Question

Why isn't the atmosphere a closed system?

1.Closed systems only exist in theory.
2.Closed systems are only for liquids, not gases.
3.The laws of physics do not apply to the atmosphere.
4.Gases from Earth escape from the higher realms of the atmosphere.

Answer 1

The atmosphere is not a closed system because it loses atoms, particularly light gases like hydrogen and helium, to space, especially at high altitudes in the ionosphere.

Step-by-step explanation:

The atmosphere isn't considered a closed system because it can exchange energy and matter with its surroundings. Specifically, at elevations above 100 kilometers, such as in the ionosphere, individual atoms can escape Earth's gravitational field. This process is known as atmospheric leakage, where lightweight atoms like hydrogen or helium can move into space due to their high velocity, which is greater than what Earth's gravity can retain. This exchange is more pronounced for lighter elements, while heavier gases are more likely to remain within the atmosphere.

In addition, concepts from thermodynamics such as the kinetic theory of gases explain that gases at higher temperatures and lower atmospheric pressures have atoms and molecules moving at higher speeds, which contributes to the possibility of escaping Earth's gravitational pull. Therefore, the Earth's atmosphere is an open system because it is not completely isolated and can have interactions with outer space, losing some of its components over time.