Posts tagged galaxy

Posted 1 year ago

Comet of the North 
Image Credit & CopyrightP-M Hedén (Clear SkiesTWAN)

Explanation: It looks like a double comet, but Comet PanSTARRS (C/2011 L4) is just offering skygazers a Messier moment. Outward bound and fading in this starry scene, the well-photographed comet is remarkably similar in brightness to M31, the Andromeda Galaxy. Tracking through northern skies just below the galaxy, the comet was captured as local midnight approached on April 3. Both comet and galaxy were visible to the eye and are immersed in the faint glow of northern lights. Our own Milky Way galaxy arcs over the snowy field near Tänndalen, Sweden. Double star cluster h and chi Persei can be spotted along the Milky Way’s arc high above the comet/galaxy pair. Follow the arc to bright Deneb, alpha star of the constellation Cygnus, at the right edge of the frame.

Posted 1 year ago

M64: The Black Eye Galaxy 
Image Credit & CopyrightMartin Pugh

Explanation: This beautiful, bright, spiral galaxy is Messier 64, often called the Black Eye Galaxy or the Sleeping Beauty Galaxy for its heavy-lidded appearance in telescopic views. M64 is about 17 million light-years distant in the otherwise well-groomed northern constellation Coma Berenices. In fact, the Red Eye Galaxy might also be an appropriate moniker in this colorful composition of narrow and wideband images. The enormous dust clouds obscuring the near-side of M64’s central region are laced with the telltale reddish glow of hydrogen associated with star forming regions. But they are not this galaxy’s only peculiar feature. Observations show that M64 is actually composed of two concentric, counter-rotating systems. While all the stars in M64 rotate in the same direction as the interstellar gas in the galaxy’s central region, gas in the outer regions, extending to about 40,000 light-years, rotates in the opposite direction. The dusty eye and bizarre rotation is likely the result of a billion year old merger of two different galaxies.

Posted 1 year ago

Comet PANSTARRS and the Andromeda Galaxy 
Image Credit & Copyright: Pavel Smilyk

Explanation: Currently, comet PANSTARRS is passing nearly in front of the galaxy Andromeda. Coincidentally, both comet and galaxyappear now to be just about the same angular size. In physical size, even though Comet PANSTARRS is currently the largest object in theSolar System with a tail spanning about 15 times the diameter of the Sun, it is still about 70 billion times smaller than the Andromeda galaxy(M31). The above image was captured on March 30, near SyktyvkarRussia. As C/2011 L4 (PANSTARRS) on the lower left recedesfrom the Sun and dims, it is returning to the northerly direction whence it came. When the comet will return is currently unknown, althoughhumans may have merged with computers by then.

Posted 1 year ago

Unraveling NGC 3169 
Image Credit & CopyrightAdam BlockMt. Lemmon SkyCenterUniversity of Arizona

Explanation: Bright spiral galaxy NGC 3169 appears to be unraveling in this cosmic scene, played out some 70 million light-years away just belowbright star Regulus toward the faint constellation Sextans. Its beautiful spiral arms are distorted into sweeping tidal tails as NGC 3169 (left) and neighboring NGC 3166 interact gravitationally, a common fate even for bright galaxies in the local universe. In fact, drawn out stellar arcs and plumes, indications of gravitational interactions, seem rampant in the deep and colorful galaxy group photo. The picture spans 20 arc minutes, or about 400,000 light-years at the group’s estimated distance, and includes smaller, dimmer NGC 3165 at the right. NGC 3169 is also known to shine across the spectrum from radio to X-rays, harboring an active galactic nucleus that is likely the site of a supermassive black hole.

Posted 1 year ago

Infrared Portrait of the Large Magellanic Cloud 
Credit: ESA / NASA / JPL-Caltech / STScI

Explanation: Cosmic dust clouds ripple across this infrared portrait of our Milky Way’s satellite galaxy, the Large Magellanic Cloud. In fact, the remarkable composite image from the Herschel Space Observatory and the Spitzer Space Telescope show that dust clouds fill this neighboring dwarf galaxy, much like dust along the plane of the Milky Way itself. The dust temperatures tend to trace star forming activity. Spitzer data in blue hues indicate warm dust heated by young stars. Herschel’s instruments contributed the image data shown in red and green, revealing dust emission from cooler and intermediate regions where star formation is just beginning or has stopped. Dominated by dust emission, the Large Magellanic Cloud’s infrared appearance is different from views in optical images. But this galaxy’s well-known Tarantula Nebula still stands out, easily seen here as the brightest region to the left of center. A mere 160,000 light-years distant, the Large Cloud of Magellan is about 30,000 light-years across.

