Find the Planet Mars – Planetarium Activities for Successful Shows

// Red Planet Mars

Could one of these points of light do something different? We have been watching for many minutes now, and we know all the points of light in the sky appear to turn very slowly throughout the night. But there isn’t much happening so far, and no one star stands out yet. Maybe we should go ahead several nights to see if anything has changed.

DIGITAL EFFECT: Show Time
Turn on the planetarium clock on the dome.

Assign each object to a section of the audience to watch.

DIGITAL EFFECT: Arrows Off
Turn the arrows off before going forward in time. Encourage the audience to keep track of the surroundings of their “possible Mars,” instead of being able to focus on the arrows themselves.

Now study your assigned object carefully. Look carefully at its position compared with the stars around it, so that you will be able to tell if it has moved.

DIGITAL EFFECT: Advance
Fade the scene off. Turn up atmosphere and the Sun. Run 14 sidereal days into the future to advance Mars about 10 degrees East. Sidereal time is used so the stars stay in position, and Mars truly is the only object that moves.

When the sky gets dark again we will be two weeks in the future, and the stars will be nearly in their same positions. But will any of our orange or red objects be different?

DIGITAL EFFECT: Night
Fade the scene back on two weeks later. Turn down atmosphere and the Sun.

DIGITAL EFFECT: Arrows On
Turn arrows on, so audience can confirm the location of their target.

What happened to your point of light?

Go from group to group. Nearly everybody will say theirs moved a little bit.

Well, we may not be certain which of the objects may have moved a little bit. Maybe we need to go ahead another two weeks to tell for sure which one is a planet. Watch your object again. Look again carefully at its position compared with the stars around it.

DIGITAL EFFECT: Arrows Off – Advance 2
Turn arrows off, in preparation for the second jump in time.

DIGITAL EFFECT: Advance 2
Fade the scene off. Turn up atmosphere and the Sun. Run another 14 sidereal days into the future to advance Mars another 10 degrees East. Fade the scene back on two weeks later.

DIGITAL EFFECT: Arrows On
Turn arrows on, so audience can confirm the location of their target.

What happened to your point of light now, eight weeks after we started?

[Now a few will have decided theirs did not move, but the Mars group will be sure that theirs did move.]

DIGITAL EFFECT: Arrows Off – Advance 3
Turn arrows off, in preparation for the third and final jump in time.

We are not sure about some of the objects but have ruled out some, and one group thinks this one (Mars) definitely did move. Perhaps members of that group would venture a prediction as to where the object will be in another 2 weeks.

Allow a member of the group to use the pointer to show where they think it will move.

Let’s all watch their object very carefully this time and see if it indeed moves against the background of stars.

DIGITAL EFFECT: Advance 3
Fade the scene off, and run 14 sidereal days into the future. Fade the scene back on two weeks later.

DIGITAL EFFECT: Arrows On
Turn arrows on, so audience can confirm the location of their target.

Did it move? [Yes.]

Is it where you predicted it would be?

So we have found the planet Mars by its motion, the same way the ancients did. In fact our word “planet” comes from the Greek word “planetes,” meaning “wanderer.” Because the Earth is turning, all the stars and planets appear to move slowly every night, together. The planets, due to their motion around the Sun, appear to turn a little faster or a little slower than the distant stars. Stars and planets have many other important differences, but we can’t tell without a telescope. The way Mars drifts against the starry background convinced astronomers centuries ago that the planets travel in orbits around the Sun, not around the Earth.

Optional
You may use digital effects to toggle the time, Mars candidate arrows, and Mars trails. You may also run more sidereal motion, 2 weeks at a time. Use to suspend or customize the Finding Mars activity.

DIGITAL EFFECT: Annual Motion
Fade off non-Mars arrows, and then run through 90 sidereal days in 15 seconds, with a trail on Mars.

DIGITAL EFFECT: End Trails
Fade off Mars trail, Mars arrows, and turn off the planetarium clock.

We have found it: that red spot of light is the planet Mars, as people have seen it throughout the ages. We find other celestial objects just as red as Mars in the early spring sky. Here’s Aldebaran in Taurus, for example, and Betelgeuse in Orion — both are red-giant stars (point out the red stars named). Following the curve of the Big Dipper’s handle leads us to Arcturus, in Boötes (point out). Antares, the name of a red-giant star in the summer sky, means “rival of Mars.”