Globular cluster M13

Around 300,000 ancient stars, packed tightly into a ball. In 1974 a radio message was sent there from here – the earliest a reply could arrive is in 50,000 years.

▶ View in the 3D model

Key figures

Distance: 22,200 light-years
Diameter: about 145 light-years
Stars: several hundred thousand
Age: about 11.6 billion years
Constellation: Hercules

Interesting facts

In 1974 the Arecibo radio telescope sent a message from humankind towards M13. It will arrive in about 25,000 years.
At the centre the stars are packed so tightly that the night sky there would be a thousand times brighter than ours.

Ancient balls of stars

Globular clusters are among the oldest objects in the Milky Way. About 150 of them swarm around our galaxy in the halo – almost as old as the universe itself.

How to find Globular cluster M13 in the sky

Between the bright stars Vega and Arcturus lies the constellation Hercules with a square of four stars. On the side facing Arcturus, about a third of the way from the upper star: a round, fuzzy patch made up of around 300,000 stars. High in the sky in summer.

Visible with: binoculars. More under Watching the sky.

Where is it?

Globular cluster M13 belongs to the “The Milky Way” level of the Cosmic Zoom (field of view about 130,000 light-years). Our galaxy: a spiral of 100 to 400 billion stars. The Sun lies in the Orion Arm, 26,000 light-years from the centre. All the neighbouring stars from the previous level are inside the tiny dot at “Sun”.

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