Astronomy Picture of the Day (APOD)

[Acriku]

For all you astronomically-suited gazers of the sky, this is an archive of over 10 years of 'pictures of the day' consistently holding an astronomic theme. Some of them are truly beautiful! This should be on everyone's bookmark list - book it now!

http://antwrp.gsfc.nasa.gov/apod/archivepix.html

[Acriku]

Today's picture:

(from the website: http://antwrp.gsfc.nasa.gov/apod/ap050823.html)

Explanation: NGC 281 is a busy workshop of star formation. Prominent features include a small open cluster of stars, a diffuse red-glowing emission nebula, large lanes of obscuring gas and dust, and dense knots of dust and gas in which stars may still be forming. The open cluster of stars IC 1590 visible around the center has formed only in the last few million years. The brightest member of this cluster is actually a multiple-star system shining light that helps ionize the nebula's gas, causing the red glow visible throughout. The lanes of dust visible left of center are likely homes of future star formation. Particularly striking in the above photograph are the dark Bok globules visible against the bright nebula. The NGC 281 system, dubbed the Pacman nebula for its overall shape, lies about 10 thousand light years distant.

[Mihail]

Explanation: Stars are battling gas and dust in the Lagoon Nebula but the photographers are winning. Also known as M8, this photogenic nebula is visible even without binoculars towards the constellation of Sagittarius. The energetic processes of star formation create not only the colors but the chaos. The red-glowing gas results from high-energy starlight striking interstellar hydrogen gas. The dark dust filaments that lace M8 were created in the atmospheres of cool giant stars and in the debris from supernovae explosions. This spectacular portion of the Lagoon Nebula was created in scientifically-assigned colors from light emitted in very specific colors by hydrogen, silicon, and oxygen. The light from M8 we see today left about 5000 years ago. Light takes about 50 years to cross this section of M8.

[Mihail]

Explanation: Posing for this cosmic family photo are the galaxies of HCG (Hickson Compact Group) 87, about four hundred million light-years distant toward the amphibious constellation Capricornus. The large edge-on spiral near picture center, the fuzzy elliptical galaxy immediately to its right, and the spiral near the top of the image are identified members of the group, while the small spiral galaxy in the middle is likely a more distant background galaxy. In any event, a careful examination of the deep image reveals other galaxies which certainly lie far beyond HCG 87. While not exactly locked in a group hug, the HCG 87 galaxies are interacting gravitationally, influencing their fellow group members' structure and evolution. This image is from the commissioning phase of an instrument on the Gemini Observatory's South Telescope at Cerro Pachon, Chile. It compares favorably with views of this photogenic galaxy group recorded by the Hubble Space Telescope.

[Mihail]

Explanation: Is the Roof of Africa on fire? A group hiking at 6 am near the top of Mt. Kilimanjaro watched the rising sun peak above the clouds and the horizon light up red. Don't worry -- in this case the highest volcano in Africa is not even erupting. The spectacular sunrise colors are caused by light scattering off the atmosphere and small cloud particles. If all of the scattered light that makes the sky blue were added back into the scene, the sunrise would appear Sun-colored and not so red. A similar light scattering effect involving small airborne dust particles causes sunsets on Mars to be red and has been used to determine the sizes of particles in the rings of Saturn. During this trek in 2000 November, a group of about 30 reached the Kilomanjaro summit after a six-day climb.

[Mihail]

Its things like these that make me believe in God. :)

Explanation: The many spectacular colors of the Rho Ophiuchi (oh'-fee-yu-kee) clouds highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the star Rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light. The Earth's daytime sky appears blue for the same reason. The red and yellow regions shine primarily because of emission from the nebula's atomic and molecular gas. Light from nearby blue stars - more energetic than the bright star Antares - knocks electrons away from the gas, which then shines when the electrons recombine with the gas. The dark regions are caused by dust grains - born in young stellar atmospheres - which effectively block light emitted behind them. The Rho Ophiuchi star clouds, well in front of the globular cluster M4 visible above on far lower left, are even more colorful than humans can see - the clouds emits light in every wavelength band from the radio to the gamma-ray.

