Dagmar
03-10-2009, 07:51 PM
Another Vision of the Universe
In 1609, Galileo improved the newly invented telescope, turned it toward the heavens, and revolutionized our view of the universe. In celebration of the 400th anniversary of this milestone, 2009 has been designated as the International Year of Astronomy.
Today, NASA's Great Observatories are continuing Galileo's legacy with stunning images and breakthrough science from the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-ray Observatory.
While Galileo observed the sky using visible light seen by the human eye, technology now allows us to observe in many wavelengths, including Spitzer's infrared view and Chandra's view in X-rays. Each wavelength region shows different aspects of celestial objects and often reveals new objects that could not otherwise be studied.
This image of spiral galaxy Messier 101 is the visible light view from the Hubble Space Telescope.
Composite images allow astronomers to see how features seen in one wavelength match up with those seen in another wavelength. It's like seeing with a camera, night vision goggles, and X-ray vision all at once.
In the four centuries since Galileo, astronomy has changed dramatically. Yet our curiosity and quest for knowledge remain the same. So, too, does our wonder at the splendor of the universe.
http://i40.tinypic.com/mcrk9d.jpg
Moon, Mercury, Jupiter, Mars
http://apod.nasa.gov/apod/image/0902/20090223mmjm900px_MikeSalway.jpg
Explanation: When the Moon rose in predawn skies on February 23rd, it sported a sunlit crescent. It also offered early morning risers a tantalizing view of earthshine, the dark portion of the lunar disk illuminated by sunlight reflected from the Earth. Of course, on that morning a remarkable conjunction with three wandering planets added an impressive touch to the celestial scene. Recorded just before sunrise, this serene skyview looks east toward a glowing horizon across Tuggerah Lake on the Central Coast of New South Wales, Australia. Along with the waning crescent Moon, the picture captures (top to bottom) bright Mercury, Jupiter, and Mars.
http://apod.nasa.gov/apod/image/0901/PIA07997_spiritmars_c800.jpg
Explanation: This month, the Mars Exploration Rovers are celebrating their 5th anniversary of operations on the surface of the Red Planet. The serene sunset view, part of their extensive legacy of images from the martian surface, was recorded by the Spirit rover on May 19, 2005. Colors in the image have been slightly exaggerated but would likely be apparent to a human explorer's eye. Of course, fine martian dust particles suspended in the thin atmosphere lend the sky a reddish color, but the dust also scatters blue light in the forward direction, creating a bluish sky glow near the setting Sun. The Sun is setting behind the Gusev crater rim wall some 80 kilometers (50 miles) in the distance. Because Mars is farther away, the Sun is less bright and only about two thirds the size seen from planet Earth
Planetary Nebula NGC 2818
http://antwrp.gsfc.nasa.gov/apod/image/0901/ngc2818_hheritage_800.jpg
Explanation: NGC 2818 is a beautiful planetary nebula, the gaseous shroud of a dying sun-like star. It could well offer a glimpse of the future that awaits our own Sun after spending another 5 billion years or so steadily using up hydrogen at its core, and then finally helium, as fuel for nuclear fusion.
Curiously, NGC 2818 seems to lie within a sparse open star cluster, NGC 2818A, that is some 10,000 light-years distant toward the southern constellation Pyxis (Compass). Since open star clusters disperse after only a few hundred million years, this one must be exceptionally old to have one of its member stars evolve to the planetary nebula stage.
At the distance of the star cluster, planetary nebula NGC 2818 would be about 4 light-years across. The Hubble image is a composite of exposures through narrow-band filters, presenting emission from nitrogen, hydrogen, and oxygen atoms in the nebula as red, green, and blue hues.
The Milky Way Over Mauna Kea
http://apod.nasa.gov/apod/image/0901/maunakea_pacholka.jpg
Explanation: Have you ever seen the band of our Milky Way Galaxy? In a clear sky from a dark location at the right time, a faint band of light becomes visible across the sky. Soon after your eyes become dark adapted, you might spot the band for the first time. It may then become obvious. Then spectacular. One reason for a growing astonishment might be the realization that this fuzzy swath contains billions of stars and is the disk of our very own spiral galaxy. Since we are inside this disk, the band appears to encircle the Earth. Visible in the above image, high above in the night sky, the band of the Milky Way Galaxy arcs. The bright spot just below the band is the planet Jupiter. In the foreground lies the moonlit caldera of the volcano Haleakala, located on the island of Maui in Hawaii, USA. A close look near the horizon will reveal light clouds and the dark but enormous Mauna Kea volcano on the Big Island of Hawaii. If you have never seen the Milky Way band or recognized the planet Jupiter, this year may be your chance. Because 2009 is the International Year of Astronomy, an opportunity to look through a window that peers deep into the universe may be coming to a location near you.
