Sure, I can fix your broken Dinosaur!

LovePosted by Eskil Sat, April 07, 2012 22:05:45
Being big, is good up to a point. After that you just get heavy and slow. Some dinosaurs had wings but where too heavy to fly. Some had long neck, but would pass out from blood loss if they used them to reach for anything, and some predators where so heavy the couldn't run. When you listen to paleontologists argue about the limitations of dinosaurs, you get the feeling that dinosaurs were not designed very well. It doesn't sound like something evolution would do.

I think that Paleontologist are looking at it all wrong. Instead of trying to figure out how these animals coped with physics, evolution probably made them perfect, It was the physics that was different. My theory is that the effective gravity was lower 65 million years ago.

No, I don't believe that the laws of physics have changed, Earth probably had comparable mass, but earths rotation is slowing down. If we imagine a past version of earth spinning a few times faster, the centrifugal force starts to counteract gravity.

If gravity was substantially lower, the brontosaurus could walk on land and raise its head without passing out because of blood loss, a tyrannosaurs would be able to run and the massive birds would be able to fly. They would all make sense from an evolutionary point of view.

Even today gravity is slightly lower at the equator, and earth is slightly flattened as the pols. It is a very slight, but if we look at the equation for centrifugal force we find that its velocity to the power of two divided by the radius. The power of two, means that the fairly insignificant centrifugal force quickly becomes very significant if we increase earths rotation.

The faster you spin the planet the further out the equator is pulled, and the further the distance between the center of earth and the equator, the stronger the centrifugal force becomes (the increased radius decreases the force, but the increased velocity makes up for it as a point on the surface has a longer distance to travel per revolution). If earth would spin at around 90 minutes per revolution, the centrifugal force would be so strong it would pull the planet apart. The equator would break lose from the surface and form the kind of rings we see around Saturn.

If we imagine that an earth day was only a few hours long in the Jurassic period, evolution would develop larger animals due to the lower effective gravity. If this theory holds up and earth rotation greatly influenced the effective gravity on earths surface, it would only do so close to the equator. Therefor you should only be able to find fossils of dinosaurs in areas that were reasonably close to the equator at the time.

I have never ever read anybody suggest this as a theory, and every time I read some article about how paleontologists argue about the limitations of dinosaurs, I think of this idea. I don't claim to be an expert, but I think its in the grand tradition of science to propose ideas, and then let others try to prove or disprove them. So please let me know how right or wrong you think I am.

While thinking of this I also discovered a new continent. Yes, I have found a continent, and I'm naming it "Eskil" (I mean, what the hell... if you don't like it i got there first). I do admit its a little like Democritus naming the Atom, or Higgs theorizing about his Boson, and then letting thousands of unnamed scientists spend years of research and millions of dollars trying to prove you right, but what can I say? I'm a busy guy, got places to go, people to meet and all that. So here we go:

Its commonly accepted that the tectonic palates once had all continents joined together to form a massive super continent commonly known as Pangaea. If we imagine that the weight of all continents where concentrated on one side of our planet, the center of gravity would shift towards that side. Yes, earth surface only makes up a tiny fraction of earths mass (most of earths heaviest metals has sunk to the core), but remember everything beneath the surface is fluid, therefore the core would move to be suspended in the center of the gravity of the surface. If the plants center of gravity would move towards this one continent, all liquid water would follow, an the sea level on the side of Pangaea would rise, and lower on the opposite side revealing a new land mass: Eskil.

I think its time to stop now, and go back to work.


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Posted by Darkshadow Mon, September 10, 2012 20:02:23

A interesting hypothesis but I am in agreement with Fede that the speed of the rotation change is nowhere near enough for it to effect gravity that much. I think a much more likely explanation for this paradox is due to the difficulty in recreating the really large creatures from just fossilised bones. The fact they claim it is impossible it is more likely due to a mistake in their model. Your are most likely right that evolution was working just as well then so it is probably safer to say these creatures were at the limits of what was possible rather than beyond them.That is not to say you should ignore the current paradox but the suggestion that physics has changed or the earths rotation has changed is Period from 2 hours to 24 hours in a 100 million years creates more problems than they solve.

