Photo: NASA
When it comes to discoveries in astronomy and the study of the objects in our own solar system, things at times seem to be moving incredibly slowly. That's why, for instance, I haven't checked how many near-Earth asteroids have been discovered in a very long time: because I wasn't expecting significant developments.
The last time I had a look was back in 2021, and the numbers put forward by NASA at the time were disconcerting: 25,705 near-Earth asteroids circling our planet, over 800 of them more than one km (0.62 miles) in diameter.
By definition, a near-Earth asteroid is something that at its closest distance from our planet is less than an astronomical unit (150 million km/93.2 million miles) away. That may seem like a lot, but in celestial mechanics, it's right next door, and at any time any of the 25k floating pieces of rock can turn dangerous.
More worrying is the fact that there are a lot more asteroids out there we haven't discovered yet. And it's impossible to estimate how many.
In the two years that have passed since I last looked, a great deal of other such dangers were discovered in the meantime. Thanks to a huge number of observations received by the Minor Planet Center, the number of detected near-Earth asteroids has risen to 31,248.
The figure includes asteroids of all shapes and size, including the ones that actually don't pose any actual danger due to their size, trajectory, or some other aspect.
But among them, there are over 10,398 asteroids larger than 140 meters (459 feet) in diameter floating around out there. If one of them hits, it has the potential to detonate with the power of a thousand times the first atomic bomb, as per the Israeli Davidson Institute of Science. And there are at least 15,000 of them left to be discovered.
Even bigger asteroids, of over a kilometer in diameter, are not rare either. We now know of 859 of them, with around 50 still left to be discovered.
The above are the figures NASA released for September 2023. In the last ten days of the month alone, ten of these known asteroids passed closer to our planet than the Moon. For the entire year so far, no less than 114 of them did the same thing.
NASA does not say how big they were, or what the closest distance from our home world was, but even in the absence of these details the picture we get from the above numbers may be terrifying.
Do keep in mind though that knowing of a danger is a good thing, so the faster the number of discovered near-Earth asteroids goes up, the better. Because if we do know one of the dangerous ones is coming, the only thing left to do is figure out a way to stop it in time.
By definition, a near-Earth asteroid is something that at its closest distance from our planet is less than an astronomical unit (150 million km/93.2 million miles) away. That may seem like a lot, but in celestial mechanics, it's right next door, and at any time any of the 25k floating pieces of rock can turn dangerous.
More worrying is the fact that there are a lot more asteroids out there we haven't discovered yet. And it's impossible to estimate how many.
In the two years that have passed since I last looked, a great deal of other such dangers were discovered in the meantime. Thanks to a huge number of observations received by the Minor Planet Center, the number of detected near-Earth asteroids has risen to 31,248.
The figure includes asteroids of all shapes and size, including the ones that actually don't pose any actual danger due to their size, trajectory, or some other aspect.
But among them, there are over 10,398 asteroids larger than 140 meters (459 feet) in diameter floating around out there. If one of them hits, it has the potential to detonate with the power of a thousand times the first atomic bomb, as per the Israeli Davidson Institute of Science. And there are at least 15,000 of them left to be discovered.
Even bigger asteroids, of over a kilometer in diameter, are not rare either. We now know of 859 of them, with around 50 still left to be discovered.
The above are the figures NASA released for September 2023. In the last ten days of the month alone, ten of these known asteroids passed closer to our planet than the Moon. For the entire year so far, no less than 114 of them did the same thing.
NASA does not say how big they were, or what the closest distance from our home world was, but even in the absence of these details the picture we get from the above numbers may be terrifying.
Do keep in mind though that knowing of a danger is a good thing, so the faster the number of discovered near-Earth asteroids goes up, the better. Because if we do know one of the dangerous ones is coming, the only thing left to do is figure out a way to stop it in time.
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