The Earth emits radiation with greatest intensity in the infrared portion of the electromagnetic spectrum. This is because the Earth's surface temperature is relatively low (around 15°C or 288K), and objects at those temperatures radiate primarily in the infrared.

While the Earth does emit radiation across a range of wavelengths, the peak intensity occurs in the infrared range, specifically around 10 micrometers. This is known as blackbody radiation, and it follows Wien's Displacement Law, which states that the wavelength of peak emission is inversely proportional to the temperature of the object.

It's important to note that the Earth also reflects sunlight, which primarily comes in the visible light range. However, the Earth's emitted radiation is primarily infrared due to its own temperature.