Each lump of the cloud in which gravity can overcome pressure can go on to become a star. Thousands of molecular clouds are found along the spiral arms of the milky way. Molecular clouds contain tiny solid particles of interstellar dust. Tiny solid particles of interstellar dust block our view of stars on the other side of a cloud. Dust blocks light, blue (shorter wvlgth) more than red (longer wvlgth) To see" through the dust in the cloud, we need to use infrared. Stars viewed through the edges of the cloud look redder because dust blocks (shorter- wavelength) blue light more effectively than (longer-wavelength) red light. Molecular clouds are favorable locations for star formation for two reasons: low temperature and high density. Magnetic fields and turbulence can also oppose gravity: increases the minimum mass for contraction. Gravity within a contracting gas cloud becomes stronger as the gas becomes denser.