Science Explained!

Randall Munroe, who writes and draws the XKCD webcomic that is one of the pages I look at nearly every day, has started a new webpage devoted to explaining sciencey stuff. Called What-if-xkcd, it answers a new question each Tuesday. The first question: what would happen if you tried to hit a baseball pitched at 90% the speed of light?   

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, they’re just hanging there, frozen.

The ideas of aerodynamics don’t apply here. Normally, air would flow around anything moving through it. But the air molecules in front of this ball don’t 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 ball’s surface. Each collision releases a burst of gamma rays and scattered particles.  

After about 70 nanoseconds the ball arrives at home plate. The batter hasn't even seen the pitcher let go of the ball, since the light carrying that information arrives at about the same time the ball does. Collisions with the air have eaten the ball away almost completely, and it is now a bullet-shaped cloud of expanding plasma (mainly carbon, oxygen, hydrogen, and nitrogen) ramming into the air and triggering more fusion as it goes. The shell of x-rays hits the batter first, and a handful of nanoseconds later the debris cloud hits.   

So, when all is said and done, there is a crater where the ball park used to be, everything for a mile around has been leveled, and the city has a sizeable firestorm to contend with. On the positive side, a careful reading of the rules of baseball, says Munroe, would indicate that the batter would be considered hit by pitch and would be awarded first base.  

This week's question is about the possibility of getting a perfect score on the SAT Test by guessing.  The conclusion:  

How certain is it? Well, if they (all 4 million 17-year olds) each used a computer to take the test a million times each day, and continued this every day for five billion years—until the Sun expanded to a red giant and the Earth was charred to a cinder—the chance of any of them ever getting a perfect score on just the math section would be about 0.0001%.   

If you enjoy reading about science, this may be a good place to gain some understanding of how things work.