Red planet will slide by full Moon in night sky

What goes round and round at 67,000 miles per hour? It’s not a high school track meet. It’s not NASCAR. It’s Earth, orbiting the Sun.

And Earth is about to pass the slower-moving Mars, as it does every 26 months.

Typically, the distance between the two planets reduces Mars to an inconspicuous point of light in our night sky. But as we “lap” Mars, the distance between Earth and the Red Planet reaches its minimum, and Mars brightens conspicuously.

This last happened early in the summer of 2001. This time the two planets will be closest to each other on Aug. 27, but with a mathematically historical difference.

Because the orbits of the planets are not circular, our approach to Mars sometimes occurs near a point in Earth’s orbit when it is closest to the Sun and Mars is at its farthest. This time, the reverse will occur. Earth was at its farthest from the Sun on July 4, and Mars will be at its closest to the Sun on Aug. 30. Taken together, these facts add up to a closer-than-normal approach.

While the appearance of Mars won’t be dramatically different than on other close approaches, astronomers calculate that this is the closest approach in thousands of years, and there won’t be a closer one until 2287.

Unfortunately for Pennsylvanians, Mars appears against the background of the constellation Aquarius during this event, which places it rather low in our sky and offsets our ability to see it well through small telescopes.

Future close approaches mere decades from now will place Mars high overhead in the sky, making it a more favorable telescopic target. When we view objects right overhead, we look through a thinner layer of Earth’s distorting atmosphere.

Having made that disclaimer, there is no excuse not to check out this event from your own back yard. Mars, a stunning red-tinted object, is currently brighter than any other star or planet in the night sky. Venus is brighter but too near the direction of the Sun this month to be observed.

This week, Mars can be seen rising in the southeastern sky at approximately 9:45 p.m. Adding further drama to the view tonight and Wednesday night will be the full Moon. Tonight, Mars will appear below and to the left of the Moon. Wednesday night, Mars will be seen just to the right of the Moon.

As Earth rotates, Mars and the rest of the starry field to the south migrate from east to west. During the 2 a.m. hour, Mars and the Moon will reach their highest points in the sky, due south. By the onset of morning twilight, they’ll be in the southwest.

Later this week, as the Moon continues to wane, it will disappear from our evening sky, and Mars will seem even more brilliant against the dark moonless background.

By the end of August, Mars will be at its brightest, rising just as evening twilight subsides. It will continue to dominate the southern evening sky throughout September and into the autumn season.

Summer children’s show

The North Museum Planetarium is a cool place to visit this summer. Not only does the planetarium have a new air conditioning system, it also features summer programming for kids.

“Rusty Rocket,” which includes a tour of the solar system, will be featured at 2 p.m. from today through Friday for children in grades 2 on up. “Wish Upon a Star” tells the story of a family taking a trip to the dark skies beyond city lights and the many wondrous things they see with a small telescope. “Wish” is for children in grades 3 and higher and will be presented at 2 p.m. Aug. 19 through 22.

Call the North Museum, 291-3941, for more information and pricing.

John C. Eliason Jr. teaches astronomy at Manheim Township High School and is director of the Planetarium at the North Museum of Natural History and Science in Lancaster.