As you may know by now, I am fascinated with the night sky. Actually, come to think of it, I am fascinated with the sky, period. I always walk looking up. Hell, I hate to admit it, but on occasion I’ve even been caught looking up while driving. I can’t help it. There are clouds — so many types of clouds! — sundogs, circumzenithal arcs, lightning and much, much more. The sky is a busy and fascinating place where you can get lost.
There are a couple of things I’ve always wanted to see: a tornado and a daytime meteor. I kind of received one of my wishes while living in Wollongong, New South Wales, Australia, so many years ago: one afternoon I looked out of my apartment window and spotted two waterspouts in the ocean. I nearly lost it. It was the coolest thing I’d ever seen.
As for daytime meteors, so far, no luck. But following the events of February 15th, 2013, I’m now not so sure I want to see one.
Unless you’ve been living under a rock (not a space one), you know of the bolide, or meteorite, that roared across the Russian sky that day. The fireball was seen streaking across the sky over Chelyabinsk, which is roughly 1500 kilometres east of Moscow. It is estimated that the fragment of space rock measured 17 metres and weighed about 10,000 tonnes before it entered our atmosphere at speeds of up to 65,000 kilometres an hour. NASA says that it released about 500 kilotons of energy. To keep that in perspective, the atomic bomb that was dropped on Hiroshima in 1945 weighed roughly 13 kilotons. With that much energy, there were consequences.
Was it the rock itself that caused damage? No. It was the sound. Sound. And this is what it sounded like:
When that rock — which by space rock standards was a mere speck, really — burned up through our atmosphere, the energy it released had to go somewhere. And it was released in sound. That shockwave rocked small Russian towns, shattered windows, shocking many people even up to a minute after they saw its vapour trails that hung in the blue sky. Reports say that around 1000 people were injured by the glass from windows that shattered when the shockwave hit.
I can’t lie: I find this absolutely fascinating. For one, this is something from space. That is cool no matter what happens. Two, it’s science at work. Soundwaves that displace so much air . . . wow. Clearly, I don’t want anyone to be hurt. Which is why I now question whether or not I want to see something like this. Nah. I still want to see it. But somewhere safe.
What is also interesting to me is that it also reminds me of our fragility. We exist on our tiny planet under a cover of a thin atmosphere that catches somewhat insignificant space debris all the time. We barely notice the debris: we may see a fast, green streak in the night sky from time to time, but rarely for most people. The atmosphere is our protector. But when things like this happen, it serves as a reminder that the atmosphere can’t protect us from everything. We are lucky to be here. It would take only one large asteroid to plunge into Earth to obliterate all life.
A question that has popped up over the past few days is one that has driven me crazy: “Why didn’t we know this was coming?” I suppose scientists should be flattered that the general public believe that science can predict everything. But that just isn’t the case. Although there is a program to warn us of potentially hazardous asteroids (PHAs), the truth is, they can’t see everything. Like I said, this particular piece of debris was relatively small: our instruments can do only so much. As well, our galaxy is full of wandering bodies left over from its formation. And our instruments can only see small parts of the sky at one time. There is no possible way that we can warn of such things. Not every time. Just be thankful that we can see the large ones coming. And sometimes, only within days.
The ironic thing about this whole event was that it happened on the same day that asteroid 2012 DA14 was to pass 27,000 kilometres from Earth. Close enough to come within the orbit of our geosynchronous satellites, but it wasn’t something that posed a danger to us. Though many assumed that the Russian meteorite was connected with 2012 DA14, it was in no way associated with it.
And, by the way, this is not the first time Russia has had such a close encounter with a meteorite. On June 30th, 1908, at approximately 7:17 a.m. local time, residents near Tunguska, Siberia, were jolted from where they stood when an estimated 220 million pound rock soared through the sky at 54,000 kilometres an hour. Reports say that the impact was felt from as far away as England. It flattened almost 2000 square kilometres of trees and killed wildlife, but there was not one reported human fatality. We should be thankful that this week’s event also spared lives.