Mars is a Basketball (For Scale)

In case you missed it, last month NASA announced the discovery of what looks like liquid water on Mars: a 20-kilometer (12.4-mile) wide lake hiding under 1.5 km (~1 mile) of ice. A lake 20 kilometers across sounds like a lot of water, even if it is deep under the ice. Why did it take so long to find if it is such a large feature? Let's put this into perspective and compare the size of the lake on Mars to the size of a dot on a basketball. The comparison might surprise you.First, let's shrink Mar...