most infrared wavelengths are absorbed by Earth's atmosphere

The main difference between gamma rays and infrared rays is in their wavelengths. Gamma rays have the shortest wavelengths while infrared rays have longer wavelengths. Gamma and infrared rays are types of electromagnetic radiation.

very small wavelengths (near-infrared, far-infrared, sub-millimeter, microwaves)

Infrared radiation has longer wavelengths.

== == Infrared light lies between the visible and microwave portions of the electromagnetic spectrum. Infrared light has a range of wavelengths, just like visible light has wavelengths that range from red light to violet. "Near infrared" light is closest in wavelength to visible light and "far infrared" is closer to the microwave region of the electromagnetic spectrum. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic.