Are these quotes accurate?
318 times as massive doesn’t mean 318 times the gravity. Since gravity falls off with distance, it’ll decrease for a planet of larger radius, given a particular mass.
In other words, if you teleport to one Earth radius from the center of Jupiter you would indeed be crushed by the intense gravity*. However, if you instead teleport to the “surface” of Jupiter (one Jupiter radius out) then the gravity would be much lower because you’re much higher up. Since Jupiter is so big, the gravity can change with height more dramatically than it can on Earth, since Earth is so much smaller.
As a more extreme example, the sun has nearly a million times the mass of Earth, but if you could stand on the surface, the gravity would only be a thousand times greater. Granted, a thousand g’s versus a million g’s, either way you’re a pancake, but on paper it’s a pretty notable difference.
This actually relates to why a black hole’s gravity is so strong. A typical black hole has a mass comparable to the sun, but a very tiny radius. This means your distance from the center can get really small before reaching the “surface”, and the gravity can keep increasing.
*This assumes that the entire mass of Jupiter is contained within an Earth radius. In reality the gravity would be significantly less because much of the mass of Jupiter will be above you. However, you’d still be crushed by the intense pressure of the atmosphere at that level, which in a roundabout way is like being crushed by gravity anyway.
Another way to look at it is that surface gravity is proportional to density times radius. Roughly speaking, Jupiter’s radius is about 10 times that of Earth, but its density is only about a quarter as great, so the surface gravity is about two and a half gees.
Generally, about an eighth of an ounce will do it for most people.
I don’t know about “typical black holes”, but the minimum is 3 stellar masses to make a stellar black hole. I guess one could call that “comparable”. Are most SBHs the minimum size? I would think there would be more massive ones than small ones.
Okay, I laughed; most excellent Thread/Username/Post combo.
As a rule of thumb, by number at least, there are more small things than large things, for any given kind of thing. This usually follows a power law of some sort, with some lower bound on size. The more interesting question is probably whether there’s more total mass in large black holes than in small ones.