A question about giant pterosaurs taking off.

[Rroff]

Maybe a child.

Quick calculations puts its ability to lift at around 20lbs maximum (likely closer to half that) which is basically a baby under a year old at most.

EDIT: Again would have to look it up but I seem to recall birds generally can lift about half their weight and carry about 1/4 their weight for any sustained distance.

 

[arknor]

Haast Eagle. Less than 1000 years ago IIRC. I doubt if they could have lifted a person, though. Killed and eaten a person, yes. Lifted one, no. Maybe a child.

this bird can live this goat so I'd think it was actually quite likely maybe not a 6ft tall person but people weren't that tall that long ago

haast were probably 15kg according to google and hunted moas that went up to 230kg

 

[Unseul]

Of course I don't (have an evidence). Dr. Francis can be militantly aggressive and dismissive all he wants, but the simple truth is - the idea that animals of a size of a Cesna and a muscle structure on those dug up bones powerful enough to stretch 13 meter wings, produce 2.5G uplift in a single flap and launch 250kg body into the air at sharp angle create way more physical problems than a simple and elegant solution that the earth inhabited by those animals was simply not the earth as we know it now.

I'm not even sure if we need any additional "proof" other than otherwise inexplicable gigantism of nearly all flora and fauna on earth confidently inhabiting the planet for hundreds of millions of years with very few size related mutations, compared to the current official version.

Dr. Francis elects to believe that all those animals lived in 1g and moved around like in Godzilla movies or dragons from GoT, and it's his right, he holds a title in his field and you and I don't.

But since I don't have a lifelong volume of bovine excrement on the subject to defend - instead of applauding men believing in dragons I elect to follow hard physics. The notion that the earth of dinos worked differently before getting hit hard with a fast earth bound bullet from space and ending hundreds of millions of years of gigantism once and for all - doesn't upset me, doesn't make any difference to me, but - you have to admit - it explains almost absolutely everything you can think of so far whereas such super giants flying, running, chasing prey, wagging 30 meter tails and mulching through tons of fuel a day required to maintain muscle mass to keep those sizes in motion in 1G, relatively unchanged, for so long... is... well... at least somewhat lacking?

You elect to follow the hard physics.

That you have no evidence for. Size of the dinosaurs is not evidence for lower gravity, as it can be explained by multiple theories (such as the one posited in the link I gave). For evidence of lower gravity, you need to show evidence that the earth was either larger and the same mass, or the same volume and less dense, and explain how and when all that suddenly changed. At the very least, even without evidence, you'd need a valid possible mechanism.

You elect not to follow the hard physics that provides good evidence and reason for why it was not the case. And you elect to not follow the evidence and reason that explains the size of the dinos.

I'd love to know how you know there were very few size related mutations back then as well . If you can point me to the genetic studies of the flora and fauna of the triassic period .

 

[builder22]

this bird can live this goat so I'd think it was actually quite likely maybe not a 6ft tall person but people weren't that tall that long ago

haast were probably 15kg according to google and hunted moas that went up to 230kg

That **** of an eagle just knocked the goat off the cliff/hill . It would’ve got dragged down with it if it never let go!

 

[EdwardTeach]

I would also factor in that they may have had better lift with the skin rather than feathers. Also, reptiles are able to make huge bursts in acceleration due to how their muscles work, I know dinosaurs were not strictly reptiles but they could have had a similar bio function that was enough to launch the thing off the ground.

Pterosaurs are not actaully Dinosaurs! They are close relatives though so your point remains valid.

 

[v0n]

Eh, what? Lower gravity? How? Gravity is a function of mass, so you're arguing that Earth gained a lot of mass between then and now. How? Planet revolving slower? What do you think caused it to speed up since then?

You elect to follow the hard physics.

For evidence of lower gravity, you need to show evidence that the earth was either larger and the same mass, or the same volume and less dense, and explain how and when all that suddenly changed. At the very least, even without evidence, you'd need a valid possible mechanism.

