Great Rift (astronomy)

Properties

To the naked eye, the Great Rift appears as a dark lane that divides the bright band of the Milky Way vertically. The Great Rift covers one third of the Milky Way, and is flanked by strips of numerous stars, such as the Cygnus Star Cloud. West of the Cepheus Clouds, the Funnel cloud/Le Gentil 3 and the bordering North America Nebula, the Great Rift starts with the Northern Coalsack at the constellation of Cygnus, where it is known as the Cygnus Rift. The Great Rift stretches from there over the Serpens-Aquila Rift; to Ophiuchus, where it broadens out; to Sagittarius, where it obscures the Galactic Center; essentially ending at Centaurus.

One of the regions obscured by the Great Rift is the Cygnus OB2 association, a cluster of young stars and one of the largest regions of star formation within 2 kiloparsecs. Similar dark rifts can be seen in many edge-on galaxies, such as NGC 891 in Andromeda and NGC 4565 (the Needle Galaxy) in Coma Berenices.

Human observation

thumb|left|Layout of some Great Rift "constellations" as represented by the Inca Dark zones obscuring the night-sky lighting mass of the bulk of the Milky Way in a dry atmosphere (or at long exposures) were recognized by many ancient civilizations in which a seasonally or regularly dry climate is a frequent feature. In South America, the Inca gave some patterns of darkness and stars names much as normal stellar constellations were, including a series of animals like llamas, a fox, toad, and others, thought to be drinking from the "great river" (the Milky Way) and seen in silhouette.

The classical Greeks sometimes described the Great Rift as being the path of devastation left by Phaeton, who tried to guide the chariot of Helios (the Sun god) across the sky before losing control, wreaking havoc, and finally being struck down by a lightning bolt of Zeus.

Modern astronomy first began to notice the rift in the 18th century, but struggled to explain it until E. E. Barnard and Max Wolf in the early 20th century, who produced the currently accepted explanation after careful photographic study.

Of this, Barnard said:

References

References

1. (2015). "A Three-Dimensional Map of Milky Way Dust". The Astrophysical Journal.
2. (2010). "Great Rift: Dark area in the Milky Way". [[Earth & Sky.
3. (2016-07-13). "Paddle the Milky Way's Dark River".
4. Pitts, Sam. "NGC 891 Edge on Galaxy (HV19)". Sams Astro.
5. Bruce McClure. (August 13, 2021). "The Great Rift is a dark swath in the Milky Way".
6. Brian Ventrudo. (August 16, 2010). "The Northern Coalsack".