Space.com Editor's Note: Each Monday, SPACE.com will explore a mysterious or little known corner of the
cosmos to enlighten earthlings about how the universe really works. This is the debut
installment of Mystery Monday.
On Aug. 27, Mars will be closer to Earth than in nearly 60,000 years. This "close approach," as
it's being billed, has some folks worried about potential dangers here on our planet.
One SPACE.com reader asks: "Will it be dangerous when Mars gets that close to Earth? It has me a little worried." Others have e-mailed to say they heard there would be earthquakes or other disasters. One of the many rumors going around says the two planets will collide.
The true gravity of the situation is benign. There is absolutely nothing to worry about.
At its closest, Mars will still be nearly 34.65 million miles (55.76 million kilometers) away.
The effectiveness of gravity is a function of mass and distance, so while the pull of an object
is said to act across the cosmos, it does so with ever-diminishing effect. At great distances
-- such as between Earth and the other planets -- the gravity of an object becomes little more
than background noise, like the hum of a Cadillac from 20 blocks away amid the cacophony of a
construction site in Midtown Manhattan.
Other readers say they heard Mars will look as big as the Moon. It will not. On Aug. 27, Mars
will look pretty much like it looks now, shining as a very bright star-like point of light.
With a telescope, of course, you can make it as big as your wallet allows.
Why the rumors?
Planetary doom prognostications pop up again and again because a handful of astrologers and
self-anointed visionaries persist in disseminating garbage about how the positions of the
planets can affect Earth by generating earthquakes, storms or other catastrophes. The Internet
has made publishing of these false claims easy and more frequent.
"Only those who are foolish enough to think the motions of the planets have a bearing on their
lives believe in this pseudo-science," says Joe Rao, SPACE.com's Night Sky
columnist. He has been getting e-mail about this, too.
"There will be those who will try and convince the masses that this close approach will mean
terrible cataclysms and catastrophes that will befall our planet," Rao said. "This close
approach between Mars and Earth will have no effect on any other celestial bodies in space,
including the Earth itself."
Forecasts of calamity typically precede alignments of several planets, as when three or more of
the worlds inside Neptune gather approximately along a line in space so that, from Earth, we
can see them bunched up in the night sky.
Groupings like this occurred in 2000 and again in 2002. Earth did not crumble.
Nothing unusual happened during other planet alignments through recorded history, either, and
nothing unusual will happen on Aug. 27, except, of course, a whole lot of people around the
world will step outside to look up at a cosmically historic event.
On that date, Mars will be slightly closer than ever in human history. The proximity owes to a
regular occurrence of the two planets being on the same side of the Sun and the rare chance
that Earth is about as far from the Sun as it ever gets just as Mars is about as close as it
ever gets. (The two planets' orbits are not quite circular). In astronomers' parlance, Mars
will be at opposition.
Mars has been almost this close during previous oppositions. In fact, the extra closeness this
time is less than 1 percent compared to a similar setup in 1971.
Mars will shine brightly. It will look great in a telescope. It will not kill you.
The gravity of Mars or any planet, given its relative small size and great distance from our
own, is simply inconsequential. The Sun and Moon do all the significant tugging around here.
And these are real effects, stabilizing Earth's rotation, creating tides in the ocean, and even
causing the rock-hard crust of the planet to rise and fall daily.
The Moon, though fairly small, is responsible for about two-thirds of tides because it is just
238,900 miles (384,402 kilometers) from Earth, on average. The much larger Sun -- even though
it's about 93 million miles (150 million kilometers) away -- contributes the rest. For the
record, the Sun makes up more than 99.8 percent of the entire mass of the solar system.
The combined gravity of all the planets, even if lined up and all as close as possible to Earth
at one moment, just doesn't matter to Earth at all compared to the Sun and Moon, according to
Still the rumors are rampant. One reader asked Joe Rao if Mars will hit Earth.
"The odds that Mars will crash into the Earth on Aug. 27 are about as good as the Detroit
Tigers winning the 2003 World Series in 4 games."
As of this writing, the Tigers were in the cellar of the Americal League Central Division with,
by far, the worst record in baseball. And Rao is joking, of course. The Tigers have a much
better chance of soaring to mythical heights than Mars has of fulfilling any of the silly
mystic forecasts you might hear.
The Greatest Space Myths, Mysteries and Hoaxes
More on this & other Mars information
Back to Skywatch index
UFO Wisconsin Home