Posted 1 year ago

M42: Inside the Orion Nebula 
Image Credit & Copyright: Reinhold Wittich

Explanation: The Great Nebula in Orion, an immense, nearby starbirth region, is probably the most famous of all astronomical nebulas. Here, glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away. In theabove deep image in assigned colors highlighted by emission in oxygen and hydrogen, wisps and sheets of dust and gas are particularly evident. The Great Nebula in Orion can be found with the unaided eye near the easily identifiable belt of three stars in the popularconstellation Orion. In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries. These nurseries contain much hydrogen gas, hot young stars, proplyds, and stellar jets spewing material at high speeds. Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun.

Posted 1 year ago

Light Echoes from V838 Mon 
Image Credit: NASAESA, H. E. Bond (STScI)

Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this had never been seen before — supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter.

Posted 1 year ago

Spin up of a Supermassive Black Hole 
Illustration Credit: Robert Hurt, NASA/JPL-Caltech

Explanation: How fast can a black hole spin? If any object made of regular matter spins too fast — it breaks apart. But a black hole might not be able to break apart — and its maximum spin rate is really unknown. Theorists usually model rapidly rotating black holes with the Kerr solution to Einstein’s General Theory of Relativity, which predicts several amazing and unusual things. Perhaps its most easily testable prediction, though, is that matter entering a maximally rotating black hole should be last seen orbiting at near the speed of light, as seen from far away. This prediction was tested recently by NASA’s NuSTAR and ESA’s XMM satellites by observing the supermassive black hole at the center of spiral galaxy NGC 1365. The near light-speed limit was confirmed by measuring the heating and spectral line broadening of nuclear emissions at the inner edge of the surrounding accretion diskPictured above is an artist’s illustration depicting an accretion disk of normal matter swirling around a black hole, with a jet emanating from the top. Since matter randomly falling into the black hole should not spin up a black hole this much, the NuSTAR and XMM measurements also validate the existence of the surrounding accretion disk.

Posted 1 year ago

Looking Through Abell 68 
Credit: NASAESAHubble Heritage/ESA-Hubble Collaboration - Acknowledgment: Nick Rose

Explanation: Want to use a cluster of galaxies as a telescope? It’s easier than you might think as distant galaxy clusters naturally act as strong gravitional lenses. In accordance with Einstein’s theory of general relativity, the cluster gravitational mass, dominated by dark matter, bends light and creates magnified, distorted images of even more distant background galaxies. This sharp infrared Hubble image illustrates the case for galaxy cluster Abell 68 as a gravitational telescope, explored by amateur astronomer Nick Rose during the ESA-Hubble Hidden Treasures image processing competition. Putting your cursor over the picture will label highlights in the scene. Labels 1 and 2 show two lensed images of the same background galaxy. The distorted galaxy image labeled 2 resembles a vintage space invader! Label 3 marks a cluster member galaxy, not gravitationally lensed, stripped of its own gas as it plows through the denser intergalactic medium. Label 4 includes many background galaxies imaged as elongated streaks and arcs. Abell 68 itself is some 2.1 billion light-years distant toward the constellation Vulpecula. The central region of the cluster covered in the Hubble view spans over 1.2 million light-years.

Posted 1 year ago

IC 1805: The Heart Nebula 
Image Credit & Copyright: Terry Hancock

Explanation: Sprawling across almost 200 light-years, emission nebula IC 1805 is a mix of glowing interstellar gas and dark dust clouds. Derived from its Valentine’s-Day-approved shape, its nickname is the Heart Nebula. About 7,500 light-years away in the Perseus spiral arm of our galaxy, stars were born in IC 1805. In fact, near the cosmic heart’s center are the massive hot stars of a newborn star cluster also known as Melotte 15, about 1.5 million years young. A little ironically, the Heart Nebula is located in the constellation of the mythical Queen of Aethiopia (Cassiopeia). This deep view of the region around theHeart Nebula spans about two degrees on the sky or about four times the diameter of the Full Moon.