More Milky Way
http://apod.nasa.gov/apod/image/0809/falsekiva_pacholka.jpg
Explanation: Is there any place in the world you could see a sight like this? Yes! This digital mosaic shows the night sky as seen from False Kiva in Canyonlands National Park, eastern Utah, USA. Diving into the Earth far in the distance is part of the central band of our Milky Way Galaxy. Much closer, the planet Jupiter is visible as the bright point just to band's left. Closer still are the park's picturesque buttes and mesas lit by a crescent moon. In the foreground is the cave housing a stone circle of unknown origin named False Kiva. The cave itself was briefly lit by flashlight during the exposure. Astrophotographer Wally Pacholka reports that getting to the cave was no easy trek. Also, mountain lions were a concern while waiting alone in the dark to record the mosaic.
Simeis 147: Supernova Remnant
http://apod.nasa.gov/apod/image/0901/s147metsavainioNBMedium_c800.jpg
Explanation: It's easy to get lost following the intricate filaments in this detailed image of faint supernova remnant Simeis 147. Also cataloged as Sh2-240 and seen towards the constellation Taurus, it covers nearly 3 degrees (6 full moons) on the sky. That corresponds to a width of 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. The remarkable narrow-band composite image in the Hubble color palette includes emission from hydrogen, sulfur, and oxygen atoms tracing regions of shocked, glowing gas. This supernova remnant has an estimated age of about 40,000 years - meaning light from the massive stellar explosion first reached Earth 40,000 years ago. But this expanding remnant is not the only aftermath. The cosmic catastrophe also left behind a spinning neutron star or pulsar, all that remains of the original star's core.
In 1609, Galileo improved the newly invented telescope, turned it toward the heavens, and revolutionized our view of the universe. In celebration of the 400th anniversary of this milestone, 2009 has been designated as the International Year of Astronomy.
Today, NASA's Great Observatories are continuing Galileo's legacy with stunning images and breakthrough science from the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-ray Observatory.
While Galileo observed the sky using visible light seen by the human eye, technology now allows us to observe in many wavelengths, including Spitzer's infrared view and Chandra's view in X-rays. Each wavelength region shows different aspects of celestial objects and often reveals new objects that could not otherwise be studied.
This image of spiral galaxy Messier 101 is the visible light view from the Hubble Space Telescope.
Composite images allow astronomers to see how features seen in one wavelength match up with those seen in another wavelength. It's like seeing with a camera, night vision goggles, and X-ray vision all at once.
In the four centuries since Galileo, astronomy has changed dramatically. Yet our curiosity and quest for knowledge remain the same. So, too, does our wonder at the splendor of the universe.
http://i40.tinypic.com/mcrk9d.jpg
Moon, Mercury, Jupiter, Mars
http://apod.nasa.gov/apod/image/0902/20090223mmjm900px_MikeSalway.jpg
Explanation: When the Moon rose in predawn skies on February 23rd, it sported a sunlit crescent. It also offered early morning risers a tantalizing view of earthshine, the dark portion of the lunar disk illuminated by sunlight reflected from the Earth. Of course, on that morning a remarkable conjunction with three wandering planets added an impressive touch to the celestial scene. Recorded just before sunrise, this serene skyview looks east toward a glowing horizon across Tuggerah Lake on the Central Coast of New South Wales, Australia. Along with the waning crescent Moon, the picture captures (top to bottom) bright Mercury, Jupiter, and Mars.
