Free Republic 4th Quarter Fundraising Target: $88,000 Receipts & Pledges to-date: $86,357
98%  
Woo hoo!! And now over 98%!! Less than $1.7k to go!! Let's git 'er done.

Keyword: astronomy

Brevity: Headers | « Text »
  • Astronomy Picture of the Day -- Aurorae over Planet Earth

    10/11/2012 4:14:24 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 11, 2012 | (see photo credit)
    Explanation: North America at night is easy to recognize in this view of our fair planet from orbit, acquired by the Suomi-NPP satellite on October 8. The spectacular waves of visible light emission rolling above the Canadian provinces of Quebec and Ontario in the upper half of the frame are the Aurora Borealis or northern lights. Encircling the poles and extending to lower latitudes, impressive aurorae seen during the past few days are due to strong geomagnetic storms. The storms were triggered by a solar coronal mass ejection on October 4/5, impacting Earth's magnetosphere some three days later. The curtains...
  • Astronomy Picture of the Day -- Nauset Light Star Trails

    10/10/2012 6:01:53 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 10, 2012 | (see photo credit)
    Explanation: In myth, Atlas holds up the heavens, but in this scene they seem to pivot around a lighthouse beacon. Photographed with a camera fixed to a tripod, the well-planned 30 minute exposure records star trails in the northern sky, reflecting the daily rotation of planet Earth. Hidden behind the top of the prominent Nauset Lighthouse on Cape Cod, Massachusetts, USA, the North Celestial Pole is at the center of all the star trail arcs. Making a complete circle, 360 degrees, in 24 hours, the star trail arcs cover 15 degrees each hour or 7.5 degrees in thirty minutes. Foreground...
  • Mystery Behind Supernova SN 1006 Solved?

    10/09/2012 3:49:42 PM PDT · by SunkenCiv · 8 replies
    Discovery News ^ | Monday, October 8, 2012 | Jennifer Ouellette
    Historical accounts from all over the world describe a spectacularly bright "guest star" in the night sky during the spring of 1006 -- what we now know as a supernova (SN 1006). Now astronomers think they have pinpointed the probable cause of that massive explosion, one thousand years later: a merging of two white dwarf stars. SN 1006 made quite a splash on its debut around May 1, 1006, in the constellation Lupus (the Wolf) just south of Scorpio. The critics raved! Monks in a Benedictine abbey in Switzerland marveled at the star's brightness, and commented on the variability of...
  • Astronomy Picture of the Day -- Simeis 147: Supernova Remnant

    10/09/2012 3:52:11 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 09, 2012 | (see photo credit)
    Explanation: It's easy to get lost following the intricate filaments in this detailed mosaic image of faint supernova remnant Simeis 147 (S147). Also cataloged as Sh2-240, it covers nearly 3 degrees or 6 full moons on the sky. That's about 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. Anchoring the frame at the right, bright star Elnath (Beta Tauri) is seen towards the boundary of the constellations Taurus and Auriga, almost exactly opposite the galactic center in planet Earth's sky. This sharp composite includes image data taken through a narrow-band filter to highlight emission from hydrogen...
  • Astronomy Picture of the Day -- Spherical Planetary Nebula Abell 39

    10/08/2012 8:17:39 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 08, 2012 | (see photo credit)
    Explanation: Ghostly in appearance, Abell 39 is a remarkably simple, spherical nebula about five light-years across. Well within our own Milky Way galaxy, the cosmic sphere is roughly 7,000 light-years distant toward the constellation Hercules. Abell 39 is a planetary nebula, formed as a once sun-like star's outer atmosphere was expelled over a period of thousands of years. Still visible, the nebula's central star is evolving into a hot white dwarf. Although faint, the nebula's simple geometry has proven to be a boon to astronomers exploring the chemical abundances and life cycles of stars. In this deep image recorded under...
  • Astronomy Picture of the Day -- The Same Color Illusion

    10/06/2012 9:43:54 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | October 07, 2012 | (see photo credit)
    Explanation: Are square A and B the same color? They are! To verify this, either run your cursor over the image or click here to see them connected. The above illusion, called the same color illusion, illustrates that purely human observations in science may be ambiguous or inaccurate. Even such a seemingly direct perception as relative color. Similar illusions exist on the sky, such as the size of the Moon near the horizon, or the apparent shapes of astronomical objects. The advent of automated, reproducible, measuring devices such as CCDs have made science in general and astronomy in particular less...
  • Astronomy Picture of the Day -- At the Heart of Orion

