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1 July 2005 (edit )
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2 July 2005 (edit )
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NGC 2346 is an unusually shaped planetary nebula. The cause of its shape is the binary system at its centre: when one of the two stars evolved into a red giant, it engulfed its companion, which stripped away a ring of material from the larger star’s atmosphere. When the red giant’s core was exposed, a fast stellar wind inflated two ‘bubbles’ from either side of the ring. |
The Egg Nebula is a prot--planetary nebula, forming as the outer layers are gently expelled from a dying red giant star which has exhausted all its nuclear fuel. The 'searchlight' effect is caused by light emerging from the thinnest parts of a thick cloud of dust surrounding the star. |
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3 July 2005 (edit )
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4 July 2005 (edit )
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This spiral galaxy in the constellation of Circinus is an example of a Seyfert galaxy, a class of active galaxy believed to be related to quasars, and which contain a super-massive black hole at their centre. The Circinus Galaxy is obscured from view by thick clouds of dust within the Milky Way, and was only discovered in 1975. |
At the centre of the Eta Carinae Nebula lies Eta Carinae, one of the most massive and luminous stars known. The nebula is considerably larger and somewhat brighter than the more famous Orion Nebula, and is the site of active star formation. It is easily visible from the Southern Hemisphere. |
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5 July 2005 (edit )
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6 July 2005 (edit )
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The Eskimo Nebula is a planetary nebula, named for its supposed resemblance to a face looking out from inside a parka. It lies about 5,000 light years away in the constellation of Gemini. The outer parts of the nebula contain comet-like filaments, up to a light year in length. |
The Cat's Eye Nebula is a planetary nebula, formed when a star like the sun ejected its outer layers at the end of its life. Long exposure images reveal several distinct episodes of mass loss from the star, with the inner bright nebula surrounded by smooth concentric rings, in turn surrounded by a giant shell of clumpy gas. |
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7 July 2005 (edit )
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8 July 2005 (edit )
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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, and can be seen in binoculars or small telescopes. |
The Orion Nebula is one of the most famous objects in the night sky. It has been known since antiquity, and can easily be seen in the constellation of Orion as a fuzzy patch below Orion's Belt (above the Belt for southern hemisphere observers. The nebula contains one of the most active star formation regions known, with an open cluster of thousands of stars being formed within it. |
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9 July 2005 (edit )
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10 July 2005 (edit )
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This image shows the expansion over a period of three years of the planetary nebula NGC 6543, the Cat's Eye Nebula. All planetary nebulae are expanding, and will eventually disperse into the interstellar medium, enriching it with heavy elements such as carbon and oxygen. Only with the very high optical resolution available with the Hubble Space Telescope can the expansions of these distant objects be accurately measured. |
The Cone Nebula is an H II region in the constellation of Monoceros. It was discovered by William Herschel in 1785, and is located about 800 parsecs or 2,600 light-years away from Earth.The Cone Nebula is part of the nebulosity surrounding the Christmas Tree Cluster, and ultraviolet light from the hot blue stars in the cluster ionises the nebula. |
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11 July 2005 (edit )
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12 July 2005 (edit )
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Planetary nebulae are formed when small to medium mass stars gently eject their outer layers once they have exhausted all the hydrogen and helium which has been burning in nuclear fusion reactions during the star's lifetime. Our Sun will become a planetary nebula in about 5 billion years' time. The Hubble Space Telescope has revealed more intricate detail and structure in planetary nebulae than astronomers had previously thought possible. |
M81 is a large spiral galaxy which lies about 12 million light years away in the constellation of Ursa Major. This image was taken in infrared light by the Spitzer Space Telescope, and reveals many star-forming regions strung out along the spiral arms. |
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13 July 2005 (edit )
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14 July 2005 (edit )
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The full story of the formation of stars has only come to be well understood in fairly recent years. The crucial step occurs deep inside dense dark blobs of gas and dust known as Bok gobules, named after Bart Bok who first studied them. Each Bok globule contains a nascent star system, but the dense cloud completely obscures the visible light from the young stars, and astronomers have to rely on infrared and radio observations to study the process. |
NGC 6496 is a spiral galaxy which lies just outside the Local Group. Over the last century, eight supernovae have been observed in the galaxy, which is more than have been seen in any other. |
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15 July 2005 (edit )
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16 July 2005 (edit )
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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.
