Friday, December 30, 2011


The monster at the center of our Galaxy is about to get fed. Recent observations by the Very Large Telescopes indicate that a cloud of gas will venture too close to the supermassive black hole at the Galactic center. The gas cloud is being disrupted, stretched out, heated up, and some of it is expected to fall into the black hole over the next two years. In this artist's illustration, what remains of the blob after a close pass to the black hole is shown in red and yellow, arching out from the gravitational death trap to its right. The cloud's orbit is shown in red, while the orbits of central stars are shown in blue. The infalling nebula is estimated to contain several times the mass of our Earth, while the central black hole, thought to correspond to the radio source Sagittariaus A*, contains about four million times the mass of our Sun. Once it falls in, nothing is expected to be heard from the doomed gas ever again.

Wednesday, December 21, 2011


What's large and blue and can wrap itself around an entire galaxy? A gravitational lens mirage. Pictured above, the gravity of a luminous red galaxy (LRG) has gravitationally distorted the light from a much more distant blue galaxy. More typically, such light bending results in two discernible images of the distant galaxy, but here the lens alignment is so precise that the background galaxy is distorted into a horseshoe -- a nearly complete ring. Since such a lensing effect was generally predicted in some detail by Albert Einstein over 70 years ago, rings like this are now known as Einstein Rings. Although LRG 3-757 was discovered in 2007 in data from the Sloan Digital Sky Survey (SDSS), the image shown above is a follow-up observation taken with the Hubble Space Telescope's Wide Field Camera 3. Strong gravitational lenses like LRG 3-757 are more than oddities -- their multiple properties allow astronomers to determine the mass and dark matter content of the foreground galaxy lenses.

Saturday, December 17, 2011

From the Hubble Site


NASA's Hubble Space Telescope presents a festive holiday greeting that's out of this world. The bipolar star-forming region, called Sharpless 2-106, looks like a soaring, celestial snow angel. The outstretched "wings" of the nebula record the contrasting imprint of heat and motion against the backdrop of a colder medium.

Sharpless 2-106, Sh2-106 or S106 for short, lies nearly 2,000 light-years from us. The nebula measures several light-years in length. It appears in a relatively isolated region of the Milky Way galaxy.

A massive, young star, IRS 4 (Infrared Source 4), is responsible for the furious activity we see in the nebula. Twin lobes of super-hot gas, glowing blue in this image, stretch outward from the central star. This hot gas creates the "wings" of our angel.

A ring of dust and gas orbiting the star acts like a belt, cinching the expanding nebula into an "hourglass" shape. Hubble's sharp resolution reveals ripples and ridges in the gas as it interacts with the cooler interstellar medium.

Dusky red veins surround the blue emission from the nebula. The faint light emanating from the central star reflects off of tiny dust particles. This illuminates the environment around the star, showing darker filaments of dust winding beneath the blue lobes.

Detailed studies of the nebula have also uncovered several hundred brown dwarfs. At purely infrared wavelengths, more than 600 of these sub-stellar objects appear. These "failed" stars weigh less than a tenth of our Sun. Because of their low mass, they cannot produce sustained energy through nuclear fusion like our Sun does. They encompass the nebula in a small cluster.

The Hubble images were taken in February 2011 with the Wide Field Camera 3. Visible narrow-band filters that isolate the hydrogen gas were combined with near-infrared filters that show structure in the cooler gas and dust.

Saturday, December 10, 2011


I've been thinking about deadlines, because Timmi Duchamp gave me a one weekend deadline for a brief essay for the Aqueduct blog. I made it.

I don't like deadlines. For the most part, I write what I want at the speed I want and don't try selling fiction before it's done. When I have had deadlines for fiction, I have usually not made them.

The writing group I'm in -- the Wyrdsmiths -- has a majority of writers who do work to deadline; and I am rethinking my attitude. Sometimes I have genuine creative reasons for writing slowly and taking time off. I need to mull ideas or figure out how to reorganize a story, because it's not heading in a direction I like. But I also suffer from perfectionism and procrastination. I will avoid writing and stall on completing stories for fear the work is not any good.

I'm not as young as I once was. As Andrew Marvell wrote, "...At my back I always hear Time's winged chariot hurrying near: and younder all before us lie deserts of vast eternity." That being so, I'd like to write more rapidly, and this leads me to consider the merits of deadlines.

Since I am writing short stories these days, I am not going to have many deadline set by editors, unless I move into the theme anthology market. But I can set my own deadlines and be serious about meeting them. Or I can simply get serious about writing every day, making production...

Spontaneity and Honesty

I have been reading Natalie Goldberg's book Writing Down the Bones. Goldberg is very much self-identified as a writer. Most of her work has about the process of writing. She is a writer who writes about how to write. She has also published poetry, which I don't find especially interesting, and a novel I didn't like. Her best work is either memoir or how-to writing books or a combination.

She studied Zen with Katagiri Roshi in Minneapolis, and what she describes is very much writing as a Zen practice. In fact, Katagiri told her writing was her practice.

She emphasizes spontaneity and honesty, writing that comes straight from the heart. I enjoy reading her and think about using her writing exercises. But in my own writing I value control and lying. My writing, especially my prose fiction, is not spontaneous; it's worked over, revised and refined. Most of my writing is fiction and untrue. In fact, it is is not even realistic. It is science fiction and fantasy. I keep thinking about the line from Hamlet: "By indirections find directions out." Using fiction, one finds or says the truth.

I draw on my own life, my experiences and feelings, but I don't show them directly. They are hidden in the tale. And my stories wander into unplanned places. In that sense, they are spontaneous. But control is always present. I am not going to become enlightened working this way. But I am reasonably happy with the stories.


These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta, the mainbelt asteroid currently being explored by NASA's Dawn spacecraft. Why are they thought to be from Vesta? Because the HED meteorites have visible and infrared spectra that match the spectrum of that small world. The hypothesis of their origin on Vesta is also consistent with data from Dawn's ongoing observations. Excavated by impacts, the diogenites shown here would have originated deep within the crust of Vesta. Similar rocks are also found in the lower crust of planet Earth. A sample scale is indicated by the white bars, each 2 millimeters long.

Sunday, December 04, 2011


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 has never been seen before. It's true that supernovae and novae expel matter out into space. But while the V838 Mon flash appears to expel material into space, what is seen here 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 ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of Monoceros the unicorn. In this Hubble Space Telescope image from February 2004, the light echo is about six light years in diameter.