An enormous balloon-like bubble being blown into space by a super-hot, massive star, the Bubble Nebula is 7 light-years across — about one-and-a-half times the distance from our sun to its nearest stellar neighbor, Alpha Centauri. It lies 7,100 light-years from Earth in the constellation Cassiopeia.
What’s happening to this spiral galaxy? Just a few hundred million years ago, NGC 2936, the upper of the two large galaxies shown, was likely a normal spiral galaxy – spinning, creating stars – and minding its own business. But then it got too close to the massive elliptical galaxy NGC 2937 below and took a dive.
Dubbed the Porpoise Galaxy for its iconic shape, NGC 2936 is not only being deflected but also being distorted by the close gravitational interaction. A burst of young blue stars forms the nose of the porpoise toward the right of the upper galaxy, while the center of the spiral appears as an eye. Alternatively, the galaxy pair, together known as Arp 142, look to some like a penguin protecting an egg. Either way, intricate dark dust lanes and bright blue star streams trail the troubled galaxy to the lower right.
In a billion years or so the two galaxies will likely merge into one larger galaxy.
Although there are no seasons in space, this cosmic vista invokes thoughts of a frosty winter landscape. It is, in fact, a region called NGC 6357 where radiation from hot, young stars is energizing the cooler gas in the cloud that surrounds them.
Located in our galaxy about 5,500 light years from Earth, NGC 6357 is actually a “cluster of clusters,” containing at least three clusters of young stars, including many hot, massive, luminous stars. The X-rays from Chandra and ROSAT reveal hundreds of point sources, which are the young stars in NGC 6357, as well as diffuse X-ray emission from hot gas. There are bubbles, or cavities, that have been created by radiation and material blowing away from the surfaces of massive stars, plus supernova explosions.
Credit: X-ray: NASA/CXC/PSU/L. Townsley et al; Optical: UKIRT; Infrared: NASA/JPL-Caltech
New awesome edge-on view of the galaxy NGC 1055 captured by ESO’s Very Large Telescope. This large galaxy is thought to be up to 15 percent larger in diameter than the Milky Way but shares the characteristic spiral arms. (Credit: ESO)
The bright clusters and nebulae of planet Earth’s night sky are often named for flowers or insects. Though its wingspan covers over 3 light-years, NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the dying central star of this particular planetary nebula has become exceptionally hot, shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust.
This sharp close-up of the dying star’s nebula was recorded by the Hubble Space Telescope and is presented here in reprocessed colors. Cutting across a bright cavity of ionized gas, the dust torus surrounding the central star is near the center of this view, almost edge-on to the line-of-sight. Molecular hydrogen has been detected in the hot star’s dusty cosmic shroud. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius).