We Missed the Doomsday Comet by a Century

June 26, 2009

There is a lot of silly hoopla over the end of the ancient Mayan calendar and therefore supposed “end” of the world in 2012 according to some interpretations (such as a rogue comet whacking us). 

But let’s take a step back and consider a real event that happened to Earth when cosmic stuff really did hit the fan.

This Tuesday June 30 will be the 101st anniversary of the mysterious Tunguska explosion that flattened a forest in central Siberia with the equivalent of between 5 to 30 megatons of TNT detonating.

For all their supposed astronomical prognostication, the Mayans missed predicting the biggest impact event to happen to Earth in recorded history.

The aerial explosion that summer morning resulted from a collision with an object estimated to be as big as a 10-story building.  The intruder disintegrated in the upper atmosphere, and the airburst incinerated an area twice that of Los Angeles.

Statistically, an impactor of this size is only supposed to smash into us about every 300 years or so.  But earlier this year two Tunguska-sized asteroids whizzed precariously close to Earth with little warning.

An asteroid named 2009 DD45 zipped within 48,800 miles of Earth on March 2 (does the DD stand for “Doom’s Day”, or are asteroids getting cup sizes now?). That’s a close shave considering it was just twice as high as the orbits of some communications satellites.

Only two weeks later a larger 150 foot-wide asteroid, 2009 FH (hmm, and acronym for “F**king Huge”?) was spotted passing the Earth at a similar distance. If you were riding along with the asteroid, at closest approach Earth would have appeared the angular size of a grapefruit held at arm's length.

The Large Synoptic Survey Telescope, schedule to begin science operations in 2015, will be able to catalog roughly half of the population of Earth-threatening Tunguska-sized asteroids, and identify almost all of the more lethal bodies that are ten times the length of a football field and larger.

But less trackable than asteroids are comets that can dive-bomb the inner solar system quickly and from any direction.

In the June 24 journal Geophysical Research Letters, Michael Kelley of Cornell University reports that the noctilucent clouds seen over Europe in the days following the Tunguska impact point to a comet rather that asteroid as the intruder.

Noctilucent clouds are the Earth's highest clouds, forming 55 miles over the polar regions during the summer months.

Kelly contends that the massive amount of water vapor spewed into the upper atmosphere by a Tunguska comet's icy nucleus was caught up in powerful swirling eddies traveling 200 miles per hour and carried across the globe.

Kelly’s hypothesis is built around his studies of the exhaust plumes from several space shuttle launches.  A single space shuttle flight injects 300 tons of water vapor high in Earth’s atmosphere. The water particles have been found to travel to the Arctic and Antarctic regions, where they form the noctilucent clouds after descending to lower altitude.

On a far more bizarre note, Russian scientist Yuriy Lavbin proposes that altruistic space aliens went on a Kamikazi mission to collide their spaceship with the Tunguska impactor to protect our planet.  He claims that 10 quartz crystals that were found near Tunguska’s ground zero have strange “laser-etched” drawings on them.  Ratcheting this up a notch into stratospheric silliness, he hypothesizes that when all stones are placed together they form a map that was part of spaceship’s navigation system.

Clearly Dr. Lavbin has been watching too many Star Trek reruns. Crystals? What a bulky way to tool around the galaxy. Even a foldable AAA TripTik would be better. Or better yet, a GPS-type navigation system using pulsar emissions.

What’s more, if an extraterrestrial spaceship actually exploded high over Tunguska there would be unmistakably exotic artifacts – not rocks -- on the ground. Remember the thousands of pieces of debris scattered across Texas, Louisiana, and Arkansas from the ill-fated space shuttle Columbia breakup in 2003?

If the aliens were smart enough to come here from another star they also would have known simple Newtonian physics. The ability of a spaceship to use kinetic energy to deflect a one million ton comet nucleus barreling along at 40,000 miles per hour is as unlikely as a grasshopper tipping over a speeding locomotive. And, wouldn’t the aliens have had directed energy weapons or “photon torpedoes” or some other advanced-tech means to knock off the intruder rather than throwing themselves under the bus?

If Lavbin’s hypothesis is correct – at least in some twisted parallel universe – then thank God the meddlesome aliens weren’t around 65 million years ago, or the dinosaurs would still be ruling our planet. Then again, maybe aliens engineered the dino’s demise as a science fair project. Anything’s possible in a world of rampant speculation untethered from rationality.  

 

Comments

[lightning09]

hmmmm,