Infrared Telescopes: Detecting the Invisible

When you were little, you may have heard of infrared telescopes and thought that they give the viewer superpowers. In a way, infrared telescopes do give us superpowers because they allow us to pinpoint infrared radiation, which is invisible to the naked eye. That’s pretty super!

Infrared Radiation

All objects with the temperature over absolute zero emit electromagnetic radiation. Electromagnetic radiation refers to the spectrum of waves that carry electromagnetic radiant energy through the electromagnetic field. Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays are all part of this spectrum.

Every day, we interact with electromagnetic radiation. Visible light is the most obvious type of electromagnetic radiation. We interact with infrared radiation too, but it is felt and not seen. The reason that infrared is invisible to our eyes is that infrared photons have lower energies than that of visible light.

All sorts of objects emit infrared radiation. Nebulae, young stars, and other galaxies all emit this radiation, and it is with the infrared telescope that scientists find these objects in the distance.
Infrared radiation requires a special type of telescope since it is not visible. As a result, optical telescopes will not be able to show you infrared radiation.

How Infrared Telescopes Work

Infrared telescopes always come with a camera. This camera includes a special solid-state infrared detector that detects the infrared radiation. This detector is how scientists are able to pinpoint and estimate the distance from the infrared radiation source.

Infrared telescopes work similarly to optical telescopes. Just like in the optical telescope, the infrared telescope uses a combination of lenses and mirrors to gather and focus radiation onto the detector. There, the detector determines the position and distance of the infrared source.

The reason that infrared telescopes work so similarly to optical telescopes is that infrared radiation and visible light are both part of the electromagnetic spectrum. This means that both are waves that can be manipulated or observed in similar fashions.

One big difference between optical telescopes and infrared telescopes, though, is that infrared telescopes are designed to minimize the amount of heat emitted from the telescope.
In order to detect infrared radiation, infrared telescopes can be based on the ground, air, or space. Ground- and air-based infrared telescopes are stifled and encounter interference from the earth’s atmosphere. Space-based scopes, on the other hand, face no interference since they are outside the earth’s atmosphere.