http://apod.nasa.gov/apod/image/0901/PIA07997_spiritmars_c800.jpg
Explanation: This month, the Mars Exploration Rovers are celebrating their 5th anniversary of operations on the surface of the Red Planet. The serene sunset view, part of their extensive legacy of images from the martian surface, was recorded by the Spirit rover on May 19, 2005. Colors in the image have been slightly exaggerated but would likely be apparent to a human explorer's eye. Of course, fine martian dust particles suspended in the thin atmosphere lend the sky a reddish color, but the dust also scatters blue light in the forward direction, creating a bluish sky glow near the setting Sun. The Sun is setting behind the Gusev crater rim wall some 80 kilometers (50 miles) in the distance. Because Mars is farther away, the Sun is less bright and only about two thirds the size seen from planet Earth
Planetary Nebula NGC 2818
http://antwrp.gsfc.nasa.gov/apod/image/0901/ngc2818_hheritage_800.jpg
Explanation: NGC 2818 is a beautiful planetary nebula, the gaseous shroud of a dying sun-like star. It could well offer a glimpse of the future that awaits our own Sun after spending another 5 billion years or so steadily using up hydrogen at its core, and then finally helium, as fuel for nuclear fusion.
Curiously, NGC 2818 seems to lie within a sparse open star cluster, NGC 2818A, that is some 10,000 light-years distant toward the southern constellation Pyxis (Compass). Since open star clusters disperse after only a few hundred million years, this one must be exceptionally old to have one of its member stars evolve to the planetary nebula stage.
At the distance of the star cluster, planetary nebula NGC 2818 would be about 4 light-years across. The Hubble image is a composite of exposures through narrow-band filters, presenting emission from nitrogen, hydrogen, and oxygen atoms in the nebula as red, green, and blue hues.
The Milky Way Over Mauna Kea
http://apod.nasa.gov/apod/image/0901/maunakea_pacholka.jpg
Explanation: Have you ever seen the band of our Milky Way Galaxy? In a clear sky from a dark location at the right time, a faint band of light becomes visible across the sky. Soon after your eyes become dark adapted, you might spot the band for the first time. It may then become obvious. Then spectacular. One reason for a growing astonishment might be the realization that this fuzzy swath contains billions of stars and is the disk of our very own spiral galaxy. Since we are inside this disk, the band appears to encircle the Earth. Visible in the above image, high above in the night sky, the band of the Milky Way Galaxy arcs. The bright spot just below the band is the planet Jupiter. In the foreground lies the moonlit caldera of the volcano Haleakala, located on the island of Maui in Hawaii, USA. A close look near the horizon will reveal light clouds and the dark but enormous Mauna Kea volcano on the Big Island of Hawaii. If you have never seen the Milky Way band or recognized the planet Jupiter, this year may be your chance. Because 2009 is the International Year of Astronomy, an opportunity to look through a window that peers deep into the universe may be coming to a location near you.
More Milky Way
http://apod.nasa.gov/apod/image/0809/falsekiva_pacholka.jpg
Explanation: Is there any place in the world you could see a sight like this? Yes! This digital mosaic shows the night sky as seen from False Kiva in Canyonlands National Park, eastern Utah, USA. Diving into the Earth far in the distance is part of the central band of our Milky Way Galaxy. Much closer, the planet Jupiter is visible as the bright point just to band's left. Closer still are the park's picturesque buttes and mesas lit by a crescent moon. In the foreground is the cave housing a stone circle of unknown origin named False Kiva. The cave itself was briefly lit by flashlight during the exposure. Astrophotographer Wally Pacholka reports that getting to the cave was no easy trek. Also, mountain lions were a concern while waiting alone in the dark to record the mosaic.
Simeis 147: Supernova Remnant
http://apod.nasa.gov/apod/image/0901/s147metsavainioNBMedium_c800.jpg
Explanation: It's easy to get lost following the intricate filaments in this detailed image of faint supernova remnant Simeis 147. Also cataloged as Sh2-240 and seen towards the constellation Taurus, it covers nearly 3 degrees (6 full moons) on the sky. That corresponds to a width of 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. The remarkable narrow-band composite image in the Hubble color palette includes emission from hydrogen, sulfur, and oxygen atoms tracing regions of shocked, glowing gas. This supernova remnant has an estimated age of about 40,000 years - meaning light from the massive stellar explosion first reached Earth 40,000 years ago. But this expanding remnant is not the only aftermath. The cosmic catastrophe also left behind a spinning neutron star or pulsar, all that remains of the original star's core.