You elect not to follow the hard physics that provides good evidence and reason for why it was not the case. And you elect to not follow the evidence and reason that explains the size of the dinos. Size of the dinosaurs is not evidence for lower gravity.

Of course it is. There are multiple wild and wilder (but also more or less sound) theories on why earth would gain surface gravity varying from changes in centrifugal forces, GEM variations (as in gravity being a function of mass and electric charge), the expanding earth (with some modern geological evidence for it), mass gain through continuous pickup of meteoric material (NASA is gathering data on that), rather bleak theories about bullet impact of a relatively small but dense object, in some variants piercing through the crust (and ending that particular era) and related speculations about change of forces in the mantle, there is the sun nucleons absorbed through pole region and forming atoms thing, others dig deeper into the electric universe theory, gravitational effect of other planets and space objects and so on - plenty to select from - all, without a doubt, much better theories than the current "dinosaurs and everything around them were big for hundreds of millions of years because they were either made of styrofoam like material or had bones made of unobtanium" schtick that we're flatearthing to poor students at the moment.

I think we can all agree that the structural engineers can't explain how sauropods moved, functioned and lifted their heads or how pterosaurs could possibly fly in 1g and botanists are perplexed about how prehistoric trees could grow so high with xylem confined to only the outer 2 inches of the trunk, and by far the simplest answer is - because none of it happened in 1g. Try 0.4, maybe even less. Cheer up and warm up to it people because it explains just about everything you can think of, and there is literally no reason to reject it - not unless you have a scientific title depending on the whole "lightweight dragons fed with extra O2" remaining on the table.

That you have no evidence for.

There is no definitive evidence to anything about prehistorical times other than what we found and can see. Everything else is theoretical. They were gigantic, seemingly for no reason. They had a good game on this planet for anywhere between 150-200 millions of the planet rotations around the sun. And then the game stopped and there was a system reboot. Humans stood up some 200,000 years ago, we found the previous gigantic inhabitants of this planet from 65 millions of years ago about 180 years back and then since about last Friday we know everything. But it was definitely NOT less gravity. Because - no, no, no and once more - no. That is so us.

Look at the whole picture. Big animals, big flora, where we find them now, continental shifts, climate changes all the way to long lasting ice ages with massive geological erosions. Everything you know about prehistorical times. Same planet. Less gravity. Different axis. Different rotation speed. Think it over. Find a hole in it. Then report back. Love ya. Bye.

The giant bug time was many millions of years earlier, by the way.

I even wrote it in that very posts you read it in. It's no fun when you guys start bursting your drinks all over keyboards and fistwhack hasty replies without even reading...

 

[Angilion]

this bird can live this goat so I'd think it was actually quite likely maybe not a 6ft tall person but people weren't that tall that long ago

That eagle doesn't lift that goat. It drags that goat off a ledge and loses height hard despite maximum effort until it lets go.

People ~1000 years ago were about as tall as people today unless they'd been malnourished during childhood and adolescence. The average height in England wasn't far off the average height today (it got significantly lower later due to the increased population density and the greatly reduced living conditions for most people). It might not have been different at all for the "native" Australians.

haast were probably 15kg according to google and hunted moas that went up to 230kg

Hunted, yes. Carried, no. Not even two of them using a line held under their dorsal guiding feathers. It's a simple question of weight ratios. A five ounce bird can't carry a one pound coconut.

 

[Angilion]

[..] I think we can all agree that the structural engineers can't explain how sauropods moved, functioned and lifted their heads or how pterosaurs could possibly fly in 1g [..]

No, we don't all agree on that. Because those explanations exist. There was a hypothesis that the biggest pterosaurs couldn't fly, but it was based on an estimated weight of >500Kg.

I'm reminded of the myth that engineers/scientists can't explain how bees fly.

