The pillars are active star forming regions in the Eagle Nebula, 7,000 light years distant; the largest of the pillars has a height of about 40 trillion kilometres (4 light years). They consist mainly of molecular hydrogen and dust. These pillars will be destroyed fairly soon either by gradual erosion from the strong stellar winds from new born stars within and around the pillars or from supernovae nearby blowing away the remaining gas and dust.
Scientists discovered a cloud of hot gas believed to be a shock wave from a supernova and thought to hit and destroy the pillars in 1,000 years’ time. As the light from the pillars takes around 7,000 years to reach Earth, the pillars likely have already been destroyed; we see the pillars as they were 7,000 years ago.
This image was taken in 1995 by NASA's Hubble Space Telescope and highlights the pillars where new stars are thought to be forming.
Image credit: NASA, Jeff Hester, and Paul Scowen (Arizona State University)