Slashdot Mirror
What Happened To the Martian Ocean and Magnetic Field? (theatlantic.com)
schwit1 writes with this story at The Atlantic that explores what may have destroyed the Martian atmosphere and ocean. The question of whether there is life on Mars is woven into a much larger thatch of mysteries. Among them: What happened to the ancient ocean that once covered a quarter of the planet's surface? And, relatedly, what made Mars's magnetosphere fade away? Why did a planet that may have looked something like Earth turn into a dry red husk? “We see magnetized rocks on the Mars surface,” said Bruce Banerdt, the principal investigator of the InSight mission to Mars, which is set to launch in March. “And so we know Mars had a magnetic field at one time, but it doesn't today. We would like to know the history—when that magnetic field started, when it may have shut down.”
Mars has no Magnetic field because it's core cooled and is no longer a active moving iron mass. it cooled faster as it has very little radioactive isotopes and being further away from the sun it has less energy pounding it to slow the cooling.
http://www.scientificamerican....
Plus we had an event late after the formation of the planets in the solar system that also added a buttload of energy, when the moon was formed from a planetary sized impact.
Do not look at laser with remaining good eye.
Very little energy reaches the Venusian surface - Venus's albedo is twice that of Earth's, so most light gets reflected from the cloud deck, and what does enter gets quickly absorbed in the clouds and thick atmosphere. Also, the crust is not what drives a dynamo, the core does. Nuclear decay is what drives terrestrial planet cores, not solar input.
Also I don't know what you mean by "rapid crust recycling", unless you mean Venus's global resurfacing events. But those only happen once every several hundred million years. And they take about 100 million years to complete, they're not rapid.
The human body can be drained of blood in 8.6 seconds given adequate vacuuming systems.
A common theory to explain Venus' slow and backwards rotation is that it suffered a large impact similar to the one that formed the Earth's moon, only in a direction counter to it's original rotation, so much that it put the brakes on Venus so hard that it's now slowly spinning in reverse.
Also it's thought that Venus is simply too close to the Sun, there was a time when the Sun wasn't as bright and water may have been on the surface but as the sun matured the "goldilocks" zone shifted outwards and Venus got cooked.