The Big Mars Hoax
As August approaches each year, we start to receive emails that claim Mars is approaching very close to the Earth, and that it will appear "as large as the full moon" in the night sky. A sample of these typical emails follows - complete with spelling errors.
Hoax: Planet Mars will be the brightest in the night sky starting August. It will look as large as the full moon to the naked eye. This will cultimate on Aug. 27 when Mars comes within 34.65M miles of Earth. Be sure to watch the sky on Aug. 27 12:30 am. It will look like The Earth has 2 Moons. Don't Miss it..... The next time Mars may come this close is in 2287. NOTE: Share this with ur friends as NO ONE ALIVE TODAY will ever see it again.
Hoax: Mars the Red Planet is about to be spectacular! This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history. The next time Mars may come this close is in 2287. Due to the way Jupiter's gravity tugs on Mars and perturbs its orbit, astronomers can only be certain that Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again. The encounter will culminate on August 27th when Mars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide. At a modest 75-power magnification Mars will look as large as the full moon to the naked eye . Mars will be easy to spot. At the beginning of August it will rise in the east at 10p.m. and reach its azimuth at about 3 a.m. By the end of August when the two planets are closest, Mars will rise at nightfall and reach its highest point in the sky at 12:30a.m. That's pretty convenient to see something that no human being has seen in recorded history. So, mark your calendar at the beginning of August to see Mars grow progressively brighter and brighter throughout the month. Share this with your children and grandchildren. NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN.
Usually these emails come with images of Mars and the Moon - side by side appearing the same size.
Strangely enough, they are variations of original authentic emails generated in 2003 when Mars did in fact make one of its closest approaches to Earth in a very long time. But even then, Mars was still a long long way from Earth. In August 2003, if you observed Mars through a good telescope using at least 75x magnification - then Mars could look the same apparent size (in the telescope's eyepiece view) as the full Moon could look to the naked eye view.
This information has been doctored and recycled each August since 2003 and is now completely out of date.
Some basic factual information about Mars are as follows:
- Mars could only appear as "large as the full moon to the naked eye" if you were in a spacecraft approaching Mars - and very close!
- The size (angular diameter) it takes in the sky is a tiny 8 seconds of arc. There are 60 seconds of arc in 1 minute of arc - and there are 60 minutes of arc in 1 degree. In comparison the (full) moon is about 1/2 degree or 1,800 seconds of arc (Mars is 8 seconds of arc or 225 times smaller).
- Earth 'catches up' to Mars in their respective orbits roughly every 2 years - and that is when they are closest to each other - referred to as opposition. Because both orbits are ellipses, and not circular, the distance between the two planets varies each time they are closest to each other. At closest they are about 57 million kilometres - at farthest just less than 100 million kilometres. But each encounter is (at the moment) becoming further away, and then gradually they will be closer again at each encounter. This is a 15 year cyclic phenomena that has been happening for... well since the solar system has been in its current configuration - billions of years. BUT - never will the two planets be so close that Mars "looks as big as the moon". At the absolute closest, Mars will still just look like a (reasonably) bright pinkish star to the naked eye.
- Unless you are going to be dead before within the next two years... you will see Mars at a 'close' approach again! And the best views will always be through a quality telescope.
There are quite a few web sites that discuss the "Mars is Big" hoax.