Great Hercules Cluster

globular cluster · M13, target of the Arecibo message

25,000 light-years from Earth

Several hundred thousand stars in a ball about 145 light-years across, around 12 billion years old. In 1974 the Arecibo radio telescope beamed a short message toward it. Travelling at the speed of light, it will take about 25,000 years to get there.

• about 25,000 light-years · 145 light-years across
• the Arecibo message has covered 51 light-years of the way so far

kind

nebula · star cluster

catalogue

M13 · NGC 6205

size

145 light-years across