Elongated Coronal Hole December 31, 2005
Posted by jtintle in NASA, SOHO, Solar Flares, Space Fotos, Sun, Sun Spot.comments closed
Hi-res TIF image ( 3.4M)
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Image Credit: SOHO
Explanation: The Earth was bathed most of this last week in a solar stream that flowed out of this long coronal hole (image from December 27, 2005). Coronal holes appear as dark area of the corona when viewed in ultraviolet light and in X-rays (seen here traversing down the upper half of the Sun in ultraviolet light). This coronal hole area is one of the largest ones seen over the past year. Since coronal holes are ‘open’ magnetically, strong solar wind gusts can escape from them and carry solar particles out to our magnetosphere and beyond. Solar wind streams take 2 – 3 days to travel from the Sun to Earth, and the coronal holes in which they originate are more likely to affect Earth after they have rotated more than halfway around the visible hemisphere of the Sun. This same hole could reappear when the Sun rotates this area around again in about two weeks. The magnetic field lines in a coronal hole open out into the solar wind rather than connecting to a nearby part of the Sun’s surface. Coronal holes are responsible for the high-speed solar wind streams that sweep through the plane where the planets orbit — and thus have a direct affect on “space weather” near the Earth. Transequatorial holes like this one affect the earth’s magnetosphere directly. Thus, many people living at the higher latitudes probably experienced mild geo-effective storming for these few days in the form of aurora displays. |
Bug Nebula December 31, 2005
Posted by jtintle in Bug Nebula, Deep Space, European Space Agency, NASA, Nebula, NGC 6302, Space Fotos.comments closed
Explanation: NGC 6302, the Bug Nebula, displaying the “z-pinch� so familiar to plasma cosmologists. The pinching of a plasma cloud into a narrow “neck� is just one of numerous indicators of high-energy electric currents. The star at the center of the pinch is hidden from view by a donut-like cloud or torus, another pattern typical of plasma discharge instabilities.
The Iris Nebula from CFHT December 31, 2005
Posted by jtintle in APoD, Deep Space, Hawaiian Starlight, Iris Nebula, Nebula, NGC 7023, Space Fotos.comments closed
Explanation: Like delicate cosmic petals, these clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the constellation Cepheus. Sometimes called the Iris Nebula and dutifully cataloged as NGC 7023, this is not the only nebula in the sky to evoke the imagery of flowers. Still, this beautiful digital image shows off the Iris Nebula’s range of colors and symmetries in impressive detail. Within the Iris, dusty nebular material surrounds a massive, hot, young star in its formative years. Central filaments of cosmic dust glow with a reddish photoluminescence as some dust grains effectively convert the star’s invisible ultraviolet radiation to visible red light. Yet the dominant color of the nebula is blue, characteristic of dust grains reflecting starlight. Dark, obscuring clouds of dust and cold molecular gas are also present and can lead the eye to see other convoluted and fantastic shapes. Infrared observations indicate that this nebula may contain complex carbon molecules known as PAHs. As shown here, the Iris Nebula is about 6 light-years across.
The Perseus Cluster of Galaxies December 31, 2005
Posted by jtintle in APoD, Deep Space, Milky Way, NASA, NGC 1275, Perseus Cluster, Rancho Del Sol Observatory, Space Fotos.comments closed
Explanation: Here is one of the largest objects that anyone will ever see on the sky. Each of these fuzzy blobs is a galaxy, together making up the Perseus Cluster, one of the closest clusters of galaxies. The cluster is seen through a foreground of faint stars in our own Milky Way Galaxy. Near the cluster center, roughly 250 million light-years away, is the cluster’s dominant galaxy NGC 1275, seen here just left of picture center. A prodigious source of x-rays and radio emission, NGC 1275 accretes matter as gas and galaxies fall into it. The Perseus Cluster of Galaxies is part of the Pisces-Perseus supercluster spanning over 15 degrees and containing over 1,000 galaxies. At the distance of NGC 1275, this view covers about 1.5 million light-years.
A Year at Saturn December 31, 2005
Posted by jtintle in APoD, Cassini, Dione, European Space Agency, Huygens, JPL, NASA, Saturn, Space Fotos, SSI, Titan.comments closed
Explanation: Arriving at Saturn in July of 2004, the Cassini spacecraft has now spent a year and a half exploring the magnificent rings and moons of the distant gas giant. The year 2005 began with Cassini’s Huygens probe landing on Saturn’s large moon Titan. Cassini’s continuing series of close flybys also revealed details and discoveries across the surface of the smog shrouded moon. In fact, with a ringside seat throughout 2005, Cassini’s cameras have made spectacular pictures of Titan along with Saturn’s other moons and rings almost common place. But often, Saturn itself provided the most dramatic backdrop. In this view, Saturn’s moon Dione lies in front of edge-on rings and the gas giant’s cloud tops draped with broad ring shadows. Dione is 1,118 kilometers across and lies about 300,000 kilometers from the ring’s edge.
