are from the region between the Sun’s orbit and the center of the galaxy (known as the “solar circle”). 
    Carbon monoxide clouds can also be used to determine how fast matter is moving relative to the Sun. This image displays what is known as the radial velocity of the carbon monoxide clouds; this is the speed the gas is moving toward or away from the Sun as determined by its Doppler shift. Near the Galactic Center radial velocities are high, indicating that molecular matter is moving out of the galactic center at great speeds.