2015年2月12日 星期四

In Pictures: DSCOVR Headed for Deep Space

On Wednesday evening, a SpaceX Falcon 9 rocketed into orbit with DSCOVR, the Deep Space Climate Observatory. Here's a photo and video roundup.



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NASA's Stratospheric Observatory for Infrared Astronomy



NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) enters the Lufthansa Technik hangar in Hamburg, Germany for its decadal inspection. Flight, aircraft maintenance, and science personnel from the Armstrong Flight Research Center worked alongside Lufthansa's 747 specialists to perform a wide range of inspections and maintenance. Image Credit: NASA/ Jeff Doughty via NASA http://ift.tt/1Mg5TkH

A Seagull Flies on a Dusty Ion Wind

Robert Gendler is an astrophotography whose work I’ve featured here many times (he helped assemble a jaw-dropping Hubble Andromeda Galaxy picture, for example). One area in which he excels is taking data from multiple big telescopes and merging them to create new views of the heavens.


His latest is a stunner: the aptly-named Seagull Nebula:


Can you see the shape of a gull in that? The head is the knot of gas to the left, and the wing shape is obvious enough. In this photo it actually looks more like a parrot to me, but that’s OK. A bird in the hand…


This is actually a vast star-forming region, a huge factory of gas and dust that is collapsing in various places to create newborn stars. Many of these stars are massive and hot, shining blue. They heat the gas up, exciting it (as we say in astronomy); the cloud is mostly hydrogen, which glows a characteristic pinkish-red when flooded by this starlight.


There’s also quite a bit of dark dust in this cloud, opaque to visible light. But the stars are so bright their light can reflect off it, and you see blue fuzz. The head of the gull is a lovely combination of both emission (red) and reflection (blue) nebulae.


Some features of the nebulae were puzzling me, so I poked around to look for other images, and found this one taken by NASA’s Wide-field Infrared Explorer (WISE):


The overall shape is the same, but there are big differences. This image is taken in the far-infrared, where the normally opaque dust glows. It’s actually a bit tough to match up features, since stars that are cool and faint in Gendler’s photo blaze away in the WISE image (and the WISE image is rotated clockwise slightly compared to the visible light image). Worse, what’s dark in Gendler’s image is bright in the WISE image, but some places are bright in both.


But note the bright blue star (called vdB 95) in the top image, located near the center bottom; it’s the brightest star in the field. See the fuzzy ring directly around it? I thought that was a reflection from inside the telescope (which is what causes the larger, sharper but fainter blue halo around it). It turns out that ring is real! You can see it in the WISE image, as well as a red arc. I suspect that star is moving at high speed through the gas and dust, and also blowing off a wind of material (like the Sun’s solar wind). That commonly causes such arc-like features in WISE images. Phenomenal.


Comparing the two, you can see other regions where stars are buried in gas and dust, and therefore are probably very young, still ensconced in their birth cocoons of material. As those stars age, their winds of subatomic particles and ultraviolet light will eat away at the dust, blowing it out, creating cavities in the nebula. Eventually the stars will wander out and travel the galaxy on their own. Thinking of them as chicks leaving the nest seems apropos for the whole theme here.


It’s possible our Sun was born in a cloud like this, our siblings and the nursery long since gone. I love soaking in the beauty of objects like this, but it’s hard not to stop and wonder that once, eons ago, we too were literally part of something like this.






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2015年2月11日 星期三

M100: A Grand Design Spiral Galaxy



Majestic on a truly cosmic scale, M100 is appropriately known as a grand design spiral galaxy. It is a large galaxy of over 100 billion stars with well-defined spiral arms that is similar to our own Milky Way Galaxy. One of the brightest members of the Virgo Cluster of galaxies, M100 (alias NGC 4321) is 56 million light-years distant toward the constellation of Berenice's Hair (Coma Berenices). This Hubble Space Telescope image of M100 was made in 2009 and reveals bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies. Studies of variable stars in M100 have played an important role in determining the size and age of the Universe. If you know exactly where to look, you can find a small spot that is a light echo from a bright supernova that was recorded a few years before the image was taken. via NASA http://ift.tt/1vixXcG

Europe's Experimental Spaceplane Completes Successful Test Flight

The IXV spaceplane, designed to demonstrate reentry technologies, splashed down in the Pacific Ocean this morning after a successful, 100-minute test flight.



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Giant Filament Seen on the Sun



A dark, snaking line across the lower half of the sun in this Feb. 10, 2015 image from NASA's Solar Dynamics Observatory (SDO) shows a filament of solar material hovering above the sun's surface. SDO shows colder material as dark and hotter material as light, so the line is, in fact, an enormous swatch of colder material hovering in the sun's atmosphere, the corona. Stretched out, that line – or solar filament as scientists call it – would be more than 533,000 miles long. That is longer than 67 Earths lined up in a row. Filaments can float sedately for days before disappearing. Sometimes they also erupt out into space, releasing solar material in a shower that either rains back down or escapes out into space, becoming a moving cloud known as a coronal mass ejection, or CME. SDO captured images of the filament in numerous wavelengths, each of which helps highlight material of different temperatures on the sun. By looking at such features in different wavelengths and temperatures, scientists learn more about what causes these structures, as well as what catalyzes their occasional eruptions. Launched on Feb. 11, 2010 aboard a ULA Atlas V rocket from Cape Canaveral Air Force Station, Fla., NASA's Solar Dynamics Observatory is designed to study the causes of solar variability and its impacts on Earth. The spacecraft's long-term measurements give solar scientists in-depth information to help characterize the interior of the sun, the sun's magnetic field, the hot plasma of the solar corona, and the density of radiation that creates the ionosphere of the planets. The information is used to create better forecasts of space weather needed to protect aircraft, satellites and astronauts living and working in space. Image Credit: NASA/SDO via NASA http://ift.tt/1EYkgIf

Faces in the Sky

What does an accomplished astrophotographer do when it’s cloudy for over two months in a row, and getting new photos of the night sky is impossible?


Why, play with pictures already taken, of course. But J-P Metsävainio did more than that: Looking through his amazing collection of gorgeous astronomical photos he’s taken over the years, he started seeing familiar objects in the nebulae, galaxies, and other cosmic objects. With time on his hands, he created a really, really funny gallery of cosmic pareidolia; things that look like other things.


As they say, a picture’s worth a thousand words. The photo at the top of this post is a great example of seeing faces in objects (that's part of the Veil Nebula, the expanding debris from a supernova, and it's several light years across), but I have to admit, Metsävainio is on to something with this shot of the Red Ghost (aka IC 63):


Some of his examples are well-known, like the Pelican, the Heart, and (seriously) the Pac-Man nebula. But he has a lot of others that took a bit of imagination, but are obvious once you see them. Several made me laugh...


If I had to pick a favorite, I’d go with this one, because I don’t know why but it’s perfect and weird and I never would’ve thought of it myself:


Ha!


This idea of seeing familiar objects in patterns is pretty common in astronomy; we’ve named tons of objects after their remarkable (or even seriously vague) resemblance to other things. Heck, that’s what constellations are! And it does help us remember and discuss them more easily. Of course, pareidolia can go wrong, and often does… but sometimes it also goes very, very right.


So take a look at Metsävainio’s gallery, and after that bit of fun, treat yourself and take a look at the collection of images he took in 2014. They may not all look like other things, but they all do look like is gorgeous.


… and one more thing. When you’re done there, prepare to have your brain melted with his 3D rotating image of the nebula IC 1396. You’re welcome.






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