Also, as an aside, if the Earth inflated (somehow) during the last few tens of millions of years (which you describe as a more or less sound theory with some modern evidence for it) that would cause gravity on the surface of Earth to be lower today than it was ~66 million years ago. Not higher.

 

[checjb]

Wow v0n, you'd rather go with complete fantasy 'science' than hard data. There is no evidence of reduced gravity in the mesozoic period to the levels you're suggesting but there after huge amounts of research into how sauropods could grow to such massive sizes. Here's a clue: Real scientists - in a range of fields - have looked at all manner of variables and concluded that they could get to those sizes without varying contents like gravity. Your theories (and I'm being charitable calling them that) simply don't match up with the understanding of people who've spent their entire careers researching this. But, of course, the standard response of the Dunning-Kruger sufferer is that "they got it wrong!" somehow.

 

[Unseul]

Of course it is. There are multiple wild and wilder (but also more or less sound) theories on why earth would gain surface gravity varying from changes in centrifugal forces, GEM variations (as in gravity being a function of mass and electric charge), the expanding earth (with some modern geological evidence for it), mass gain through continuous pickup of meteoric material (NASA is gathering data on that), rather bleak theories about bullet impact of a relatively small but dense object, in some variants piercing through the crust (and ending that particular era) and related speculations about change of forces in the mantle, there is the sun nucleons absorbed through pole region and forming atoms thing, others dig deeper into the electric universe theory, gravitational effect of other planets and space objects and so on - plenty to select from - all, without a doubt, much better theories than the current "dinosaurs and everything around them were big for hundreds of millions of years because they were either made of styrofoam like material or had bones made of unobtanium" schtick that we're flatearthing to poor students at the moment.

I think we can all agree that the structural engineers can't explain how sauropods moved, functioned and lifted their heads or how pterosaurs could possibly fly in 1g and botanists are perplexed about how prehistoric trees could grow so high with xylem confined to only the outer 2 inches of the trunk, and by far the simplest answer is - because none of it happened in 1g. Try 0.4, maybe even less. Cheer up and warm up to it people because it explains just about everything you can think of, and there is literally no reason to reject it - not unless you have a scientific title depending on the whole "lightweight dragons fed with extra O2" remaining on the table.



There is no definitive evidence to anything about prehistorical times other than what we found and can see. Everything else is theoretical. They were gigantic, seemingly for no reason. They had a good game on this planet for anywhere between 150-200 millions of the planet rotations around the sun. And then the game stopped and there was a system reboot. Humans stood up some 200,000 years ago, we found the previous gigantic inhabitants of this planet from 65 millions of years ago about 180 years back and then since about last Friday we know everything. But it was definitely NOT less gravity. Because - no, no, no and once more - no. That is so us.

Look at the whole picture. Big animals, big flora, where we find them now, continental shifts, climate changes all the way to long lasting ice ages with massive geological erosions. Everything you know about prehistorical times. Same planet. Less gravity. Different axis. Different rotation speed. Think it over. Find a hole in it. Then report back. Love ya. Bye.



I even wrote it in that very posts you read it in. It's no fun when you guys start bursting your drinks all over keyboards and fistwhack hasty replies without even reading...

You appear to just be listing stuff now, without actually thinking about it.

Let's pick the most obvious one. Expanding earth theory. How does the expanding earth theory fit with lower gravity in the past? You get more gravity if the earth is smaller, not less. More dense = more gravitational pull.

I wouldn't ask a structural engineer how a sauropod moved, there's better people to ask. They might have some answers. In fact, they do. For flight too. We can never be fully sure, but if it's proven possible, then it's possible.

For earth to go from 0.4g, to 1g today, it's not hard to work out the sort of mass gain you're talking about, and it's a lot.

Centripetal force, I'm really not going to bother going through with all the calculations, but it's looking like you'd get through a single day in less than 2 hours, for the earth to be spinning fast enough to achieve that... we can measure the spin, we can calculate the effect of the moon, it really wasn't going that fast back then.

