# Dinosaurs and Treetops **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [September 3, 1999, 1:55pm UTC](https://boards.straightdope.com/t/dinosaurs-and-treetops/867 "1999-09-03T13:55:00Z")\ **Posts on this page:** 4\ **Page:** 4
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [March 21, 2000, 6:02am UTC](https://boards.straightdope.com/t/dinosaurs-and-treetops/867/61 "2000-03-21T06:02:00Z")
Concerning the variable rate of the angular momentum transferred between the earth and moon. I remember reading an article recently (on [talkorigins.org](http://talkorigins.org)?) which provided the theory that the shape of the land masses alter the rate at which the moon drags on the earth. This sort of makes sense. The big bulge of water the moon is making that we call the tides is going to drag a lot less against one super continent called pangaea, then against a series of spread out continents which go almost from the north end to the south end of the earth. Anybody heard about this/understand it/have links? ---
**Author:** ![Myron\_Van\_Horowitzski](https://avatars.discourse-cdn.com/v4/letter/m/9de053/32.png) [@Myron\_Van\_Horowitzski](https://boards.straightdope.com/u/Myron_Van_Horowitzski)\ **Post date:** [March 21, 2000, 4:50pm UTC](https://boards.straightdope.com/t/dinosaurs-and-treetops/867/62 "2000-03-21T16:50:00Z")
Why were dinosaurs so big? The answer \ can be found here: [http://www.christiananswers.net/dinosaurs/questions.html](http://www.christiananswers.net/dinosaurs/questions.html) * * * Imbibo, ergo sum. ---
**Author:** ![JonF](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@JonF](https://boards.straightdope.com/u/JonF)\ **Post date:** [March 21, 2000, 5:42pm UTC](https://boards.straightdope.com/t/dinosaurs-and-treetops/867/63 "2000-03-21T17:42:00Z")
Perhaps i should let sleeping dogs lie, but I can’t resist. Raydot14: > [@](#): > > If sufficient dust (mass) collects to form a star large enough to become a supernova why does the supernova have to undergo an explosion before it can implode and become a black hole? If it is burning up it’s “fuel” it should losing mass and never become a black hole. If it had sufficient mass from beginning it should have become a black hole instantly. 1. Gravitational attraction is a _nonlinear_ function of distance. It is proportional to the square of the radius from one center of mass to another. 2. An elementary result from first-year college physics is the proof that a uniform spherical shell of matter exerts no gravitaional force on anything inside. From these facts, it’s relatively easy to calculate the relationship of a non-black-hole star to some piece of matter (which might be part of the star): A. Either the matter is outside the star and is far enough away that it can (but not necessarily will) escape the gravitational pull of the star, or B. The matter is inside the star and is not affected (graitationally) by the portion of the star’s matter that is farther away from the center, and can (but not necessarily will) escape. A black hole forms only when the star contracts enough that the mass inside a relatively small radius from the center is high enough to prevent escape. As for the energy questions, a star radiates energy by “converting” mass to energy. (It’s more correct to say that it converts one form of mass-energy to another form). A star can lose a _lot_ of photons without a measurable effect on the mass, but eventually the star’s mass is reduced noticably. The process of collapse and/or explosion is complicated, because of radiation pressure and thermal effects and the size of a star (it takes a long time for something to propagagate from the center of a star to the outside). * * * jrf ---
**Author:** ![Loren\_Pechtel](https://avatars.discourse-cdn.com/v4/letter/l/d2c977/32.png) [@Loren\_Pechtel](https://boards.straightdope.com/u/Loren_Pechtel)\ **Post date:** [March 22, 2000, 1:01am UTC](https://boards.straightdope.com/t/dinosaurs-and-treetops/867/64 "2000-03-22T01:01:00Z")
> [@](#): > > Originally posted by JonF: > \*\*2. An elementary result from first-year college physics is the proof that a uniform spherical shell of matter exerts no gravitaional force on anything inside. > \*\* ``` I'm afriad I must object to the term "elementary" here. While I have the stated education, I certainly don't regard the calculation as elementary, nor was it something that was discussed. (Gravity was barely touched upon, never applied.) ``` [Previous page](https://boards.straightdope.com/t/dinosaurs-and-treetops/867.md?page=3)