Astronomers have created probably the most delicate radio picture ever of an historic star cluster – and found a radio sign on the centre of it.

The picture, which will be seen above, is of the second brightest globular cluster within the night time sky, referred to as 47 Tucanae.

Star clusters are an historic relic of the early universe and "very old, giant balls of stars that we see around the Milky Way", astronomer Dr Arash Bahramian defined.

Dr Bahramian, from the International Centre for Radio Astronomy Research (ICRAR) in Australia, stated: "They're incredibly dense, with tens of thousands to millions of stars packed together in a sphere.

"Our picture is of 47 Tucanae, one of the vital huge globular clusters within the galaxy. It has over 1,000,000 stars and a really vivid, very dense core."

It took greater than 450 hours of observations on the Australia Telescope Compact Array to create the picture, which is the deepest and most delicate radio picture ever compiled by an Australian radio telescope.

More from Sky News:New discovery 'challenges our understanding of the universe'Doomed moon lander to 'burn up' after failed mission

Radio waves from celestial objects - corresponding to planets and stars - journey via area as mild does, and radio telescopes can intercept them.

Astronomers can then convert these alerts into radio pictures.

The 47 Tucanae cluster was first catalogued within the 1700s and will be seen with the bare eye.

Two potential causes for mysterious radio sign

Seeing it intimately has allowed astronomers to find the beforehand undetected faint sign coming from its centre.

There are two potential causes for the sign, lead creator Dr Alessandro Paduano has stated.

The first is that the cluster comprises a black gap, which might be "be a highly significant discovery" and the second is that there's a pulsar - a rotating neutron star that emits radio waves.

"A pulsar this close to a cluster centre is also a scientifically interesting discovery, as it could be used to search for a central black hole that is yet to be detected," Dr Paduano stated.