As for them being gigantic. So what? Just because we don't have anything as big today, doesn't mean it's impossible. If, as theorised, they were actually using bone structure and respiratory systems similar to birds, it's unlikely that mammals could evolve that way, but judging dinosaurs on the biology of mammals is just wrong.

I'm looking at the big picture. Massive picture. Cosmic picture in fact. You can either disregard physics as we currently know it (and leave some big old holes by doing so), or perhaps, you know, it's just a case of working out the biology.

 

[Nasher]

Higher O2 is why animals grew much bigger back then. Just like the higher CO2 is why there were also larger plants.

Earth's gravity has not changed since it was first formed.

 

[v0n]

Also, as an aside, if the Earth inflated (somehow) during the last few tens of millions of years (which you describe as a more or less sound theory with some modern evidence for it) that would cause gravity on the surface of Earth to be lower today than it was ~66 million years ago. Not higher.

You get more gravity if the earth is smaller, not less.

Wow... As high gravity as moon, or as little gravity as Jupiter? At this point - gentlemen, please don't - how could we possibly resolve anything with arguments like that.

I wouldn't ask a structural engineer how a sauropod moved, there's better people to ask.

Just ask one. You are in a thread that's exactly about it.

 

[Brizzles]

They didn't flap their wings to take off, wings just assist in it.

An aircraft doesn't flap it wings to take off, it just runs fast and glides.

Basic gravity vs something which explains why Aer Lingus inflight meals are rank or whatever.

 

[Unseul]

So the earth expanded and gained significant mass at the same time. Any evidence?

I've looked up the opinions of biomechanical experts. Far more appropriate than a structural engineer...

 

[Angilion]

Wow... As high gravity as moon, or as little gravity as Jupiter? At this point - gentlemen, please don't - how could we possibly resolve anything with arguments like that.

You quote text from me saying that if the Earth got bigger the gravity on the surface would get lower and text from Unseul saying that if the Earth was smaller the gravity on the surface would get higher. Are you thinking those two contradict each other despite saying the same thing?

Then you bring in the moon and Jupiter as if they were counter-arguments because they're different sizes. Which is downright weird. Do you believe that Earth has the same mass as the moon or the same mass as Jupiter? Or both at the same time, somehow?

Gravity is a function of mass. Gravity on the surface of a body is almost entirely a function of that body's mass and the distance from the centre of gravity of that body to the part of the surface you're on. For a perfect sphere of uniform density with no other sources of gravity within range, gravity on the surface is mass divided by the square of the radius. That'll be an extremely close approximation in almost all cases. It will only be significantly out if the body is well off spherical, has a very variable density or is very close to a very strong gravitational field from something else.

The gravity on the surface of the moon is lower than the gravity on the surface of Earth despite being smaller than Earth because the moon has a far lower mass than Earth.
The gravity on the "surface" of Jupiter is higher than the gravity on the surface of Earth despite being larger than Earth because Jupiter has a far higher mass than Earth.

I feel odd having to explain that.

 

[bainbridge]

It was an arms race, and with higher co2 and o2 there was more fuel to build bigger.

 

[Unseul]

Of course, v0n is also ignoring the fact that if we cut down to 0.4g, the atmosphere becomes 60% thinner. Don't know if you've ever been to high altitude, but I don't think life in general would fair too well in an atmosphere the equivalent of 6000m altitude.

 

[v0n]

You quote text from me saying that if the Earth got bigger the gravity on the surface would get lower and text from Unseul saying that if the Earth was smaller the gravity on the surface would get higher.

Gravity is a function of mass.

The gravity on the surface of the moon is lower than the gravity on the surface of Earth despite being smaller than Earth because the moon has a far lower mass than Earth.
The gravity on the "surface" of Jupiter is higher than the gravity on the surface of Earth despite being larger than Earth because Jupiter has a far higher mass than Earth.

I feel odd having to explain that.

