SIM will produce advances in many other branches of astronomy. It will triangulate the positions of individual stars anywhere in our galaxy and even in some nearby galaxies. These measurements will establish the first rungs of the cosmic distance ladder by which astronomers infer the distances to all objects in the universe. The scientific riches from the Hubble Space Telescope show much more than we ever dreamed. The distant universe is filled with billions of faint infant galaxies.
Galaxies are clouds of hundreds of billions of stars like our own Milky Way.
We still do not know how they are made, but the HST tells us how to look for them. The expansion of the Universe after the Big Bang has stretched the wavelengths of light so that galaxies that are really blue look red to us. This is called the Doppler shift, or red shift, and the farther the galaxy, the nearer we see it to the beginning of time, and the redder it looks. To see baby galaxies just after they form, we need to use infrared wavelengths 3 to 20 times longer than visible light. The HST photos show magnificent pillars of gas where stars are being formed right now, but the newest stars are hidden from view by dust grains inside the clouds.