Ewen

Definition

Ewen is often associated with Edward Mills Purcell, who alongside Harold Ewen, discovered the 21 cm hydrogen line. This discovery marked a significant advancement in radio astronomy, helping astronomers study interstellar gas.

5 Must Know Facts For Your Next Test

1. The 21 cm hydrogen line was first detected by Harold Ewen and Edward Mills Purcell in 1951.
2. This discovery provided direct evidence of the distribution of hydrogen gas in our galaxy.
3. The 21 cm line corresponds to the radio wave emitted by neutral hydrogen atoms.
4. It allows astronomers to map spiral arms and other structures within galaxies.
5. The detection of the 21 cm line opened up new methods for measuring galactic rotation curves.

Review Questions

Related terms

Neutral Hydrogen (H I): Neutral hydrogen atoms that emit at a wavelength of 21 cm when their electron flips its spin state

Radio Astronomy:

A field of astronomy that studies celestial objects via their radio frequency emissions

Galactic Rotation Curve:

A plot showing how orbital velocity varies with distance from a galaxy's center