[via APOD]
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A jewel of the southern sky, the Great Carina Nebula, aka NGC 3372, spans over 300 light-years.
Near the upper right of this expansive skyscape, it is much larger than the more northerly Orion Nebula. In fact, the Carina Nebula is one of our galaxy’s largest star-forming regions and home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun.
Put a satellite in a circular orbit about 42,000 kilometres from the center of the Earth (36,000 kilometres or so above the surface) and it will orbit once in 24 hours. Because that matches Earth’s rotation period, it is known as a geosynchronous orbit. If that orbit is also in the plane of the equator, the satellite will hang in the sky over a fixed location in a geostationary orbit.
As predicted in the 1940s by futurist Arthur C. Clarke, geostationary orbits are in common use for communication and weather satellites, a scenario now well-known to astroimagers.
[via APOD]
The snow capped Teide volcano is reflected in a pool of water in this nearly symmetric night sky view from the Canary Island Tenerife.
Bright north star Polaris stands above the peak in an exposure that also captures the brilliant trail of a polar orbiting Iridium satellite.
Of course, with the camera fixed to a tripod, the stars themselves produce concentric trails in long exposures, a reflection of the Earth’s rotation around its axis.
Large astronomical observatories also take advantage of the calm Canary Island sky.
[via discovery.com]
Astronomers presenting at the American Astronomical Society (AAS) meeting in Washington D.C. on Jan. 4, have reported the detection of the emission generated by a black hole as it devoured a white dwarf star in the elliptical galaxy NGC 1399.
This may not appear to be a huge deal to begin with — stars being eaten by supermassive black holes in the centers of galaxies have been detected before — but it would appear that this particular white dwarf was ripped apart and then devoured by a mysterious “intermediate-mass” black hole.
[via APOD]
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An asterism is just a recognized pattern of stars that is not one the 88 official constellations. For example, one of the most famous (and largest) asterisms is the Big Dipper within the constellation Ursa Major. But this pretty chain of stars, visible with binoculars towards the long-necked constellation of Camelopardalis, is also a recognized asterism. Known as Kemble’s Cascade, it contains about 20 stars nearly in a row, stretching over five times the width of a full moon.
[via io9]
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Here are some vampires we don’t mind sparkling. This globular cluster, Messier 30, contains two types of ancient stars that have managed to keep themselves brilliant and young. One type relies on interstellar collisions; the other drinks from its neighbors.
Messier 30 is an unusual cluster. It’s an ancient cluster, and yet it is filled with blue stars, stars that tend to age and die more quickly than other types of stars. Astronomers have termed these unusually old blue stars “blue stragglers,” and they believe that there are two reasons these stars still exist.
Image by Nico Camargo and courtesy www.citizensky.org. Used under Creative Commons license.
Some kind of obstruction is blocking our view of Epsilon Aurigae, a star in the constellation Auriga. Its exact nature is unknown — but astronomers say that if you’ve got a telescope, you could help them figure it out.
Epsilon Aurigae is a binary system, or a star locked in a pattern of mutual orbit with a second body. It lies in the constellation Auriga, about two thousand light-years away from Earth. We like this star, because it gives us the chance to shout out to some old-school Green Day.
[via APOD]
What would it look like to travel across the known universe? To help humanity visualize this, the American Museum of Natural History has produced a modern movie featuring many visual highlights of such a trip.
The video starts in Earth’s Himalayan Mountains and then dramatically zooms out, showing the orbits of Earth’s satellites, the Sun, the Solar System, the extent of humanities first radio signals, the Milky Way Galaxy, galaxies nearby, distant galaxies, and quasars. As the distant surface of the microwave background is finally reached, radiation is depicted that was emitted billions of light years away and less than one million years after the Big Bang.
[via APOD]
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Birds don’t fly this high. Airplanes don’t go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description.
Pictured above, the Space Shuttle Atlantis lifted off to visit the International Space Station during the early morning hours of 2001 July 12. From a standing start, the two million kilogram rocket ship left to circle the Earth where the outside air is too thin to breathe and where there is little noticeable onboard gravity. Rockets bound for space are now launched from somewhere on Earth about once a week.
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Beautiful island universe M94 lies a mere 15 million light-years distant in the northern constellation of the hunting dogs, Canes Venatici. A popular target for astronomers, the brighter inner part of the face-on spiral galaxy is about 30,000 light-years across.
Traditionally, deep images have been interpreted as showing M94′s inner spiral region surrounded by a faint, broad ring of stars. But a new multi-wavelength investigation has revealed previously undetected spiral arms sweeping across the outskirts of the galaxy’s disk, an outer disk actively engaged in star formation. At optical wavelengths, M94′s outer spiral arms are followed in this remarkable discovery image, processed to enhance the outer disk structure. Background galaxies are visible through the faint outer arms, while the three spiky foreground stars are in our own Milky Way galaxy.