    10/06/2012 1:07:39 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 06, 2012 | (see photo credit)
    Explanation: Near the center of this sharp cosmic portrait, at the heart of the Orion Nebula, are four hot, massive stars known as the Trapezium. Gathered within a region about 1.5 light-years in radius, they dominate the core of the dense Orion Nebula Star Cluster. Ultraviolet ionizing radiation from the Trapezium stars, mostly from the brightest star Theta 1 Orionis C powers the complex star forming region's entire visible glow. About three million years old, the Orion Nebula Cluster was even more compact in its younger years and a recent dynamical study indicates that runaway stellar collisions at an earlier...
  • Astronomy Picture of the Day -- Aurora and Fireball Over Norway

    10/05/2012 4:40:53 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | October 05, 2012 | (see photo credit)
    Explanation: What's happening behind that mountain? A convergence of variable sky spectacles. One night in mid-September near Tromsø, Norway, high red aurora could be seen shimmering through lower green aurora in a way that created a striking and somewhat unusual violet glow. Suddenly, though, the sky flashed with the brightest fireball the astrophotographer had ever seen, as a small pebble from outer space violently crashed into the Earth's atmosphere. The glow illuminated the distant mountain peak known as Otertinden of the Lyngen Alps. The bright meteor, which coincidently disappeared behind the same mountain, was also reflected in the foreground Signalelva...
  • Astronomy Picture of the Day -- NGC 7293: The Helix Nebula

    10/05/2012 4:40:35 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | October 04, 2012 | (see photo credit)
    Explanation: A mere seven hundred light years from Earth, in the constellation Aquarius, a sun-like star is dying. Its last few thousand years have produced the Helix Nebula (NGC 7293), a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. A total of 58 hours of exposure time have gone in to creating this deep view of the nebula. Accumulating narrow band data from emission lines of hydrogen atoms in red and oxygen atoms in blue-green hues, it shows remarkable details of the Helix's brighter inner region, about 3 light-years across, but...
  • Astronomy Picture of the Day -- Goat Aurora Over Greenland

    10/03/2012 3:19:15 AM PDT · by SunkenCiv · 21 replies
    NASA ^ | October 03, 2012 | (see photo credit)
    Explanation: Sometimes it's hard to believe what you see in the sky. During the Shelios Expedition to Greenland in late August, even veteran sky enthusiasts saw auroras so colorful, so fast changing, and so unusual in form that they could remember nothing like it. As the ever changing auroras evolved, huge shapes spread across the sky morphed from one familiar form into another, including what looked to be the head of a goat (shown above), the head of an elephant, a strange green-tailed comet, and fingers on a celestial hand. Even without the aurora, the sky would be notable for...
  • Astronomy Picture of the Day -- An Ancient Stream Bank on Mars

    10/02/2012 3:33:37 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 02, 2012 | (see photo credit)
    Explanation: Fresh evidence of an ancient stream has been found on Mars. The robotic rover Curiosity has run across unusual surface features that carry a strong resemblance to stream banks on Earth. Visible in the above image, for example, is a small overhanging rock ledge that was quite possibly created by water erosion beneath. The texture of the ledge appears to be a sedimentary conglomerate, the dried remains of many smaller rocks stuck together. Beneath the ledge are numerous small pebbles, possibly made smooth by tumbling in and around the once-flowing stream. Pebbles in the streambed likely fell there as...
  • Astronomy Picture of the Day -- Introducing Comet ISON

    10/01/2012 3:46:01 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | October 01, 2012 | (see photo credit)
    Explanation: Could this dim spot brighten into one of the brightest comets ever? It's possible. Alternatively, the comet could break up when it gets closer to the Sun, or brighten much more modestly. Sky enthusiasts the world over are all abuzz, though, from the more optimistic speculations -- that the newly discovered C/2012 S1 (ISON) could develop a spectacular tail or briefly approach the brightness of the full Moon toward the end of 2013. Comet ISON currently is very faint but is just visible at magnitude 18 in the above image. The comet, discovered just over a week ago from...
  • Astronomy Picture of the Day -- A Galaxy Collision in NGC 6745

    09/30/2012 4:03:09 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | September 30, 2012 | (see photo credit)
    Explanation: Galaxies don't normally look like this. NGC 6745 actually shows the results of two galaxies that have been colliding for only hundreds of millions of years. Just off the above digitally sharpened photograph to the lower right is the smaller galaxy, moving away. The larger galaxy, pictured above, used to be a spiral galaxy but now is damaged and appears peculiar. Gravity has distorted the shapes of the galaxies. Although it is likely that no stars in the two galaxies directly collided, the gas, dust, and ambient magnetic fields do interact directly. In fact, a knot of gas pulled...
  • Astronomy Picture of the Day -- NGC 7023: The Iris Nebula

