Asteroids
The small 150 foot diameter asteroid with the designation 2012 DA14 became newsworthy when it was determined that it would slip by the Earth just beneath our geosynchronous communication satellites on February 15, 2013. But then, coincidentally on the same day, a much smaller asteroid only about 55 feet in diameter coming at the Earth from the opposite direction stole its thunder. It plunged into our atmosphere at 40,000 miles per hour, burned brighter than the sun, and then disintegrated above Chelyabinsk, a Russian city of 1.1 million people near the boundary between Europe and Asia. It detonated at an altitude of about 40,000 feet with the force of 30 Hiroshima atomic bombs, blowing out thousands of windows and collapsing an old zinc factory. At least 1200 people were injured, mostly by flying glass. Had the asteroid hit the ground intact, the destruction would have been much worse.
This was the largest meteor strike since the Tunguska blast in 1908 took out about 770 square miles of forest in a wilderness area of Siberia. The Tunguska blast in 1908 was caused by an asteroid about six times larger than the one that hit Chelyabinsk, though exploding at around the same altitude.
The Chelyabinsk strike has caught the attention of a world that until now had been mostly oblivious to the danger it faced from the detritus of the solar system. If you go outside tonight after dark and stare at the dark sky away from city lights, on average you will witness about three meteors streaking across the sky every hour. Those are much smaller versions of what hit Russia on February 15. Most of the meteors you see will be the size of sand grains; occasionally, you’ll see grape and softball sized rocks which burn bright and are designated fireballs. Objects the size of what hit Russia this month hit our planet on average about once every 100 years; the Tunguska size objects hit on average about once every 1000. Asteroids like DA14, Tunguska, and Chelyabinsk are so small that very few of them have been or even can be tracked with the limited number of telescopes devoted to studying asteroids.
Someone once commented that the reason the dinosaurs died out is because they didn’t have a space program. Although dinosaur-killer-sized asteroids (about 10 kilometers in diameter) are rare—and we are tracking about 90 percent of them—a Tunguska sized strike would make for a very bad day if it happened over a city: think Hiroshima on August 6, 1945.
For most of human history we were not even aware of the danger from the skies, just as for most of human history we had no way of predicting the approach of hurricanes or tornados, and just as we had no way of doing anything about earthquakes. But now in California our buildings and overpasses are designed to survive earthquakes up to 8 on the Richter scale. Our satellites track hurricanes and tropical storms, warning those in their paths of the approaching danger, giving them sufficient time to prepare and evacuate.
We now have the technology to find and track all the rocks speeding about the solar system, and we have the ability to nudge them away if we found one on a collision course. We simply must decide: do we want to protect ourselves—or are we satisfied to accept the rare and intermittent danger and just hope for the best?
Interestingly, two companies have been formed in the last few months: Planetary Resources and Deep Space Industries. Both companies are planning to track and find asteroids that pass near Earth, search for valuable minerals, move those that are valuable, and mine them. While they are not doing all this for the purpose of saving the world from being hit—that would be an obvious side effect.
Planetary Resources was started by and is being financed by billionaires, such as the founders of Google—a multibillion dollar corporation. They recognize the potential for enormous profit possible from asteroid mining. An asteroid the size of the one that smashed into Chelyabinsk on February 15 contains metals—such as platinum, gold and some other rare earth minerals—worth billions of dollars. An asteroid the size of the one that hit Tunguska in 1908 is valued in the multiple trillions of dollars. It could contain more platinum, for instance, than has been mined in all of human history here on Earth. In fact, platinum exists on Earth only because of all the asteroids that have smashed into our planet in the past over the eons.
So, even though our government (and the governments of other nations) are likely to simply dither and accomplish little in the way of protecting us from the cosmic threat—the potential for profit from these cosmic rocks will spur industry to do the job for us instead. And in the course of them making enormous piles of cash, the government will then happily tax them with very little dithering.
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Two of my friends have just started blogs. One is a photographer and one is a newly minted lawyer who just recently passed her California Bar Exam (on the first try!)
KCNewman Photography – finding beauty in the small things
I’ve also added their links to my Blogroll.
