Friday, September 14, 2007

Mars Really Is Looming Large

Mars Really Is Looming Large
by Dave Adalian

Used to be Mars was a hot topic of astronomical conversation only once every two years.

That’s how long it takes Earth to swing around the Sun and catch up with the fourth planet of our solar system, which itself is racing along in the same direction.

These days, thanks to the Internet, Mars reappears every August, and it’s always going to be the size of a full moon when it arrives. At least that’s what emails my readers forward to me say. The questions they usually send along with these emails run like this:

“I know this can’t possibly be true, but I wanted to know for sure so I don’t miss it if it is, so is it?”


Welcome to the annual Mars hoax, an unsinkable chain letter saying Mars will appear the same size as the full moon in August. The people who email know this can’t be right, but the allure of Mars is such they want it to be. So do I. But, alas, it isn’t going to happen. Never.

But the god of war will be here soon, and this year, Santa won’t be the only thing dressed in red, white and black showing up on Christmas Eve.

Mars reaches opposition on Dec. 24. It will rise as the Sun sets and stay up all night. It does this because the red planet is opposite the sky from Sol, which is what “opposition” means.

It also means the time to start watching Mars is now.

The reason my hopeful correspondents know Mars isn’t going to be the size of the full moon is we’d start seeing it looming ridiculously large months before the big show. The same is true for this lesser but at least real apparition: Mars is already showing itself, rising around 11 p.m. between Orion and Gemini and getting high enough for good viewing by 1 a.m.

And, Mars isn’t sitting still. Right now Earth and the red planet are zooming toward each other at around 25,000 mph. In October 2006, Mars was on the other side of the Sun from Earth, 243 million miles away. Now, a year later, Mars is just over 90 million miles distant, and the gap is shrinking fast.

Between now and Christmas Eve, Mars will come 35 million miles closer to Earth and brighten by a factor of four, all the while rising earlier and earlier each night. Just step outside and you can watch it happen.


The Tulare Astronomical Association and the Tulare County Office of Education will present The Stars of Autumn, a planetarium program written and narrated by Starry Nights columnist Dave Adalian on Oct. 5 and Nov. 2 with a free star party to follow. For details, check the Starry Nights blog at or the Pena Planetarium website at


This column appeared originally in the Visalia (Calif.) Times-Delta and Tulare (Calif.) Advance-Register on Sept. 20, 2007.

No comments: