Two views of the Whirlpool galaxy (M51)
Top image: NASA, ESA, S. Beckwith (STScI), and the Hubble Heritage Team (STScI/AURA);
Bottom image: NASA/JPL-Caltech/R. Kennicutt (Univ. of Arizona)/Digitized Sky Survey
At top is an image of the Whirlpool galaxy (M51) taken in visible light by the Hubble Space Telescope. The image is an excellent example of a spiral galaxy, a rotating windmill-like structure of arms. The outer parts of the arms spin more slowly than the central parts, giving the arms a curved shape. One arm at the top of the image is particularly stretched because it is feeling the gravitational tug from the second galaxy passing behind the Whirlpool.
At bottom is the infrared view of this same galaxy, taken by the Spitzer Space Telescope. The infrared image reveals the galaxy's dustier, star-forming regions, which are obscured from Hubble's view. The James Webb Space Telescope will see into these regions with seven times the resolution and hundreds of times the sensitivity of Spitzer, revealing individual stellar nurseries and star clusters that are normally detectable only in our own Milky Way.