Geoboffins believe gigantic volcanoes kickstarted Mars' oceans A team of geophysicists have developed a new theory explaining how eruptions from some of the biggest volcanoes in the Solar System could have led to oceans on Mars. Tharsis, a region in equatorial Mars stretching about 5,000 kilometers across, is home to some of the biggest volcanoes on the planet. The largest one, Olympus …
The entire quote reads: "“If you took the oldest and youngest ocean and spread the water over the entire planet, the water would be at least 280 and 85 meters deep,” he explained to The Register."
The oldest scenario was 280 meters, the youngest 85.
With a uniform topography indicating impact with a body roughly 290,000 km in diameter. Such a large body would have gravity capable of 'splashing' oceans and atmosphere into space and attracting the rest. Pterodactyl wingspan, at double today's Peruvian Condor indicates Earth's atmosphere was four times denser during the Jurassic. Earth's atmosphere is subject to solar wind, ionization and splashing from meteor impacts and is constantly eroding. Volcanoes do some minor replacement, see....
"Earth's Missing Geothermal Flux" at FauxScienceSlayer website
"...With a uniform topography indicating impact with a body roughly 290,000 km in diameter."
Decimal point error? For comparison, Jupiter, with an equatorial diameter of around 142,000 km, is roughly half the size of your proposed impactor. Mars has an equatorial diameter of a little under 6,400 km diameter, or about 1/45th the diameter of the size of your impactor.
Earth's atmosphere was not four times denser during the Jurassic - I think you're thinking of the periods when oxygen levels are thought to have been higher than the present. In any case, a more dense atmosphere would not be an aid to flight as it would also lead to greater drag and favour shorter 'wingspans', as we see in penguins and, umm, fish (although it has to said that the density of most animals is about the same as water, so their wings and fins don't need to support their weight against gravity, and an atmosphere that was four time more dense than today would still be less dense than water, so flying animals would still need longer wings (or fins) than a fish or penguin).
And FWIW, any winds or storms in an atmosphere four time as dense as today would be incredibly destructive with regards to vegetation - only very robust ground hugging species would survive.
@Faux Science Slayer
There have been birds just in the past 10M years with far bigger wingspan than a condor - that does not imply massive climactic differences.
In many cases size of animals is not limited by simple "single factor" scenarios as a whole host of competing costs and benefits kick in.
e.g. the condor can fly very well, not expending too much energy and cover large distances at a good speed (ideal for carrion searching) - increasing wingspan a lot would only give relatively small increase in speed / range but would come at the cost of higher food requirements, body more effort to move on ground /more awkward to take off (i.e. harder to escape ground based predators).
With higher food requirementrs would there be enough carrion (remember it has to compete with other carrion eaters & finite rate of dying animals as not an active hunter)
Greater size could make the bird less "agile" in manouvering in the air (remember condor is not 100% immune from aerial predators, if it was far larger & clumsier a smaller eagle / hawk might be more likely to risk attacking it )
Even basic things like nesting sites may be more problematic with increased size past a certain point.
Condors could be larger (they have not reached a mechanical / cardio vascular size limit), but for whatever combination of reasons, there is insufficient advantage in doing so.
Ecosystems are complex (though people are doing a good job of making many of them simpler by heavily reducing / wiping species out) and it is too easy to make rash assumptions.
The occasional one can be valid, e.g. in times of higher average temperaure and oxygen levels then insects could exceed maximum possible sizes we see now as the passive spiracle based "breathing" system of insects limits their size due to limits on )2 delivery over distance and so higher O2 and tempearature would facilitate larger insects as more O2 and higher temps increase gas speed. But in general size X must mean physical factor Y are wrong.
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