NGC 1999: Reflection Nebula in Orion - 2000-03-02

A dusty bright nebula contrasts dramatically with a dusty dark nebula in this Hubble Space Telescope image recorded shortly after December's orbital servicing mission. The nebula, cataloged as NGC 1999, is a reflection nebula, which shines by reflecting light from a nearby star. Unlike emission nebulae, whose reddish glow comes from excited atoms of gas, reflection nebulae have a bluish cast as their interstellar dust grains preferentially reflect blue starlight. While perhaps the most famous reflection nebulae surround the bright young stars of the Pleiades star cluster, NGC 1999's stellar illumination is provided by the embedded variable star V380 Orionis, seen here just left of center. Extending right of center, the ominous dark nebula is actually a condensation of cold molecular gas and dust so thick and dense that it blocks light. From our perspective it lies in front of the bright nebula, silhouetted against the ghostly nebular glow. New stars will likely form within the dark cloud, called a Bok globule, as self-gravity continues to compress its dense gas and dust. Reflection nebula NGC 1999 lies about 1500 light-years away in the constellation Orion, just south of Orion's well known emission nebula, M42.  

Exploring the Antennae - 2022-03-31

Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. Stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm that lasts for hundreds of millions of years. But the galaxies' large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning over 500 thousand light-years, this stunning view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkably sharp ground-based image, an accumulation of 88 hours of exposure captured during 2012-2021, follows the faint tidal tails and distant background galaxies in the field of view. The suggestive overall visual appearance of the extended arcing structures gives the galaxy pair, also known as Arp 244, its popular name - The Antennae.  

New Stars In 30 Doradus - 1999-10-01

Compare these matched Hubble Space Telescope views (visible-light on top; infrared on bottom) of a region in the star-forming 30 Doradus Nebula. Find the numbered arrows in the infrared image which identify newborn massive stars. For example, arrows 1 and 5 both point to compact clusters of bright young stars. Formed within collapsing gas and dust clouds, the winds and radiation from these hot stars have cleared away the remaining obscuring material making the clusters easily apparent in both visible and infrared images. But still shrouded in dust and readily seen only in the penetrating infrared view are newborn stars and star systems indicated by arrows 2, 3, and 4. Perhaps even more remarkable are the infrared bright spots indicated by arrows 6 and 7. Exactly in a line on opposite sides of the bright cluster at arrow 5, they may actually be caused by symmetric jets of material produced by one of the young cluster stars. These luminous spots are each about 5 light-years from the cluster and would correspond to points at which the energetic jet material impacts the surrounding dust clouds.  

Fata Morgana: A Possibly Titanic Mirage - 2012-04-15

Did this mirage help sink the Titanic? The optical phenomenon called Fata Morgana can make strange shapes or a false wall of water appear above a watery horizon. When conditions are right, light reflecting off of cold water will be bent by an unusual layer of warm air above to arrive at the observer from several different angles. A conceptually comparable mirage can make a setting Sun appear strangely distorted or a distant pavement appear wet. One hundred years ago today, such a Fata Morgana mirage might have obscured real icebergs from the clear view of crew onboard the Titanic. Additional evidence for this distortion hypothesis arises from the nearby vessel SS Californian which reported sightings consistent with Fata Morgana mirages. The above Fata Morgana mirage was taken off the US Pacific coast in 2008.  

Crescent Neptune and Triton - 2021-07-25

Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase. The elegant picture of the ice-giant planet and its cloudy moon was taken from behind just after closest approach in 1989. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth. The unusual vantage point also robs Neptune of its familiar blue hue, as sunlight seen from here is scattered forward, and so is reddened like the setting Sun. Neptune is smaller but more massive than Uranus, has several dark rings, and emits more light than it receives from the Sun.