What forms of light can be observed with telescopes at sea level?

Visible light

Radio waves

Explanation:

Although these different types of electromagnetic radiation share many basic properties (for example, they all travel at the same speed - the speed of light - ), each interacts differently with matter. For example, our body is transparent to X-rays, but it is not transparent to visible light; Our eyes respond to visible light, but not to gamma rays, and our radios detect radio waves, but not ultraviolet light. Visible light, some regions of infrared radiation and millimeter and radio waves can be seen from the earth's surface. Therefore, astronomers require different types of telescopes to detect radiation at these varied wavelengths. For example, a radio telescope that detects radio waves from space is very different from an X-ray telescope, or an ordinary optical telescope. On the other hand, some regions of the infrared, ultraviolet light, X-rays and gamma rays require telescopes outside the Earth's atmosphere, since it prevents their passage.