"It's The End Of The World As We Know It" (R.E.M.)

I got an email from my brother the other day. He'd been driving from Seattle to Denver and, in the AM static of late-night radio in the wide-open spaces, heard some doomsayer predicting the apocalypse in 2019 thanks to an asteroid that had us in its sights. My brother is a reasonable, rational, intelligent guy, but he still needed some re-assurance that we weren't going to end up like the finale in a cosmic "Mythbusters" episode. So this is what I wrote him in response.

Mark Twain said it best: "The trouble ain't that there is too many fools, but that the lightning ain't distributed right." Over the past 30 years of employment in this business I have collected what is now amounting to a fairly fat folder of various "end of the world as we know it" theories, schemes, alleged cover-ups, etc. In case you missed them (I certainly did) there were at least a half-dozen apocalypses since 1984. I'm talking about complete annihilation of the planet and all we hold dear to our hearts. It's possible that I might have missed three of them for colonoscopies when I was under general anesthesia, but reliable sources tell me that the only things I missed while in dreamland was my own extreme flatulence. Someday after I retire I'm going to write a book...

The rock in question, (89959) 2002 NT7, caused a brief stir when it was first found in 2002 as the first object to rate a positive value on the "Palermo Scale", an empirical impact threat hazard rating. Values of zero indicate that the potential threat is comparable to that of a random event. A value of 1 indicates that there's a 10-fold increase in risk over the random background level, 2 means 100 times, etc. This li'l guy had an initial value of 0.06 (big woo...) As often happens with these things, once an orbit is determined, we can go "data mining" in old photographic plate collections and find older observations of an object which can then be used to furhter refine its orbit. About 3 months after 2002 NT7 was found, its image was duly tracked to an older survey plate, and the new orbit (fitting both the contemporary and older observations) changed its Palermo Scale rating to -0.25. In other words you're more likely to get bonked by a random event than by this particular one.

Now, all that aside, there are plenty more where this guy came from. Asteroid (99942) Apophis is a similar critter. When initially discovered in 2004 it racked up a Palermo Scale of 1.10, and some early calculations indicated that there was a 2.7% chance of it hitting us on 4/13/2029. Subsequent data have refined the orbit enough so that we now know it won't hit us at that time, but it will whizz by at a distance of some 20,000 miles. There was some probability that this close pass would deflect the asteroid enough to set up another possible impact on 4/13/2036, but a battery of optical and radar observations made over the past few years have reduced this chance to about 1:250,000. The object has been measured with radar instruments, so we know its size is about 250 meters. Were this to plop down in Puget Sound you and your immediate neighbors between Bellingham and Tacoma would not be happy campers, but this won't send folks east of Idaho scrambling for the rosary beads or bomb shelters. Unless it lands on the Yellowstone Caldera...

But seriously, folks...we now know that asteroids hit the earth all the time, relatively speaking. Last winter one in the 25-50 meter class landed in Somalia. It scared the bejeebers out of a few Bedouin, and an airline pilot saw its flash from ~250 km away, but it exploded in the atmosphere and basically scattered small rocks over a wide swath of Sahara desert. Objects of this size hit us ~2 or 3 times a year. Objects on the 100 meter class smack us every couple of centuries. Apophis-sized objects hit every few millennia. They will produce impressive results. I've stood many times on the rim of Meteor Crater in AZ, the result of the most recent such encounter ~50,000 years ago. Yes, it's a very impressive hole in the ground, but once you're ~10 km from it you'd never know anything cataclysmic had happened.

Why don't we see more of these types of craters on the earth? Well, 70% of the planet is covered with water, and 90% of the population inhabits 3% of the surface. "If a tree falls in a forest..."

Now we know from the geological record that there have been some major "show-stoppers" which have occurred in the dim & distant past, viz. the dinosaurs, the great Cambrian extinction, etc. As a species we owe our very existence to these events, so its only natural to suppose that one might eventually do us in. Do I lose sleep over it? Nope. Won't do me any good. I'm confident that Apophis will sail by merrily in 2029 and 2036. If I live long enough it will be a really cool thing to watch in the telescope. However, one of Apophis' undiscovered buddies could smack us tomorrow with little or no warning.

Since 1994 various groups have been operating remote telescopes to survey the night sky to look for what we call NEOs (Near Earth Objects). In the course of this work they have discovered hundreds of thousands of rocks of various sizes, and out of this vast collection they have identified ~1500 "PHAs" (Potentially Hazardous Asteroids). These are generally ones that have a 1:100,000 or better chance of hitting us in the next 1000 years that could potentially result in near-global-scale effects. At these odds I can tell you in all sincerity that none of them will hit us in that time span.

However, I can't tell you anything about the estimated 300 - 500 that we haven't found yet... :-)

But if you're a die-hard doomsayer all of this is moot. The next date for the end of the world is December 21, 2012. That's when the current 13-baktun series in the Mayan Calendar ends and the calendar supposedly resets, with the usual attendant bad shit happening. What the doomsayers don't tell you is that the Maya had another cycle in their calendar called a "sun", equivalent to five 13-baktun cycles. Five suns is equivalent to ~26,000 years, which happens to be the precessional cycle of the Earth's rotational poles. Prophets of the End of Times? Nope...the Maya were just damn good astronomers!

My brother replied to this today with a wonderful pearl of wisdom he ascribes to an old Sicilian proverb: "The Mother of Stupidity is always pregnant".

The Boys Are Back In Town...

Some of you may have noticed that my posts seem to have some sort of connection to music now and then. As with many of us, I'm sure, certain events become associated with certain songs. The song in today's Ramble was by a group named Thin Lizzie. I was never a big fan, but this song still gets a fair amount of airplay on the "classic rock" stations.

So why should I care about this song? Well, today I had my third colonoscopy. Seems I'm a veritable polyp factory, so, lucky me, I'm on the "view every 2" year plan. Lots of people seem to fear this procedure. Not me. I don't mind it a bit. It beats surgery any day. I think what most people fear is the prep for the procedure, which is no picnic but is on the whole pretty benign. Once you've gotten past the prep, the rest is easy-peasy.

The best part of the whole deal is that you are blissfully unaware of what they're doing to you. They gave me Propofol, aka "Milk of Amnesia". Yes, it's what killed Michael Jackson, but it hasn't killed me. Yet.

So here's where the music comes in. My doc loves classic rock. It's playing in the background as I'm wheeled into the exam room. Two years ago, as I was going under, the boom box happened to be playing Led Zeppelin's "Dazed and Confused". The last thing I remember was the beginning of Jimmy Page's solo where he uses the cellist's bow to get those whoopy effects out of his Gibson. How appropriate.

Today, I related the story back to my doc, and he switches the box to a really good guitar song by a group who's name I didn't quite commit to memory before memory got erased. But for some reason, Thin Lizzie's song seemed to keep playing over and over in my head for what seemed like forever. But then *boing* ... I'm awake.

So now I have two songs to remind me when my next exam is due. As far as today went, I had a sessile polyp and several smaller ones excised, so they're still finding happy homes in my gut. I'll have to go back in another two years, but as long as the tunes are decent I won't mind. Wonder if my doc will take requests ...