A house cat is smaller than an aircraft carrier, not larger– in world of ‘NYT’ correction

US Politics
on 6 Comments

This is off my usual topic when ranting about the New York Times, but I found it funny seeing how the NYT goes about retracting a dumb mistake. It probably isn’t fair to generalize from this, but it is tempting. Not Middle East material, but I wanted to share.

I enjoyed the above article in last Sunday’s Times Magazine quite a bit– “A new initiative to beam messages into space may be our best shot yet at learning whether we’re alone in the universe. There’s just one problem: What if we’re not?” Author Steven Johnson pointed out that those who receive the message might seek “the destruction of all life on earth.”

But unfortunately Johnson quoted a science fiction writer, David Brin, who claimed that in 50 years we would be able to launch a few kilograms at half the speed of light (maybe so) and (here is the mistake) the energy would make the impact that killed the dinosaurs look small.

This is a mistake a bright high school kid with an interest in physics could have caught. The energy of the asteroid that killed the dinosaurs is usually estimated to be in the 100 million
megaton range. The energy of ” several” kilograms going at half the speed of light is roughly 16 to 17 megatons if we take several to mean 5.

The original story said the few kilograms going at one half the speed of light had kinetic energy much greater than the asteroid. The reality is that it is millions of times less.

A number of nerds pointed this out to the Times (I was one), and the Times correction says that the energy would be less, not greater, than the asteroid impact.

An earlier version of this article misstated the impact a few kilograms traveling half the speed of light would have if they collided with Earth. The impact would be less than that of the asteroid that killed off the dinosaurs, not more.

That is true in the same sense that a house cat is smaller, not larger than a WW 2 aircraft carrier. That is the size of the mistake they made. A house cat has a mass of several kilograms, but you would need a 30,000 ton object going at half the speed of light to equal the dinosaur-killing asteroid impact.

This isn’t the kind of mistake most non-nerds are going to care about, but it shows not only some sloppiness, but a realization that if they admitted the size of the mistake they would look a bit silly to anyone who cared.

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6 Responses

  1. Walker
    July 7, 2017, 1:28 pm
  2. ahadhaadam
    July 7, 2017, 2:24 pm

    Maybe that’s why the New York Times calculates the energy of an Israeli tank shell traveling at 1,000 meters per second towards a Palestinian home as having equal energy to that of a rock thrown by a Palestinian teen – hence the symmetrical conflict portrayal which is the bedrock of NYT journalism when it comes to Israel-Palestine. Any chance they would ever correct that?

    • Donald Johnson
      July 7, 2017, 8:26 pm

      Good analogy. They would probably take the same approach– acknowledge if pressed that a rock thrown by a boy does have less energy than an artillery projectile traveling at 1 km per second.

      Gotta look at Walker’s link.

  3. Keith
    July 7, 2017, 5:18 pm

    DONALD JOHNSON- “The energy of ” several” kilograms going at half the speed of light is roughly 16 to 17 megatons if we take several to mean 5.”

    Assuming current or projected efficiency in conversion of fuel to velocity, how much energy/fuel would be required to accelerate your 5 kilogram projectile to half the speed of light? I suspect that energy reality is completely overlooked by modern science fiction which fails to deal with the energy reality of space travel. My background doesn’t permit me to make the calculations, but apparently yours does. Thanks.

    • Donald Johnson
      July 7, 2017, 7:16 pm

      I am not a rocket scientist either, but you are no doubt correct to be skeptical about how easy it would be. I said maybe in 50 years because who knows what might be doable in 50 years, but at present it looks very very hard. Here is a paper that pours some cold water on the overoptimistic assumptions people make concerning antimatter rockets.

      https://trs.jpl.nasa.gov/bitstream/handle/2014/38278/03-1942.pdf?sequence=1&isAllowed=y

      Of course manufacturing and safely storing the stuff is the biggest problem. I would imagine you would have solar powered factories in space. Only lunatics would do it on earth.

      • Donald Johnson
        July 7, 2017, 8:23 pm

        I skimmed through the link above ( only skimmed– reading it seriously would be a major project) and to get to 0.5 c using his assumptions requires a mass ratio close to 30. So it would take 150 kilograms of matter and antimatter to get the 5 kilos up to that speed.

        You would calculate the number to be much less if you see the standard relativistic rocket equation ( given in the following link) and assumed a much higher exhaust velocity as a science fiction writer probably would have done or as I would have done but according to the preceding link the standard equation isn’t accurate for antimatter powered rockets and reality is an ugly thing for people who want to go zipping along at a respectable fraction of c.

        http://www.relativitycalculator.com/images/rocket_equations/AIAA.pdf

        Anyway, back to more normal mondoweiss topics. I thought it was interesting how the NYT handled a factor of six million error acknowledgement. Not very openly, it turns out.

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