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20 Aug 2003 00:00
August is proving an unforgettable month for amateur astronomers as they turn their gaze on Mars, now at its closest to Earth since Neanderthals walked our planet.
On the 27th of this month, the Red Planet will be 55.76 million kilometres (34.65 million miles) from Earth, according to Belgian astronomer Jean Meeus, who says proximity of this kind last occurred nearly 60 000 years ago.
Like racing cars, the Earth—the third rock from the Sun—has the inside track over Mars, the fourth planet, as they orbit the Sun.
Earth takes a nippy 365 days to make a circuit, whereas Mars takes 687 Earth days because it is farther out.
This celestial ballet means Earth whizzes past Mars once every 26 months or so. However, the two planets take a slightly egg-shaped path around the Sun, and this factor mainly determines just how close the flyby will be.
In fact, the next time the two planets will be closer than in 2003 will be in the distant future—in 2287.
On August 27, Mars will shine red and orange, not of course as big as the Moon or anything near its size, but certainly as bright as Jupiter, the regal giant of our solar system, ever gets.
Skygazers have been thirsting for the moment.
“The Red Planet will present a large enough disk for backyard astronomers with good-sized telescopes to discern some of the planet’s features, such as the polar ice cap, dark surface features and perhaps even storm clouds,” the specialist website space.com says.
Mars has always cast a spell on Earth, either as a divine body, a fictionalised source of invasion or as Earth’s verdant twin.
Dreamers see it as mankind’s first colony in space, a stepping stone to a wider conquest of the Solar System and, who knows, the galaxy beyond.
“The Earth is the cradle of humanity, but we cannot live forever in a cradle,” the Russian physicist Konstantin Tsiolkovsky, an early visionary of interplanetary travel, wrote in 1911.
No fewer than four new probes—two US, one European and one Japanese—are hurtling towards Mars, with their main goal to resolve the great enigma: does life, or the potential for it, exist on Earth’s neighbour? The first of these rendezvous, by Europe’s Mars Express orbiter and the Beagle-2 lander it is carrying, is scheduled for December 25.
But even if these missions confirm that Mars holds water—the essential substance for making it a staging post for humanity—many, many years are likely to pass before a human sets a footprint in its dusty surface.
In 1952, the German scientist Wernher von Braun, father of the Nazis’ V-2 rocket but also a pioneer of the US space programme, sketched his own ideas for what it would take to get Man to Mars.
The big technical challenge then, as now, is that our chemical rockets, designed for orbital flight or at most a trip to the Moon, are just too slow, cramped and fuel-inefficient for a trip spanning tens of millions of kilometers (miles).
At such speeds, the first martian astronauts would have to spend around six months just to get there; a year or so there to carry out experiments, prepare for the return trip and wait for the planetary alignment to close once more; and another six months to get back.
Call it a round trip of two and a half years: an odyssey that would place extraordinary stresses on the crew’s mental and physical health, their supplies and equipment.
“The conventional propulsion techniques which we have mastered today mean that we have to take the path of economy,” says Richard Heidmann, a former executive with the French rocket engine maker Snecma and president of Planete Mars, the French branch of the Mars Society, which promotes interest in our ochre neighbour.
“In other words, we have to take trajectories which do not use up lots of fuel, but they are slow.”
Until a faster technology emerges—NASA, for instance, is dusting off old ideas for nuclear propulsion—Mars will remain a twinkling but forever distant lure.
Factfile on Mars:
distance from the Sun, about half as much again as the distance
between the Sun and Earth.
diameter is 12,756 kms (7,973 miles)
F), at the poles in winter. Maximum temperature: 27 C (80.6 F) in
summer on equator
percent nitrogen, 1.6 percent argon, 0.13 percent oxygen. Pressure
at surface is less than 1/100th Earth’s atmospheric pressure.
speculate water lurks close to surface. Northern hemisphere is
smooth and flat, southern hemisphere is deeply cratered, rugged
highlands. North pole has a large, permanent cap of what is
believed to be mainly water ice. South pole has a small cap, which
may be frozen carbon dioxide (CO2) and almost disappears during the
the highest known volcano in the Solar System; Tharsis Dome, a
mysterious bulge 10 kms (six miles) high and 4,000 kms (2,500
miles) across; Valles Marineris, a canyon 4,000 kms (2,500 miles)
long and up to seven kms (four miles) deep.
(3,738 miles) from surface; Deimos, diameter 12 kms (eight miles),
orbit 20,062 kms (12,538 miles) from surface.—Sapa-AFP
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