Posted by Taslem Tue, June 05, 2012 23:22:17

Pangaea would not significantly alter the weight distribution of the Earth. The tallest mountains are flat compared to the difference in radius of the Earth at the equator and poles.

Posted by maxoverdrive Sun, May 06, 2012 11:29:57

too bad eskil was subducted as pangea was split apart which would dispose of all actual evidence :(

Posted by Icefox Sat, April 28, 2012 20:55:08

This is a cool idea! Unfortunately there is no real geological evidence pointing to Earth's rotation being THAT much higher in the past.

Mainly, if Earth were rotating much faster, it would bulge out at the equator and flatten at the poles. This would tend to make faults in the crust, extensional cracks near the equator where it is bulging and compressional kinks/folds near the poles where it is flattening. These are big planet-wide features; people think they've found them on Mercury and the Moon, which used to spin rapidly but are now tidally locked. I've done a fair amount of geology but never never seen anyone find anything like that on Earth.

Also the main reason the Earth's spin slows down is because of tidal drag from the Moon. We can roughly calculate how fast this should slow the Earth down, and it's not fast enough to make such a big difference.

The center of gravity does shift as the continents move around! I dunno if the effect is big enough to expose new land on the far side of the planet from Pangaea (the ocean is pretty deep). But it would be cool to try to run the numbers! Such things totally make local gravity anomalies, which can make the sea level change. Check it out:

Personally, I think the answer to how dinosaurs coped with physics is just that paleontologists and biologists don't know as much as they think they do. :-)

Posted by Chuck Mon, April 16, 2012 14:24:30

I find it kind of hard to believe but still it makes a lot of sense. It also explains giant insects and if the meteorites that hit Earth decreased its rotation, it could explain what killed them.

Posted by ChrisH Mon, April 09, 2012 01:19:07

I found a bigger flaw: For rotation periods below 14 hours, the earth could not hold it's atmosphere for billions of years (unless somehow replenished).

Posted by ChrisH Mon, April 09, 2012 00:48:35

I did some of my own calculations (see near the bottom of the post) :

I calculated that gravity would be cancelled-out by a day that is 1.41 hours long (which closely matches the result of a similar calculation by Asimov).

As dinosaurs would need a gravity that is at least 2.2 times lower, I calculated that the day would 'only' need to be 1.9 hours long. That is still very short, and sounds like it could have all sorts of problems. One "killer" problem is that it would reduce atmospheric pressure, making it harder for the same dinosaurs to fly/live, basically reducing the "plausible dinosaur" effect of a lower gravity. So you would need an even faster rotation, but we are already very close to the "no gravity" limit, beyond which the earth would start to pull itself apart.

So it does not seem possible to solve the dinosaur problem using ONLY a faster rotation speed.... but perhaps it could be PART of the solution????

Posted by ChrisH Sun, April 08, 2012 01:18:36

Bah, I should have said "3-5 times" not "100 times". That's what I get for speed-reading your own 3-month-old summary.

Posted by ChrisH Sun, April 08, 2012 01:16:11

The idea of faster rotation is an interesting solution, which I'd not heard before, but there are other possible solutions too, such as a much higher (say 100 times!) atmospheric pressure:

Maybe both rotation & atmospheric pressure are part of the answer? That way neither needs to be as 'unbelievably' high...

Posted by Eskil Sun, April 08, 2012 00:42:17

Interesting Paper, Thanks! 23h would not be enough, As the paper suggests deriving evidence using fossil, or by extrapolating current conditions is difficult. Earth distance to the sun must have been similar 65 million years ago to now, for life to survive, therefor it must have rotated about the same rate. The paper argues that physics actually has changed and that it therefor traveled faster. I'm however concerned with earths rotation around its own axis. While the forces discussed would have would have impacted earths rotation only marginally, for our purpose, it docent rule out that other forces did not (Impacts perhaps?). One could argue that the very existence of Dinosaurs, is evidence of a lower effective gravity. Again I don't in anyway pretend to have evidence for this theory.

Posted by Fede Sat, April 07, 2012 23:23:46

This might be interesting: (see tables on page 3). Faster, but probably not enough.

If we want to go back to 180 million years ago (Jurassic period) a day was probably 23hr long, which means that the speed at the equator might have been ~485.5 m/s ±4%, while now it is 465.1 m/s.