Strange Idea Of The Week

[Dr Adequate]

It's quite a read. Let's cut to the chase at the end of chapter 3:

To produce an effective buoyancy force on dinosaurs the Earth's atmosphere would have to be thick enough to have a density comparable to the density of water. By summing the forces acting on a typical dinosaur such as a Brachiosaurus the density of the necessary atmosphere is calculated as:

D_F = D_S = 1/(1 - SF)

where D_F is the density of the fluid, D_S is the density of the substance submerged in the fluid such as the dinosaur, and S.F is the scaling factor. Inserting into this equation a scaling factor of 3.2 and an overall vertebrate density of 970 kg/m^3, the Earth's atmospheric density during the late Jurassic period can be calculated to be 670 kg/m^3. This says that to produce the necessary buoyancy so that the dinosaurs could grow to their exceptional size, the density of the Earth’s air near the Earth’s surface would need to be 2/3’s of the density of water.

It may be difficult for some people to imagine how the Earth could have had such a dense atmosphere. But nevertheless, the wonders of our reality often exceed the limitations of many people’s imagination. The thick atmosphere solution violates no property of science. It is the correct solution.​

 

[technoextreme]

To produce an effective buoyancy force on dinosaurs the Earth's atmosphere would have to be thick enough to have a density comparable to the density of water.​

Just by this I can tell this is a load of bull. The implications of this are extremely odd and impossible.

 

[Naughtyhippo]

Soooooooooooo, if the atmosphere had been less dense, dinosaurs would've floated?

Does this mean our skyscrapers have foundations to tether them to the ground and prevent them floating away?

 

[Jimbo07]

Soooooooooooo, if the atmosphere had been less dense, dinosaurs would've floated?

Does this mean our skyscrapers have foundations to tether them to the ground and prevent them floating away?

Other direction. If the atmosphere had been less dense at the time, the dinosaurs would have obviously collapsed under their own weight...

... in much the same way that skyscrapers and elephants typically do now...



ETA: Or astronauts on the moon, for that matter.

... ooh, floating dinosaurs (not like those stupid actually swimming pleisosaurs) would be awesome! "Hey Frank!" "Hey Bill! Awesome day for a float outside, huh?"

 

[technoextreme]

Soooooooooooo, if the atmosphere had been less dense, dinosaurs would've floated?

Does this mean our skyscrapers have foundations to tether them to the ground and prevent them floating away?

You have it backwards. Anyway I was thinking that the oceans would have floated on the atmosphere.

 

[Naughtyhippo]

See, I knew I had something bass-ackwards.

 

[PixyMisa]

Whee.

I like how he goes into scaling factors, explaining why larger animals are a different shape to small ones, and then totally ignores all of that to prove that dinosaurs could not exist. Or whatever.

Not to mention that if air had been 500 times denser then than now, pterosaurs would have been shaped like fish rather than birds.

Also, if we've lost 99.8% of our atmosphere in the last 65 million years, we should probably be worried.

 

[Jimbo07]

See, I knew I had something bass-ackwards.

Yes, but to your credit, you're nowhere near as wrong as Esker...

physics instructor, indeed, grumblegrumblegrumble...

 

[fuelair]

I'm pretty sure all this was covered back in the 70s - without recourse to silliness.

 

[Mojo]

I'm pretty sure all this was covered back in the 70s - without recourse to silliness.

By Anne Elk, perhaps?

 

[Naughtyhippo]

The atmosphere was different in the past if memory serves though - wasn't there an atmosphere much richer in oxygen during the time of the giant insects? And insects cannot today get much bigger as their breathing system will breakdown in the comparatively oxygen poor atmosphere?

 

[Darat]

James P. Hogan been going on about a theory that gravity was different when the dinosaurs evolved: http://www.jamesphogan.com/bb/bulletin.php?id=1060

...In short, for whatever reason, the gravity in times gone by must have been less than it is now.....​

 

[Freethinker]

Gravity is clearly increasing rapidly. As recently as 20 years ago, I could wipe out trying to land a dirt bike, and get up almost instantly and hop back on the bike and be back to speed before the back of the field caught me. Now it's all I can do to get up after I tie my shoes.

 

[Third Eye Open]

Well, the increased air density was clearly caused by the large ice shell that was surrounding the earth at that time, pressing down on the atmosphere.

 

[tyr_13]

The atmosphere was different in the past if memory serves though - wasn't there an atmosphere much richer in oxygen during the time of the giant insects? And insects cannot today get much bigger as their breathing system will breakdown in the comparatively oxygen poor atmosphere?

That's correct. There were times when the we had much, much more oxygen when there were six foot long dragon flies. There were also times when we had several times the CO2 levels, and that was when many of our trees evolved. The reason that trees change color in the fall is in part because of CO2 deprivation. If we had more CO2 today, trees would grow faster though the year.

There are a lot of cool stuff like that in our past. However, I don't see how that justifies this paper! I mean really, how did that work? Wouldn't that atmosphere have too much pressure to breath with lungs?

 

[Loss Leader]

My dream is to come up with one unified theory that encompasses snowball earth, swimming apes and floating dinosaurs. And then get it published at The Agony Booth.

 

[tyr_13]

Make the apes into ninja bigfoot. Then you'd get a book deal.

FYI, that is my theory why for all the searching we have no good videos, fur, dead bodies, evidence, of BF, they are all ninja.

 

[Madalch]

And he thinks that, back then, the atmosphere was pure carbon dioxide.

 

[quarky]

Whales require a liquid medium to handle their mass. Structural requirements lose efficiency as the beast gets larger. Big dinos were likely pushing the limits. As per brain size limits, a huge body is implied, to minimize damage from acceleration of the body mass.

 

[shadron]

That's correct. There were times when the we had much, much more oxygen when there were six foot long dragon flies. There were also times when we had several times the CO2 levels, and that was when many of our trees evolved. The reason that trees change color in the fall is in part because of CO2 deprivation. If we had more CO2 today, trees would grow faster though the year.

There are a lot of cool stuff like that in our past. However, I don't see how that justifies this paper! I mean really, how did that work? Wouldn't that atmosphere have too much pressure to breath with lungs?

I'd be interested in seeing where you derived that from. AFAIK, the atmospheric components have been pretty stable (say, +/-5%) over the last 200 million years. Yes, CO2 has gone up and down, but inasmuch as it is currently only about .03%. a doubling or tripling is down in the noise, were it not for its effects on plant growth and greenhouse effect*. You don't need more oxygen, or more pressure, to support 6' dragonflys, just a proper ecological niche and time.

And no - the atmospheric pressure being higher or lower doesn't really affect lung performance. The pressures equalize, inside and out, and the mechanics still work.

* anti-AGWs: Please don't start another AGW fight over this; it is only an incidental statement of fact.