Lesson2e . Lava Tubes and Density. Lava tubes. Lava pouring out of Lava Tube. Collapsed Lava Tube on Earth . Lava flows in channels also. Lunar Rille (means “groove”). Topographical map of Mars. Olympus Mons. Lava Tubes on Mars – Pavonis Mons.
Lava Tubes and Density
Surface A is likely to be older. We can see a number of impact craters in surface A. But surface B seems to be missing craters.
Not much. It only tells us there is a lot of room for people to expand into.
V = L x L x L = L3
V = 4πR3/3
We can test this by comparing to rocks we find on the surface.
This is very different. How can we explain this?
The density we calculated for the Earth was the average density. It doesn’t mean that the density is the same everywhere inside.
Research on the composition of meteorites shows that many are composed of high fractions of iron.
The iron has to be in the interior of the Earth and not much on the surface.
The average density we have been discussing is the Earth’s compressed density. It depends on the material in the Earth and how much that material is compressed by the Earth’s gravity.
If we want to know what planets are made of, we do not want to take into account the force of gravity. This is the uncompressed density. It only depends on the material in the planet.
Let’s see what we can deduce about the four Galilean moons, Io, Europa, Ganymede, and Callisto.