Cambridge, MA — Comet Hale-Bopp dazzled us for weeks. The Perseid
meteor shower thrilled us for one night. But the world hasn’t seen
anything like the planetary traffic jam that’s going to occur the
last week of April and the first two weeks in May!

Inching across the sky like bumper-to-bumper commuters on their way
to work, a rare planetary alignment will allow sky observers to see
every planet in our solar system in a single evening! “There will be
other opportunities in the future to see the planets in different
configurations,” says Philip Sadler, Director of the Science
Education Department at the Harvard-Smithsonian Center for
Astrophysics (CfA) in Cambridge, MA, ” but it won’t be anything like
this for at least another 70 years. This is truly a
once-in-a-lifetime experience.”

Even more amazing, two very special events will occur during this
planetary line-up. On May 10, the planets Mars and Venus will appear
to pass so close to one another that, to the naked eye, the Roman God
of War and the Roman Goddess of Love will become one.

Earlier, on May 5, something even more spectacular will happen. The
bright planets Mars, Saturn and Venus will group together to form a
perfect equilateral triangle in the western sky. This dazzling
configuration will be visible almost everywhere on Earth. In the
Middle East, this pyramid-shaped specter will hang directly above

Oddly enough, more than 2,000 years ago, this same grouping of
planets may have caught the attention of the Biblical Magi. On April
1, 2 B.C., the planets Mars, Saturn and Venus came together to form a
perfect equilateral triangle over the city of Bethlehem. Now, in the
21st Century, amid the turmoil taking place in the Middle East, the
ancient Roman gods of Love, War and Agriculture/Wisdom, are coming
together to look down upon this war-ravaged landscape once again.

In the past, many different configurations of planetary alignments
have been seen from Earth. They occur due to the random positions of
the planets in their eccentric orbits around the Sun. In the early
1980s and in May of 2000, the planets stacked up directly behind the
Sun. Many people thought the combined gravitational pull might
create havoc here on Earth resulting in giant earthquakes, sweeping
tidal waves or erupting volcanoes. But, the collective gravitational
pull was so insignificant, nothing happened. What was the reason? The
other planets are simply too small or too far away in space to affect
us back on Earth. To see just how insignificant the gravitational
pull of the planets can be, let’s do what many good, red-blooded
Americans like to do. Let’s go shopping!

Imagine if we stood in the produce section of a grocery store and
held up a big yellow grapefruit representing the Sun. The planet
Mercury would be the size of a small grain of salt orbiting around it
18 feet away. Venus would be somewhat larger, like a grain of sugar
you get in those little brown packets at the coffee shops, 34 feet
away. Earth, also a grain of sugar, would be located 50 feet away.
Mars also would be the size of a grain of salt 75 feet away. As for
the rest of the planets: Jupiter, a cherry-sized tomato, would be
found at 240 feet; Saturn, the size of a green grape, at 420 feet;
Uranus, a frozen green pea, at 300 yards; Neptune, also the size of a
frozen pea, at 470 yards; and Pluto, represented by a speck of dust,
would orbit our grapefruit-sized Sun at a distance of 475-600 yards.
As you’ve probably guessed, not much gravitational pull is exerted on
the Earth by these grocery store lightweights!

In late April and early May, when the planets line up, they will not
be arranged behind one another or the Sun. Instead, they will present
a beautiful line across the sky from horizon to near zenith. For a
period of a little more than three weeks, anyone looking west at
sunset will be able to see the planets Mercury, Venus, Mars, Saturn
and Jupiter. A few hours later at 4 A.M., armed with a large-size
amateur telescope, they can continue their grand tour by observing
Uranus, Neptune, Pluto, a few wandering asteroids and maybe even
Comet Ikeya-Zhang in the east. Finally, by quickly glancing down at
the ground, they will have completed their grand tour of the solar
system. “Seeing nine worlds in just one night is something few
astronomers can say they’ve accomplished,” waxes Sadler. ” I can’t
wait to do it myself!”

