The Lagoon Nebula (catalogued as Messier 8 or M8, NGC 6523, Sharpless 25, RCW 146, and Gum 72) is a giant

interstellar cloud An interstellar cloud is an accumulation of gas, plasma, and cosmic dust in galaxies. Put differently, an interstellar cloud is a denser-than-average region of the interstellar medium, the matter and radiation that exists in the space between ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Sagittarius. It is classified as 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 emission n ...

and has an

H II region An H II region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds of light year ...

. The Lagoon Nebula was discovered by Giovanni Hodierna in 1654 and is one of only two star-forming

nebula A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...

e faintly visible to the eye from mid-northern latitudes. Seen with

binoculars Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most binoculars are sized to be held ...

, it appears as a distinct cloud-like patch with a definite core. Within the nebula is the

open cluster An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

NGC 6530.

Characteristics

The Lagoon Nebula is estimated to be between 4,000–6,000

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s away from the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. In the sky of Earth, it spans 90' by 40', which translates to an actual dimension of 110 by 50 light years. Like many nebulae, it appears pink in time-exposure color photos but is gray to the eye peering through

or a

telescope A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...

, human

vision Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain und ...

having poor color sensitivity at low light levels. The nebula contains a number of

Bok globule In astronomy, Bok globules are isolated and relatively small dark nebulae containing dense cosmic dust and gas from which star formation may take place. Bok globules are found within H II regions, and typically have a mass of about two to 50 sol ...

s (dark, collapsing clouds of protostellar material), the most prominent of which have been catalogued by E. E. Barnard as B88, B89 and B296. It also includes a funnel-like or

tornado A tornado is a violently rotating column of air that is in contact with the surface of Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the ...

-like structure caused by a hot

O-type star An O-type star is a hot, blue star of spectral type O in the Yerkes classification system employed by astronomers. They have surface temperatures in excess of 30,000 kelvins (K). Stars of this type have strong absorption lines of ionised h ...

that emanates

ultraviolet light Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of th ...

, heating and ionizing gases on the surface of the nebula. The Lagoon Nebula also contains at its centre a structure known as the Hourglass Nebula (so named by

John Herschel Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor and experimental photographer who invented the blueprint and did botanical work. ...

), which should not be confused with the better known Engraved Hourglass Nebula in the constellation of

Musca is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe in diameter p ...

. In 2006, four

Herbig–Haro object Herbig–Haro (HH) objects are bright patches of nebula, nebulosity associated with newborn stars. They are formed when narrow jets of partially plasma (physics), ionised gas ejected by stars collide with nearby clouds of gas and dust at several ...

s were detected within the Hourglass, providing direct evidence of active

star formation 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"—Jeans instability, collapse and form stars. As a branch of astronomy, sta ...

by accretion within it.

References

External links

Breaking Waves in the Stellar Lagoon
— ESA/ Hubble Photo Release
Messier 8, SEDS Messier pages

NightSkyInfo.com – M8, the Lagoon Nebula

Messier 8, Lagoon Nebula, Map

Astronomy Picture of the Day (APOD): Lagoon Nebula

(

Astronomy Picture of the Day Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include ...

2012 March 12) *
7/30/2015 Photo release

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

Lagoon Nebula on Instagram
{{Sky, 18, 03, 37, -, 24, 23, 12, 4100 Carina–Sagittarius Arm H II regions Messier objects NGC objects Sagittarius (constellation) Sharpless objects Astronomical objects discovered in 1654 Articles containing video clips Star-forming regions

Characteristics

See also

References

External links