пятница, 12 февраля 2016 г.

LIGO Detects Gravitational Waves from Merging Black Holes

Gravitational radiation has been directly detected. The first-ever detection was made by both facilities of the Laser Interferometer Gravitational-Wave Observatory (LIGO) in Washington and Louisiana simultaneously last September. After numerous consistency checks, the resulting 5-sigma discovery was published today. The measured gravitational waves match those expected from two large black holes merging after a death spiral in a distant galaxy, with the resulting new black hole momentarily vibrating in a rapid ringdown. A phenomenon predicted by Einstein, the historic discovery confirms a cornerstone of humanity's understanding of gravity and basic physics. It is also the most direct detection of black holes ever. The featured illustration depicts the two merging black holes with the signal strength of the two detectors over 0.3 seconds superimposed across the bottom. Expected future detections by Advanced LIGO and other gravitational wave detectors may not only confirm the spectacular nature of this measurement but hold tremendous promise of giving humanity a new way to see and explore our universe. via NASA http://ift.tt/20Xw6La

четверг, 11 февраля 2016 г.

Galaxies in the River

Large galaxies grow by eating small ones. Even our own galaxy practices galactic cannibalism, absorbing small galaxies that get too close and are captured by the Milky Way's gravity. In fact, the practice is common in the universe and illustrated by this striking pair of interacting galaxies from the banks of the southern constellation Eridanus, The River. Located over 50 million light years away, the large, distorted spiral NGC 1532 is seen locked in a gravitational struggle with dwarf galaxy NGC 1531 (right of center), a struggle the smaller galaxy will eventually lose. Seen edge-on, spiral NGC 1532 spans about 100,000 light-years. Nicely detailed in this sharp image, the NGC 1532/1531 pair is thought to be similar to the well-studied system of face-on spiral and small companion known as M51. via NASA http://ift.tt/1QVr7Gd

вторник, 9 февраля 2016 г.

Light Pillars over Alaska

What's happening behind those houses? Pictured here are not auroras but nearby light pillars, a nearby phenomenon that can appear as a distant one. In most places on Earth, a lucky viewer can see a Sun-pillar, a column of light appearing to extend up from the Sun caused by flat fluttering ice-crystals reflecting sunlight from the upper atmosphere. Usually these ice crystals evaporate before reaching the ground. During freezing temperatures, however, flat fluttering ice crystals may form near the ground in a form of light snow, sometimes known as a crystal fog. These ice crystals may then reflect ground lights in columns not unlike a Sun-pillar. The featured image was taken in Fort Wainwright near Fairbanks in central Alaska. via NASA http://ift.tt/1nSIfTe

понедельник, 8 февраля 2016 г.

Advanced LIGO: Gravitational Wave Detectors Upgraded

Accelerate a charge and you'll get electromagnetic radiation: light. But accelerate any mass and you'll get gravitational radiation. Light is seen all the time, but, so far, a confirmed direct detection of gravitational radiation has been elusive. When absorbed, gravitational waves create a tiny symmetric jiggle similar to squashing a rubber ball and letting go quickly. Separated detectors can be used to discern gravitational waves from everyday bumps. Powerful astronomical sources of gravitational radiation would coincidentally jiggle even detectors on opposite ends of the Earth. Pictured here are the four-kilometer-long arms of one such detector: the LIGO Hanford Observatory in Washington state, USA. Together with its sister interferometer in Louisiana, these gravitational wave detectors continue to be upgraded and are now more sensitive than ever. via NASA http://ift.tt/1W2fAWX

воскресенье, 7 февраля 2016 г.

Five Planets at Castell de Burriac

February's five planet line-up stretches across a clear sky in this predawn scene. A hilltop Castell de Burriac looms in the foreground, overlooking the town of Cabrera de Mar near Barcelona, Spain, planet Earth. The mosaicked, panoramic image looks south. It merges three different exposure times to record a bright Last Quarter Moon, planets, seaside city lights, and dark castle ruins. Seen on February 1st the Moon was near Mars on the sky. But this week early morning risers have watched it move on, passing near Saturn and finally Venus and Mercury, sliding along near the ecliptic toward the dawn, approaching the February 7 New Moon. via NASA http://ift.tt/1PZChqj

суббота, 6 февраля 2016 г.

Massive Stars in NGC 6357

Massive stars lie within NGC 6357, an expansive emission nebula complex some 6,500 light-years away toward the tail of the constellation Scorpius. In fact, positioned near center in this ground-based close-up of NGC 6357, star cluster Pismis 24 includes some of the most massive stars known in the galaxy, stars with nearly 100 times the mass of the Sun. The nebula's bright central region also contains dusty pillars of molecular gas, likely hiding massive protostars from the prying eyes of optical instruments. Intricate shapes in the nebula are carved as interstellar winds and energetic radiation from the young and newly forming massive stars clear out the natal gas and dust and power the nebular glow. Enhancing the nebula's cavernous appearance, narrowband image data was included in this composite color image in a Hubble palette scheme. Emission from sulfur, hydrogen, and oxygen atoms is shown in red green and blue hues. The alluring telescopic view spans about 50 light-years at the estimated distance of NGC 6357. via NASA http://ift.tt/1R9z4d3

пятница, 5 февраля 2016 г.

Dwarf Planet Ceres

Dwarf planet Ceres is the largest object in the Solar System's main asteroid belt, with a diameter of about 950 kilometers (590 miles). Ceres is seen here in approximately true color, based on image data from the Dawn spacecraft recorded on May 4, 2015. On that date, Dawn's orbit stood 13,642 kilometers above the surface of the small world. Two of Ceres' famous mysterious bright spots at Oxo crater and Haulani crater are near center and center right of this view. Casting a telltale shadow at the bottom is Ceres' cone-shaped, lonely mountain Ahuna Mons. Presently some 385 kilometers above the Cerean surface, the ion-propelled Dawn spacecraft is now returning images from its closest mapping orbit. via NASA http://ift.tt/20t6SaU