Final answer:
The Earth heats through absorption of solar radiation with the angle of insolation affecting energy received. Solar radiation and earth's infrared radiation maintain the Earth's temperature, influenced by the greenhouse effect.
Step-by-step explanation:
Earth's surface heats up through the process of absorption of solar radiation, which comprises various types of energy, including ultraviolet rays, visible light, and infrared. This absorbed energy is then re-radiated into space primarily as heat. The angle at which sunlight strikes Earth's surface is called the angle of insolation, and it significantly affects the amount of energy that a specific location on Earth receives.
The Earth maintains a relatively constant temperature due to the energy balance between the incoming solar radiation and the infrared radiation emitted by Earth. However, the greenhouse effect alters this balance by trapping long-wavelength infrared radiation, which is re-emitted by the Earth's surface. Factors such as the concentrations of greenhouse gases like carbon dioxide influence the strength of the greenhouse effect and can thus affect Earth's surface temperature.