🪐intro to astronomy review

Infrared

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Infrared is a type of electromagnetic radiation with wavelengths longer than visible light but shorter than microwaves. It is commonly used in astronomy to observe celestial objects that are not visible in the optical spectrum due to dust or distance.

Pep mascot

5 Must Know Facts For Your Next Test

  1. Infrared radiation has wavelengths ranging from about 700 nanometers (nm) to 1 millimeter (mm).
  2. It is emitted by all objects based on their temperature, with warmer objects emitting more infrared radiation.
  3. Astronomers use infrared telescopes to detect heat from stars, planets, and other celestial bodies obscured by interstellar dust.
  4. The Earth's atmosphere absorbs much of the infrared radiation from space, so many infrared observations are conducted using high-altitude balloons or space-based telescopes.
  5. Infrared spectroscopy helps identify molecular compositions and temperatures of distant astronomical objects.

Review Questions