The planet Mars will come closest to Earth for all of 2007 on December 18.
At a distance of about 88 million kilometers – or 55 million miles – this will be Mars’ nearest approach to our planet until the year 2016. But, no, Mars will not now or ever appear as large as the full moon – as has been erroneously reported in a widely circulated e-mail hoax.
It’s true that Mars now appears largest in our sky until 2016. But the diameter of Mars is still less than one one-hundredth that of the full moon as seen from Earth. If you could see them side by side in space, you’d find that Mars’ true diameter is about twice that of moon. So Mars would have to be twice the moon’s distance to look the same size. It’d have to be about 800 thousand kilometers – 500 thousand miles – away to appear as big as the full moon.
And again Mars is closest tonight until 2016 at 55 million miles away. On December 18, Mars at its closest looks like an exceptionally brilliant reddish “star.” You can tell that it’s Mars, because this ruddy planet shines with a much brighter and steadier light than the twinkling stars. Look for Mars in the east at nightfall.
According to the mathematical wizard Jean Meeus, Mars will be closest to Earth on December 18, at 11:45 p.m. Universal Time. For the Central Time Zone in the United States, that converts to 5:45 p.m. tonight (Dec. 18).
Because of Mars’ nearness to Earth right now, many telescopes will be pointing at the red planet in December and January. Be forewarned. It takes a lot of patience and persistence to find Mars’ surface features through a telescope. At times, Earth’s atmosphere isn’t steady (twinkling stars indicate atmospheric turbulence) and Martian dust storms sometimes obscure the view. Knowing what filters to use on the telescope is also a plus. Looking at Mars is – at best – a tantalizing experience.