Portal:Astronomy/Picture/June 2005

Featured pictures on the Astronomy Wikiportal, June 2005

1 June 2005 ()	2 June 2005 ()
The city of Paris, photographed from Earth orbit by astronauts aboard the International Space Station. The River Seine winds its way through the center of the image. The gray and purple pixels are the urban areas, and the patchwork of green, brown, tan and yellow surrounding the city is farmland	The Hubble Space Telescope was launched in 1991, and revolutionised astronomy by returning images of unprecedented sharpness and angular resolution from its vantage point above the atmosphere. This photo was taken during the second servicing mission in 1997, during which astronauts replaced old instruments with new ones and repaired the guidance systems and thermal insulation of the space telescope
3 June 2005 ()	4 June 2005 ()
From Earth, the surface of Venus is permanently hidden from view by a dense and global covering of sulphuric acid clouds. The only direct images of the surface were returned by the Soviet Venera program in the 1970s and 1980s. Several probes landed on the planet, but none survived for more than two hours before being destroyed by the fearsome temperatures and atmospheric pressure at the surface. This image was taken by the Venera 13 probe in 1982.	The Coalsack Nebula is a dark nebula in the constellation of Crux Australis. Dark nebulae consist of cold dense clouds of gas and dust, which are only seen because they obscure visible light from more distant objects. Dark nebulae are often the location of star formation, which can be revealed within them by observations at infrared and radio wavelengths, which are much less affected by absorption and scattering by interstellar material
5 June 2005 ()	6 June 2005 ()
The Hubble Deep Field was produced in 1995 from images accumulated when the Hubble Space Telescope observed one very small patch of sky over 10 days. Almost every object seen in the HDF is a distant galaxy; only a few local stars contaminate the field. The HDF gave astronomers significant insights into the earliest stages of galaxy formation, and was later supplemented by the Hubble Deep Field South and the Hubble Ultra Deep Field	The collision of Comet Shoemaker-Levy 9 with Jupiter in 1994 was the first time astronomers had observed a collision between two Solar System bodies. This chain of craters on Jupiter's moon Ganymede provides evidence that comets must quite frequently be fragmented by the planet's gravity before colliding with it or its moons.
7 June 2005 ()	8 June 2005 ()
The Crab Nebula is the best known example of a supernova remnant. It formed when a massive star exploded as a supernova in 1054, an event that was witnessed and recorded by Chinese astronomers. Charles Messier included the nebula as the first object in his catalogue of objects which might be confused with comets	Near the centre of the globular cluster M4 lies the pulsar PSR B1620−26. The pulsar is extremely dense and only a few miles across, and rotates about 100 times per second, directing a pulse of electromagnetic radiation towards the earth once during each rotation. Small variations in the intervals between pulses reveal the presence of both a white dwarf and a large Jupiter-sized planet orbiting the pulsar.
9 June 2005 ()	10 June 2005 ()
The Hubble Space Telescope has provided many spectacular images of planetary nebulae, revealing hitherto unexpected structure and detail in these remnants of medium and low mass stars. The Saturn Nebula was nicknamed by Lord Rosse in the 1840s due to a supposed resemblance in his telescope to the planet Saturn.	The Sombrero Galaxy (M104), has a prominent lane of dust giving it a supposed resemblance to a sombrero hat. It has a very prominent bulge, making it an Sa-type galaxy in Edwin Hubble’s galaxy classification scheme.
11 June 2005 ()	12 June 2005 ()
File:Planetary Nebula A39.jpg George Abell is well known for compiling a catalogue of galaxy clusters but also catalogued planetary nebulae with low surface brightnesses. Abell 39 is extremely spherical in shape, although a mystery for astronomers is that the central star does not lie exactly at the centre of the sphere, but is displaced by about 0.1 light years.	Spiral galaxy NGC 3982 has numerous spiral arms filled with bright stars, blue star clusters, and dark dust lanes. It lies about 68 million light years from Earth and can be seen with a small telescope in the constellation of Ursa Major.
13 June 2005 ()	14 June 2005 ()
The Hubble Ultra Deep Field was the result of a million seconds of exposure time on the Hubble Space Telescope. It combined data from the Advanced Camera for Surveys and Near Infrared Camera and Multi-Object Spectrometer, and revealed over 10,000 galaxies in a patch of sky about 3 arcminutes in diameter, some of which are among the most distant objects known.	Centaurus A is named because it is the strongest source of radio waves in the constellation of Centaurus. It is the closest active galaxy to our own, and its intense radio emission can be seen extending in giant lobes from the centre of the galaxy in this combined optical and radio image.
