Why it was possible for dinosaurs to exist ?

[Dlouro]

I don't know why everybody is telling me that I think bumblebees can't fly.

 

Off course BUMBLEBEES CAN FLY . I know that .

Like Galileu " and yet they fly "

The moon was closer to earth between 2 and 4 percent.

The day was about 23 hours.

About the earth size I think that 200 million years of dust, comets and meteors can increase the size. I reckon is a small amount but all those things added could make a change.

[Moontanman]

I don't know why everybody is telling me that I think bumblebees can't fly.

 

Off course BUMBLEBEES CAN FLY . I know that .

Like Galileu " and yet they fly "

The moon was closer to earth between 2 and 4 percent.

The day was about 23 hours.

About the earth size I think that 200 million years of dust, comets and meteors can increase the size. I reckon is a small amount but all those things added could make a change.

 

 

200 million years of dust would only be a drop in the bucket if you are postulating that lower gravity helped dinosaurs exist. I'm not sure what the moon being slightly closer or the day being slightly shorter has to do with it. Please elaborate...

[Dlouro]

200 million years of dust would only be a drop in the bucket if you are postulating that lower gravity helped dinosaurs exist. I'm not sure what the moon being slightly closer or the day being slightly shorter has to do with it. Please elaborate...

 

I will try .

Pangaea was located more around the equator than our continents today. Because the earth rotated faster the centrifugal force was bigger meaning less gravity maybe around 3 percent . Moon closer to Earth means also bigger tidal forces and a smaller lunar month

The atmosphere was denser and increased the buoyancy of the animals reducing the weight. Also there was more oxigen than today so more energy for them.

About the earth mass is a theory that it's not disapproved but I agree that it's controversial. But I remind you that in the past collisions with space dust were more frequent.

But as I said when we look at those elegant an slender animals compared with today elephants we can see a big difference.

[Moontanman]

I will try .

Pangaea was located more around the equator than our continents today. Because the earth rotated faster the centrifugal force was bigger meaning less gravity maybe around 3 percent . Moon closer to Earth means also bigger tidal forces and a smaller lunar month

The atmosphere was denser and increased the buoyancy of the animals reducing the weight. Also there was more oxigen than today so more energy for them.

About the earth mass is a theory that it's not disapproved but I agree that it's controversial. But I remind you that in the past collisions with space dust were more frequent.

But as I said when we look at those elegant an slender animals compared with today elephants we can see a big difference.

 

 

The multi giga tons of matter necessary to significantly affect the mass of the earth would render the surface uninhabitable due to the energy released. Even dust adds energy, much like the idea that comets struck the earth and froze mammoths in place it is a total non starter. A comet impact would have incinerated mammoths not freeze them.

 

The same would be true for the millions of giga tons of mass the earth would have to pick up over 200 million years. I would like to see a citation about the oxygen content being higher and the atmosphere being denser and more buoyant?

 

You think sauropods were slender?

 

You need to support these notions...

[Dlouro]

There are many articles about the levels of Oxigen in the Jurassic atmosphere. The percentage was between 26 and 30 near the end. today is about 21

https://commons.m.wikimedia.org/wiki/File:Sauerstoffgehalt-1000mj.svg

The level of CO2 was 7 times bigger than today wich increased the density.

Maybe I choose the wrong word because I don't think in english but in portuguese. What I ment was more like elegant comparing to elephants.

What I know for sure is that they walked on land not on water.

Also there were many catastrophic events in the last 200 millions years . And if you count , let's say , 200 tons of cosmic dust per year slowly accumulated on earth that will change the mass without releasing lots of energy.

I don't get it when you only criticise me and don't offer nothing in return. I saw a problem and want some ideas. If i think sauropods as large birds as you said that doesn't explain the huge size because the large bird that exists today is to small.

[swansont]

I don't know why everybody is telling me that I think bumblebees can't fly.

 

Off course BUMBLEBEES CAN FLY . I know that .

Like Galileu " and yet they fly "

The moon was closer to earth between 2 and 4 percent.

The day was about 23 hours.

About the earth size I think that 200 million years of dust, comets and meteors can increase the size. I reckon is a small amount but all those things added could make a change.

if you count , let's say , 200 tons of cosmic dust per year slowly accumulated on earth that will change the mass without releasing lots of energy.

 

 

The great thing about science is that we can quantify such things and make more precise statements. Currently the earth is losing mass

http://scitechdaily.com/earth-loses-50000-tonnes-of-mass-every-year/

 

 

Even if we were adding 100 million metric tons a year (10^11 kg), in 100 million years that's 10^19 kg. That's less than 2 parts per million increase in mass in that time.

