MemberSeptember 25, 2021 at 2:27 pm
So when an interloping planet hit the Earth, it was less likely to stick to Earth, and instead more likely to end up at Venus, Asphaug explained.
“The Earth acts as a shield, providing a first stop against these impacting planets,” he said. “More likely than not, a planet that bounces off of Earth is going to hit Venus and merge with it.”
Emsenhuber uses the analogy of a ball bouncing down a staircase to illustrate the idea of what drives the vanguard effect: A body coming in from the outer solar system is like a ball bouncing down a set of stairs, with each bounce representing a collision with another body.
“Along the way, the ball loses energy, and you’ll find it will always bounce downstairs, never upstairs,” he said. “Because of that, the body cannot leave the inner solar system anymore. You generally only go downstairs, toward Venus, and an impactor that collides with Venus is pretty happy staying in the inner solar system, so at some point it is going to hit Venus again.”
Earth has no such vanguard to slow down its interloping planets. This leads to a difference between the two similar-sized planets that conventional theories cannot explain, the authors argue.
“The prevailing idea has been that it doesn’t really matter if planets collide and don’t merge right away, because they are going to run into each other again at some point and merge then,” Emsenhuber said. “But that is not what we find. We find they end up more frequently becoming part of Venus, instead of returning back to Earth. It’s easier to go from Earth to Venus than the other way around.”
MemberSeptember 25, 2021 at 4:23 pm
Wow, the fact of material merging with Venus is amazing.