In reality it's actually slightly more, shall we say - esoteric - than "function of mass" but it will do for the purpose of this exercise: so having explained all the above to yourself you still think planets gravity would be lower if the Earth of prehistoric animals was bigger?

Secondary question - would you be keen on checking if our Earth today, is of a constant mass, is gaining mass or is loosing mass?

 

[Unseul]

In reality it's actually slightly more, shall we say - esoteric - than "function of mass" but it will do for the purpose of this exercise: so having explained all the above to yourself you still think planets gravity would be lower if the Earth of prehistoric animals was bigger?

Secondary question - would you be keen on checking if our Earth today, is of a constant mass, is gaining mass or is loosing mass?

You're going to need to define bigger.

You were the one who raised the expanding earth theory. Expanding earth theory is that the earth is getting larger, which is why the continents have moved apart, much like if they had been drawn on a balloon and inflated. However, assuming equal, or at least roughly equal, mass, an earth with a smaller radius historically, would have had a higher, not lower, gravity.

Could you also please explain how all these massive dinosaurs survived with only 60% of the atmosphere denisty we have today?

Really, the simpler explanation is that we're still working out the biology (and there seems to be a pretty good idea about it now). Lowering gravity by more than half, adds so many more issues that it's really not the simple explanation you think it is.

 

[v0n]

You were the one who raised the expanding earth theory. Expanding earth theory is that the earth is getting larger, which is why the continents have moved apart, much like if they had been drawn on a balloon and inflated.

I'm not particularly fond of the expanding earth theory where people demonstrate it on inflated balloons myself - it's too much of a "Flinstones lived with Dinos" cartoonish oversimplification that gives wrong picture and draws ridicule but oddly, that's how it's often portrayed by people, even with doctorates (and it clearly creates issues). I also don't fully subscribe to EET's core belief on the subject. But yes - in principle - the earth was smaller, with less mass, less gravity, possibly of different energy dynamics and with completely different layout, so different that we find ichtiosaurs and various prehistoric sea creatures fossilised at the bottom of "then-seas" often in the middle of landmasses at elevations of 150-300 meters above sea level (maybe even higher, good Quora question I suppose) of "our Earth" today.

However, assuming equal, or at least roughly equal, mass, an earth with a smaller radius historically, would have had a higher, not lower, gravity.

It wasn't going supernova. It was smaller and had less mass. And was rotating slower. Since then it gained mass and additionally is also rotating faster. Speculatively. Theoretically.

Could you also please explain how all these massive dinosaurs survived with only 60% of the atmosphere denisty we have today?

It's a non issue in this speculation - if we suddenly had less gravity now, in the next five minutes, for us, humans that would be an issue, but density of the atmosphere is also dependant on temperature, composition and mass of the atmosphere and where's our IPCC hockeystick graph on that?

Really, the simpler explanation is that we're still working out the biology (and there seems to be a pretty good idea about it now). Lowering gravity by more than half, adds so many more issues that it's really not the simple explanation you think it is.

"By half" is just one of the speculations. But yes - even the most optimistic biomechanical computer models, can barely explain horizontal movement of the largest creatures, but fail with anything related to how they would stand up, rise their heads up, etc - the more muscle mass you give them to allow for basic mechanics, the more blood and pressure you give them to not blackout and collapse over while waving those massive heads and tails in 1g, the more you realise that the examples of bone structure that we dig up would have to be made of some scifi aerated supermaterials. And yet their size wasn't a biological problem. It wasn't a one time fluke, a one off giraffe species, back in those days having a dysfunctional "dino" that shouldn't be able to stand up, migrate, eat, **** and generally function every day on grasslands "near you" - was pretty much standard for hundreds of millions of years. And everything else was aptly gigantic too. An able and agile T-rex twice the weight of today's elephant running and chasing a pray on two legs, yet our lighter elephant has massive bones to support its weight on all fours in comparison. Now that creates real issues?