Five Things About Viewing Mars in August

1. How did the “Mars in August” e-mail get started in the first place?

In 2003, when Mars neared opposition — its closest approach to Earth in its 22-month orbit around the sun — it was less than 56 million kilometers (less than 35 million miles) away. This was the closest it had been in over 50,000 years. The e-mail that circulated back then said that Mars, when viewed through a telescope magnified 75 times, would look as large as the moon does with the unaided eye. Even back in 2003, to the unaided eye, Mars looked like a reddish star in the sky to our eyes, and through a backyard telescope it looked like a small disc with some dark markings and maybe a hint of its polar ice cap. Without magnification, it never looked as large as the moon, even back in 2003!

2. Can the moon and Mars ever look the same size?

No. The moon is one-quarter the size of Earth and is relatively close — only about 384,000 kilometers (about 239, 000 miles) away. On the other hand, Mars is one-half the size of Earth and it orbits the sun 1-1/2 times farther out than Earth’s orbit. The closest it ever gets to Earth is at opposition every 26 months. The next opposition is in January 2010.

At that time, Mars will be 98 million kilometers (61 million miles) from Earth, almost twice as far as in 2003. So from that distance, Mars could never look the same as our moon.

3. Is Mars visible in August 2009?

Mars rises in the east at about 1:30 a.m. this month and is best seen closer to dawn. It is a ruddy star-like object about the same brightness as the brightest stars you’ll see. Look for Mars above the constellation Orion in the pre-dawn sky. The moon is close by on the mornings of August 15 and 16. The brighter object in the sky below and left of Mars is Venus!

4. Can I see Mars and the moon at the same time this month?

If you get up before sunrise on August 15 and 16, you can see the waning crescent moon pass by Mars. The next two mornings, August 17 and 18, you’ll see the moon pass by Venus, which is the bright object below Mars in the morning sky. This will be a great time to compare the sizes of the moon and Mars for yourself!

5. Will the “Mars in August” e-mail return next year?

Most certainly! But next year, you’ll be armed with facts, and perhaps you will have looked at the red planet for yourself and will know what to expect. And you will know exactly where to put that email. In the trash!