“Ghostly hand” in the Milky Way appears in new telescope image

What appears to be a ghostly hand reaching across the universe toward a helpless spiral galaxy in a new telescope image is a rarely seen cosmic phenomenon, according to astronomers.

A Dark Energy Camera captured a stunning image of the “God’s hand”a globule comet 1,300 light years from Earth in the constellation of Puppis. The camera is mounted on the Víctor M. Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile.

Comet globules are a type of Bok globule, or dark nebula. These isolated cosmic clouds are filled with dense gas and dust, surrounded by hot, energetic material. Comet globules are unique because they have extended tails, like those seen on comets — but that’s the only comet-like thing about them.

It is not yet known how cometary globules arise in such distinct structures. Historically, it has also been difficult for scientists to detect faint clouds.

The new image of the hand-shaped light feature shows CG 4, one of many cometary globules found in the Milky Way. The twisted cloud appears to be stretching toward a spiral galaxy known as ESO 257-19 (PGC 21338). But the galaxy is more than 100 million light-years from the cometary globule.

CG 4 has a dusty main head, which resembles a hand, 1.5 light years in diameter, and has a long tail that extends 8 light years. A light year is the distance that light travels in one year, which is equivalent to 9.46 trillion kilometers.

A surprising celestial discovery

Astronomers discovered the cometary globules by chance in 1976 while observing images captured by the United Kingdom’s Schmidt Telescope in Australia. These cosmic phenomena are difficult to detect because they are incredibly faint, and the tails of the globules are often blocked from view by stardust.

But the Dark Energy Camera has a special filter that can detect the incredibly faint red glow emitted by ionized hydrogen present at the outer edge and head of CG 4. Hydrogen only produces this characteristic red glow after being hit by radiation from hot stars and nearby masses.

While stellar radiation allows the cometary globule to be visible, it is also destroying the globule’s head over time. However, there is enough gas and dust inside the globule to aid in the birth of several stars the size of our Sun.

Cometary globules can be found throughout our galaxy, but most are in the Gum Nebula, a glowing cloud of gas believed to be the slowly expanding remnants of a stellar explosion that occurred about 1 million years ago. The Gum Nebula is considered to contain 31 cometary globules in addition to CG 4.

Astronomers believe there are a few ways the globules can acquire their distinctive comet-like shapes.

The globules may have once been round-shaped nebulae, like the iconic Ring Nebula, that were disturbed over time by a supernova — perhaps even the one that formed the Gum Nebula.

But cosmic phenomena can also be the result of winds and radiation released by nearby hot, massive stars.

Astronomers believe that stars may be the underlying cause, as all cometary globules found in the Gum Nebula have tails pointing away from the center of the nebula. And at the center of the nebula is the supernova remnant, as well as a pulsar, or a rapidly spinning neutron star that formed when a much larger star collapsed and exploded.