Andromeda Galaxy from Mt Laguna
Pelican nebula close-up
The prominent ridge of emission featured in this vivid skyscape is designated IC 5067. Part of a larger emission nebula with a distinctive shape, popularly called The Pelican Nebula, the ridge spans about 10 light-years and follows the curve of the cosmic pelican’s head and neck. The Pelican Nebula close-up was constructed from narrowband data mapping emission from sulfur, hydrogen, and oxygen atoms to red, green, and blue colors. Fantastic, dark shapes inhabiting the view are clouds of cool gas and dust sculpted by energetic radiation from young, hot, massive stars. But stars are also forming within the dark shapes. In fact, twin jets emerging from the tip of the long, dark tendril below center are the telltale signs of an embedded protostar cataloged as Herbig-Haro 555. The Pelican Nebula itself, also known as IC 5070, is about 2,000 light-years away.To find it, look northeast of bright star Deneb in the high flying constellation Cygnus.
Image credit & copyright: Martin Pugh
Astronauts aboard the International Space Station captured the Sarychev volcano in action on January 30th 2014.
Image credit: NASA
It came from outer space
Named after its discoverer, the French-Armenian astronomer Agop Terzan, this is the globular cluster Terzan 7 — a densely packed ball of stars bound together by gravity. It lies just over 75 000 light-years away from us on the other side of our galaxy, the Milky Way. It is a peculiar cluster, quite unlike others we observe, making it an intriguing object of study for astronomers.
Evidence shows that Terzan 7 used to belong to a small galaxy called the Sagittarius Dwarf Galaxy, a mini-galaxy discovered in 1994. This galaxy is currently colliding with, and being absorbed by, the Milky Way, which is a monster in size when compared to this tiny one. It seems that this cluster has already been kidnapped from its former home and now is part of our own galaxy.
Astronomers recently discovered that all the stars in Terzan 7 were born at around the same time, and are about eight billion years old. This is unusually young for such a cluster. The shared birthday is another uncommon property; a large number of globular clusters, both in the Milky Way and in other galaxies, seem to have at least two clearly differentiated generations of stars that were born at different times.
Some explanations suggest that there is something different about clusters that form within dwarf galaxies, giving them a different composition. Others suggest that clusters like Terzan 7 only have enough material to form one batch of stars, or that perhaps its youthfulness has prevented it from yet forming another generation.
Image credit: NASA, ESA, and A. Sarajedini (University of Florida); Acknowledgement: Gilles Chapdelaine
Herschel Crater on Mimas of Saturn
Mimas, one of the smaller round moons of Saturn, sports Herschel crater, one of the larger impact craters in the entire Solar System. The robotic Cassini spacecraft orbiting Saturn took the above image of Herschel crater in unprecedented detail while making a 10,000-kilometer record close pass by the icy world. Shown in contrast-enhanced false color, the above image includes color information from older Mimas images that together show more clearly that Herschel’s landscape is colored slightly differently from more heavily cratered terrain nearby. The color difference could yield surface composition clues to the violent history of Mimas.
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA
This week, the light from a star that exploded 12 million years ago finally reached earth.
Astronomers observed the supernova in galaxy M82. Shown here are two views of that galaxy: the first photo taken in December, and the second yesterday, showing the new giant ball of light. Despite being 12 million light-years away, M82 is considered to be practically a next-door neighbor of our own galaxy, and is easily viewable by backyard astronomers.
Supernovas are caused by either the sudden gravitational collapse of the core of a massive star, or the accumulation of material in a dwarf star that raises the core temperature and triggers runaway nuclear fusion. They are short-lived, but not instant events - the light from the explosion can last for weeks or even months before fading out. This particular star was a white dwarf, and its supernova is expected to continue to brighten for the next two weeks as the explosion grows. The energy released in a single supernova event can often exceed what our Sun will emit over its entire lifespan.
Across the thousands of galaxies in the entire universe supernovae are quite common - astronomers record a few hundred new ones every year. While none have been observed within the Milky Way since 1604, observed supernova remnants suggest our galaxy sees two to three per century. This is the nearest supernova to Earth in 21 years.
Photo: UCL Mathematical and Physical Sciences on Flickr
(via: Peterson Field Guides)