Astronomy

Some Views Of The Heavens
Photo Source and Most Text:NASA

As we gaze up into the heavens we sometimes forget what is really up there. The reason for this is that many of us live in cities and the night sky is obscured by the many lights around us. Even those of us that live in the country are limited in what we see by the power of the human eye. As we peer into limitless space, we may see millions of stars and the real lucky ones, those that live in those sparsely populated areas might even see some distant galaxies but you really need a powerful telescope to appreciate the full beauty of the night sky.

NASA has taken some really amazing photos of this sky and I thought that you might enjoy seeing some of them. I share some of these with you.

In 1987 a star in one of the Milky Way's satellite galaxies exploded. In 1994 the Hubble Space Telescope, in orbit around the earth, took a very detailed picture of the remnants of this explosion. This picture, above, showed unusual and unexpected rings, and astronomers are not sure how they formed.
Imagine a hurricane that lasted for 300 years! This picture of the planet Jupiter was taken by the Voyager 1 spacecraft as it passed the planet in 1979. Jupiter, a gas giant planet with no solid surface, is the largest planet in the solar system and is made mostly of the hydrogen and helium. Clearly visible in the photo is the Great Red Spot, a giant, hurricane-like storm system that rotates with the clouds of Jupiter. It is so large three complete Earths could fit inside it. Astronomers have observed this giant storm on Jupiter for over 300 years.
The M100 galaxy is a large spiral galaxy similar to our own Milky Way, containing over 100 billion stars. It is over 150 million light years away, so the light we see left when dinosaurs roamed the Earth. The picture was taken in 1993 with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope.
Three thousand light years away, a dying star throws off shells of glowing gas. This Hubble Space Telescope image reveals "The Cat's Eye Nebula" to be one of the most complex "planetary nebulae" known. In fact, the features seen in this image are so complex that astronomers suspect the visible central star may actually be a double star system. The term planetary nebula, used to describe this general class of objects, is misleading. Although these objects may appear round and planet-like in small telescopes, high resolution images reveal them to be stars surrounded by cocoons of gas blown off in the late stages of evolution.
An asteroid with a moon! The robot spacecraft Galileo whose primary mission is to explore the Jupiter system, has encountered and photographed two asteroids during its long journey to Jupiter. The second asteroid it photographed, called Ida, was discovered to have a moon which appears as a small dot to the right of Ida in this picture. The tiny moon, named Dactyl, is about one mile across, while the potato shaped Ida measures about 36 miles long and 14 miles wide. Dactyl is the first moon of an asteroid ever discovered. The names Ida and Dactyl are based on characters in Greek mythology.
The Firework Nebula, known to astronomers as "GK Per", is the result of a type of stellar explosion called a nova. In a nova, a very compact star called a white dwarf blasts away gas that had accumulated on its surface. In this case the nova occurred in the year 1901 and is called Nova Persei 1901. This nova became as bright as one of the brighter stars we see in the night sky, but then faded until only a telescope could see it. Soon astronomers could see an expanding shell of gas that eventually became this spectacular nebula. The unusual "fireworks" type feature of this nebula is still a matter of research and discussion.
In April of 1970, after an explosion damaged their spacecraft, the Apollo 13 astronauts were forced to abandon their plans to make the third manned lunar landing. Still, while coasting around the moon in their desperate attempt to return to earth they were able to photograph the moon's far side. The large, dark, smooth looking feature on the left in this picture is known as the "Mare Moscoviense". It was created by a lava flow filling in a large impact crater on the lunar surface. As suggested by the name, the Mare Moscoviense was first photographed by an early Soviet lunar probe.

OK, I know this is not exactly an astronomy photo but I included it because it is interesting.

In April of 1970, after an oxygen tank exploded and damaged their service module, the Apollo 13 astronauts were forced to abandon their plans to make the third manned lunar landing. The extent of the damage is revealed in this photo, taken as the crippled module was drifting away - jettisoned prior to their reentry and eventual safe splashdown. An entire panel on the right side of the module is seen to have been blown away and damage to internal structures is apparent.

Sometimes one of the largest concentrations of mass known can act like a lens. Almost all of the bright objects in this image are galaxies in the cluster known as Abell 2218. The cluster is so massive and so compact that it bends light from galaxies that lie behind it, causing many of them to appear as stretched out arcs. Many dim, elongated arcs are visible on this photograph. This picture was taken with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope.
his Hubble Space Telescope image of a group of faint galaxies "far, far away" is a snap shot of the Universe when it was young. The bluish, irregularly shaped galaxies revealed in the image are up to eight billion light years away and seem to have commonly undergone galaxy collisions and bursts of star formation. Studying these objects is difficult because they are so faint, however they may provide clues to how our own Milky Way Galaxy formed.
NASA's COBE satellite scanned the heavens at infrared wavelengths in 1990 and produced this premier view of the central region of our own Milky Way Galaxy. The Milky Way is a typical spiral galaxy with a central bulge and extended disk of stars. However, gas and dust within the disk obscure visible wavelengths of light effectively preventing clear observations of the center. Since infrared wavelengths, are less affected by the obscuring material, the Diffuse InfraRed Background Experiment (DIRBE) on board COBE was able to detected infrared light from stars surrounding the galactic center and produce this image. Of course, the edge on perspective represents the view from the vicinity of our Sun, a star located in the disk about 30,000 light years out from the center. The DIRBE experiment used equipment cooled by a tub of liquid helium to detect the infrared light which, composed of wavelengths longer than red light, is invisible to the human eye.
The fuzzy blobs seen above may be some of the first ever images of entire solar systems forming right before our eyes. This close up of the Orion Nebulae taken by the Hubble Space Telescope shows only a few stars, but these stars are surrounded by proto-planetary disks known as "proplyds." As the stars have only just recently formed - in the past few million years - the disks around them are likely condensing to form planetary systems and may be similar to the disk that formed our own solar system 5 billion years ago. These HST results suggest that stars with planets may be relatively common place. Are there extra-terrestrial civilizations out there as well?
The star masked by a dust cloud at the left of the above photo is expelling an energetic beam of charged particles into interstellar space. This jet, moving from left to right, has burrowed through much interstellar material, and now expands out into the interstellar space. Although jet particles move at nearly three hundred kilometers per second , we still do not see any daily movement because of the enormous distances involved. In fact, the jet is trillions of kilometers long. This stellar jet occurs in a system called HH-47 which is located near the edge of the Gum Nebula.
Left is the best yet color image of the asteroid Gaspra based on data returned by NASA's Galileo spacecraft. Color variations have been added to high resolution images and enhanced to highlight changes in reflectivity, surface structure and composition. The illuminated portion of the asteroid is about 11 miles long. Galileo encountered Gaspra on October 29, 1991 during the cruise phase of its mission to study the Jovian system. When it arrives at Jupiter, in December 1995, the robot spacecraft's atmospheric probe will descend into Jupiter's atmosphere, becoming the first ever probe to enter the atmosphere of a gas giant planet.
In the center of the this photograph lies a star with one of the hottest surface temperatures yet confirmed. This bright white dwarf star's surface has been measured at greater than 200,000 degrees Celsius - more than 30 times hotter than that of our own Sun. The white dwarf's extreme heat makes it glow extraordinarily bright: intrinsically more than 250 times brighter than the Sun. The star is at the center of the planetary nebula titled NGC 2440, which lies inside our Milky Way Galaxy. The above computer sharpened image was taken by the Hubble Space Telescope.

I hope you enjoyed these photographs, I tried to pick out some of the most interesting ones. Some time in the future I will do another page of NASA's best.



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