[Moontanman]

There are many articles about the levels of Oxigen in the Jurassic atmosphere. The percentage was between 26 and 30 near the end. today is about 21

https://commons.m.wikimedia.org/wiki/File:Sauerstoffgehalt-1000mj.svg

The level of CO2 was 7 times bigger than today wich increased the density.

Maybe I choose the wrong word because I don't think in english but in portuguese. What I ment was more like elegant comparing to elephants.

What I know for sure is that they walked on land not on water.

Also there were many catastrophic events in the last 200 millions years . And if you count , let's say , 200 tons of cosmic dust per year slowly accumulated on earth that will change the mass without releasing lots of energy.

I don't get it when you only criticise me and don't offer nothing in return. I saw a problem and want some ideas. If i think sauropods as large birds as you said that doesn't explain the huge size because the large bird that exists today is to small.

 

 

The same amount of energy is released when 200 tons of sand grains hit the earth as a 200 ton rock. Google terror birds, all birds were not small. Using your logic since bats are so small elephants cannot exist and the atmosphere does not add significant buoyancy to anything that is denser than air.... Even birds drop like rocks if they stop flying...

 

I criticize you because you are so far off the mark there is precious little to show you. You think you saw a problem, your incredulity does not a problem make. The dinosaurs were large, so far you have offered no explanation as to why you don't think they could be large other than pseudo science of the worst kind...

[swansont]

The same amount of energy is released when 200 tons of sand grains hit the earth as a 200 ton rock.

 

Another thing we can analyze.

 

The potential energy released is 62.5 MJ per kg. There will be KE, too, so let's round up to 100 MJ/kg. So 10^13 J for 100 tons. Over the course of a year, that's a little over 300 kW. A paltry amount. A half a nanowatt per square meter. So even beefed up to my earlier 100 million tons, that's half a milliwatt per square meter.

 

Compare with the ~kilowatt of solar radiation we get per square meter from the sun albeit half the time, and varying with angle. Still, six orders of magnitude.

[Moontanman]

 

Another thing we can analyze.

 

The potential energy released is 62.5 MJ per kg. There will be KE, too, so let's round up to 100 MJ/kg. So 10^13 J for 100 tons. Over the course of a year, that's a little over 300 kW. A paltry amount. A half a nanowatt per square meter. So even beefed up to my earlier 100 million tons, that's half a milliwatt per square meter.

 

Compare with the ~kilowatt of solar radiation we get per square meter from the sun albeit half the time, and varying with angle. Still, six orders of magnitude.

 

 

I was thinking more of the amount of mass necessary to increase the earths mass significantly enough from being smaller and have gravity weak enough to allow larger animals. Of course there are other reasons why this is a non starter, less mass means less gravity and a loss of atmosphere.

 

I admit that I was using the standard talking points of this very old argument that says the earth was about the size of mars, I apologize for that assumption...

[michel123456]

This is not an attempt of skepticism. You understand me wrong. It was possible in the past that earth was smaller and with less gravity, also i still doubt that in a engineering point of view the dinosaurs could walk today in our planet with the current conditions. I just want to understand how it was possible for those big animals to survive in the past and I include also the big mammals. I am an engineer by formation and I am just asking for answers by the experts in the field. It is strange that when someone asks something that for him it's not so obvious the answer is almost always a little bit rude.

Forgive me for thinking.

The image of a smaller Earth with bigger animals living on it reminds me the lamplighter of The Little Prince.

 

It is not coherent.

One would expect small animals living on a small planet, and large animals living on a large planet.

I even wonder if there exist some formula giving the scale of animals dimensions to the planet radius, or to the planet mass? Here on Earth it varies from viruses (if they count as animals) to the blue whale. Could we theoretically encounter E.T. organism larger than the Everest mountain living on a gigantic planet? Or is our dimension totally unrelated to the planet we are living on?

[swansont]

I was thinking more of the amount of mass necessary to increase the earths mass significantly enough from being smaller and have gravity weak enough to allow larger animals. Of course there are other reasons why this is a non starter, less mass means less gravity and a loss of atmosphere.

Right. We can scale up the numbers. We need around 4 orders of magnitude more to get to the 1% level of mass increase, so now we're at a few watts. To get 100% (a doubling) gets us to a few hundred watts. That would be significant, but then that level of sedimentation from the sky and the world would probably look very, very different.

 

Accretion leading to any gravitationally significant mass increase is a non-starter.

[John Cuthber]

The article in Wikipedia says that I am right. No aeronautical engineer said that....

 

Also I never said that dinosaurs couldn't walk. What I said was that I doubt that they could walk today with the current conditions in our planet.

Matter of definition: it says "Additionally, John Maynard Smith, a noted biologist with a strong background in aeronautics, has pointed out that bumblebees would not be expected to sustain flight, as they would need to generate too much power given their tiny wing area. ".

It's beside the point.

