Recent Cuba meteorite estimated to have weighed about 360 tons


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Using its imaged track from several sources, scientists have now estimated the size and weight of the recent spectacular fireball over Cuba as being several meters across and weighing about 360 tons.

After reconstructing the trajectory in the atmosphere, the Colombian astronomers “played back” the impact and found that the culprit, a rock with an estimated size of several meters and a weight of about 360 tons, came from an eccentric orbit around the Sun with an average distance to our star of 1.3 astronomical units (1 astronomical-unit = 150 million km). Before impacting the Earth, the rock completed a turn around the Sun every 1.32 years. All that came to an end on February 1, 2019 when both, the rock and the Earth, found themselves at the same point in space, at the same time. The worse part was for the rock!

The article spends most of its time selling a computer model the scientists have developed that they claim can predict the approach trajectory of meteorites, something I find quite unconvincing. However, the result above is important for different reasons. Routinely astronomers today discover new small asteroids just days before they zoom harmlessly past the Earth. Each time one of these new near Earth asteroids is found, the press automatically goes into “Chicken Little mode,” suggesting that should this object have hit the Earth it would have caused massive damage.

Most of these newly discovered asteroids are about the same size as the Cuba meteorite, if not smaller. Thus, this meteorite gives us a clear idea of how completely harmless these other near Earth asteroids are. In fact, this impact suggests to me that in most cases an asteroid would have to be about ten times larger to pose a significant threat.

Keep this number — 360 tons — in mind the next time another near Earth asteroid is discovered.

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4 comments

  • Andrew_W

    Thus, this meteorite gives us a clear idea of how completely harmless these other near Earth asteroids are

    It seems likely to me that this was a C-type meteorite, if it had been a several hundred ton S or M-type it may have hit Earths surface mostly intact.

  • Andrew_W: You make a very good point that I should have considered. The question remains: Would a nickel-iron asteroid of this size (several meters) and weight (about 350 tons) produce any significant damage?

    I suspect not, in most cases. Only if the asteroid is coming in from a high angle orbit at great speed would it pose a greater threat.

  • Edward

    Robert wrote: “Routinely astronomers today discover new small asteroids just days before they zoom harmlessly past the Earth.

    The main reason that these small asteroids are noticed only days before they come to closest approach is because they are small. They are not large enough for us to notice while they are still farther away.

    The article notes that the scientists needed three observations to calculate the meteor’s orbit. Interestingly, if you have distance information, it only takes two observations. In the movie “Roxanne,” the title character says that she thinks she discovered a comet but wouldn’t know for a few days. This is because comet hunters need three observations to calculate the object’s orbit to verify that it is in a cometary orbit; they have no distance information.

    Robert wrote “The article spends most of its time selling a computer model the scientists have developed that they claim can predict the approach trajectory of meteorites, something I find quite unconvincing.

    I think I understand the reasoning that they apply. They associate their “Monte Carlo” type of model with orbits that resemble already known asteroid orbits. Where there are a number of similar asteroid orbits, then the conclusion seems to be that there are even more, so we might expect asteroids that land in various locations on Earth to come from directions that match their “predictions” for the various locations.

    If future sightings match their predictions, then the value may be in concentrating our meteor-searches in the directions that are likely to fall in areas that would be most adversely affected. Fortunately, we now have lots of cameras around the planet, so sightings may become common enough for the model to be well tested in the next few decades.

    Although, with luck, we will have already found all the dangerous asteroids by then.

  • wayne

    Armageddon
    “Get my phone book!”
    https://youtu.be/TzRYJGbtEjc
    0:32

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