The "Grand Conjunction" of May 5, 2000

Explanatory Diagrams

 
Plan View of the Solar System on May 5, 2000 (71 kb JPEG image, 959 x 719 pixels)

 
View from Earth looking toward the Sun on May 5, 2000 (45 kb JPEG image, 959 x 719 pixels)

What's happening?

As shown in the Plan View diagram above, many of the planets in the solar system happen to fall along one general line during April and May 2000. Mercury, Venus, Mars, Jupiter, and Saturn are all aproximately on the opposite side of the Sun from Earth.

The second diagram shows the view from Earth's position. All of planets are within about a 30 degree region around the Sun. The Moon is also along this direction during May 3rd to May 5th, 2000.  If you measure precisely the time when these seven bright objects are closest together as seen from Earth, it happens on May 5, 2000.

The "grand conjunction" is simply that all of the objects in the solar system that you can see with the unaided eye will be in one part of the sky.
 

How do I observe it?

This gathering is not observable without special equipment. The Sun is so bright that you cannot see most of the planets around it.

You can perhaps see Mars just after sunset or Venus just before sunrise, but even they are difficult to see because they will be very close to the horizon.

The Moon is not visible either. It is in the new moon phase, which presents a dark hemisphere toward Earth.

See the bottom of this web page for a view from a telescope in space.
 

Will it affect Earth?

No.

The planets affect Earth only by the pull of their gravity. The dominant gravitational pull on Earth is the Sun, which holds Earth in its orbit. After the Sun, the Moon's gravity has the next largest effect, and it produces the tides in Earth's oceans.

Compared to the Sun and the Moon, the gravitational pull of all the other planets combined is tiny. Really, really small, and not worth worrying about. In fact, the change in the Moon's pull as it gets closer and further away during its orbit is many, many times stronger than the change of having all the planets on one side or another. The planets are just too far away for this alignment to have any measurable effects.

Consider a tug-of-war between 10 burly men on each side. A two-year-old can pull on the rope all she wants and it won't make any difference. That's the best comparison I've found.
 

How often does this happen?

On average, alignments like this happen once every 10 years. However, the last one occurred in February, 1962. The one before that was in January, 1962. You can see that these alignments don't happen at regular intervals. But, looking over the last two centuries, about 23 such alignments occurred. That averages to about once a decade.
 

So what does it mean?

Not a whole lot. People get excited at chance coincidences, and this is one of them.

Doesn't it just sound intriguing that most of the planets are on the other side of the solar system? Wouldn't that make the solar system lopsided?

Well, the truth of the matter can be calculated with Newton's law of gravity. And it shows that this coincidence doesn't have any consequences.

What would be cool is if we could see it, but, alas, we are denied even that. [See below for a spacecraft image.]

Image During the Conjunction

Image (with the Sun's light blocked) on May 5, 2000  (195 kb JPEG file) -- This image was taken by the LASCO experiment on the SOHO satellite. This experiment uses a disk to block the light of the Sun in order to study the hot gas around the Sun (called the "corona"). Jupiter and Saturn appear to the left of the Sun, and Mercury appears to the right. The image is about 20 degrees across and does not include Mars or Venus. The Moon is in new moon phase, and thus is not bright.

For those with fast connections -- a very big version of this image (913 kb JPEG image)


Last updated:  May 5, 2000