Looking at the planets spread out across the sky during this
alignment also demonstrates, better than any book, how our solar
system formed 4 billion years ago; something astronomers just
recently have begun seeing around other distant stars in space. “Our
solar system condensed out of a nebular dust cloud that flattened
down into a giant disk that resembled a big pizza pan,” says CfA
astrophysicist David Wilner. “Utilizing instruments like the Hubble
Space Telescope and data from the Infrared Astronomical Satellite, we
are now witnessing the formation of new solar systems spread out into
flattened discs of gas and dust. We are even detecting large lumps of
materials in the dust disks that may be the signatures of planets in
formation. Astronomers are now assembling snapshots of our own past
frozen in time billions of years ago.”

This pathway of planets, or the ecliptic as astronomers call it, is
what remains after our dust cloud coalesced into planets. Tracing the
path of this ancient dust ring across the sky is easy. Stand
sideways facing south with your right hand extended and pointing to
where the Sun recently set along the western horizon. Now, extend
your arm up to point at the Moon or a bright planet overhead.
Connecting these two points together, continue to sweep your arm in
an arc until it reaches the opposite horizon. Bingo! You have just
traced out the ecliptic. All the planets will be found along this
line and nowhere else. And this is where the traffic jam will occur.

“Coincidentally,” says Sadler, ” have you ever wondered why the
twelve signs of the zodiac were chosen? Why someone you know wasn’t
born under the sign of Hercules or Orion?”

To the Greeks and Romans, the ecliptic was the Highway of the Gods or
the path the planets and Moon moved across at night and the Sun
traveled during the daytime. “Located directly behind this highway
were the twelve special constellations the Gods passed by as they
moved across the sky. They constituted the signs of the zodiac. This
was the basis for astrology – religious beliefs and basic sky
observations mixed together. It should not be confused with the
science of astronomy that emerged centuries later,” says Sadler.

Today, it is widely held by many historians and planetarium directors
that a conjunction of the planets, similar to the one on May 5,
accounts for the Star of Bethlehem that sent the Magi on their way to
seek the Christ child. Certainly the timing was right. An almost
identical triangular alignment of Saturn, Mars and Venus did take
place on April 1, 2 B.C. And the planets Jupiter, Saturn and Mars
also formed a triangular conjunction in 6 B.C., in the constellation
Pisces, the sign of the Christians. However, renowned astronomical
historian Prof. Owen Gingerich of the CfA disagrees. “The very, very
short duration of a grouping of planets was not the Star of
Bethlehem,” he states. “A conjugation like this would have meant
nothing to the Magi. It was not part of their astrological tradition.
It really wasn’t until Kepler became fascinated with the harmony of
the planets in the 16th century that the idea of a planetary
conjunction came about to try to attach a scientific explanation to
this event. In fact, Kepler even went so far as to add an imaginary
supernova to the conjunction of planets in 6 B.C. to try to make it
even more spectacular to catch the Magi’s attention. “

Will this event be religiously significant or just an astronomical
oddity? Is it the most dramatic way to visualize how our solar system
formed? Or, is it an exciting challenge for amateur astronomers to
conduct their only whirlwind tour of the solar system in just one
evening? Answering yes to any or all of the above makes the
alignment of late April and early May something not to be missed.
Nothing like it will occur again in our lifetime. At the very least,
it presents a wonderful opportunity for friends and family to come
together and share an experience beyond the daily routine. It also
may be an opportunity to ponder our fragile existence on this tiny
blue world racing around an ordinary yellow star with eight other
planetary companions and maybe help us, just a little bit, bring our
own world back into perspective.

Headquartered in Cambridge, Massachusetts, the Harvard-Smithsonian
Center for Astrophysics (CfA) is a joint collaboration between the
Smithsonian Astrophysical Observatory and the Harvard College
Observatory. CfA scientists organized into seven research divisions
study the origin, evolution, and ultimate fate of the universe.

Visit our web site at:

— Live-cam images of the planets April 22- May 16

— Downloadable classroom activities

— Suggestions on how to best photograph the event

CD-Rom Sky Charts images are available for Television News Casters

For more information contact:

David A. Aguilar

Director of Public Affairs


Christine Lafon

Public Affairs Specialist