Different Forms of Light

Light is an electromagnetic wave, and each wave is characterised by its wavelength. Our eyes can detect only a small range of wavelengths, specifically between 400 nm and 800 nm, which is known as visible light. Beyond this range, there are many types of electromagnetic waves that are invisible to us because our eyes are not sensitive to them.

The table below shows the types of electromagnetic waves and their wavelengths:

Our eyes can see only the visible radiation, so we use optical telescopes with regular lenses or mirrors to observe this light from space. However, many celestial objects emit radiation outside the visible spectrum, such as X-rays, gamma rays, and radio waves. To study these, we use specialised telescopes like X-ray telescopes, gamma-ray telescopes, and radio telescopes, which are designed to detect and analyse these invisible forms of light.