When less energy is radiated from a terrestrial planet, its ________ increases until a new ________ is achieved. a. temperature; equilibrium b. size; temperature c. equilibrium; size d. temperature; size

Understanding planetary temperature is crucial when studying terrestrial planets. A planet's temperature is primarily influenced by how much energy it receives from its star and how much energy it radiates back into space.

When a terrestrial planet receives a significant amount of energy from its star, its surface heats up. This energy can come in the form of visible light, ultraviolet radiation, and other electromagnetic waves. The heated surface then radiates energy back into space, primarily in the form of infrared radiation.

The balance between the energy a planet receives and the energy it radiates is what determines its overall temperature. When this balance is disturbed, the temperature of the planet will adjust until a new balance—or equilibrium—is reached.

Energy equilibrium is a state of balance where the energy coming into a planetary system equals the energy going out.

• Incoming energy typically comes from the star the planet orbits.
• Outgoing energy is the heat radiated back into space.

For terrestrial planets, achieving energy equilibrium is critical for maintaining stable temperatures. If less energy is radiated because of atmospheric changes or other factors, the planet will absorb more heat, leading to an increase in temperature. This rise in temperature continues until a new equilibrium is achieved.

Imagine it like a bathtub: If the faucet (incoming energy) fills it faster than the drain (radiated energy) can empty, the water level (temperature) rises. Once the inflow matches the outflow, the water level stabilizes - this is equilibrium. The same principle applies to planetary energy balance.

Terrestrial planets, unlike gas giants, have solid, rocky surfaces. Examples include Earth, Mars, Venus, and Mercury. Their ability to absorb and radiate energy is influenced by their atmosphere and surface properties.

Several factors affect their energy radiating capabilities:

• Albedo: The reflectivity of a planet's surface and atmosphere. A higher albedo means more sunlight is reflected back into space, keeping the planet cooler.
• Atmospheric composition: Gases like carbon dioxide and methane can trap heat, increasing the greenhouse effect and raising the planet's temperature.
• Surface features: Oceans, deserts, and ice caps can all impact how much energy is absorbed and radiated.

Understanding these factors helps in predicting how a terrestrial planet's temperature might change in response to different conditions. A planet's atmosphere plays a significant role in maintaining temperatures suitable for life, which is why studying energy radiation and equilibrium is vital in planetary science.