Ophiuchus: what you didn't know about the zodiac's 'new' constellation

OK, by now we know that Ophiuchus has crashed the zodiac party to the great consternation of many Sagittariuses (Sagitterii?).

Thanks to the inscrutable ways of the Internet, the world has apparently now discovered what astronomers have known for millennia: that the 12 signs of the zodiac are about as scientifically accurate as "Mission to Mars," and that, in fact, there is a 13th sign of the zodiac, Mr. Ophiuchus.

Granted, first impressions didn't go that well. But we're here to say that Ophiuchus isn't such a bad guy. In fact, according to one myth, he would have healed the entire world and made humankind immortal if Zeus hadn't gotten a wee big jealous and struck him down with a thunderbolt. (Been there, done that). But at least the big Z had the heart to put our man in the heavens and give him a nice snake to hold. Sort of like a Homeric pension plan.

Aside from all that ancient ancient claptrap, Ophiuchus also has a couple astronomical claims to fame, too. So don't dismiss him as a poor man's Sagittarius just yet.

First, he's big. Of the 88 constellations, Ophiuchus comes in at No. 11, in terms of amount of the sky occupied. Among the zodiac, only Virgo (No. 2) and Aquarius (No. 10) are bigger.

Second, Ophiuchus includes Barnard's Star, which is six light-years away – the second closest star to us after the Alpha Centauri system. Discovered in 1916, Barnard's Star is a red dwarf – a dim bulb not even visible to the naked eye on Earth. Barnard's Star is so dim that a hypothetical planet would need to orbit the star at a distance of 5.6 million miles to receive the same heat that the Earth gets from the sun. The Earth, by contrast, is 93 million miles from the sun.

But in the 1970s, when scientists incorrectly thought they detected a planet around Barnard's Star, it was the focal point of Project Daedalus, a bid to prove that star travel wasn't so far-fetched. A group of scientists determined that a nuclear pulse rocket driven by nuclear fusion (not currently possible, but not out the realm of possibility) could reach 12 percent of the speed of light and arrive at Barnard's Star in 50 years.

Four centuries ago, Ophiuchus was a matter of astronomical curiosity for another reason. It contained the last supernova definitely observed in our galaxy, the Milky Way. The event set the astronomical atwitter. At its height, it was brighter than any star, brighter than any planet except Venus, and could be seen in the day for three weeks in 1604.

The supernova has now been connected with the German astronomer, Johannes Kepler – it is known as Kepler's Supernova – but at the same time Italian astronomer Galileo Galilei pointed to it as evidence that the theory of the heavens as unchanging was wrong.

Four hundred years later, Ophiuchus appears to be offering the same lesson about the zodiac.