CG 4, commonly referred to as God's Hand, is a

star-forming region Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars. As a branch of astronomy, star formation includes ...

located in the

Puppis Puppis is a constellation in the southern sky. Puppis, the Latin translation of " poop deck", was originally part of an over-large constellation Argo Navis (the ship of Jason and the Argonauts), which centuries after its initial description, w ...

constellation, about from Earth. It is one of several objects referred to as " cometary globules", because its shape is similar to that of a

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or Coma (cometary), coma, and sometimes also a Comet ta ...

. It has a dense head formed of gas and dust, which is around in diameter, and an elongated faint tail around in length. , and the nearby cometary globules, generally point away from the

Vela Supernova Remnant __NOTOC__ The Vela supernova remnant is a supernova remnant in the southern constellation Vela. Its source Type II supernova exploded approximately 11,000–12,300 years ago (and was about 800 light-years away). The association of the Vela super ...

, located at the center of the Gum Nebula.

Discovery

In 1976, photographs from the

UK Schmidt Telescope The UK Schmidt Telescope (UKST) is a 1.24 metre Schmidt telescope operated by the Australian Astronomical Observatory (formerly the Anglo-Australian Observatory); it is located adjacent to the 3.9 metre Anglo-Australian Telescope at S ...

—operated by the

Australian Astronomical Observatory The Australian Astronomical Observatory (AAO), formerly the Anglo-Australian Observatory, was an optical and near-infrared astronomy observatory with its headquarters in North Ryde in suburban Sydney, Australia. Originally funded jointly by the ...

—showed several objects resembling comets, located in the Gum Nebula, an

emission nebula An emission nebula is a nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star. Among the several different types of emissio ...

of the constellation. Due to their particular shape, these objects came to be known as cometary globules. Each globule has a dense, dark, ruptured head and a very long tail, with the latter pointing away from the

. As a part of the ESO Cosmic Gems program, the

European Southern Observatory The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 mem ...

released an image of in January 2015 showing the head of the nebula.

Structure

The head of cometary globule resembles a comet with a dusty cavernous mouth, as photographed by the European Southern Observatory's

Very Large Telescope The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across, ...

in 2015. Composed of relatively dense, dark matter, it is an opaque structure that is being illuminated by the glow of a nearby star. An obscure red glow limbing the globule is possibly caused by emission from ionized hydrogen. The mouth of the globule appears to be ready to consume the edge-on spiral galaxy . In reality, the galaxy is over a hundred million light-years further away from the globule.

References

{{Reflist Dark nebulae Puppis Star-forming regions