This Wonderful Universe ~ {ERG} - Page 5

LoneRanger · #61 04-02-2008, 06:20 PM

Hot Gas and Dark Matter

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Credit: ESA, NASA, R. Mushotzky

Explanation: Is the gravity of the above galaxies high enough to contain the glowing hot gas? Superposed on an optical picture of a group of galaxies is an image taken in X-ray light. The X-ray picture, taken by ROSAT, shows confined hot gas highlighted in false red color, and provides clear evidence that the gravity exerted in groups and clusters of galaxies exceeds all the individual component galaxies combined. The extra gravity is attributed to dark matter, the nature and abundance of which is the biggest mystery in astronomy today.

LoneRanger · #62 04-02-2008, 06:24 PM

Earth's Moon, A Familiar Face

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Credit: Clementine, BMDO, NRL, LLNL

Explanation: The above mosaic of the Earth's Moon was compiled from photos taken by the spacecraft Clementine in 1994. This image represents the side of the Moon familiar to Earth dwellers. The Moon revolves around the Earth about once every 28 days. Since its rate of rotation about its axis is also once in 28 days, it always keeps the same face toward the Earth. As the Moon travels around its orbit, the Earth based view of the half of the Moon that faces the Sun changes causing the regular monthly progression of Lunar phases. Humans first crashed a spacecraft into the Moon in 1959, but the first humans to reach the Moon landed in 1969. There are now golf balls on the Moon.

LoneRanger · #63 04-02-2008, 06:27 PM

Ganymede: Moonquake World

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Credit: NASA, Voyager, Copyright Calvin J. Hamilton

Explanation: Ganymede probably undergoes frequent ground shaking events not unlike terrestrial earthquakes. Ganymede, the largest moon of Jupiter and the Solar System, has a thick outer coating of water ice. Passing Voyager spacecraft found a large number of cracks and grooves in the ice so it is thought that Ganymede, like the Earth, has large shifting surface masses called tectonic plates. Ganymede was discovered by Galileo and Marius in 1610, and is larger than the planets Mercury and Pluto.

LoneRanger · #64 04-02-2008, 06:30 PM

Europa: Ancient Water World

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Credit: NASA, Voyager, Copyright Calvin J. Hamilton

Explanation: Beneath the cold icy surface of Jupiter's moon Europa are probably the only oceans of water in our Solar System outside of Earth. These oceans, possibly 50 kilometers deep, might also be the most likely local place to find extra-terrestrial life. Europa's smooth surface is unlike any other known planet or moon, giving evidence for relatively few craters or mountains. Europa was discovered by Galileo and Marius in 1610.

LoneRanger · #65 04-02-2008, 06:34 PM

Callisto: Dark Smashed Iceball

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Credit: NASA, Voyager

Explanation: Callisto is a dirty battered world, showing the most beaten surface of Jupiter's major moons. Made of a rocky core covered by fractured ice, Callisto's past collisions with large meteors are evident as large craters surrounded by concentric rings. The four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto were all discovered by Galileo and Marius in 1610 with early telescopes and are now known as the Galilean satellites.

LoneRanger · #66 04-02-2008, 06:37 PM

Distant Galaxies

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Credit: NASA, STScI, Rogier Windhorst and Simon Driver (Arizona State University), Bill Keel (University of Alabama)

Explanation: This 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.

landsick22 · #67 04-02-2008, 07:59 PM

mits777 · #68 04-04-2008, 08:47 AM

goood info...

keeep posting..

LoneRanger · #69 04-06-2008, 08:17 PM

The Milky Way's Center

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Credit: NASA, COsmic Background Explorer (COBE) Project

Explanation: 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.

LoneRanger · #70 04-06-2008, 08:32 PM

The Last Moon Shot

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Credit: NASA, The Apollo Program

Explanation: In 1865 Jules Verne predicted the invention of a space capsule that could carry people. In his science fiction story "From the Earth to the Moon", he outlined his vision of constructing a cannon in Florida so powerful that it could shoot a "Projectile-Vehicle" carrying three adventurers to the Moon. Over 100 years later, NASA, guided by Wernher Von Braun's vision, produced the Saturn V rocket. This rocket turned Verne's fiction into fact, launching 9 Apollo Lunar missions and allowing 12 astronauts to walk on the Moon. Pictured above is the last moon shot, Apollo 17, awaiting a night launch in December of 1972. Spot lights play on the rocket and launch pad while the full Moon looms in the background. Humans have not walked on the lunar surface since. Should we return to the Moon?

LoneRanger · #71 04-06-2008, 08:44 PM

White Dwarfs Cool

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Credit: NASA, HST, WFPC 2, H. Richer (UBC)

Explanation: The circled stars in the above picture are from a class that is hard to see in the cosmos: white dwarfs. The entire photo covers a small region near the center of a globular cluster known as M4. Researchers using the Hubble Space Telescope discovered a large concentration of white dwarfs in M4. This was expected - low mass stars, including the Sun, are known to evolved to the white dwarf stage. White dwarfs do not usually evolve further, they just gradually cool down from their high temperatures. It is hoped that studying how these stars cool could lead to a better understanding of their ages, of the age of their parent globular cluster, and hopefully even the age of our universe!

LoneRanger · #72 04-06-2008, 08:47 PM

Proplyds: Infant Solar Systems

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Credit: NASA, HST, WFPC 2, C.R. O'Dell (Rice U.)

Explanation: 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?

LoneRanger · #73 04-06-2008, 08:50 PM

Spiral Galaxy M83

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Credit: Anglo-Australian Telescope photograph by David Malin

Explanation: Long winding spiral arms are clearly evident on this spectacular picture of the spiral galaxy M83. The blue color of the spiral arms is caused by the relatively large fraction of young blue stars there. Dark dust lanes are mixed in with the stars and trace the spiral structure of the galaxy. This galaxy contains many billions of stars, and its light took many millions of years to reach us. Our own Milky Way Galaxy would appear similar to this if viewed from images from the Anglo-Australian Telescope (AAT).

LoneRanger · #74 04-06-2008, 08:53 PM

Elliptical Galaxy M87

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Credit: Anglo-Australian Telescope photograph by David Malin

Explanation: Elliptical galaxy M87 is a type of galaxy that looks much different than our own Milky Way Galaxy. But even for an elliptical galaxy M87 is peculiar. M87 is much bigger than an average galaxy, appears at the center of a whole cluster of galaxies known as the Virgo Cluster, and shows a very high number of globular clusters. These globular clusters are visible as faint spots surrounding the bright center of M87. In general, elliptical galaxies contain similar numbers of stars as spiral galaxies, but are ellipsoidal in shape (spirals are mostly flat), have no spiral structure, and little gas and dust. This picture is number sixty on a publicly posted list of images from the Anglo-Australian Telescope (AAT).

LoneRanger · #75 04-06-2008, 08:56 PM

The Far Side

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Credit: The Soviet Lunar Program

Explanation: This historic picture was humanity's first glimpse of the far side of the Moon. It was taken by the Soviet spacecraft Luna 3 in October of 1959. Luna 3 followed closely on the heels of another Soviet probe, Luna 2, which had become the first spacecraft to impact the Moon on September 13th of that same year.

Why does the Moon have a far side? Gravitational tidal forces within the Earth-Moon system have synchronized the Moon's period of rotation around its axis with its orbital period at about 28 days. So, as the Moon moves around its orbit its rotation exactly compensates, keeping the same face toward the Earth.