Milky Way Center Unveiled
Milky Way Center Unveiled
Great Observatories Explore Galactic Center
Where can a telescope take you? Four hundred years ago, a telescope took Galileo to the Moon to discover craters, to Saturn to discover rings, to Jupiter to discover moons, to Venus to discover phases, and to the Sun to discover spots. Today, in celebration of Galileo’s telescopic achievements and as part of the International Year of Astronomy, NASA has used its entire fleet of Great Observatories, and the Internet, to bring the center of our Galaxy to you. Pictured above, in greater detail and in more colors than ever seen before, are the combined images of the Hubble Space Telescope in near-infrard light, the Spitzer Space Telescope in infrared light, and the Chandra X-ray Observatory in X-ray light. A menagerie of vast star fields is visible, along with dense star clusters, long filaments of gas and dust, expanding supernova remnants, and the energetic surroundings of what likely is our Galaxy’s central black hole. Many of these features are labeled on a complementary annotated image. Of course, atelescope’s magnification and light-gathering ability create only an image of what a human could see if visiting these places. To actually go requires rockets.
The graceful arc of the Milky Way begins and ends at two mountain peaks in this solemn night sky panorama. Created from a 24 frame mosaic, exposures tracking Earth and sky were made separately, with northern California’s Mount Lassen at the left and Mount Shasta at the far right, just below the star and dust clouds of the galactic center. Lassen and Shasta are volcanoes in the Cascade Mountain Range of North America, an arc of the volcanic Pacific Ring of Fire. In the dim, snow-capped peaks, planet Earth seems to echo the subtle glow of the Milky Way’s own faint, unresolved starlight.
Click the link to watch four short videos simulating the Antennae galaxy merger, our own eventual galaxy merger, and one that follows the distribution of materials in mergers.
Barred Spiral Milky Way
A recent survey of stars conducted with the Spitzer Space Telescope is convincing astronomers that our Milky Way Galaxy is not just your ordinary spiral galaxy anymore. Looking out from within the Galaxy’s disk, the true structure of the Milky Way is difficult to discern. However, the penetrating infrared census of about 30 million stars indicates that the Galaxy is distinguished by a very large central bar some 27,000 light-years long. In fact, from a vantage point that viewed our galaxy face-on, astronomers in distant galaxies would likely see a striking barred spiral galaxy suggested in this artist’s illustration. While previous investigations have identified a small central barred structure, the new results indicate that the Milky Way’s large bar would make about a 45 degree angle with a line joining the Sun and the Galaxy’s center. DON’T PANIC … astronomers still place the Sun beyond the central bar region, about a third of the way in from the Milky Way’s outer edge. (2005 August 25 )
Milky Way.
If you look for it, perhaps you can see the large dark shape that the Australian Aborigines named “The Emu”
Sagittarius A*
The supermassive black hole at the center of the Milky Way is known as Sagittarius A* (or Sgr A*, for short). Astronomers have known for a long time that Sgr A* is relatively quiet compared to other black holes of similar size.
Jupiter and Milky Way as seen from the rocky shores of the Mediterranean Sea near Cape Gelidonya, Turkey.
Ghostly Zodiacal light, featured near the center of this remarkable panorama, is produced as sunlight is scattered by dust in the Solar System’s ecliptic plane. In the weeks surrounding the March equinox (today at 1732 UT) Zodiacal light is more prominent after sunset in the northern hemisphere, and before sunrise in the south, when the ecliptic makes a steep angle with the horzion. In the picture, the narrow triangle of Zodiacal light extends above the western horizon and seems to end at the lovely Pleides star cluster. Arcing above the Pleides are stars and nebulae along the plane of our Milky Way Galaxy.
Astronomers have glimpsed what could be the youngest known star at the very moment it is being born. Not yet fully developed into a true star, the object is in the earliest stages of star formation and has just begun pulling in matter from a surrounding envelope of gas and dust.
Scientists found the object using the Submillimeter Array in Hawaii and the Spitzer Space Telescope. Known as L1448-IRS2E, it’s located in the Perseus star-forming region about 800 light-years away in our Milky Way Galaxy.
Stars form out of large, cold, dense regions of gas and dust called molecular clouds that exist throughout the galaxy. Astronomers think L1448-IRS2E is in between the prestellar phase, a particularly dense region of a molecular cloud first begins to clump together, and the protostar phase, when gravity has pulled enough material together to form a dense, hot core out of the surrounding envelope.