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NGC 55 is a member of the Local Group of galaxies, which includes the Milky Way and the Andromeda Galaxy. It appears cigar-shaped because we see it almost edge-on. The brightest blue patches in this ultraviolet image show the locations of active star-forming regions. |
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17 July 2005 (edit )
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18 July 2005 (edit )
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The planetary nebula M2-9 lies about 2,100 light years away from Earth. Like about 10% of planetary nebulae, its shape is strongly bipolar. Its elongated wings are believed to be due to the interaction of outflowing material from a dying star at the centre with a binary companion orbiting at a distance of about 60 billion kilometres. |
The Large Magellanic Cloud is a satellite galaxy orbiting the Milky Way, along with its companion the Small Magellanic Cloud. Visible only from the southern hemisphere, the Clouds were first brought to the attention of northern astronomers following the round-the-world expedition of Ferdinand Magellan in 1519-1522 |
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19 July 2005 (edit )
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20 July 2005 (edit )
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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. Ground based observations reveal an almost circular ring, which is the edges of a thin shell of material surrounding the inner nebula. This Hubble Space Telescope reveals the very thin gas spread throughout the brighter ring. |
The hot blue star Rigel illuminates this reflection nebula in the constellation of Orion. Interstellar dust preferentially reflects blue light in a process known as Rayleigh scattering, which gives reflection nebulae a characteristic blue colour. Skies on Earth are blue because of the same process. |
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21 July 2005 (edit )
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22 July 2005 (edit )
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The spiral galaxy NGC 3184 has a small nucleus and large sprawling spiral arms. In 1999, astronomers witnessed a supernova explosion in the galaxy, which reached an apparent magnitude of 14.5. |
Comet Hyakutake was a surprise celestial visitor in 1996. As astronomers awaited the entry into the inner solar system of Comet Hale-Bopp, the comet discovered by Yuji Hyakutake raced past the Earth at a distance of just 0.1 astronomical units, one of the closest cometary passages for many decades. It became very bright, and was well seen by large numbers of people in the Northern Hemisphere |
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23 July 2005 (edit )
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24 July 2005 (edit )
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The Triangulum Galaxy is the third-largest member of the Local Group, after the Andromeda Galaxy and the Milky Way. It was one of the earliest galaxies which was proved to be external to our own, by Edwin Hubble in 1926; before then, astronomers believed the so-called ‘spiral nebulae’ were objects within our own galaxy. |
Galaxy mergers and collisions are rather common within galaxy clusters. The Cartwheel Galaxy suffered a collision millions of years ago when one of the galaxies at the right tore through it. The collision triggered an enormous wave of star formation, which expanded outwards in a ring forming billions of hot blue stars. |
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25 July 2005 (edit )
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26 July 2005 (edit )
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M101, also known as the pinwheel galaxy, is a spiral galaxy in Ursa Major, and is the largest member of a galaxy cluster called the M101 group. It was one of the first galaxies found to have a spiral structure. |
NGC 7742 is a spiral galaxy with a prominent yellow nucleus surrounded by spiral arms containing many young, hot blue stars. It is a Seyfert galaxy, a type of active galaxy powered by a super-massive black hole at the centre, and first studied by astronomer Carl Seyfert in the 1940s. |
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27 July 2005 (edit )
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28 July 2005 (edit )
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The first planet to be discovered since ancient times, Uranus is a gas giant orbiting almost three billion kilometres away from the Sun. Like Jupiter and Saturn, Uranus has clouds in its atmosphere, but the contrast between the clouds and their surroundings is very low. Many images show Uranus as an almost featureless blue disc. |
Valles Marineris is an enormous canyon on Mars, over 4,000 kilometres in length, up to 600 km wide and 10 km deep. It was named after the Mariner spacecraft which first imaged it, and is believed to be a giant tectonic fault. |
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29 July 2005 (edit )
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30 July 2005 (edit )
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The bright nebula NGC 1999, which shines from the light of a nearby variable star, is shown here, courtesy of NASA.
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Picture of the Whirlpool Galaxy, or M51, as it was discovered by Charles Messier. It is a spiral galaxy in the Canes Venatici constellation, and is visible by binoculars at 37 million light years distance.
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31 July 2005 (edit )
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The William Herschel Telescope is part of the Isaac Newton Group of Telescopes at the Observatorio del Roque de los Muchachos on the island of La Palma, Spain. The WHT has a primary mirror 4.2m in diameter, and is a vital resource for European astronomers.
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