What is it like inside the Eagle nebula?

The Pillars of Creation can be found within the Eagle nebula. Image Credit: NASA

The glow of the Eagle nebula is generated by the massive O- and B-type stars that populate its centre. Many times more massive than the Sun, these enormous stars burn hot and fast, ejecting ionising radiation and stellar wind into the heart of the nebula, sending shock waves through the cloud.

M16 is coming to the end of its star-forming lifetime and the remaining molecular cloud has been forced out to the edges, leaving the centre comparatively empty and bathed in ultraviolet radiation. However, There are still some pockets of star-forming activity left.

The largest stars are concentrated in the north- eastern corner of the nebula, where they have carved a semi-circular basin into the molecular cloud. The shock wave generated by these enormous stars is compressing the gas in the north bay, while sources of infrared light, that could be newly forming stars, are visible within the dust. There is also evidence of masers – water molecules in the vicinity of star- forming regions that absorb energy, emitting this out as microwaves.

To the south are the iconic Pillars of Creation, three distinctive lanes of dark dust and gas. These eerie stalagmites on the floor of the nebula have resisted erosion for far longer than the surrounding gases, forming structures several light years tall. They are bordered on either side by older, cooler stars, which would once have showered the columns with radiation, sculpting them inwards towards the heart of the nebula. As these stars aged, the columns stretched out, reaching towards the cluster of massive stars in the north bay.

The Eagle nebula is an intense region of star formation. Image Credit: ESO

Most of the material along the lengths of the pillars has been stripped away, but the caps still contain pockets of denser gas and dust. As the radiation from the ionising stars reaches the tops of the pillars, the gas is boiled away in a process known as photoevaporation, leaving visible streamers twisting out from the surface of the pillar caps.

Beneath the outer gas layers, regions of denser gas start to become visible. Known as EGGs, or evaporating gas globules, these dense pockets are larger than the Solar System and are thought to be the precursors to protostars. When buried within the pillars, the dense EGGs accumulate matter from the molecular cloud, gradually becoming massive enough to initiate nuclear fusion.