Mars Looms Big & Bright as It Nears Record-Breaking Close Approach
A Sky & Telescope Press Release
August 5, 2003Contact:
Marcy L. Dill, Marketing Director
617-864-7360 x143, mdill@SkyandTelescope.com
|Note to Editors/Producers: This release is accompanied by publication-quality graphics and a broadcast-quality animation; see details on page 2. For more movies and animations, or to arrange for an interview with one of Sky & Telescope's Mars experts, please contact Marcy Dill.|
Late in August the planet Mars the most Earthlike world known beyond our own will pass closer to Earth than it has done in nearly 60,000 years.
Already Mars is blazing big, bright, and fiery yellow-orange in the late-evening sky. You can't miss it. For all of August and September, Mars shines many times brighter than the brightest star in the summer sky. Anyone can see it, no matter how little you know about the stars or how badly light-polluted your sky may be.
In early to mid-August, look for Mars glaring like a bright orange star in the southeastern sky after about 10 or 11 p.m. (local daylight-saving time); in late August after about 9 or 10 p.m.; and in September or later, after twilight fades. Later in the night Mars climbs higher in the sky and shifts over to the south.
Mars will be at its closest to Earth on the night of August 26-27. It will pass 34,646,418 miles (55,758,006 kilometers) from our planet (measured center to center) at 5:51 a.m. Eastern Daylight Time on the 27th. However, Mars will look just about as brilliant for at least a week or two before and after that date.
There has been some confusion over exactly how much of a record this Mars passage is setting. Roger Sinnott, a senior editor of Sky & Telescope magazine, got to the bottom of the matter, finding 57,617 BC to be the correct date of the last Mars passage that came so close. That was 59,619 years ago (taking into account that there was no "year zero" between 1 BC and AD 1). For the full story, see the Sky & Telescope article "A Mars Record for the Ages" in the magazine's June issue, page 94, and also available online.
We won’t have to wait as long for the next passage of Mars that will be so close. Mark your calendar for August 28, 2287.
However, for all practical purposes in terms of how Mars will look, it came nearly as close in 1988. That year it reached an apparent diameter of 23.8 arcseconds as seen in a telescope; this year it will top out at 25.1 arcseconds wide (the angular size of a penny seen at a distance of 500 feet). And Mars will make another good pass by Earth in October 2005, appearing 20.2 arcseconds wide.
As the world awakens to this year’s Mars event, writes Daniel M. Troiani in the June Sky & Telescope, "a rush not seen since the 1986 visit of Halley’s Comet could overwhelm the telescope market. The event is almost a certainty to fire the public’s imagination as few other astronomical events can."
However, Mars is always a pretty tough target in a telescope. To begin with, it’s only about half the size of Earth. Even at its closest, under high magnification, it will appear as only a surprisingly small, bright ball with some subtle dark markings, possible white clouds around its edges, and perhaps the bright white South Polar Cap shrinking in the warmth of the Martian late spring. The brightest yellow areas visible on Mars are deserts covered by fine, windblown dust. The dark markings are terrain displaying more areas of bare rock or darker dust. Mars rotates every 24½ hours, so you can see it turning in just an hour or two of watching.
To see much detail on Mars, several things all have to be working in your favor. You’ll need at least a moderately large telescope with high-quality optics. (For the lowdown on how to select a telescope wisely, see "Choosing Your First Telescope".) And you’ll need to wait until Mars rises high in the sky, well above the thick, murky layers of atmosphere that hug the horizon. And the atmospheric "seeing" must be good. This is the astronomer’s term for the constant fuzzing and shimmering of highly magnified telescopic images due to the tiny heat waves that are always rippling through the atmosphere. The seeing changes from night to night and sometimes from minute to minute.
More about Mars and its unusual close approach is in the June, July, and August issues of Sky & Telescope and online in Observing > Celestial Objects > Planets.