Skip to comments.Relativistic Baseball
Posted on 08/04/2013 9:27:49 AM PDT by 1rudeboy
What would happen if you tried to hit a baseball pitched at 90% the speed of light?
Lets set aside the question of how we got the baseball moving that fast. We'll suppose it's a normal pitch, except in the instant the pitcher releases the ball, it magically accelerates to 0.9c. From that point onward, everything proceeds according to normal physics.:
The answer turns out to be a lot of things, and they all happen very quickly, and it doesnt end well for the batter (or the pitcher). I sat down with some physics books, a Nolan Ryan action figure, and a bunch of videotapes of nuclear tests and tried to sort it all out. What follows is my best guess at a nanosecond-by-nanosecond portrait:
The ball is going so fast that everything else is practically stationary. Even the molecules in the air are stationary. Air molecules vibrate back and forth at a few hundred miles per hour, but the ball is moving through them at 600 million miles per hour. This means that as far as the ball is concerned, theyre just hanging there, frozen.
The ideas of aerodynamics dont apply here. Normally, air would flow around anything moving through it. But the air molecules in front of this ball dont have time to be jostled out of the way. The ball smacks into them so hard that the atoms in the air molecules actually fuse with the atoms in the balls surface. Each collision releases a burst of gamma rays and scattered particles.
These gamma rays and debris expand outward in a bubble centered on the pitchers mound. They start to tear apart the molecules in the air, ripping the electrons from the nuclei and turning the air in the stadium into an expanding bubble of incandescent plasma. The wall of this bubble approaches the batter at about the speed of lightonly slightly ahead of the ball itself.
Silly premises lead to silly conclusions. Nothing new in that.
Interesting website. I’ve been aware of the XKCD cartoons, but not this.
Physics is not “silly,” in my opinion. Go and show this link to a niece or a nephew of a younger age, and see what happens.
Indeed. They're weren't relativistic, but they still made an awfully big "bang"!
This technology is very far outin miles and years. A pair of satellites orbiting several hundred miles above the Earth would serve as a weapons system. One functions as the targeting and communications platform while the other carries numerous tungsten rodsup to 20 feet in length and a foot in diameterthat it can drop on targets with less than 15 minutes notice. When instructed from the ground, the targeting satellite commands its partner to drop one of its darts. The guided rods enter the atmosphere, protected by a thermal coating, traveling at 36,000 feet per secondcomparable to the speed of a meteor. The result: complete devastation of the target, even if its buried deep underground. (The two-platform configuration permits the weapon to be reloaded by just launching a new set of rods, rather than replacing the entire system.)
Popular Science, Rods from God, June 1, 2004.
Thanks for making my point. (And your's is not an opinion, it's a fact, Jack.) The silly part is the premise of a 0.9c baseball in a dense atmosphere. It would have burned up long before ever getting to 0.9c. Ever see a small piece of space debris entering the thin outer atmosphere at 0.0000...c? Poof. Shooting star. Gone. You cannot suspend basic physics, go on to construct some "what if?" scenario, and then claim it's still covered by physics.
Oh, as to your suggestion, I would not knowingly subject any young relatives of mine to silly stuff like that before they had a firm grasp on the real principles of physics.
(That’s what public schools are for, anyway. Heh.)
We'll suppose it's a normal pitch, except in the instant the pitcher releases the ball, it magically accelerates to 0.9c. [emphasis added]
My favorite bit:
We have not yet considered the existence of a Supergirl.*
*She can't mate with Superman because she's his first cousin. And only a cad would suggest differently.
The various incarnations of Supergirl:
Totally logical within the premise of the Superman mythos. My favorite thought experiment is what happens when post-pubescent Clark Kent 'whacks off'? Even in farm country Kansas, super sperm will find ...
In a word, all are toast [in an imperceptible instant.]
There's no point at all continuing with (my premise) ‘physics’ after the (silly) premise ‘magically’. So yes, *my* premise.
My point stands: Silly premises lead to silly conclusions.
We can do this all day if you want. (Actually, I'll quit right here. No point arguing against an intentional fallacy.)
The linked site says :
A careful reading of official Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered "hit by pitch", and would be eligible to advance to first base.
They don't give the kinetic energy, though. This follows directly from K = (gamma - 1)mc2. With beta=0.9 , this comes to 1.29 mc2, i.e. 29% greater than the rest energy.
I always recall this illustration:
Half a dime is about 1 gram and a baseball is about 150 grams, so we're talking about 200 gram equivalent in kinetic energy at 0.9c. If the Hiroshima bomb was about 10 kilotons, we've got a 2 megaton explosion.
"That's the wonderful thing about science, one gets such wholesale returns in speculation on such a trifling investment of fact." - Mark Twain
Then you best burn most physics textbooks and rid the world of such things as frictionless pulleys, massless ropes connecting point masses, frictionless surfaces, continuous mass distributions etc.
I knew the pitchers were getting fast, but...
Simplification (e.g., a point mass) to enable mathematical description is not the same as ‘magic’ as used in the article. JMHO.
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