IC 2118: The Witch Head Nebula December 28, 2005
Posted by jtintle in APoD, Deep Space, NASA, Nebula, Space Fotos.comments closed
Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble — maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula is associated with the bright star Rigel in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel, located just outside the top right corner of the above image. Fine dust in the nebula reflects the light. The blue color is caused not only by Rigel‘s blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth’s daytime sky to appear blue, although the scatterers in Earth’s atmosphere are molecules of nitrogen and oxygen. The nebula lies about 1000 light-years away.
The Mysterious Cone Nebula December 28, 2005
Posted by jtintle in APoD, Deep Space, NASA, Nebula, Space Fotos.comments closed
Credit & Copyright: R Jay GaBany (Cosmotography.com)
Explanation: Sometimes the simplest shapes are the hardest to explain. For example, the origin of the mysterious cone-shaped region seen on the far left remains a mystery. The interstellar formation, dubbed the Cone Nebula, is located about 2700 light years away. Other features in the image include red emission from diffuse interstellar hydrogen, wispy filaments of dark dust, and bright star S Monocerotis, visible on the far right. Blue reflection nebulae surround the brighter stars. The dark Cone Nebula region clearly contains much dust which blocks light from the emission nebula and open cluster NGC 2264 behind it. One hypothesis holds that the Cone Nebula is formed by wind particles from an energetic source blowing past the Bok Globule at the head of the cone.
Smooth Sections on Asteroid Itokawa December 28, 2005
Posted by jtintle in APoD, Asteroid, Deep Space, Hayabusa, ISAS, Itokawa, JAXA, NASA, Space Fotos.comments closed
Explanation: Why are parts of this asteroid’s surface so smooth? No one is yet sure, but it may have to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock. The unusual asteroid is currently being visited by the Japanese spacecraft Hayabusa that is documenting its unusual structure and mysterious lack of craters. Last month, Hayabusa actually touched down on one of the smooth patches, dubbed the MUSES Sea, and collected soil samples that will eventually be returned to Earth for analysis. Unfortunately, the robot Hayabusa craft has been experiencing communications problems and so its departure for Earth has been delayed until 2007. Computer simulations show that 500-meter asteroid Itokawa may impact the Earth within the next few million years.
Hydrogen and Dust in the Rosette Nebula December 24, 2005
Posted by jtintle in APoD, Deep Space, Space Fotos.comments closed
Explanation: At the edge of a large molecular cloud in Monoceros, some 3,000 light years away, dark filaments of dust are silhouetted by luminous hydrogen gas. The close up view of the Rosette Nebula dramatically suggests that star formation is an on going process in the region, with dark filaments sculpted by winds and radiation from hot, young stars. Ultraviolet radiation from the young stars also strips electrons from the surrounding hydrogen atoms. As electrons and atoms recombine they emit longer wavelength, lower energy light in a well known characteristic pattern of bright spectral lines. At visible wavelengths, the strongest emission line in this pattern is in the red part of the spectrum and is known as “Hydrogen-alpha” or just H-alpha. Part of IPHAS, a survey of H-alpha emission in our Milky Way Galaxy, this image spans about 25 light-years.
Andromeda Island Universe December 24, 2005
Posted by jtintle in APoD, Deep Space, Space Fotos.comments closed
Explanation: The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy some two million light-years away. But without a telescope, even this immense spiral galaxy – spanning over 200,000 light years – appears as a faint, nebulous cloud in the constellation Andromeda. In contrast, a bright yellow nucleus, dark winding dust lanes, gorgeous blue spiral arms and star clusters are recorded in this stunning telescopic digital mosaic with a cumulative exposure of over 90 hours. While even casual skygazers are now inspired by the knowledge that there are many distant galaxies like M31, astronomers seriously debated this fundamental concept only 80 years ago. Were these “spiral nebulae” simply outlying components of our own Milky Way Galaxy or were they instead “island universes” — distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis debate of 1920, which was later resolved by observations of M31 in favor of Andromeda, island universe.
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