Berlin, May 3 (IANS/EFE): The European Southern Observatory, or ESO, released an image Thursday that shows the intense activity that occurs inside an interstellar cloud when stars form.

The image was captured by the 1.54-meter Danish telescope at the ESO's La Silla Observatory in Chile and shows the intense activity inside an interstellar cloud.

"The gas in the clouds of NGC 6559, mainly hydrogen, is the raw material for star formation. When a region inside this nebula gathers enough matter, it starts to collapse under its own gravity. The center of the cloud grows ever denser and hotter, until thermonuclear fusion begins and a star is born," the ESO said in a statement.

The hot and brilliant young stars born in the interstellar cloud energize the hydrogen gas remaining around them in the nebula, the ESO said.

"The gas then re-emits this energy, producing the glowing threadlike red cloud seen near the center of the image. This object is known as an emission nebula," the ESO said.

Solid dust particles made of heavier elements, such as carbon, iron and silicon, are also found inside NGC 6559.

"The Milky Way fills the background of the image with countless yellowish older stars. Some of them appear fainter and redder because of the dust in NGC 6559," the ESO said.