The universe is expanding like a balloon—every point is receding from every other point. Distant galaxies move away from us at a velocity proportional to its distance. This rate is measured to be appr...The universe is expanding like a balloon—every point is receding from every other point. Distant galaxies move away from us at a velocity proportional to its distance. This rate is measured to be approximately 70 km/s/Mpc. Thus, the farther galaxies are from us, the greater their speeds. These “recessional velocities” can be measure using the Doppler shift of light. According to current cosmological models, the universe began with the Big Bang approximately 13.7 billion years ago.