15 June 2005 ()	16 June 2005 ()
File:Horseheadnebula.jpg Bearing a remarkable resemblance to a horse's head, the Horsehead Nebula is one of the best known dark nebulae, although it is very difficult to see except in quite large telescopes. The emission nebula against which it is silhouetted is part of a giant cloud of hydrogen gas, which also includes the Orion Nebula, the Flaming Tree Nebula and Barnard's Loop.	File:Comet-hale-bopp.jpg Comet Hale–Bopp broke many records when it appeared in 1995, some two years before its perihelion date. It lay beyond the orbit of Jupiter when it was found, a record distance for a cometary discovery. It became a great comet during April and May 1997, being brighter than apparent magnitude 0 for eight weeks, and was visible to the naked eye for 18 months – twice as long as any previously observed comet.
17 June 2005 ()	18 June 2005 ()
File:Pr3 400galaxypix.jpg The galaxy Abell 1835 IR1916 is one of the most distant ever observed. It is only visible from Earth due to the effects of gravitational lensing caused by a galaxy cluster at a smaller distance along the line of sight. It is believed to lie at a distance of 13.2 billion light years, meaning we are seeing it as it was just 500 million years after the Big Bang.	The Helix Nebula is one of the closest planetary nebulae, but is not easy to see in small telescopes due to its very low surface brightness. Hubble Space Telescope images reveal a large number of comet-like knots with 'tails' hundreds of millions of miles long, swept out by a stellar wind from the dying star at the centre of the nebula.
19 June 2005 ()	20 June 2005 ()
The Pleiades are one of the most famous open clusters, and have been known since ancient times. They are prominent to the naked eye, and long exposure photographs reveal delicate wisps of reflection nebulosity around the stars. This Hubble Space Telescope image shows one of the brightest patches of nebulosity, near the star Merope.	The Eagle Nebula is a star-forming region about 7,000 light years away from Earth. This Hubble Space Telescope image, dubbed The Pillars Of Creation, reveals the dark clouds of gas inside which new stars are being born.
21 June 2005 ()	22 June 2005 ()
M87 is an elliptical galaxy about 50 million light years away in the constellation of Virgo, and like most if not all galaxies it contains a super-massive black hole at its centre. The black hole powers an enormous polar jet of electrons and ions moving at almost the speed of light.	File:Nebular knots in the Ring Nebula.jpg The Ring Nebula is one of the best known planetary nebulae, and was formed probably a few thousand years ago when a Sun-like star shed its outer layers at the end of its life. Although the nebula appears smooth and regular from the ground, the higher optical resolution of the Hubble Space Telescope reveals intricate structure.
23 June 2005 ()	24 June 2005 ()
The rings of Saturn are one of the most famous sights in the night sky, and are spectacular even when viewed through a very small telescope. They consist of millions of icy fragments extending over a region some 400,000 kilometres across. The origin of Saturn’s rings is not yet understood.	The Trifid Nebula is a star-forming H II region, so called because it is divided into three lobes by lanes of dust. It lies about 9,000 light years away from Earth in the constellation of Sagittarius. This Hubble Space Telescope image reveals a jet of material emerging from a cloud of dust, propelled by a young star within.
25 June 2005 ()	26 June 2005 ()
Mercury is a rather poorly studied planet. It has only been visited by one spacecraft, Mariner 10 in 1974 and 1975, and only half its surface has been mapped in detail. It rotates about its axis exactly 1.5 times in each orbit around the Sun, the only orbital resonance in the solar system with a value other than 1:1.	The Cat's Eye Nebula is one of the most intricate and complex planetary nebulae known. This Hubble Space Telescope image reveals a mass of twists and knots of material in the nebula's inner region. The origin of this structure is not yet well understood by astronomers.
27 June 2005 ()	28 June 2005 ()
Venus is the brightest object in the sky after the Sun and the Moon, often appearing as a brilliant morning star or evening star. Its surface is completely obscured by dense clouds, which appear blank and featureless in visible light. Ultraviolet observations can reveal the otherwise-invisible detail and structure in the clouds.	M91 is an example of a barred spiral galaxy, in which the spiral arms originate not from the nucleus of the galaxy but from the ends of a bar extending outwards from the nucleus. The origin of the bar in galaxies like this is not well understood. Recent evidence suggests our own galaxy may be a barred spiral.
29 June 2005 ()	30 June 2005 ()
The strikingly-shaped Engraved Hourglass Nebula is a planetary nebula lying about 8,000 light-years away. The cause of its curious shape is not fully undersood, but may be due to a dense band of gas in the plane of the central star's equator, which is sculpting the outflowing stellar wind into the form seen.	Pluto is the most distant planet from the Sun during most of its orbit, and is the least well studied – it is the only planet yet to be visited by a space probe. Debate continues as to whether it is even a planet at all. This image was produced by mapping brightness changes as Pluto was occulted by its moon Charon.
31 June 2005 ()
This montage of images demonstrates the resolving power of the Hubble Space Telescope. Although the galaxy is at a distance of 6.5 million light years from Earth, the HST’s Advanced Camera for Surveys reveals individual stars in the outer parts of the galaxy.