Question Hi! I was wondering how much kinetic energy would an asteroid require to create Valles Marineris on a Mars like planet? I know that an asteroid impact would never produce a formation shaped like Valles Marineris but can you give some estimates on the energy needed? Would a hundred petajoules be enough?
Answer That would be a gross estimate, indeed, since not a whole lot is known about the deeper geology of Mars. There's a mission going there (Russian/European) that I was just reading about earlier today, in fact, that may help. Also, the manner in which it happened would be important. Just to move aside the rock inside? Making some assumptions about the geometry and density, the valley probably contains about 7*10^18 kg of rock. So just to lift it an average distance (the height above the average height*2, you'd need at least 10^23 Joules to do it. So that's a million times what you were talking about, even lacking efficiencies thrown in and forgetting about the mass of the asteroid. I'd say you'd need 10x that to actually do it, so a trillion trillion joules (10^24) would be enough. And to think that these are small energies compared to supernovae...
I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.
I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.
Education/Credentials Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.