Consider a helium atom that is part of Earth's atmosphere and is initially at the planet's surface, where the temperature is \(20^{\circ} \mathrm{C}\). To what maximum altitude can this atom rise if its speed is equal to the root-meansquare speed of the helium in the atmosphere? The mass of a helium atom is \(6.646 \times 10^{-27} \mathrm{~kg}\), the mass of Earth is \(5.97 \times 10^{24} \mathrm{~kg}\), and Earth's radius is \(6.38 \times 10^{6} \mathrm{~m}\). (Careful! The value of \(g\) varies with altitude.)