[Mihail]

Explanation: April's spectacular geocentric celestial event was a rare hybrid eclipse of the Sun - a total or an annular eclipse could be seen depending on the observer's location. For Fred Espenak, aboard a gently swaying ship within the middle of the Moon's shadow track about 2,200 kilometers west of the Galapagos, the eclipse was total, the lunar silhouette exactly covering the bright solar disk for a few brief moments. His camera captured a picture of totality revealing the extensive solar corona and prominences rising above the Sun's edge. But for Stephan Heinsius, near the end of the shadow track at Penonome Airfield, Panama, the Moon's apparent size had shrunk enough to create an annular eclipse, showing a complete annulus of the Sun's bright disk as a dramatic ring of fire. Pictures from the two locations are compared above. How rare is such a hybrid eclipse? Calculations show that during the 21st century just 3.1% (7 out of 224) of solar eclipses are hybrid while hybrids comprise about 5% of all solar eclipses over the period 2000 BC to AD 4000.

[Jack Leaf]

Wow. Those are absolutely beautiful.

[Mihail]

Explanation: Subtle and delicate in appearance, these are filaments of shocked interstellar gas -- part of the expanding blast wave from a violent stellar explosion. Recorded in November 1997 with the Wide Field and Planetary Camera 2 onboard the Hubble Space Telescope, the picture is a closeup of a supernova remnant known as the Cygnus Loop. The nearly edge-on view shows a small portion of the immense shock front moving toward the top of the frame at about 170 kilometers per second while glowing in light emitted by atoms of excited Hydrogen gas. Not just another pretty picture, this particular image has provided some dramatic scientific results. In 1999, researchers used it to substantially revise downward widely accepted estimates of distance and age for this classic supernova remnant. Now determined to lie only 1,440 light-years away, the Cygnus Loop is thought to have been expanding for 5 - 10 thousand years.

[Acriku]

Wow. Those are absolutely beautiful.

Search through the archive, there are hundreds and hundreds of incredible pictures. The more detailed ones tend to be higher in the list (since the technology was improved only as time went by). I've collected all the ones I've cherished and put them on my iPod (the picture one) and I can admire them anywhere. You're right, they are absolutely beautiful.

[TMA_1]

My favorite pic came from the Hubble. It is a scan from deep space, the light is billions of years old. I remember when I first saw it I was puzzled for a split second, then realized that all the disks I was seeing were galaxies. thousands of them. Very similar looking to the picture posted above with the galaxies. I dont think anybody on earth can look at these kinds of pictures without feeling at least a bit of awe and wonder.

[Davidu]

This is great AK... Keep it up.

If anyone around here would make a space game they should be reffering to you for info.

PS did you play Battlecruiser3000AD?

[Dante]

Its things like these that make me believe in God. :)

Funny. It's things like this that make me believe the exact opposite.

[Acriku]

This might be what you're referring to TMA (or something similar):

Explanation:  The image above is part of the Hubble Deep Field and represents humanity's most distant yet optical view of the Universe. Galaxies like colorful pieces of candy fill the field, some as faint as 30th magnitude (about four billion times fainter than stars visible to the unaided eye). The dimmest objects are the most distant galaxies and reveal what the Universe looked like in the extremely distant past, perhaps less than one billion years after the Big Bang. To make the Deep Field image, astronomers selected an uncluttered area of the sky in the constellation Ursa Major (the Big Dipper) and pointed the Hubble Space Telescope at a single spot for 10 days accumulating and combining many separate exposures. With each additional exposure, fainter objects were revealed. The final result can be used to explore the mysteries of galaxy evolution and the infant Universe.

Note: all explanations in this thread are accredited to different contributors, the above accredits:  R. Williams, The HDF Team (STScI), and NASA.

[Mihail]

Davidu, you praise me too much. Anyone could have done that.

And Dante, that picture is beatiful, but it dissuades you from believing in God?

[TMA_1]

yup that's it acriku... damn its beautiful. I mean words cant really do justice to the stuff you see in these pictures. In that picture alone you are viewing thousands of galaxies, each with their own individual characteristics, each with billions of stars. It just blows me away.

thanks acriku for posting the pic, saved it on my comp.