Messier 54 facts for kids

M54 as seen by the Hubble Space Telescope

Messier 54, also called M54 or NGC 6715, is a huge group of stars known as a globular cluster. You can find it in the constellation called Sagittarius, which looks like a teapot in the night sky.

A famous astronomer named Charles Messier first discovered this cluster in 1778. He added it to his list of objects that looked a bit like comets but weren't.

Where is Messier 54 Located?

For a long time, scientists thought M54 was part of our own Milky Way galaxy. But in 1994, they made an exciting discovery. They found out that M54 actually belongs to a different, smaller galaxy. This galaxy is called the Sagittarius dwarf elliptical galaxy, or 'Sag DEG' for short.

This means M54 is not a part of our galaxy at all! It's an outsider, visiting from a nearby galaxy.

How Far Away and How Big is M54?

Messier 54 is incredibly far from us. It is about 87,000 light-years away. A light-year is the distance light travels in one year. That's a very, very long way!

The cluster itself is also huge. It stretches about 150 light-years across. M54 is one of the most tightly packed globular clusters known. This means its stars are very close together.

How Bright is Messier 54?

Messier 54 shines with a lot of light. It is about 850,000 times brighter than our own Sun. Imagine how many Suns it would take to make that much light!

Its brightness, when seen from a standard distance, is called its absolute magnitude. For M54, this is −10.0, which is very bright.

Finding Messier 54 in the Sky

If you want to try and find M54, it's fairly easy to locate in the night sky. It is close to a bright star called ζ Sagittarii in the Sagittarius constellation.

However, even with a small telescope, you won't be able to see individual stars in M54. It's just too far away and the stars are too close together. You'll see it as a fuzzy ball of light.

A Black Hole at its Heart?

In July 2009, a group of astronomers found something amazing. They found signs of a medium-sized black hole right at the center of Messier 54.

This is a big deal because black holes are usually found in the centers of much larger galaxies. Finding one in a globular cluster like M54 is quite rare and interesting for scientists.

See also

In Spanish: Cúmulo globular M54 para niños