Earth moving in on Mars in orbital race

May 17, 2001
Web posted at: 7:15 a.m. EDT (1115 GMT)

larger A composite image of Mars created with images snapped by the Mars Global Surveyor. The picture is a composite of color strips taken on nine successive orbits from pole-to-pole over the planet in March 1999. The color in this picture is computer-enhanced and is not as it would appear to the human eye

(CNN) -- It may be several years before NASA or other space agencies send any humans to Mars, but everyone on Earth is getting a bit closer to the red planet.

In fact, by the time you finish reading this sentence, you'll be 31 miles (50 km) closer to Mars.

"We're heading for a close encounter with Mars," said Dr. Tony Phillips, an astronomer at NASA Marshall Space Flight Center.

Currently, Earth is moving toward the red planet at about 22,000 mph and soon will be closer to Mars than in the past 12 years.

Earth won't ever catch Mars, of course, but while its orbit swings closer, it will be a great time for sky watchers to view martian features not usually visible from Earth.

"The next few months will be a great time to look at Mars," says astronomy professor George Lebo, a NASA Summer Faculty Fellow at the Marshall Space Flight Center. "You won't need a telescope to see it. By early June Mars will outshine everything except Venus, the Moon, and the Sun itself."

Earth gets closest to Mars on June 21, just 42 million (68 million km) miles away. After that, the two planets start moving apart.

Mars is easy to spot because of its very striking reddish color, according to Phillips. The planet is bright in the sky, but doesn't twinkle like a star.

Mars already is a brilliant morning star for early risers in the northern hemisphere. It can be spotted about 30 degrees above the southern horizon.

"The southern hemisphere is a much better place to see Mars," said Phillips. Mars can be seen arcing high overhead before dawn.

As the space narrows between Earth and Mars, sky watchers using even small, 4 to 6 inch telescopes may be able to make out some features on Mars, including clouds, surface markings and polar caps.

The Mars viewing gets even better in coming years.

In 2003, Earth will swing closer to Mars than it has since 1924, according to Phillips. In 2018 and 2020, the planets will be so close, that Phillips says it would an ideal time to launch the first humans to the red planet.

He notes that NASA has no official plans to go to Mars.

But NASA's newest Mars probe, 2001 Mars Odyssey, will soon provide a different view of the red planet. Odyssey blasted off April 7 and will enter Mars orbit on October 24. During the probe's two and a half year mission, it will monitor space radiation, seek out underground water, and identify interesting minerals on the martian terrain.

Another NASA probe already is circling Mars. Launched on November 7, 1996, Mars Global Surveyor started its mapping mission on April 1, 1999 and has sent back hundreds of pictures.