Tue 12 Dec 2017 13:07
A Way to Visualize Relative Masses of Things in the Solar System
Every so often we hear things in the news about the solar system: a mission
to a planet or asteroid, talk of manned missions to mars, arguments about
whether Pluto is a planet or not. We tend to have pretty sketchy ideas of
what most bodies in the solar system are like compared to Earth. The fact
is that they're more wildly different in size and mass than we might think.
Let's look at mass. Imagine you decide to row across San Francisco bay in a 12-foot aluminum rowboat. You pack a couple of suitcases, your 15 inch Macbook Pro (can't go without connectivity) and your ipad mini, you get in your rowboat and start rowing. As you row, you get hungry, so you pull out a Snickers bar. Now imagine that the USS Nimitz, a massive nuclear-powered aircraft carrier, passes by. There you are, in a rowboat with your two suitcases, your Macbook Pro, your iPad, and your Snickers bar, alongside a huge supercarrier.
Well, the mass of the sun compared to the earth is like that aircraft carrier compared to you and your boat. The mass of Mars is like your two suitcases. The mass of the moon is like your 15 inch Macbook Pro, and the mass of Pluto is like your iPad mini. As for the Snickers bar, it's like Ceres, the largest of the asteroids.
Now let's suppose the massive wake of the aircraft carrier tips over your rowboat and leaves you in the water. Along comes a rich tech founder in his 70 foot yacht, and fishes you out. That yacht is like Jupiter, the largest planet.
So forget any mental images you might have of planets being something like the Sun, only a bit smaller and cooler. The sizes of things in the solar system are really quite different, and there is nothing, absolutely nothing, in the solar system that is anything quite like the Sun.