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The Honolulu Advertiser
Posted on: Sunday, November 25, 2007

December a busy month for Mars

By Carolyn Kaichi
Bishop Museum

Jupiter loses command of the night sky next month, exiting into the glow of the sunset to eventually emerge ahead of the sun in the morning sky. However, another planet moves into center stage, perhaps not as large and bright as Jupiter, but definitely holding its own set of mysteries.

Mars reaches opposition next month, rising as the sun sets on Christmas Eve. Six days earlier, the Red Planet reaches its closest point to Earth's orbit, roughly 54.8 million miles away.

These two Martian events, closest approach and opposition, happen roughly every two years as Earth catches up to slower Mars in its longer orbit around the sun. During opposition, Earth is between the sun and the fourth planet, resulting in Mars and the sun being opposite in the sky (opposition). Because Mars' orbit is not perfectly circular in fact it's relatively oval some oppositions are better than others. You may recall the Mars Madness that occurred in August 2003, where that opposition brought Earth and Mars closest in recorded history, or 60,000 years.

Since then, an e-mail circulates around the Internet every summer touting the same August 2003 event, and confuses the issue even more by indicating the Red Planet would appear as large as the full moon.

Even if you were only half paying attention to all the excitement surrounding the 2003 opposition, you would have noticed if Mars looked like the full moon in our skies. So why does that e-mail still recur? If more folks would check the facts before hitting the "forward" button on their e-mails, we would have a lot less misunderstandings.

So here are some facts: looking like a bright, orange, star-like object, Mars will appear bigger and brighter than anything natural in the night sky besides the moon during the last half of December. (Remember Venus is in the morning sky and Jupiter is behind the sun by then.)

On Dec. 18, it will be at its closest point to Earth, 54.8 million miles away, roughly 60 percent farther than it was in 2003. Still, this will be the best opposition from now until 2016, and the next time Mars will be comparably close as it was in 2003 will be in 2050.

So for now, look for the rusty orange glow of the planet in the constellation Gemini, although observing with a telescope is better. Mars has many features that are easier to see during this window of opportunity and your local amateur astronomy group will be happy to help. See www.hawastsoc.org for star party locations and times on O'ahu.

THE GEMINIDS

The Geminid Meteor Shower peaks on the morning of Dec. 14 at 7 a.m. Unfortunately, dawn is not the ideal time to see a lot of meteors, but if you are up before the sun that morning, you might spot some before it gets light. Gemini rises early in the evening and will be high in the western sky in the pre-dawn hours on that Friday, and the moon is not in the sky at the time.

The Geminids are a product of an object called 3200 Phaethon, which is either a burnt-out comet or asteroid, that circles the sun every 1.5 years. Scientists aren't sure how to classify 3200 Phaethon because it doesn't match the typical characteristics of either a comet or an asteroid, but it is the debris from this object that is suspected to produce the meteors we see every December.

3200 Phaethon is due to make a close pass of the Earth on Dec. 10, around 13 million miles. That's about half the average distance of our planet from our nearest planetary neighbor Venus. In astronomical terms, that's considered a Near Earth Object, or NEO. There are thousands of NEOs that have been identified and just as many that haven't yet been discovered. At least 894 of known NEOs have been categorized as PHAs, or Potentially Hazardous Asteroids, and the name means just what it sound like asteroids that may pose a threat to Earth.

Who's watching out for these and what can we do about one that may cross our path? Look for more information on this topic in a future article.

NEW SPACE STATION LAB

The Atlantis prepares to launch in early December to deliver the European Space Agency's Columbus Laboratory-the newest component to the International Space Station. If the schedule holds, in early 2008 the Endeavour will then shuttle the Japanese lab module, called Kibo, to the space station in February.

THE PLANETS

Earth:

The Winter Solstice falls on Dec. 21 at 8:08 p.m. HST.

Mercury:

Mercury is not making it easy to spot next month as it spends most of the month hiding behind the sun. Look for the little planet in the western sky in January.

Venus:

Venus is an early riser in the hours before dawn, rising by 4 a.m. in early December and a half-hour later by the end of the month. On Dec. 5 a slim crescent Moon hangs just south of the brightest planet.

Mars:

The constellation Gemini is a focal point next month with Mars, the Geminid Meteor Shower and the full moon all vying for attention in the same space. Until the Moon enters the vicinity on the 23rd and 24th, Mars will be the brightest light in Gemini. But the radiant, or the "center" of the meteor shower is next to Gemini brother Castor, and at least on the weekend of Dec. 14, may detract from Mars' spotlight.

Jupiter:

You may be able to spot Jupiter during the first week of the month after the sun has set, but only if you have a clear view to the west. Jupiter is heading toward conjunction and will be behind the sun's glow on Dec. 22. Look for Jupiter to rise ahead of the sun in the morning sky after the first week of January.

Saturn:

Saturn is up by 12:30 a.m. at the start of the month and a week later enters the evening sky by rising in the east before midnight. On Dec. 1, it appears very close to the third-quarter moon and then again on the 28th as the moon again approaches another third quarter phase in the same month.

Reach Carolyn Kaichi at hokupaa@bishopmuseum.org or 847-8203.

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