Astronomy Picture of the Day – The Flare and the Galaxy

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2015 September 2


The Flare and the Galaxy
Image Credit & Copyright: Martin Mark

 

Explanation: Is this person throwing a lightning bolt? No. Despite appearances, this person is actually pointing in the direction of a bright Iridium flare, a momentary reflection of sunlight off of a communications satellite in orbit around the Earth. As the Iridium satellite orbits, reflective antennas became aligned between the observer and the Sun to create a flash brighter than any star in the night sky. Iridium flares typically last several seconds, longer than most meteors. Also unlike meteors, the flares are symmetric and predictable. The featured flare involved Iridium satellite 15 and occurred over southern Estonia last week. In this well-planned image, a spectacular night sky appears in the background, complete with the central band of our Milky Way Galaxy running vertically up the image center.

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Astronomy Picture of the Day – Spiral Galaxy in Collision

Astronomy Picture of the Day

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2012 August 12

Spiral Galaxy NGC 4038 in Collision I

mage Credit: Data Collection: Hubble Legacy Archive;

Processing: Danny Lee Russell

 

Explanation: This galaxy is having a bad millennium.  In fact, the past 100 million years haven’t been so good,  and probably the next billion or so will be quite tumultuous.  Visible on the upper left, NGC 4038 used to be a normal spiral galaxy, minding its own business, until NGC 4039, toward its right,  crashed into it.  The evolving wreckage, known famously as  the Antennae, is pictured above.  As gravity  restructures each galaxy, clouds of gas slam into each other,  bright blue knots of stars form, massive stars form and  explode,  and brown filaments of dust are strewn about.  Eventually the  two galaxies will converge into one larger spiral galaxy. Such collisions are not unusual, and even our own  Milky Way Galaxy has undergone several in the past and is  predicted to collide with our neighboring  Andromeda Galaxy in a few billion years. The  frames that compose this image were taken by the orbiting Hubble Space Telescope by professional astronomers to  better understand galaxy collisions. These frames — and many other deep space images from  Hubble — have since been  made public,  allowing an interested amateur to download and  process them into this visually stunning composite.

Astronomy Picture of the Day for April 14th

Astronomy Picture of the Day

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

See Explanation.  Clicking on the picture will download the highest resolution version available.

Barred Spiral Galaxy NGC 1300
Image Credit: Hubble Heritage Team, ESA, NASA 

 

Explanation: Big, beautiful, barred spiral galaxy NGC 1300 lies some 70 million light-years away on the banks of the constellation Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the largest Hubble images ever made of a complete galaxy. NGC 1300 spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy’s dominant central bar and majestic spiral arms. In fact, on close inspection the nucleus of this classic barred spiral itself shows a remarkable region of spiral structure about 3,000 light-years across. Unlike other spiral galaxies, including our own Milky Way, NGC 1300 is not presently known to have a massive central black hole.

Astronomy Picture of the Day for Feb. 6th

Astronomy Picture of the Day

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2012 February 6
See Explanation.  Clicking on the picture will download the highest resolution version available.

Dust of the Orion Nebula
Image Credit & Copyright: Nicolás Villegas 

Explanation: What surrounds a hotbed of star formation? In the case of the Orion Nebula — dust. The entire Orion field, located about 1600 light years away, is inundated with intricate and picturesque filaments of dust. Opaque to visible light, dust is created in the outer atmosphere of massive cool stars and expelled by a strong outer wind of particles. The Trapezium and other forming star clusters are embedded in the nebula. The intricate filaments of dust surrounding M42 and M43 appear brown in the above image, while central glowing gas is highlighted in red. Over the next few million years much of Orion’s dust will be slowly destroyed by the very stars now being formed, or dispersed into the Galaxy.

Astronomy Picture of the Day for Jan. 27th

Astronomy Picture of the Day

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2012 January 27
See Explanation.  Clicking on the picture will download the highest resolution version available.

NGC 3239 and SN 2012A
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, University of Arizona 

 

Explanation: About 40,000 light-years across, pretty, irregular galaxy NGC 3239 lies near the center of this lovely field of galaxies in the galaxy rich constellation Leo. At a distance of only 25 million light-years it dominates the frame, sporting a peculiar arrangement of structures, young blue star clusters and star forming regions, suggesting that NGC 3239 (aka Arp 263) is the result of a galaxy merger. Appearing nearly on top of the pretty galaxy is a bright, spiky, foreground star, a nearby member of our own Milky Way galaxy almost directly along our line-of-sight to NGC 3239. Still, NGC 3239 is notable for hosting this year’s first confirmed supernova, designated SN 2012A. It was discovered early this month by supernova hunters Bob Moore, Jack Newton, and Tim Puckett. Indicated in a cropped version of the wider image, SN 2012A is just below and right of the bright foreground star. Of course, based on the light-travel time to NGC 3239, the supernova explosion itself occurred 25 million years ago, triggered by the core collapse of a massive star.

Hubble Image Gallery for December 27th

Spiral Galaxy M100

An image of the grand design spiral galaxy M100 obtained with the second generation Wide Field and Planetary Camera (WFPC-2), newly installed in the Hubble Space Telescope. Though the galaxy lies several tens of millions of light-years away, modified optics incorporated within the WFPC-2 allow Hubble to view M100 with a level of clarity and sensitivity previously possible only for the very few nearby galaxies that compose our “Local Group.” Just as one does not learn about the diversity of mankind by conversing only with your next door neighbor, astronomers must study many galaxies in a host of different environments if they are to come to understand how our own galaxy, out star, and our earth came to be. By expanding the region of the universe that can be studied in such detail a thousand fold, the WFPC-2 will help the Hubble Space Telescope to fulfill this mission.

Astronomy Picture of the Day for December 23rd

Astronomy Picture of the Day

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2011 December 23
See Explanation.  Clicking on the picture will download the highest resolution version available.

Shell Galaxy NGC 7600
Image Credit & Copyright: Ken Crawford (Rancho Del Sol Observatory)
Collaboration: Andrew Cooper (MPA), Carlos Frenk, John Helly, Shaun Cole (Institute for Computational Cosmology),David Martinez-Delgado (MPIA), Star Stream Pilot Survey Group 

Explanation: Similar in size to the Milky Way, elliptical galaxy NGC 7600 is about 160 million light-years distant. In this deep image, spanning about 1/2 degree on the sky toward the constellation Aquarius, NGC 7600 sports a remarkable outer halo of nested shells and broad circumgalactic structures. The tantalizing features can be explained by the accretion of dark matter and stars on a cosmic timescale. In fact, a movie generated by simulating galaxy formation using a cosmological model with cold dark matter for the halos of merging galaxies reproduces the appearance of NGC 7600 in amazing detail. The remarkable simulation movie is available here on Vimeo and here in other formats. It presents compelling evidence that detailed features of galaxy mergers observed with small, wide field telescopes on planet Earth, are natural consequences of galaxy formation and fundamental properties of dark matter.