This ring of dark matter is not new-news from Hubble, but it caught my eye as I was scrolling through the mighty folder of space images this morning. Dark perhaps, but a nice shade of blue!

May 15, 2007: Astronomers using NASA’s Hubble Space Telescope have discovered a ghostly ring of dark matter that formed long ago during a titanic collision between two massive galaxy clusters. The ring’s discovery is among the strongest evidence yet that dark matter exists. Astronomers have long suspected the existence of the invisible substance as the source of additional gravity that holds together galaxy clusters. Such clusters would fly apart if they relied only on the gravity from their visible stars. Although astronomers don’t know what dark matter is made of, they hypothesize that it is a type of elementary particle that pervades the universe.

This Hubble composite image shows the ring of dark matter in the galaxy cluster Cl 0024+17. The ring-like structure is evident in the blue map of the cluster’s dark matter distribution. The map was derived from Hubble observations of how the gravity of the cluster Cl 0024+17 distorts the light of more distant galaxies, an optical illusion called gravitational lensing. Although astronomers cannot see dark matter, they can infer its existence by mapping the distorted shapes of the background galaxies. The map is superimposed on a Hubble Advanced Camera for Surveys image of the cluster taken in November 2004.

Credit & Copyright: Piotrek Sadowski, astrofotografia.com.pl

Eh, yeah, this is today’s APOD and I try not to do that, but it’s awfully pretty for a Friday, don’t you think?

Dark shapes with bright edges winging their way through dusty NGC 6188 are tens of light-years long. The emission nebula is found near the edge of an otherwise dark large molecular cloud in the southern constellation Ara, about 4,000 light-years away. Formed in that region only a few million years ago, the massive young stars of the embedded Ara OB1 association sculpt the fantastic shapes and power the nebular glow with stellar winds and intense ultraviolet radiation. The recent star formation itself was likely triggered by winds and supernova explosions, from previous generations of massive stars, that swept up and compressed the molecular gas. A false-color Hubble palette was used to create this sharp close-up image and shows emission from sulfur, hydrogen, and oxygen atoms in red, green, and blue hues. At the estimated distance of NGC 6188, the picture spans about 200 light-years.

Today’s post comes from the This Is Just Plain Cool Dept: the Common Extensible Cryogenic Engine (CECE) during a hot-fire test. Rocket engines are amazing to behold (preferably, from a safe distance) — consider this a MOAR POWER gift from me to you, this Thursday.

Spacecraft attempting to land on an unfamiliar surface need to perform a maneuver called “deep throttling” — a step that allows the vehicle to precisely throttle down to perform a smooth, controlled landing. NASA and industry partners have demonstrated this type of engine control capability to help design a more reliable and robust descent engine that could be used to land space exploration vehicles on the moon, an asteroid or another planet.

The Common Extensible Cryogenic Engine, also known as CECE, recently completed the fourth and final series of hot-fire tests on a 15,000-pound thrust class cryogenic technology demonstrator rocket engine, increasing the throttling capability by 35 percent over previous tests. This test series demonstrated this engine could go from a thrust range of 104 percent power down to 5.9 percent. This equates to an unprecedented 17.6:1 deep-throttling capability, which means this cryogenic engine can quickly throttle up and down.

Credit: NASA, ESA, R. O'Connell (University of Virginia), F. Paresce (National Institute for Astrophysics, Bologna, Italy), E. Young (Universities Space Research Association/Ames Research Center), the WFC3 Science Oversight Committee, and the Hubble Heritage Team (STScI/AURA)

This spectacular Hubble image came out Tuesday, and I just LOVE IT.

Like a July 4 fireworks display, a young, glittering collection of stars looks like an aerial burst. The cluster is surrounded by clouds of interstellar gas and dust—the raw material for new star formation. The nebula, located 20,000 light-years away in the constellation Carina, contains a central cluster of huge, hot stars, called NGC 3603.

This environment is not as peaceful as it looks. Ultraviolet radiation and violent stellar winds have blown out an enormous cavity in the gas and dust enveloping the cluster, providing an unobstructed view of the cluster.

