One billion good reasons to be afraid

65 million years ago an enormous lump of rock – a comet or asteroid over a mile in diameter – crashed into the Earth at enormous speed – perhaps 200 times the speed of sound – leaving a crater 193 km wide and 48 km deep.

Think about that for a moment.

Much of the rock was vapourized on impact, leaving a thin deposit that can be found in layers of rock all around the world today. The explosion wiped out all the dinosaurs and led to the extinction of half of the world’s other animal species.

I don’t wish to alarm you, but this wasn’t the first time such a collision had taken place, and it won’t be the last.

In 1994 the comet Shoemaker-Levy 9 struck the planet Jupiter with the force of 6 million megatonnes – 75 times the explosive power of all the nuclear weapons ever built. It left a hole in Jupiter roughly the size of the Earth.

There are probably more than a billion asteroids wandering haphazardly around the solar system and two or three of them narrowly miss the Earth each week. One or two small ones actually hit the Earth’s surface every year. Tracking such objects is tricky as they are very small by astronomical standards and irregular in their motion. If one happened to cross the Earth’s orbit we probably wouldn’t even see it coming, and the Earth would smash into it at nearly 100,000 mph.

Even if we had telescopes trained to spot killer asteroids, we probably couldn’t do anything to prevent a collision.

Space is a dangerous place. Our continued existence is perhaps more precarious than many people realize. Don’t imagine that God or nature will look after us, because history demonstrates that’s not true.

For humans to continue to exist in the long term, we need to live on more than a single planet. If you ever need a reason for justifying the cost of manned space exploration, perhaps this is it.

9 responses to “One billion good reasons to be afraid

  1. Cheery thought, our Steve !

  2. Have you seen the movie Particle Fever? I saw it last night. Excellent. Physicists all over the place chasing down the Higgs.

    If a killer asteroid was coming at me and there was no way out, I would go outside to watch until I was gone.

    • It would certainly be spectacular to watch, but I doubt you would see anything unless you were some miles away, and then only for a second or two!

      I haven’t heard of Particle Fever, but it sounds worth watching. Of course, it would be a better movie if the Higgs created a black hole that threatened to swallow the Earth unless a lone scientist can stop it against all the odds and get the girl too.

  3. Thank you for starting my Friday off on such a cheery note!

    But, good reminder. All of this focus on disasters in space makes me kind of against further exploration, but that’s more about us making sure the ships that carry our astronauts into space are sound than it is about space exploration.


    • I guess my point is that if we don’t succeed in getting into space and colonising other planets and star systems, then the disaster will be right here on Earth!

  4. All the same, there’s very little reason for personal fear. At a personal level, you are vastly more likely to be killed by something other than an asteroid impact. Even collectively, there is arguably little reason to prepare countermeasures against asteroids.

    The human race is going to end some time. Either an asteroid or a supernova gamma burst or some other calamity is going to do it, or perhaps we’ll just evolve gradually into something completely different. I’m not really sure that allowing the existence of the human species to exist for a longer period of time is really that strong a moral imperative.

    • Yes, I wasn’t trying to frighten anyone. The chance of being killed by an asteroid is negligible. However, as a species, asteroids pose a significant existential threat. And it’s a threat we can do something about in the long term, so I think there is actually rather a strong moral imperative to do just that.

  5. So did you write this post in response to today’s WordPress Daily Prompt about a worst case scenario? If so, I think you nailed it!

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