Mars Will NOT Look as Big as the Full Moon, But You Can Watch it Get Closer

By Nancy Atkinson - July 1, 2009 at 9:21 AM UTC | Planetary Science
Mars2009AsBigAsFullMoon-NoC.jpg

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For criminy's sake, I just got one of those "Mars as big as the full Moon in August" emails. For one more time: this is completely false and it couldn't possibly happen. Besides, in 2009 Mars is all but unobservable until the end of the year, and even next year it won't be much better. So can we please see an end to these erroneous emails???

But Mars

is

coming closer to Earth (it happens like clockwork every 26 months) and the folks at Emory University have created a

real-time distance calculator that shows Mars' geocentric distance from us.

It's really fun to see how quickly Mars is coming closer to Earth (but pleeeeease it is not going to look as big the full Moon!!!) The distance is calculated in miles (sorry rest of the world) and shows up in blue when Mars is approaching and red when Mars begins to move farther from Earth. Very fun!

And if you need to know why Mars will not look as big as the full moon, see below.

Even at its closest approach, which happened back in 2003, Mars was 35 million miles (56 million km) away from Earth. You would have to magnify Mars 75 times to make it look as big as the full Moon, without a telescope. Mars won't come this close again until 2287.

Here's a graph from Robin Scagell at

Popular Astronomy

(below) which shows how the distance from Earth to Mars varies over the next few decades, shown as the size that Mars will appear in the sky. 25 arc seconds is about half the apparent size of Jupiter in the sky, which is the largest that Mars appeared in 2003.

[caption id="attachment_33803" align="aligncenter" width="580" caption="Apparitions of Mars 2003-2042. Credit: Popular Astronomy"]

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Mars as big as the full moon just ain't gonna happen, folks.

We've discussed the Mars Hoax email every years since 2003. Here are the UT articles for

2008

,

2007

,

2006

, and

2005

. And if you need more there are a few from Phil Plait the Bad Astronomer:

here

,

here

,

here

, and

here's the original one back in 2003.

And while I'm at it, I also recently got a

"North Pole at Sunset" email.

Another NOT.

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com