If everything radiates electromagnetic energy, why can we not see objects at room temperature in a dark room?

Electromagnetic radiation consists of waves of electric and magnetic energy moving together through space. This radiation contains different frequencies, some of which are visible to the human eye, while others are not. The spectrum of electromagnetic radiation ranges from very low frequencies, such as radio waves, to very high frequencies, like gamma rays.

The electromagnetic spectrum is divided into several sections, ranging from low to high frequencies. These sections include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. Among these sections, only the visible light spectrum can be detected by the human eye. The visible light spectrum has wavelengths ranging from approximately 380 nm (violet) to 750 nm (red). Objects that emit or reflect electromagnetic radiation at these wavelengths can be seen by the human eye.

Objects at room temperature emit electromagnetic radiation mainly in the infrared region of the electromagnetic spectrum. This is due to the thermal energy of the objects causing the emission, which excites the atoms and molecules in the object, resulting in the production of electromagnetic radiation. The frequency of the electromagnetic radiation emitted by an object depends on its temperature, as described by Planck's Law.

Since objects at room temperature emit electromagnetic radiation mainly in the infrared region, and our eyes are sensitive only to the visible light region of the electromagnetic spectrum, we cannot see objects at room temperature in a dark room. This is because the frequency and wavelength of the emitted radiation do not overlap with the visible light spectrum that our eyes can detect. If an object were heated to a high enough temperature, it would emit electromagnetic radiation in the visible light spectrum, allowing us to see it in a dark room. For example, the filament in an incandescent light bulb heats up to a temperature that produces visible light when electricity passes through it, illuminating the dark room.