When one looks over smaller distances, though, galaxies can mutually attract each other due to gravity, thus are in fact moving toward each other. Our Milky Way and the nearby Andromeda Galaxy are two examples of such a pair of galaxies that are moving toward each other due to gravity.

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That said, the stars in both the Andromeda galaxy and our Milky Way will be affected by the merger. The Andromeda galaxy contains about a trillion stars. The Milky Way has about 300 billion stars. Stars from both galaxies will be thrown into new orbits around the newly merged galactic center.

The rate of universal expansion is 68 kilometers per second per megaparsec. A parsec is 3.26 million light-years, while a megaparsec is a million parsecs. For every parsec away a galaxy is from ours, you add 68 km/s to its velocity. Once we get out to about 4,200 megaparsecs away, galaxies travel faster than light.

Scientists are able to tell that the galaxy is coming closer to us because of the light coming from Messier 90. “The galaxy is compressing the wavelength of its light as it moves towards us, like a slinky being squashed when you push on one end,” Hubble representatives said in the statement.

This nearby galaxy’s redshift measurement is negative, meaning it is actually blueshifted, or headed toward the Milky Way, not away from it. The simple answer to this is no, they do not. In fact, almost all galaxies are observed to have redshifts.

So, if radio waves are shifted into the ultraviolet part of the spectrum, they are said to be blueshifted, or shifted toward the higher frequencies. Gamma rays shifted to radio waves would mean a shift to lower frequency, or a redshift.

Redshifts greater than 1 are possible if the redshift is caused by relativistic motion or by cosmological expansion. It is caused by the expansion of space between the time when the light is emitted and when it is received by an observer.