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  • Rapt in Awe

    My Journey through the Astronomical Year

    Think of this as a "companion text" to this, the main web site. Not required reading, butI hope you'll find it interesting and helpful.

Mars will NOT be close to Earth, nor “as large as the Moon” in August 2010, August 2011 – or ever!

(Note – this post has been updated in key places for 2011.)

Sorry I have to write this, but every August since 2003 I have gotten these questions about a spectacular showing of Mars in our sky because an anonymous email makes the rounds of the Internet causing people to get excited. THIS EMAIL IS NOT TRUE. I wrote about it on this site in 2009 and in 2010 ( received a well-meaning email from a friend who forwarded  a slightly different variation on this theme that uses a PowerPoint attachment.  I suspect there are a lot more innocent folks who are looking forward to something that just isn’t going to happen – this year, or ever.

The most outrageous claim in this email goes something like this:

On the night of Aug. 27, the planet Mars will come closer to Earth than it has in the past 60,000 years, thereby offering spectacular views of the Red Planet.  Mars will appear to the naked eye as bright as and as large as the full moon. No one living today will ever see this again!

No one living today will ever see this. Period. OK. here’s the simple truth.  At 3 am  August 27, 2011 Mars will be rising in the east and be about one fist – 10 degrees – above the horizon. It will shine about as bright as two nearby stars, Castor and Pollux – actually a little brighter than one and a little dimmer than the other – and be roughly one fist south of them. As always it will have a reddish tinge to it, but to the naked eye look just like any bright star. (On August 27, 2010 about 45 minutes after sunset, Mars appeared in the western sky very close to the horizon and right next to Venus which outshone it by a whole lot. In fact, Venus was more than 100 times brighter than Mars, but both still looked like stars. In binoculars you should be able to see them both in the same field of view  and to the other side of Venus you’ll see a bright star, Spica. You may be able to just squeeze all three in the same binocular field of view.  In a very good telescope, Mars will look like a very tiny planet, about one-fifth the size it is when it actually does make a close approach to Earth.  Mars and the Earth are relatively  close to one another  – 35 to 60 million miles apart – every two years. That’s when amateur astronomers turn their telescopes on it  and the last time that happened was in January of 2010. It will happen again in 2012. It will be nice then. It will not be spectacular and it will never be as described in this bogus email.

When Mars is at its closest it shows a disc about 24 arc seconds wide.  The moon is roughly 30 minutes of arc – half a degree – in our sky. That means the Moon routinely is about 75 times as large in our sky as Mars can ever get. 

Is there any truth in the email? Yes, there are some grains of truth here, but even they are usually distorted. This all began because in August 2003 Mars really did make an unusually close approach to Earth – but by unusual we mean just a bit closer than it gets routinely every two years.  During a close approach such as the one in 2003 Mars can be 24 seconds of arc across – and sometimes it’s “close” approach means its half that size. In August of 2010 it will be just one-fifth that size – 4.5 arc second across!

In short, this Mars email is just another Internet urban legend telling us things that would be fun if they were true, but really are far, far from the truth. For details on this, please visit the Snopes.com site – in fact, anytime you receive an email that sounds too good to be true – on almost any subject – check snopes.com before you forward the email to friends. It’s a great clearing house for getting out the truth on these legends.

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