Close Encounters of the Martian Kind: Opposition 2003, What is an Opposition?

"For Mars alone enables us to penetrate the secrets of astronomy which otherwise would remain forever hidden from us."
-- Johannes Kepler, New Astronomy, 1609

Though the diagram is not to scale, it illustrates how Mars is in opposition to Earth.

A Martian Opposition occurs when Mars is opposite the Sun relative to Earth, meaning that you could draw a straight line through all three with the Earth in the middle. Mars has an opposition about every 25 months.

This year, the Mars opposition occurs at the same time that Mars is at perihelion, which means Mars, in its orbit, is closest to the Sun. To understand this, you need to understand that the orbits of the planets are not completely round, but rather elongated circles called ellipses. About every 15 to 17 years, Mars is both at opposition and perihelion and at these times Mars is closer to Earth than other times when there is just an opposition.

But wait! We've been saying that Mars will be closer to Earth than in all of recorded history: what's the deal? Well, Mars will be closer to Earth than it has been for tens of thousands of years and we'll go into why in the section about why this opposition is so special.

This diagram compares various Martian oppositions and their distances to Earth.

At 5:51 a.m. EDT on the night of August 27, 2003, Mars will be within 34,646,418 miles (55,758,006 km) of Earth. To compare this to an earlier opposition: in 2001 when Mars was last at opposition, the red planet was more than 41 million miles (67 million km) from Earth. The most recent perihelion and opposition took place in September 1988 when Mars passed within 36.5 million miles (58.7 million km) of Earth.

When will Mars be this close to Earth again? The next, closer approach will occur on August 28, 2287 when Mars will be 34.62 million miles (55.69 million km) away. But we won't be around for that one, so you don't want to miss this close approach!

Mars is slightly smaller than Earth, and much smaller than Jupiter and Saturn. Normally, Mars looks quite small in a telescope and you need good seeing conditions to make out any surface details. But during an approach like this, Mars will be beautiful in even a small telescope.

Close Encounters of the Martian Kind

What is an opposition?

Why will Mars be larger than usual and this event so rare?

Where and When to see Mars!

Timeline for Mars in 2003/2004 - What to Look for on the Red Planet!

Close Encounters of a Red Kind: Retrograde Motion of Mars

Mars through a Telescope: Getting the Most from the Red Planet

The Martian Sky: Stargazing from the Red Planet

More about Mars the planet

Constellations

The Solar System