as bright as giant Jupiter– and reveal elusive surface details to amateur and professional astronomers alike.

The new year also promises two total eclipses of the moon – the first visible in parts of the United States in more than three years – and an assortment of meteor showers and beautiful conjunctions of moon and planets.

But, barring an unexpected bright comet or meteor approach, Mars may get the most attention from stargazers.

During the summer months this year, the ‘spirograph-like’, elliptical Earth and Martian orbits will bring Mars to within 35 million miles of Earth. The next nearest approach won’t occur again until the 23rd century. Mars can vary in its proximity to Earth by nearly ten percent.

Even small telescope viewers will be able to follow and photograph seasonal changes in the polar caps, surface features and hints of Martian weather in the clouds that form around Olympus Mons, the largest volcano in the solar system. On Mars, super-sized volcanoes sculpted the landscape by releasing huge amounts of lava.

The much heralded Martian surface features, including the darker colorations and dry channel networks that led Percival Lowell to declare them as ‘canals’, will be big and bright all summer long this year.

The year’s first lunar eclipse will begin just after 10 p.m. EDT on May 15.

An early summer and late autumn lunar eclipse on tap
Credit: Noel Munford (Palmerston North Astronomical Society, New Zealand)

Total eclipses of the moon occur when the moon passes through the circular shadow that the Earth casts into space and is fully shaded from direct sunlight. Although masked by the Earth completely or partially from the Sun for as much as an hour and a half, scattering of sunlight off the limbs of our atmosphere doesn’t leave the moon without illumination. Instead the blood-bright color of long-wavelength red light enshrouds the moon’s otherwise familiar grey pallor.

If skies are clear, observers will watch the sunlit moon slowly engulfed and dimmed by the shadow’s darkness. Totality will last 53 minutes, from 11:14 p.m. until 12:06 a.m. EDT, with the moon’s face turned an eerie, coppery color. The hue is produced by sunlight filtered, reddened and scattered by the rim of the Earth’s atmosphere. Because of changes in terrestrial dust in the atmosphere, each lunar eclipse is unique in appearance.

The Moon is believed to play an important role in Earth’s habitability. Because the Moon helps stabilize the tilt of the Earth’s rotation, it prevents the Earth from wobbling between climatic extremes. Without the Moon, seasonal shifts would likely outpace even the most adaptable forms of life.

The second eclipse will occur on Saturday evening, Nov. 8.

What Next?

NASA does have funding in its budget to investigate some questions relevant to possible future human exploration of Mars. The 2001 Mars Odyssey, for example, an orbiter launched on April 7, 2001, contains an experiment to measure the amount of damaging radiation that humans travelling to Mars would need to protect themselves against.

Two Mars Exploration Rovers (MERs) will be launched by NASA in 2003. Experiments performed by the MERs will help to determine whether resources are available on Mars that will be needed to support humans living there. The two Mars Exploration Rovers are targeting what imagery indicates might have been ancient dry lake beds and other geologically interesting sites in early 2004.

One enhanced feature of the MER mission plan is more mobility for its rovers. Compared to the stunningly successful Pathfinder mission in 1997, these bigger Mars Exploration Rovers (MER) can trek up to a football field–330 feet (100 meters)– per Martian day. Making remote manuevers over those distances means getting very good topological maps, while knowing where every interesting rock or hazard might tip and block the rovers’ paths. Seen globally, the darker areas on Mars are generally more rocky while the bright areas are dusty, but a much enhanced topography goes into site selection beforehand, and then much later after landing to roam the surface. Potentially hundreds or thousands of pebbles and boulders can pock mark a landing site on the scale of a 100 yards per day. In total, the football field milestone is almost as far in one Martian day as the 1997 Sojourner rover did over its entire, many-month-long lifetime. Starting in January 2004, MER surface operations will last for at least 90 Martian days, or longer if hardware health is maintainable.

Once an interesting target is identified on the ground, the Mars Rovers’ will employ what is their primary science payload, a collection of 5 instruments (and a rock abrasion tool) called the Athena package. Mission planners look forward to even more close-up views of the two primary sites slated for the early 2004 rendezvous.

The European Space Agency will also launch a mission in 2003, a combined orbiter/lander. Current plans are for its lander, Beagle 2, to contain biological experiments designed to search directly for evidence of life on Mars.

Future missions to Mars will perform additional experiments to understand better the possibilities and challenges of supporting a human mission. And astronauts living aboard the International Space Station will improve NASA’s understanding of the effects of long-term exposure to microgravity. But NASA’s Mars-exploration roadmap for the next 20 years contains no plan to actually send human explorers there.

Related Web Pages

Mars THEMIS Site
MER 2003 Prime Landing Sites
Bring Mars to Life – Chris McKay (Mars Society)
Mars Exploration: Planetary Protection (Mars Now Team and the California Space Institute)

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