1. How Do Astronomers Gather Information About Space?

2. All of the information we have from the universe comes from radiation.

3. Objects in the universe, such as stars and galaxies, emit radiation.

4. Radiation travels as waves
Radiation travels as waves. Different kinds of radiation have different wavelengths and energies.

5. We cannot see most of the radiation, but telescopes collect the radiation for study.

6. The entire collection of different kinds of radiation is called the Electromagnetic Spectrum.

7. The electromagnetic spectrum is a continuum of waves divided into regions based on wavelengths.

8. The only region in the electromagnetic spectrum that our eyes are sensitive to is the visible region.

9. Most of the visible region comes from the Sun.

10. When light is passed through a prism, it bends and separates into its different wavelengths. This pattern of wavelengths is called a spectrum.

11. Spectroscopy is the study of the spectrum.
A spectroscope is used to separate light into its component wavelengths.

12. Astronomers can determine the object’s temperature, density and the direction of motion.

13. Each element composing a star has a unique spectrum
Each element composing a star has a unique spectrum. Just like a fingerprint…..

14. Astronomers use the spectral patterns from stars and other objects to determine what elements compose the object.

15. Here is an example of a spectrum from a real star: