The Helix Nebula in Hydrogen and Oxygen.Explanation: Is the Helix Nebula looking at you? No, not in any biological sense, but it does look quite like an eye. The Helix Nebula is so named because it also appears that you are looking down the axis of a helix. In actuality, it is now understood to have a surprisingly complex geometry, including radial filaments and extended outer loops. The Helix Nebula (aka NGC 7293) is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The featured picture, taken in the light emitted by oxygen (shown in blue) and hydrogen (shown in red), was created from 74 hours of exposure over three months from a small telescope in a backyard of suburban Melbourne, Australia. A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin.
Composed of gas and dust, the pictured pillar resides in a tempestuous stellar nursery called the Carina Nebula, located 7500 light-years away in the southern constellation of Carina. Taken in visible light, the image shows the tip of the three-light-year-long pillar, bathed in the glow of light from hot, massive stars off the top of the image. Scorching radiation and fast winds (streams of charged particles) from these stars are sculpting the pillar and causing new stars to form within it. Streamers of gas and dust can be seen flowing off the top of the structure. Hubble's Wide Field Camera 3 observed the Carina Nebula on 24-30 July 2009. WFC3 was installed aboard Hubble in May 2009 during Servicing Mission 4. The composite image was made from filters that isolate emission from iron, magnesium, oxygen, hydrogen and sulphur. These Hubble observations of the Carina Nebula are part of the Hubble Servicing Mission 4 Early Release Observations.
Galaxies in our universe grow and evolve through collisions. When they smash together, galaxies distort and change as gravitational effects spark new star formation and feed supermassive black holes. The entire process can even bind the parties involved into a new, bigger galaxy that may bear no resemblance to the pieces that built it.
The universe is vast, with galaxies containing gas, dust, stars, and planets sprinkled throughout. But this sprinkling isn’t random; although some galaxies are indeed truly alone, most are not, but instead are congregating through gravity. NGC 1706, captured in this stunning Hubble Space Telescope image, is one of about 50 galaxies bound together in a group that lies in the direction of the southern constellation Dorado the Swordfish. The brilliant face-on spiral and its neighbors sit about 230 million light-years away.
Astronomers know that most galaxies house supermassive black holes in their centers, from the largest galaxies down to small dwarfs. They also know that when supermassive black holes are actively feeding, they can slow or even stop the formation of stars in their home. Although this relationship has been well established for large galaxies, it has not been studied much in dwarf galaxies. Now, researchers have discovered that black holes in dwarf galaxies are capable of shutting down star formation, just like their more massive counterparts. The finding, published October 11 in The Astrophysical Journal, shows that winds of energetic gas and particles blasted out by supermassive black holes can stop star formation in dwarf galaxies. It is the first time that black hole winds in dwarf galaxies have been studied in such detail, according to the team. And it’s an intriguing find, because astronomers didn’t expect such strong winds from the black holes in dwarf galaxies. They also didn’t expect those winds to stop, or quench, star formation galaxy-wide.
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