Yomi wrote:Why are we acting like Life sustaining planets is some kind of everyday thing. It's pretty rare in the real world too.
In fact, as of now we know of exactly 1 planet with life.
We have something known as the Drake equation, which can be used to discern how many civilisations that send signals into space for us to detect there are in the galaxy. It boils down to N (amount of civilisations) ~= L (length of life of average civilisation in years). Of course there's a bunch of fractions that go into the full equation, and one of them is the fraction of planets with intelligent life that send out signals for us to detect. We can ignore that, because the Supreme Kai doesn't need signals. So our version would be N ~= L / s (s = fraction of planets with signals). L can have vastly varying values, obviously, but we can look at Earth's various historical civilisations to get a rough estimate. It gives about 1000 years or so. The fraction of planets with signals is part of a larger series of fractions which we have ignored, so it's not as small as you might think. It may be 1/10, or maybe even 1/5. That gives us N ~= 1000 * 5, N ~= 5000. 5000 eligible planets in the real world Milky Way, basically. Not too bad, that, but definitely not a lot.
I'm talking about applying real world stuff to fiction here, obviously. We have to remember that in Dragon Ball, the universe may or may not be large, but it is so, so
finite.
How many galaxies are there in Universe 7? Well, it might be 4, and it might be more. There's links aplenty in the earlier pages of this thread where we can read about that. It seems like 4 galaxies is the best option. The definition of galaxy is quite loose, though, and I'm wondering if calling it "four galaxy groups" is better. A galaxy group is... well, a group of galaxies close to each other. That definition allows for regions of empty space within one Dragon Ball galaxy. So we'll say four galaxy groups. How many galaxies are there in a galaxy group? Difficult to say, but less than 50, otherwise it'd be a cluster. It doesn't really have to be more than a couple. If we assume that they're compact groups, there are about 5. So there being about 20 galaxies in Universe 7 doesn't seem like too wild of an estimate... It also gives roughly 100,000 ningen planets, as I like to call them, and that's a nice round number.
Then, we just apply periodic Buu since the beginning of time, millions of years of bad work etiquette by Beerus and Shin, and a handful of centuries of Frieza's empire (which I've found to be by far the most devastating factor), and suddenly 28 ningen planets doesn't seem so farfetched anymore.