On August 27, Earth and Mars had an encounter unlike any since prehistoric times. The Red Planet came closer to Earth than it has in 60,000 years. Our planetary neighbor will not be this near again until August 28, 2287!
Over the next few weeks, Mars and Earth will remain in the same neighborhood. With Venus currently hidden by the Sun's glare, only the Moon will outshine Mars. Museums, astronomy clubs and stargazers have been hosting "star parties" to celebrate. Earthlings around the globe are gathering beneath the night sky to get this once-in-a-lifetime look. And Mars is putting on quite a show.
A RED-HOT VIEW
Mars is usually about 50 million miles away from Earth. Over the past few weeks, it moved to within 34 million miles. That may sound like worlds away, but in our vast solar system, it's pretty darn close!
At this distance, the Red Planet looks bright, steady and remarkably red. Even basic telescopes offer an especially clear view of the surface details of Mars, including dust clouds, volcanoes and broad bright plains.
The staff of Horizon Elementary School, in Madison, Alabama, hosted a star party on August 26. About 300 kids and their parents attended. NASA scientists brought a few high-powered telescopes, including one that displayed its view of Mars on a large-screen TV. The image was so clear that kids could see a polar ice cap. "It was a really amazing sight," says Mary Young, a sixth grader at the school.
THE RED PLANET'S SHINING MOMENT
On their way around the sun, Mars and Earth come a bit closer to each other every 26 months or so. That's when the Earth, which has a smaller orbit and is faster moving, laps the slower, more distant Mars. But nothing since the Stone Age can compare to this most recent flyby.
The conditions on August 27 were just right for the history-making encounter. Both Earth and Mars were on the same side of the sun, in a straight line, with Earth in the middle. Mars was not only close to our planet but also at its closest point to the sun. This made for an unusually big and brilliant view.
When Earth catches up to Mars at the same time that Mars is relatively near the Sun, there can be an especially close encounter. The last time this happened, in 1988, the two planets were 10,000 miles short of this year's record.
Both amateur astronomers and serious scientists are enthusiastic about Mars's latest exposure. They are benefiting from the extra-close look and from information gathered by Global Surveyor, a NASA satellite in the planet's orbit. Surveyor is taking photographs, studying the planet's atmosphere and mapping its surface.
Mitzi Adams, a NASA astronomer, is thrilled by the possibility that the close-up of Mars is inspiring a new generation of stargazers. "It's really exciting that we're getting information out to kids that will help them identify planets," Adams says. "I remember when I was younger, looking for Mars and wondering, 'Is that really it?' But there's no mistaking this planet."
As Earth rapidly orbits away from Mars, the Red Planet will appear dimmer. People will stop throwing star parties. But Mars Madness will not fade. Two Mars Exploration Rovers are currently on their way to Mars. The crafts are scheduled to touch down early next year. They will search for signs of microscopic life and evidence of water below the Martian surface. NASA expects the rovers to pave the way for future explorations of Mars, including the possibility of human visits.
Who knows? The next time Mars comes this close, humans may be able to see Earth from the Red Planet. "Earth would be faint," Adams says, "but it would still be impressive--and very blue."
Did You Know?
MARS's day lasts 24 hours and 37 minutes. A year--the time it takes to orbit the sun--lasts 687 days.
MARS has less than half the gravity of Earth. If you weigh 70 pounds on Earth, you would weigh only 27 pounds on Mars.
MARS's diameter is about 4,220 miles. That is about half the size of Earth's diameter.
MARS has the largest known volcano in the solar system. The volcano, Olympus Mons, is about three times as tall as Mount Everest.
MARS was named after the Roman god of war because of its blood-red color. Iron-rich dust and rock give Mars a red surface and a pink sky.
The Path of the Planets
The distance between Earth and Mars changes daily as the two planets travel around the Sun. It takes Mars almost two Earth years to complete its orbit. For the next few weeks, Mars and Earth will move apart. But Mars will still be brighter and more visible than usual. For the best view, look southeast at about 9 p.m. your local time.