Mars Doubles In Brightness

September 23, 2005

Ready to be amazed? Step outside tonight around midnight and look east. About halfway up the sky you'll see the planet Mars. It looks like an intense red star (as photographed here on Sep 8 by Stan Richard in rural Jasper County, Iowa), the brightest light in the midnight sky other than the Moon.

Image: Mars and the Pleiades, photographed on Sept. 8th by Stan Richard in rural Jasper County, Iowa.

Here's the amazing part: Between now and the end of October, Mars, already so bright, will double in brightness again. Imagine that.

Mars is getting brighter for the simple reason that it's getting closer. Earth and Mars have been converging for months and on Oct. 30th at 0319 Universal Time, the two worlds will be just 69 million kilometers apart—the closest approach of Mars and Earth for the next 13 years.

The timing is practically perfect for Halloween. Millions of kids and their parents will be outdoors after dark trick-or-treating on Oct 31st. Mars will rise at sundown that night, bright enough to be seen even from urban-lit cities. Furthermore, purists insist, Mars isn't really red, it's pumpkin-colored. Could it get any better?

Oh, yes.

In 2003, the last time Earth and Mars converged, Mars was bright, but it was also low, never climbing more than about 34o above the horizon as seen from North America and Europe. In 2005, on the other hand, Mars is going be much higher in the sky: about 66o.

This is good news for people with backyard telescopes, because planets high in the sky look crisp and clear. Lower down, near the horizon where the air is thick, they become murky and indistinct. Mars in 2005 is nicely placed for detailed, high-magnification viewing.

Already backyard astronomers are seeing some extraordinary things—like the "purple haze." Winter is beginning at the Martian north pole, and icy-blue clouds are gathering there. The vast cloud bank is easily seen through 10-inch and larger telescopes, purple enough to remind some observers of Jimi Hendrix. The view will only improve as Oct. 30th approaches.

NASA is taking advantage of the close encounter to send a robot-ship to Mars. Named Mars Reconnaissance Orbiter, it left Earth in August carrying, among other things, the biggest camera ever sent to another planet.

The High Resolution Imaging Science Experiment, or "HiRISE", weighs 145 lbs (on Earth); its primary optical mirror is a half-meter wide; and it can take pictures with 1200 megapixels of digital resolution.

From Mars orbit, this monster camera can see things as small as a dishwasher. It's due to arrive in March 2006 to begin mapping Mars in exquisite detail for explorers of the future.

By the time the orbiter reaches Mars it will have traveled more than 400 million km. You only need to go as far as your backyard. Look up, and be amazed.

Source: Science@NASA (Author: Dr. Tony Phillips)