Press Release

Mars Looms Big & Bright as it Nears Record-breaking Close Approach

By SpaceRef Editor
August 5, 2003
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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 “A Mars Record for
the Ages” in the magazine’s June issue, page 94, and online at
http://SkyandTelescope.com/observing/objects/planets/article_970_1.asp.

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.

Telescope Tips

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 24
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” at
http://SkyandTelescope.com/howto/scopes/article_241_1.asp.) 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 at
http://SkyandTelescope.com/observing/objects/planets/.

Graphics and an Animation

SKY & TELESCOPE is making two illustrations, one photograph, and one
animation available to editors and producers. See the online version of
this press release on our Web site at
http://skyandtelescope.com/aboutsky/pressreleases/article_1018_1.asp.

Permission is granted for one-time, nonexclusive use of these materials in
print and broadcast media, as long as appropriate credits (as noted in each
caption) are included. Web publication must include a link to
SkyandTelescope.com. Also available are broadcast-quality movies and
animations showing Mars as seen in a backyard telescope and rotating on its
axis to display its various surface features; television producers should
contact Marcy Dill at 617-864-7360 x143 or mdill@SkyandTelescope.com.

Caption for orbit diagram: The orbits of the Earth (blue) and Mars (red)
around the Sun. Mars moves in a noncircular orbit, and it will be closest
to the Sun precisely when Earth moves past it on August 27th. On that date
at 5:51 a.m. Eastern Daylight Time, the two planets will be only 34.6
million miles apart — their closest pairing in nearly 60,000 years. The
sizes of the Sun and planets are not to scale. Also available is a
QuickTime animation showing the Earth overtaking Mars in orbit; it also
shows how Mars’s visible disk grows and shrinks as the planets move around
the Sun throughout 2003. SKY & TELESCOPE illustration by Steven Simpson.

Caption for evening sky scene: Because it is close to Earth in space, Mars
looks like a dramatically bright “star” in the sky. Mars shines low in the
southeast at about 10 p.m. at the beginning of August — but earlier (soon
after dusk) in September. It gets higher in the sky and shifts toward the
south during the night. Most people notice the planet’s yellow-orange hue,
which is due to the color of its surface. SKY & TELESCOPE illustration by
Steven Simpson.

Caption for photo of Mars: Seen through a backyard telescope, Mars displays
a mottled bright and dark appearance. Its surface is covered with rocks and
deposits of fine, windblown sand. Also seen is its white south polar cap,
consisting of frozen water and carbon dioxide (“dry ice”). This image, fro
the morning of August 2, 2003, is a composite of about 500 frames of video
shot with a Celestron 14-inch telescope and a PlanetCam from Adirondack
Video Astronomy. Photo by Johnny Horne; courtesy SKY & TELESCOPE.

SpaceRef staff editor.