Close encounter, by celestial standards
(Dave Perlman, Chronicle Science Editor) Mars edges closer to Earth than at any time in the past 60,000 years. Sixty thousand years ago, the Neanderthal people and early modern humans must surely have watched a faint but familiar point of light in the southeastern sky grow brighter and brighter until its brilliant topaz-yellow light outshone everything in the nighttime heavens save the moon.
We will never know what those people may have thought or feared, because they left no record among their rare artifacts. But today we do know what they were seeing: It was the distant planet Mars, flying on its elliptical track around the sun and closing its gap on Earth’s orbit while it appeared to blaze in brightness as the two planets neared.
That same phenomenon is occurring once again as Mars draws closer to Earth day by day, and on Wednesday at precisely 2:51 a.m. PDT, the fabled Red Planet will pass 34,646,437 miles from Earth — closer than it has been in the past 60 millennia.
Few recent astronomical events have excited people on Earth more than this close encounter of the planetary kind. For weeks, stargazers have been fascinated by the growing brilliance of the ordinarily dim reddish planet. Watchers in the High Sierra report that it already seems brighter than the bright planets Jupiter and Venus.
Amateur astronomers have been observing and photographing the Martian approach. The Hubble Space Telescope will be beaming back fresh Martian images this week, and every astronomical observatory in the world has trained telescopes on the planet at least once each night and will continue observations for weeks.
Already amateur astronomers all around Northern California are holding “star parties” where they unlimber their own telescopes to watch the brilliant planet and invite the public to share the sight.
Mars rises in the southeastern sky while it is still twilight, so its brightness will not be apparent until well after dark — about 9 or 9:30 p.m., according to Andrew Fraknoi, chair of the Foothill College Astronomy Program, and it is best seen low in the south-southeastern sky well after 10 p.m. as it moves toward the west-southwest until dawn. The phenomenon will be visible well into September.
Although amateurs with relatively decent telescopes should be able to spot the Martian south polar ice cap and perhaps some of the roughest features of the planet’s red surface, people equipped only with good binoculars will see little more than an exceptionally bright orange-yellow spot where a much fainter Mars would ordinarily be, Fraknoi said.
In fact, something somewhat similar occurs about every two years because of the difference in relative speeds of Mars and Earth as each orbits the sun. Earth takes a year by our calendar to revolve around the sun, while the Martian orbit takes almost twice as long — 687 Earth-days — because it lies farther from the sun than Earth.
Orientation Skymap (click to enlarge)
