The Local Sheet in astronomy

Astronomy

Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 is a nearby region of the observable universe

Observable universe

In Big Bang cosmology, the observable universe consists of the galaxies and other matter that we can in principle observe from Earth in the present day, because light from those objects has had time to reach us since the beginning of the cosmological expansion...

 where the Milky Way

Milky Way

The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

, the members of the Local Group

Local Group

The Local Group is the group of galaxies that includes Earth's galaxy, the Milky Way. The group comprises more than 30 galaxies , with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy...

 and other galaxies share a similar peculiar velocity

Peculiar velocity

Peculiar motion or peculiar velocity refers to the true velocity of an object, relative to a rest frame.-Galactic astronomy:In galactic astronomy, the term peculiar motion refers to the motion of an object through space.Local objects are usually related in terms of proper motion and radial...

. This region lies within a radius of about 7 Mpc

Parsec

The parsec is a unit of length used in astronomy. It is about 3.26 light-years, or just under 31 trillion kilometres ....

, and galaxies beyond that distance show markedly different velocities. The Local Group has only a relatively small peculiar velocity of with respect to the Local Sheet. Typical velocity dispersion of galaxies within the Local Sheet is only in the radial direction.

A significant component of the mean velocity of the galaxies in the Local Sheet comes as the result of the gravitational attraction of the Virgo Cluster

Virgo Cluster

The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly away in the constellation Virgo. Comprising approximately 1300 member galaxies, the cluster forms the heart of the larger Local Supercluster, of which the Local Group is an outlying member...

 of galaxies. This results in a peculiar motion of about toward the cluster. A second component is directed away from the center of the Local Void

Local Void

The Local Void is a vast, empty region of space, devoid of matter, located within the Virgo Supercluster and lying adjacent to our own Milky Way galaxy. Discovered by Brent Tully of the American Astronomical Society in Honolulu, Hawaii, the Local Void is millions of light years in length, the exact...

; an expanding region of space spanning an estimated 45 Mpc that is only sparsely populated with galaxies. This component has a velocity of .