Lots of talk about Mars right now. Closest approach in 60,000 years. Which is true, of course, but from some comments/questions I’ve gotten from friends, they seem to have gotten the impression that it’s going to be huge the next few nights and then go away. So here’s a few facts to settle things down a bit:
First, it’s true that this is the closest approach in 60,000 years. Why? Here’s a term for you: “perihelic opposition”. Perihelion is the term for the closest approach of a planet to the sun on it’s eliptical orbit. Opposition is the term used to describe the Earth and another planet being in a straight line drawn out from the sun. The significance, for planets outside the Earth’s orbit, is that this is the brightest we see that planet, because we’re seeing the full face of the planet. Perihelic opposition means that this lineup is occurring at the time the other planet is making it’s closest approach to the sun. IOW, it’s about as close to Earth as it ever gets. And that’s what’s happening now.
However: it took several months for this alignment to occur, during which time Mars was nicely visible (although in the early morning hours). And Mars will continue to be visible for several months, this time in the evening hours, as the Earth and Mars slowly move apart. So, enjoy the show now. Find somebody with a telescope, and look through it. But come back again a few times during the fall, Mars will still put on a good show.