Final answer:
An infrared satellite image represents heat, specifically long wave infrared radiation, which is used in remote sensing to detect and analyze objects on Earth based on their temperature-related emissions.
Step-by-step explanation:
An infrared satellite image represents heat, which is essentially the long wave infrared radiation that's reflected off the Earth's surface and often trapped by greenhouse gases. This type of satellite imagery is particularly useful in remote sensing technology, as it provides detailed data about the earth's surface. Infrared radiation can pass through the atmosphere, get absorbed and re-emitted in all directions by greenhouse gas molecules, thereby warming the Earth's surface and lower atmosphere. Reconnaissance satellites utilize this technology to detect objects by their infrared emissions, which vary in intensity proportional to the object's absolute temperature.
Additionally, remote sensing with infrared technology is used in various applications beyond satellite imagery, such as in detecting heat loss from houses using infrared cameras and for heating purposes using infrared lamps.