Eye in the sky: Time nearly up for Hourglass Nebula as it runs out of nuclear fuel

The sands of time are running out for the central star of this hourglass-shaped planetary nebula.

With its nuclear fuel exhausted, this brief but spectacular closing phase of MyCn18 – better known as the Engraved Hourglass Nebula – occurs as its outer layers are ejected.

Located 8,000 light-years away from Earth in the southern constellation Musca, the sun-like star’s core is in the process of becoming a cooling, fading white dwarf.

Astronomers used the Hubble Space Telescope to make a series of images of planetary nebulae in the mid-1990s, including this one.

Delicate rings of colourful glowing gas – nitrogen-red, hydrogen-green, and oxygen-blue – outline the tenuous walls of the hourglass.

The unprecedented sharpness of Hubble’s image has revealed surprising details of the nebula ejection process.

And it is these that are helping scientists to resolve the outstanding mysteries of the complex shapes and symmetries of planetary nebula.

MyCn18 was discovered by Annie Jump Cannon and Margaret W Mayall during their research on an extended Henry Draper Catalogue, an astronomical star encyclopedia compiled between 1918 and 1924.

The astronomers described it as a small faint planetary nebula, but the march of technology allowed scientists Raghvendra Sahai and John Trauger of the Jet Propulsion Laboratory to capture this stunning image using Hubble in January 1996.

MyCn18’s hourglass shape is thought to have arisen from the expansion of a fast stellar wind within a slowly expanding cloud which is denser near its equator than its poles. – DailyMailUK

Is it just a coincidence? There are very few. The hourglass of time before the start of Armageddon has nearly run out – while the hourglass in the heavens, that of the Hourglass Nebula, confirms this for all those whose eyes are open to recognizing the signs.