The idea that "according to my calculations, bumblebees can't fly" is still simply an assertion that you have not got the right calculations.

The same is true of your idea that a dinosaur couldn't walk. It seems you still have not cottoned on to the fact that you are simply wrong.

 

The conditions today are very similar.

in particular, gravity can't have changed by more than a small fraction.

so, if you say they couldn't walk today then you are actually saying they couldn't walk when, in fact, they did.

[Moontanman]

The image of a smaller Earth with bigger animals living on it reminds me the lamplighter of The Little Prince.

allumeurdereverbere.jpg

 

It is not coherent.

One would expect small animals living on a small planet, and large animals living on a large planet.

I even wonder if there exist some formula giving the scale of animals dimensions to the planet radius, or to the planet mass? Here on Earth it varies from viruses (if they count as animals) to the blue whale. Could we theoretically encounter E.T. organism larger than the Everest mountain living on a gigantic planet? Or is our dimension totally unrelated to the planet we are living on?

 

 

Mass and gravity would have an effect on the size of organisms but higher gravity would result in smaller creatures. lower gravity would result in larger creatures... that pesky cube square law would apply....

[michel123456]

 

 

Mass and gravity would have an effect on the size of organisms but higher gravity would result in smaller creatures. lower gravity would result in larger creatures... that pesky cube square law would apply....

And have lower gravity been ruled out?

 

Lower gravity can be achieved by several means:

1. less mass. That is not likely

2. greater rotational speed

3. larger radius (keeping same mass = lower density)

Edited July 20, 2016 by michel123456

[swansont]

And have lower gravity been ruled out?

 

Lower gravity can be achieved by several means:

1. less mass. That is not likely

2. greater rotational speed

3. larger radius (keeping same mass = lower density)

 

 

Yes.

 

To the extent that those parameters could change, none would give appreciable gravitational (or net force) variations. Certainly not the factor of ~2 or more the OP is implying.

[Dlouro]

When science acknowledge the fact that all those bones were from enormous extinct animals everybody, at the time, saw there was a big problem about how it was possible those animals could even move. I finished my studies in early seventies and I remember quit well that was more or less an agreement that the sauropods lived in water like hippos . The dinosaur tracks found around the world proved that they were land animals. Since then nobody investigated in deep the biomechanics of those beasts.

I'm just trying to figure out a solution.

Saying that they existed so where's the problem or conditions on earth were the same as today it's just a way to run away from the problem.

Worse yet is telling me that 100 tons off small specs of dust per year is the same as a rock of 100 tons.

Does anybody saw how a albatross starts the flight ? A big pterodactyl had a wing span of almost ten meters . Like a F16

Running away from the facts is not a correct manner to discuss it.

I still keep my idea, is not pseudoscience . Those are facts.

Edited July 20, 2016 by Dlouro

[Strange]

Worse yet is telling me that 100 tons off small specs of dust per year is the same as a rock of 100 tons.

 

 

In what way are they different?

 

How much difference to the gravity does 40,000 tons of dust per year make? How much difference does this make over 200 million years? (This is a very simple calculation, so I assume you have already done it to support your idea.)

 

 

 

I still keep my idea, is not pseudoscience . Those are facts.

 

If you haven't done the calculations and they don't support your idea then it is not just pseudoscience, it is nonsense.

[Dlouro]

The same amount of energy is released when 200 tons of sand grains hit the earth as a 200 ton rock. Google terror birds, all birds were not small. Using your logic since bats are so small elephants cannot exist and the atmosphere does not add significant buoyancy to anything that is denser than air.... Even birds drop like rocks if they stop flying...

 

 

200 tons of sand grain in a day release the same amount of energy as a 200 ton rock but the effect it's not the same.

But I agree now that the space dust did not increased the mass in a significant way.

 

But the problem remains.

[pzkpfw]

... Since then nobody investigated in deep the biomechanics of those beasts. ...

On what do you base this?

[Dlouro]

Searching, talking to palaeontologists, seminars but just in my country. The answer normally is that they existed so no need to reply.

Today is much easier but before internet I buyed a few hundred books about life , evolution. Sometimes waiting 2 months for importing.

Edited July 21, 2016 by Dlouro

[John Cuthber]

When science acknowledge the fact that all those bones were from enormous extinct animals everybody, at the time, saw there was a big problem about how it was possible those animals could even move. ...

I'm just trying to figure out a solution.

Saying that they existed so where's the problem or conditions on earth were the same as today it's just a way to run away from the problem.

Worse yet is telling me that 100 tons off small specs of dust per year is the same as a rock of 100 tons.

Does anybody saw how a albatross starts the flight ? A big pterodactyl had a wing span of almost ten meters . Like a F16

Running away from the facts is not a correct manner to discuss it.

