Friday, January 19, 2007

Comet madness

In 1910, the appearance of Halley's Comet led to an outbreak of popular fear. Astronomers had recently discovered that the comet's tail contained the deadly gas cyanogen - and the earth was expected to pass right through it. People fearing cyanide poisoning bought gas masks and "comet pills" to protect themselves. Of course, nobody died (well, possibly someone choked on one of them).

Today, we have our own madness over Comet Mcnaught, with it variously being mistaken for a "an object falling from the sky" and a plane on fire - leading to calls to the fire service and police. You'd think the fact that it wasn't moving might signal to people that it wasn't anything of the sort - but apparently not.

Meanwhile, I've finally seen it (despite the clouds), and it is indeed magnificant. Halley in 1986 was just a fuzzy blob, wheras McNaught is quite spectacular. It's not a patch though on some of the Great Comets I've been reading about, which had tails stretching 90 degrees or more across the sky. Something that big and bright seems to come along every 25 years or so, so there's a good chance that I'll be able to see one in my lifetime.


Obviously ignorance of the laws of physics was as common in 1910 as today. Here's why you won't be poisoned by a comet full of C2N2:

1. The comet, including any cyanogen is travelling at high speed in an orbit around the sun. That stops the material in it from mixing with the earths atmosphere in any quantity. (If it did interact with the earth to any extent, the comet would disappear quickly).

2. The recommended maximum tolerable concentration of C2N2 is 10ppm. To reach this concentration in the earths atmosphere, you would need 5 x 10^13 kg of the stuff. (50 gigatonnes). I don't believe comets are that big.

According to the same MSDS I got the toxicity data from, a recommended antidote is amyl nitrite. AKA poppers - so I suppose everyone was snorting poppers the moment the saw the comet. Fun!

Posted by Rich : 1/19/2007 11:53:00 AM

I too, saw it last night (in Auck), and it is indeed impressive....

Haleys in '86 was a wash-out.... a fuzzy blob as you say...

A couple of years after that was Hale-Bop... actually pretty good.... with a tail tail having visible length.... but this one is far brighter and the tail a good 3-5 times longer... I highly recommend anyone to go have a look...

Look in the direction of the sun just after its set below the horizon (ie West) , and it will be a little to the left of that, and last night was visible for a good 90 mins or more after sun-set, before it too set below the horizon...

Posted by Anonymous : 1/19/2007 02:07:00 PM