Originally Posted By: Marchimedes
Took a quick look around in this here thread and didn't see my Monkey post. (Actually I have many, many Monkey posts but as far as I can remember I've only one Monkey in space post. That one.) Please to forgive me if this is a repost.

In a empty universe we plunk down a Monkey in a spacesuit. Space suit has one of those trap doors on his butt, you know, the kind little kids have...

only on the Monkey spacesuit the trap door is airlocked.

So the Monkey, being a Monkey, is gonna crap in his hand and fling the feces. This is strong Monkey who was once the ace pitcher in the jungle league so he's got quite an arm and can fling feces at near c (speed of light, I know you nerds know this but this gives me an opportunity to call you nerds).

Off goes the feces and the Monkey himself of course will go off in the exact opposite direction of the feces. Monkey and feces are going Hell bent for leather in opposite directions. The instant feces leaves Monkey's hand it is travelling at it's maximum velocity. Instantly gravity will begin slowing down both Monkey and feces as this universe is empty except for the Monkey, and now his feces. Eventually the Monkey and his feces will halt and begin travelling towards each other.

A side question: Will the feces halt and start travelling towards the Monkey before the Monkey halts as the Monkey has greater mass? These are the kinds of things that pester me. Obviously I am a great thinker.

So, that is the Monkey in space post. I went a long way to set up the Monkey universe for you. This philosophy also applies to my "why the universe appears to be expanding at an accelerating rate from our perspctive" theory. I tie things together like that. Any holes in the Monkey in space theory?

I'll take your frightened silence as a no.


Same universe without the Monkey. Or the feces.

Unless you live in a cave much like the cave where I keep a guy for screaming at you'd know I have some, er, difficulties with c being the universal speed limit so lettuce beat that dead horse some more.

Plunk down a couple of hyper massive black holes (I use black holes cause they are the densest things I know of except for perhaps whatever it was that big banged) buku light years apart. Lettuce say both black holes are travelling at 99.99% c directly towards each other.

They should accelerate towards each other, right?

What is to keep the black holes from exceeding c given there is enough space between them at the onset?

Originally Posted By: redewenur

A reminder: There's no known limit, such as c, on velocity of objects relative to each other, only relative to the spacetime through which they move.

Nuttin relative here. Take each black hole's speed on it's own.

Since the monkey and his departed dung are the only objects in Monkey Universe, with no other points of reference, it's meaningless to talk of which stops first. And since your monkey is such an ace pitcher, they would be well beyond mutual escape velocity, and never the twain shall meet.


The two objects approaching c - from the point of view of a stationary observer - would each gain mass approaching infinity. To accelerate them to c would take energy x time = infinity. In other words, it's not going to happen.

See here (bottom of page):
"Getting even faster is expensive" and the included chart.
"Time is what prevents everything from happening at once" - John Wheeler