Range from gamma rays to radio waves. Harmful rays such as X-rays and gamma rays are absorbed by oxygen and nitrogen in the upper layers of the atmosphere. This radiation has a high frequency which makes it dangerous for life forms. Ultraviolet radiation is absorbed by ozone at around 100 km altitude. Infrared is absorbed by water vapor and carbon dioxide at an altitude of 20 km. The remaining wavelengths come from the visible spectrum, near infrared, microwaves and radio waves. Many of these waves are reflected back into space, but the remaining visible light, in the near infrared, provides enough solar energy to support plant life and warm the environment.