A New Spin

A New Spin (cont'd)

5. What, then, made it possible for them to take their place in the earth's history?

In one word: weight or rather, lack of it!

It's the weight, not necessarily the size, which gives rise to all the restrictions discussed above. It was the weight that slowed down the mass which hung on the spring in the high school physics experiment; and it's the cause for slowing down the big animals and, of course, the ultimate limit to their growth.

It follows that if we take for granted the existence, in the past, of the big lizards (the size of which can exist only on a world many times smaller than the planet Earth) their weight must have been much lower than what their size suggests.

heavy

6. But aren't weight and size one and the same?

Not necessarily! You must have seen the grainy black-and-white video-clip of an astronaut hopping like a jack rabbit with all his gear on his back. His size hasn't changed on the moon but his weight has.

Take the case of the whale discussed above. When its weight is stated it refers, no doubt, to its 'virtual weight' on land, not in its natural environment (i.e., in the sea) where it would be much lower (which by the way, explains how it could grow to such a size without violating the limit-to-growth).

The big dinosaurs' size is given but their weight is only deduced. After all, when their remains are dug up, they never come wrapped and labeled stating their weight like a package of beef on the shelf of your neighborhood supermarket. The weight is only estimated and is based on the size of the finding; and on the assumption that weight was then what it's now. This assumption could of course be wrong. As we have seen above, it's most likely wrong.

The size of a single big dinosaur may have been equal to the combined size of a herd of 20 elephants, but its weight must have been no more than that of a single member of the herd, so that it complied with the limit-to-growth and remained viable. Such an animal could roam around, forage and do what elephants do today despite its huge size.

There is an added bonus to this. It explains how a giant predator could have functioned. The weight of what is usually considered to be an eight-ton beast, would proportionally fall somewhere between that of a lion and a grizzly bear, which would render it well suited to its role.

7. Are we talking change in gravity, then?

Yes and no! Generally speaking, gravity is responsible for a given body weight. But this is somewhat of a generality. In fact there are two more factors that participate in determining the weight. These are buoyancy and centrifugal force.

Both of these factors act in diminishing the weight of the body, but their effect is so minimal that it can be safely neglected. The centrifugal force constitutes less than one percent of the force of gravity and buoyancy even way less than that. Therefore, it's not a terrible mistake to say that gravity determines the weight.

This is the situation nowadays. If we are to investigate the possibility that weight was different in the past, we ought to examine all the factors involved, not just gravity, in order to try and determine the reason for the lowered weight. Take for example buoyancy. While its effect is negligible on land, it's a major factor in the sea and is the main reason for the weight of a whale to be what it is in its environment. (A way less than what it would be on land.) Buoyancy, therefore, should not be dismissed off hand without any consideration of its possible cause for the weight change.

Let us examine gravity itself first. In order to bring the weight of a big dinosaur to that of an elephant, gravity in the past had to be one twentieth of what it's today. That suggests that the earth, subsequent to the time of the dinosaurs, gained mass by either colliding or somehow merging with an extraterrestrial body some 19 times its own original mass. Experts, however, can point to permanent marks in the form of craters as a result of collisions with very small objects relative to the earth. Therefore, it's impossible that a collision with a body, 19 times more massive than the earth, has not left any mark whatsoever on the earth's surface. Hence, an increase in gravity must be ruled out as a cause for the weight change.

Next we look at buoyancy. Every object on earth is immersed in air (in essence, a form of fluid) just as it would be if immersed in water for a sea creature. Buoyancy constitutes a major factor in water but only a minor one in the air. The reason is that the density of water is nearly a thousand times that of air. While the air could have changed throughout that time in composition and concentration, it could not have changed in density in any significant way to make much of a difference. Therefore buoyancy can also to be ruled out as the cause for weight change.

The only factor that is left is the centrifugal force. Although there is no direct proof that the centrifugal force was any different in the past, there is equally no proof to the contrary. The mere existence of big animal fossils may, by itself, constitute such a proof.

8. What is centrifugal force and how could it affect the weight?

The centrifugal force arises due to rotation. The classic example is a rock tied to one end of a rope. As the rope is held at the other end and is being rotated fast in the horizontal plane, the rope becomes taut. The centrifugal force tends to pull the rock away from the center of rotation.

Now, those of you who are card-carrying members of the 'Flat-Earth-Society', will have to take my word for the next statement: the earth is rotating on its axis. How fast does it rotate? Fast is of course a relative term, and as far as we can tell, it doesn't move at all since everything around us moves at the same speed. But to compare it to, say, a ticket-carrying driver (speeding ticket, that is) it's way faster. In fact, at the region of maximum speed, any point is zooming by at a velocity due to the earth's rotation which exceeds that of a supersonic jet going at Mach-1.

The rotational velocity gives rise to a centrifugal force which opposes that of gravity. Consequently, its effect is to reduce somewhat the gravitational pull and hence, the weight of any object on the surface of the earth. However, as things stand now, the centrifugal force effect is minimal and is usually neglected.

As for everybody out there (with or without membership cards) you have to take my word for it that at the time of the dinosaurs the earth was spinning on its axis close to 17 times faster than it does today. How did the

earth come to spin so fast? For all we know, there is no reason why it didn't do so from the 'beginning' but more on that later.

A faster spinning earth would have constituted a strange world indeed. You could have been persuaded, in such a world, to consider 'working from home' (also known as: 'Telecommuting' or, 'Telework') since by the

time you would have made it to the office most of the day would have gone by. It would have taken only around three-quarters of an hour from dawn to dusk. But other than that, not much of a difference. It wouldn't be possible to tell that the earth is spinning fast more than than it's today.

It did make all the difference for the giants of that time though. It enabled them to carry on with their lives and function as intended. (And, hence, there would be no need to constantly try and 'shoehorn' them into functioning in the present state of slow spin.) The biggest land animal ever would have weighed just as much as an African-Elephant, a weight, which most likely was the limit-to-growth on land then, as it's now.

Next: What is it that made earth's spin to slow down?

i. 'What is this?'

ii. --The short answer:

iii. --The long answer:

iv. For the impatient:

v. 'What is next then?'

1. The bigger they are ...

2. Is there a limit to growth?

3. Not convinced yet? What does rate have to do with it?

4. Why aren't any such big animals alive today?

5. What, then, made it possible for them to take their place in the earth's history?

6. But aren't weight and size one and the same?

7. Are we talking change in gravity, then?