There are several examples of things that emit radiation but do not emit visible light. Here are a few notable ones:
X-rays: X-rays are a type of electromagnetic radiation with high energy and shorter wavelengths than visible light. They are commonly used in medical imaging to visualize bones and tissues, as well as in other applications such as airport security scanners.
Gamma rays: Gamma rays are the most energetic form of electromagnetic radiation. They have even shorter wavelengths and higher frequencies than X-rays. Gamma rays are often emitted during nuclear reactions and radioactive decay processes.
Radioactivity: Radioactive materials emit various types of radiation, including alpha particles, beta particles, and gamma rays. These emissions occur due to the unstable nature of the atomic nucleus. Radioactive elements like uranium, radium, and plutonium are examples of substances that emit radiation.
Microwaves: Microwaves are a form of electromagnetic radiation with longer wavelengths than visible light. They are commonly used for cooking in microwave ovens, as well as in telecommunications and radar systems.
Infrared radiation: Infrared radiation has longer wavelengths than visible light and is commonly associated with heat. It is emitted by objects with a temperature above absolute zero. Infrared radiation is used in various applications, including night vision technology, thermal imaging, and remote controls.
Ultraviolet (UV) radiation: UV radiation has shorter wavelengths than visible light. It is emitted by the Sun and can cause sunburns and skin damage. UV radiation is also used in sterilization processes and in certain industrial applications.
Cosmic rays: Cosmic rays are high-energy particles, primarily originating from outer space. They include protons, electrons, and atomic nuclei. Cosmic rays can have various effects on Earth's atmosphere and can pose risks to astronauts and electronics in space.
It's important to note that while some forms of radiation may not be visible to the human eye, they can still have significant effects on living organisms and require appropriate precautions and safety measures.