In the October issue Scientific American published an article on Pterosaurs (not dinosaurs, not birds), long extinct of course. Not the first article on the subject, … but it seems that we do finally have proof that these dinosaur-munching monstrosities had developed powered flight, with anti-stall features and self launch (not just gravity assisted launch). The biggest types had body weights of over 600 pounds, and how they flew. Not long ago scientist had put the mass limit for any biological plane at about 30 to 40 pounds (based on best guesses of known muscle power density, lift coeff. etc.). Some the size of an F-16, jaws twice the length of those belonging to T-Rex, how these monster flew at all remained a mystery for a long time.
What did most likely bring them down in the end ? IFR conditions prevailing for months after the asteroid impact, just burrowing (the way it seems some bird species survived) didn’t work them. They were neither used nor adapted to dig their ways out of danger – they were the danger.
What an amazing world 
The atmospheric oxygen concentration has been higher and lower than 21% in the past. Higher would enable natural selection to increase energy release rate. Lower could lead to extinction of such organisms.
Higher concentration would increase wildfires, as well as decomposition and recycling of minerals.
The Earth has slowed it’s spin, I don’t know if this would affect the effective weight, due to what we must not call centrifugal force.
Maoraigh wrote:
I don’t know if this would affect the effective weight
Trivially (and even then, only relatively close to the equator).
AJ wrote:
how these monster flew at all remained a mystery for a long time.
till in the 30ies of the last century we could not even explain, why a bumblebee can fly (against pupolar believe, today we can!). Not surprising that explaining flight dynamics of an animal that was extinct more than 50 million years ago is even more difficult…
What did most likely bring them down in the end ?
The extinction event at the end of the K-time killed all animals of that size – so all heavy and super traffic was ultimately grounded at this time …
Still in the 30ies of the last century we could not even explain, why a bumblebee can fly
That’s a fun fact, only it’s nonsense. What was originally the thing was that the flight if the bumble bee cannot be explained using aerodynamics of lifting surfaces (wings). It still cannot , because that is not how the wings of the bumble bee works.
I’m delighted to see that someone else shares my fascination with this distant and extraordinary lost world. There’s been a fair bit of nutty stuff about how Pterosaurs couldn’t fly and how air pressure had to be 20 bar or something. The actual evidence suggests an environment much like today’s, and leaves the fascinating question of ‘how did they fly?’ wide open. Some failed model airplane experiments have not helped along the way, somewhat in the vein of no-one yet recreating the Wrights first flights authentically either, and that’s not far from living memory!
There’s great work to be done in explaining how they did fly, and consideration of their vast distribution, suggesting perhaps flying over very long distances. And greatest of all, building a modern replica that confirms rather than confuses the idea that these astonishing animals really did exist!
PS it’s been my privilege over the years to use the Cessna to visit various dino sites. Dinosaur National Monument of course, with the convenient airport at Vernal, Utah. The Cleveland-Lloyd quarry, rather less convenient from the Carbon County airport, but stunning on the ground (hundreds of animals in the same place, perhaps a waterhole lethally poisoned with volcanic gasses) and from the air – well, revelatory. From the air you can see how the terrain formed a trap, and that the exposed strata is only one of many where similar burials may one day be found, At Dinosaur NM, you can see how the folded strata presented quite literally a wall of Dinosaurs to the early explorers, and how the landscape is full of similar folds.
To me, greatest of all are the exposed outcrops west of Grand Junction Colo., where less than an hour in a rental car will bring you to a hillside where they are still there – despite generations of souvenir hunters, actual real dinos that once lived in this very place still lying where they fell so very long ago. And to me the most moving, a dried up river wash near the old Saint George airport in Utah, where one evening the local paper described the discovery of a trail of dino footprints. Next morning I’m following the directions (" Turn left at the water tank, follow the trail for 3 miles, make a right" etc.), until with a jolt I realise that I’m walking in an ancient stream bed and there, at my feet, are their footprints! I find that I’m moving cautiously, reverentially, and peering around the next bluff almost expecting to see the footprint owners nonchalantly grazing. The places that a Cessna can take you – Valles Marineris on Mars (N end of the Canyon, up by Page, Ariz) and here, to the Cretacious.
So to those who still choose to doubt the veracity of ancient life, I say this – go and see for yourself!
(Vertebra of juvenile Diplodocus, lying just where the animal fell, 100 million years ago. Rabbit valley, near Grand Junction, Co.)
I’ve visited Rabbit Valley a few times. There were explanatory leaflets from a box on a post. On one occasion they’d been removed and replaced with anti-evolution religious tracts