Most of the stars in the cluster were born around the same time but differ in size, mass, temperature, and color. The course of a star’s life is determined by its mass, so a cluster of a given age will contain stars in various stages of their lives, giving an opportunity for detailed analyses of stellar life cycles. NGC 3603 also contains some of the most massive stars known. These huge stars live fast and die young, burning through their hydrogen fuel quickly and ultimately ending their lives in supernova explosions.

Star clusters like NGC 3603 provide important clues to understanding the origin of massive star formation in the early, distant universe. Astronomers also use massive clusters to study distant starbursts that occur when galaxies collide, igniting a flurry of star formation. The proximity of NGC 3603 makes it an excellent lab for studying such distant and momentous events.

This Hubble Space Telescope image was captured in August 2009 and December 2009 with the Wide Field Camera 3 in both visible and infrared light, which trace the glow of sulfur, hydrogen, and iron.

Apollo 15 Lunar Module Pilot James Irwin salutes the U.S. flag

Today’s NASA Image of the Day — what a fun shot! — reminded me of the photo above, which I used to have as a mini-poster in my room. Happy early birthday, America, and to all my readers, have yourselves a great 4th of July weekend! (Or a great weekend in general!)

Image via The Project Apollo Image Gallery.

Moonrise taken during ISS Expedition 15, by @Astro_Clay

Two gorgeous views of the Moon from the ISS, one from Expedition 15 (top), the other from a week ago (bottom.) As an aside, I went out for the first time (intentionally) looking for the ISS this weekend, and saw it twice! It was much brighter than normal (so SpaceWeather.com told me) and was quite easy to spot. Sunday night, it was about the brightness (in my unschooled opinion) of Venus, cutting across the twilight sky. Very beautiful.

Moon over Earth, photo by @Astro_Wheels

M8 Lagoon Nebula, photo by Paul Haese

This beautiful image of the Lagoon Nebula is the work of Paul Haese… and what amazing work it is!

This emission nebula is located in the constellation of Sagittarius. It lies at a distance of 4000-6000 light years and has the dimensions of 110 light years by 70 light years. The nebula has a number of areas known as Bok globules. These are areas that are collapsing and likely to produce new solar systems in millions of years time.

This was a recent NASA Image of the Day — I love the colors, and the nostalgia…. Soon I’ll be nostalgic over the shuttle program, and that makes me a bit ill. In the same way I marvel over bits of shuttle being hoisted here and there in the VAB, I’m amazed to see chunks of rocket in the air like this. I know they have to assemble themselves somehow, it’s just still… amazing to me, to see such big pieces of hardware lifted up. I’m amazed by skyscrapers too, fwiw.

This image from 1967 shows the S-II stage of the Saturn V rocket as it was hoisted onto the A-2 test stand at the Mississippi Test Facility (now the Stennis Space Center). This was the second stage of the 364-foot tall moon rocket, which was powered by five J-2 engines.

Aurora Australis Observed from the International Space Station, acquired May 29, 2010

Some terrific Aurora Australis photos for your Tuesday! Above, this amazing photo, found via Discovery News’ Big Pic, shows a ribbon of green snaking across the planet, while below, this photo by astronaut Doug Wheelock has a more bluish, more dragon-shaped aurora (in my opinion.)

A breath-taking masterpiece being painted in the sky over the South Pole. Photo by @Astro_Wheels

Image Credit: NASA/Carla Cioffi

I’ve seen and heard snippets of this poem, but never read it in entirety before this week. It is a beautiful thing. (Hat tip to John C. Wright for posting it!) It seems to fit well with this lovely launch photo — the rocket in question delivered three individuals into orbit on Wednesday, and to the ISS yesterday.

High Flight
by John Gillespie Magee, Jr.

Oh, I have slipped the surly bonds of earth
And danced the skies on laughter-silvered wings;
Sunward I’ve climbed, and joined the tumbling mirth
Of sun-split clouds…and done a hundred things
You have not dreamed of…wheeled and soared and swung
High in the sunlit silence. Hov’ring there,
I’ve chased the shouting wind along, and flung
My eager craft through footless halls of air.
Up, up the long, delirious, burning blue
I’ve topped the windswept heights with easy grace
Where never lark, or even eagle flew.
And, while with silent, lifting mind I’ve trod
The high untrespassed sanctity of space
Put out my hand, and touched the face of God.