    09/29/2012 6:53:10 PM PDT · by SunkenCiv · 15 replies
    NASA ^ | September 29, 2012 | (see photo credit)
    Explanation: Like delicate cosmic petals, these clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the constellation Cepheus. Sometimes called the Iris Nebula and dutifully cataloged as NGC 7023 this is not the only nebula in the sky to evoke the imagery of flowers. Still, this remarkable image shows off the Iris Nebula's range of colors and symmetries in impressive detail. Within the Iris, dusty nebular material surrounds a hot, young star. The dominant color of the brighter reflection nebula is blue, characteristic of dust grains reflecting starlight. Central filaments of the...
  • New Comet Discovered—May Become "One of Brightest in History" (outshine the moon)

    09/28/2012 1:20:52 PM PDT · by NYer · 24 replies
    National Geographic ^ | September 27, 2012 | Andrew Fazekas
    Sky-watchers in Australia ogle comet Lovejoy late last year. If astronomers' early predictions hold true, the holidays next year may hold a glowing gift for stargazers—a superbright comet, just discovered streaking near Saturn.Even with powerful telescopes, comet 2012 S1 (ISON) is now just a faint glow in the constellation Cancer. But the ball of ice and rocks might become visible to the naked eye for a few months in late 2013 and early 2014—perhaps outshining the moon, astronomers say.The comet is already remarkably bright, given how far it is from the sun, astronomer Raminder Singh Samra said. What's more, 2012...
  • Astronomy Picture of the Day -- APOD: 2012 September 28 - Stars in a Dusty Sky

    09/28/2012 4:06:50 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 28, 2012 | (see photo credit)
    Explanation: Bright star Markab anchors this dusty skyscape. At the top right corner of the frame, Markab itself marks a corner of an asterism known as the Great Square, found within the boundaries of the constellation Pegasus, the flying horse. The wide and deep telescopic view rides along for some 5 degrees or about 10 times the angular diameter of the Full Moon, with blue reflection nebulae scattered around the scene. And even though this line-of-sight looks away from the plane of our Milky Way galaxy, it covers a region known to be filled with nearby molecular clouds. The associated...
  • Astronomy Picture of the Day -- Stars and Dust Across Corona Australis

    09/27/2012 7:50:09 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | September 27, 2012 | (see photo credit)
    Explanation: Cosmic dust clouds sprawl across a rich field of stars in this sweeping telescopic vista near the northern boundary of Corona Australis, the Southern Crown. Probably less than 500 light-years away and effectively blocking light from more distant, background stars in the Milky Way, the densest part of the dust cloud is about 8 light-years long. At its tip (upper right) is a group of lovely reflection nebulae cataloged as NGC 6726, 6727, 6729, and IC 4812. A characteristic blue color is produced as light from hot stars is reflected by the cosmic dust. The smaller yellowish nebula (NGC...
  • Newly spotted comet may outshine the full moon

    09/26/2012 6:29:10 PM PDT · by SunkenCiv · 89 replies
    New Scientist ^ | Tuesday, September 25, 2012 | Jeff Hecht
    Vitali Nevski and Artyom Novichonok, of the International Scientific Optical Network (ISON) in Russia, discovered comet C/2012 S1 (ISON) on 21 September via images taken with a 40-centimetre reflecting telescope. Other sky-watchers soon spotted it, and the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts, announced the find yesterday. From the combined observations, astronomers were able to trace the comet's recent path and find images of it dating back to late December 2011. From there they calculated a near-parabolic orbit that has comet ISON headed almost straight towards the sun. Astronomers at the Remanzacco Observatory in Italy think that...
  • Astronomy Picture of the Day -- A Space Shuttle Over Los Angeles

    09/25/2012 9:17:10 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | September 26, 2012 | (see photo credit)
    Explanation: It's not every day that a space shuttle lands at LAX. Although this was a first for the major Los Angeles airport hub, it was a last for the space shuttle Endeavour, as it completed its tour of California skies and landed, albeit atop a 747, for the last time. During its last flight the iconic shuttle and its chase planes were photographed near several of California's own icons including the Golden Gate Bridge in San Francisco, the Hollywood Sign, and the skyline of Los Angeles. Previously, in May, the space shuttle Enterprise was captured passing behind several of...
  • Astronomy Picture of the Day -- Unusual Spheres on Mars

    09/24/2012 9:14:37 PM PDT · by SunkenCiv · 40 replies
    NASA ^ | September 25, 2012 | (see photo credit)
    Explanation: Why are these strange little spheres on Mars? The robotic rover Opportunity chanced across these unusually shaped beads earlier this month while exploring a place named Kirkwood near the rim of Mars' Endeavor Crater. The above image taken by Opportunity's Microscopic Imager shows that some ground near the rover is filled with these unusual spheres, each spanning only about 3 millimeters. At first glance, the sometimes-fractured balls appear similar to the small rocks dubbed blueberries seen by Opportunity eight years ago, but these spheres are densely compacted and have little iron content. Although it is thought that these orbs...