I still keep my idea, is not pseudoscience . Those are facts.

When science first looked at bumblebees they saw there was a problem; how did they fly?

And so they studied some more, and they answered that question.

 

The same happened with the dinosaurs. You have been told the answer- repeatedly. yet you ignore this and pretend there's still a problem.

 

You are the oner "running away form the problem".

The problem is that we know they walked and we know the Earth's gravity was the same.

You keep trying to run away from those facts.

 

Your ideas don't hold up to scrutiny- whether or not they are "pseudoscience" isn't the point.

They are wrong.

 

Things have moved on a lot since you did your studies in the 70s.

They have moved on a lot since the 90s

Since dinosaurs were built like birds- light + strong- there isn't a problem.

[michel123456]

When science first looked at bumblebees they saw there was a problem; how did they fly?

And so they studied some more, and they answered that question.

 

The same happened with the dinosaurs. You have been told the answer- repeatedly. yet you ignore this and pretend there's still a problem.

 

You are the oner "running away form the problem".

The problem is that we know they walked and we know the Earth's gravity was the same.

You keep trying to run away from those facts.

 

Your ideas don't hold up to scrutiny- whether or not they are "pseudoscience" isn't the point.

They are wrong.

 

Things have moved on a lot since you did your studies in the 70s.

They have moved on a lot since the 90s

Since dinosaurs were built like birds- light + strong- there isn't a problem.

Then why evolution didn't produce that kind of animals (dimensional speaking) again?

Or to put the question differently, why are all current land animals smaller than dinosaurs were?

Edited July 22, 2016 by michel123456

[studiot]

 

Then why evolution didn't produce that kind of animals (dimensional speaking) again?

Or to put the question differently, why are all current land animals smaller than dinosaurs were?

 

Which one do you want?

 

http://imgur.com/gallery/HyfVJIu

@ diouro

Did you find anything useful in the BBC programs I indicated?

There was also a similar recent BBC series about the history of the Earth, incorporating our best knowledge to date.

https://www.google.co.uk/search?q=BBC+Earth+Story&hl=en-GB&gbv=2&tbm=isch&oq=BBC+Earth+Story&gs_l=img.3..0i24l4.1672.5422.0.5859.15.12.0.3.3.0.187.1654.0j11.11.0....0...1ac.1.34.img..1.14.1699.FSAy_-R-Yq4

There is an explanation of why we think there has been no significant change to the Earth's mass or size since the accretion phase.

This is simply because large bodies grow at the expense of smaller ones so a large body will sweep its orbital zone relative clear of material.

The only way the body can then grow is by attracting another large body that is passing, but this has not happened in the last few thousand million years.

As to dinosaurs themselves, both yourself and Michel might like to try to read a copy of Professor Bakker's book

Dinosaur Heresies.

https://www.google.co.uk/search?q=Bakker+Dinosaur+Heresies&hl=en-GB&gbv=2&tbm=isch&oq=Bakker+Dinosaur+Heresies&gs_l=img.3...85922.92016.0.92250.24.11.0.13.13.0.172.1284.1j9.10.0....0...1ac.1.34.img..10.14.1300.iPyLKOi5V6Y

As regards the atmosphere, the only comprehensive history over geological timescales that I know of is here

https://www.google.co.uk/search?q=the+emerald+planet&hl=en-GB&gbv=2&tbm=isch&oq=the+emerald+planet&gs_l=img.3..0j0i24l2.2281.6250.0.6484.18.11.0.7.7.0.234.1561.0j9j1.10.0....0...1ac.1.34.img..1.17.1748.vKBElm1nouE

Edited July 22, 2016 by studiot

[michel123456]

Which one do you want?

 

These ones. Land animals.

 

 

 

(Water animals have the help of buoyancy)

or this one

[studiot]

 

 

These ones. Land animals.

 

 

I asked because you second sentence is not another way of putting your first one.

Your first one included all animals.

 

However your question is a fair one and related to the OP.

 

A possible answer is the OP idea that the prevailing conditions constrain or force animal size is a good one.

Unfortunately he is focusing on the wrong conditions IMHO.

 

So the main condition determining size is thought to be the availability of food.

It is interesting to note that under suitable conditions species can shrink as well as grow.

For example the fossil pygmy elephants found in some Mediterranean islands, thought to have crossed from Africa when the med was dry and then shrunk to fit the food supply when stranded on islands.

 

https://en.wikipedia.org/wiki/Dwarf_elephant

 

Note the biggest dinosaurs were thought to be vegetarian, like the blue whale in the picture.

Plants in the time of the dinosaurs were larger than today, so perhaps obtaining and digesting enough to grow to the larger size was easier then.

Predators obviously had to become large enough to overcome the behemoths, would a modern lion be capable of taking one on?