Local Sheet

Our home is in a big group.

Many galaxies live near us. They move in a similar way. This group is like a long wall. It marks the edge of a big empty space.

There is a ring of giant galaxies too.

Ten of these are shaped like spirals. Two are shaped like ovals. They sit on both sides of our group.

These galaxies are part of a huge web. It is a very big part of space.

The Local Sheet is a large region of space.

It is a thin wall of galaxies. Most bright galaxies nearby belong to it. This sheet is part of the Virgo Supercluster. It also forms one edge of the Local Void. The Local Void is a huge, empty part of space. It is about 150 million light-years across. Galaxies in the sheet move away from the center of the void. They also move toward the Virgo Cluster. This happens because of gravity.

A ring of twelve large galaxies surrounds our Local Group. We call this ring the Council of Giants. Ten of these are spiral galaxies. Two are elliptical galaxies, which are shaped like ovals. These two ovals are Maffei 1 and Centaurus A. They sit on opposite sides of our group. The ring has a radius of about 10 million light-years. This region was studied in 1987 by Brent Tully and Richard Fisher. They called it Cloud 14 in their book.

The Local Sheet is a huge part of our space.

It is a thin wall of many galaxies. Most bright galaxies near us belong to this sheet. It is part of a larger area called the Virgo Supercluster. This sheet also marks one edge of the Local Void. The Local Void is a giant, empty space.

Galaxies in the sheet move in a special way. They have a peculiar velocity, which means they move differently than the rest of space. Two things cause this motion. First, gravity pulls them toward the Virgo Cluster. Second, they move away from the center of the Local Void. The void is a vast region of space. It is about 150 million light-years across. This expansion pushes the galaxies outward.

Scientists first described this region in 1987. Astronomer Brent Tully and his colleague Richard Fisher studied it. They wrote about it in a book called The Nearby Galaxies Atlas. They originally called the area Cloud 14. Tully believes the Local Sheet is just one part of the Coma-Sculptor Cloud. He says it is the part that moves together. Other experts like McCall think the names mean the same thing.

There is a ring of large galaxies called the Council of Giants.

This ring surrounds our Local Group. It has a radius of about 10 million light-years. The center is 15 million light-years from our Sun. Ten of these galaxies are spirals. Two are elliptical galaxies named Maffei 1 and Centaurus A. These two sit on opposite sides of our group.

Think of the Local Sheet like a thin layer of dust. It sits between much larger things in space. The sheet is about 10 million light-years across. It is also about 1 million light-years thick. It is tilted 8 degrees from the Virgo Supercluster. This shape helps us map our place in the universe. Most galaxies in the sheet are late-type galaxies. This is different from the Virgo Cluster. In that cluster, many galaxies are early-type.

The Local Sheet is a massive galaxy filament in our cosmic neighborhood. It is an extragalactic region where many galaxies move together. This shared motion is known as a peculiar velocity. The Milky Way and the members of our Local Group are part of this sheet. Most bright galaxies near us belong to this specific structure.

The sheet is a thin part of the larger Local Volume. It also exists within the Virgo Supercluster, which is a much larger collection of galaxies.

To understand the sheet, we must look at its unique shape and size. The Local Sheet is a very thin, flat structure. It has a diameter of about 10 million light-years. However, it is only about 1 million light-years thick. This shape makes it look like a wall or a thin layer. This wall forms one boundary of the Local Void. The Local Void is a vast, empty region of space.

This void is estimated to be 150 million light-years across.

The movement of galaxies in the Local Sheet is caused by two main forces. First, the gravity of the Virgo Cluster pulls on them. This creates a peculiar motion toward that massive cluster. Second, galaxies move away from the center of the Local Void. This void is an expanding region of space with very few galaxies. This expansion pushes the galaxies outward at a velocity of about 240 kilometers per second. These two forces combine to create the specific motion we observe in the sheet.

There is a famous group of galaxies within the sheet called the Council of Giants. This is a ring of twelve large galaxies. The ring surrounds our own Local Group. It has a radius of about 10 million light-years. The center of this ring is located 15 million light-years from the Sun.

Most of these galaxies are spirals. Specifically, ten of the twelve are spiral galaxies. The remaining two are elliptical galaxies. These two ellipticals are named Maffei 1 and Centaurus A. They sit on opposite sides of our Local Group.

We can see specific details about the galaxies in this Council. For example, the Sculptor Galaxy is 11 million light-years away. The galaxy M81 is about 12 million light-years from us. Centaurus A is an elliptical galaxy located 11 million light-years away. Each galaxy has a different stellar mass. This mass is often measured using a logarithm of its mass in solar masses. These diverse galaxies help scientists understand the structure of our local space.

Astronomers first identified this region in 1987. An astronomer named Brent Tully and his colleague Richard Fisher described it. They published their findings in a book called The Nearby Galaxies Atlas. In that book, they originally called the region Cloud 14. The region is also known as the Coma–Sculptor Cloud. There is some debate about the exact names used. Tully believes the Local Sheet is only the co-moving part of the Coma-Sculptor Cloud. This means it is the part where galaxies move together. However, other researchers like McCall consider the two terms to be the same thing.

The Local Sheet is different from other galaxy clusters like the Virgo Cluster. Most galaxies in the sheet are late-type galaxies. In contrast, more than half of the giant galaxies in the Virgo Cluster are early-type galaxies. The sheet is also tilted at an angle of 8 degrees from the Local Supercluster. This orientation is important for mapping the universe. Scientists use the Supergalactic coordinate system to track these positions. This system uses the Local Sheet and the Supergalactic Plane as its base.