Amazing new Hubble Space Telescope image shows galaxy a spiral galaxy being shredded right before our eyes. The image shows ESO 137-001, in the southern constellation of Triangulum Australe, framed against a field of foreground stars in our own galaxy, as it moves through the middle of the galaxy cluster Abell 3627 (not shown). Matter in the cluster is violently ripping the spiral’s entrails out into space, leaving behind bright blue streaks indicating vigorous young, massive star formation. The process tearing the galaxy apart isn’t gravitational: it’s ram-pressure stripping, an effect resulting from the drag force felt by an object moving through a viscous fluid. In this case, the “fluid” is low-density gas heated to millions of degrees that is often observed in massive galaxy clusters. Meanwhile, ESO 137-001’s gravity is trying to hold the rest of the galaxy together as it endures these harsh conditions.
Why isn’t the hot gas visible in the above image? Due to its high temperature, the gas emits most in x-rays. When the image is combined with Chandra X-Ray Observatory Data, the galaxy’s path through the hot gas becomes visible like the wake of a boat zipping across a lake:
Ram-pressure stripping is a key mechanism in understanding the evolution of galaxies in cluster environments. It is unknown whether ESO 137-001 will survive this particular encounter; sometimes such interactions lead to the complete destruction of galaxies that fall into such clusters. At a minimum, ESO 137-001 will probably be stripped of most of its gas, halting future star formation.
"We have almost doubled just today the number of planets known to humanity." NASA on Wednesday announced a flood of new discoveries from the exoplanet-hunting Kepler spacecraft, reporting 715 newly-verified planets orbiting 305 different stars. Four of the new planets are in their host stars’ habitable zones, leading to intriguing possibilities of their suitability for the emergence of life. Many of the planets are in multiple-planet ‘solar systems’ and some 95 percent range in size between Earth and Neptune. ”The Kepler team continues to amaze and excite us with their planet hunting results,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate.
Today’s announcement is among the last hurrahs of Kepler’s primary mission. Failures among the reaction wheels necessary for keeping the spacecraft trained on its target will soon result in a repurposing secondary mission known as “K2”.
A new visualization of the orbits of more than 100,000 asteroids from Sloan Digital Sky Survey data. Put together by UC Berkeley planetary astronomer and self-described “data visualization enthusiast” Alex Parker, the view in the video bobs above and below the plane of the Solar System in a little more than three minutes, while colored points representing asteroids detected by SDSS during its eight-year primary survey whirl around the absent Sun. The colors correspond to asteroid mineralogical types, showing the sorting of those types as a function of distance from the Sun. The magenta dots floating in two clouds beyond and apart from the others? Those are Trojan asteroids locked in orbit by the mutual gravity of Jupiter and the Sun, forever leading or trailing the largest planet. This stunning visualization is set to the ethereal “Tamxr” by LJ Kruzer.
The European Southern Observatory (ESO) has released a beautiful new image of the open star cluster Messier 7. This new view of a middle-aged star cluster (also known as “M7”) comes in the form of an ESO photo release. Using the MPG/ESO 2.2-metre telescope at La Silla Observatory in Chile, the image was taken with the Wide-Field Imager and shows a window of sky about 1° across, or twice as wide as a full Moon. The cluster stars are the big, (mostly) blue ones in the foreground, about 1000 light years away; the thousands of other, fainter stars are many times more distant as the line of sight in this view is one of the most dense through our Galaxy’s disk.
At 200 million years old, Messier 7 is a snapshot in the middle of the evolution of a typical star cluster: the gas and dust from which the stars formed are long gone, but the resulting stars are still near each other in space. The blue stars are evolving rapidly and will be the first to disappear, while the longer-lived cluster stars will slowly drift apart over the next billion years or so. According to the photo release, “As they age, the brightest stars in the picture — a population of up to a tenth of the total stars in the cluster — will violently explode as supernovae. Looking further into the future, the remaining faint stars, which are much more numerous, will slowly drift apart until they become no longer recognisable as a cluster.”
Dark skies are now protected right on Berlin’s doorstep. The International Dark Sky Association (IDA) announced today it has named Westhavelland Nature Park the world’s newest International Dark Sky Reserve. In Germany, the Reserve will be known as “Sternenpark Westhavelland.”
Westhavelland Nature Park is situated only 45 miles (70 km) west of Berlin, the most populous city in Germany, yet its sparse population and protected status put the experience of a dark night sky within easy reach of nearly six million people in the Berlin-Brandenburg Metropolitan Region. The new Dark Sky Reserve consists of a mix of 290 square miles (750 square kilometers) of public and private land within the Nature Park.
“Even though the communities in the Nature Park struggle with implementation challenges, they join us in the vision that dark nights are precious and worthy of protection,” said Park Superintendent Kordula Isermann. “That is especially significant because it takes guts to stand up for a dark night sky in Eastern Germany.”
The stars at night remain big and bright, deep in the heart of Texas. The International Dark Sky Association (IDA) today named Dripping Springs, Texas, an International Dark Sky Community — only the sixth so designated in the world.
Dripping Springs, about 25 miles west of Austin, bills itself as the “Gateway To The Hill Country” and is often the first stop in Texas for visitors coming from the east. “When people enter the Dripping Springs area at night, many of them notice something is different – the skies over the city are not spoiled by light pollution,” explained Todd Purcell, Mayor of Dripping Springs. “This is evidence that the city and the people who live in and near the city value the natural environment, including the beauty of the Hill Country and high quality of the night sky.”
The award was based on Dripping Springs’ adoption of good outdoor lighting policy and demonstration of broad community support for dark skies protection and conservation. In recognizing the city, IDA hopes it will serve as a model for other communities in Texas and beyond.
Today begins the Year of the Horse in Chinese culture. Marked by “lunar new year" (the first new moon after the start of a solar, or calendar, year), each year in the Chinese lunar calendar refers to one of twelve figures marking China’s traditional zodiac identifications.
In honor of the new year, above are depicted two celestial horses, Pegasus and Equuleus. The constellations are shown in an excerpt from Plate 10 of Johann Elert Bode's 1801 star chart Uranographia Sive Astrorum. Detailed scans of this atlas, held by many to be one of the most beautiful ever published, are available via the Linda Hall Library.
The dark night skies over southwest Ireland have been recognized as the world’s newest International Dark Sky Reserve. Today the International Dark Sky Association announced it has designated part of County Kerry as the “Kerry International Dark Sky Reserve”. It is the first of its kind in the northern hemisphere awarded “Gold-tier” status, placing it among an elite group of the darkest locations to receive IDA recognition.
The new Reserve sits on the Iveragh Peninsula, home to nearly 4,000 residents, and incorporates approximately 270 square miles (700 square km) of territory. The IDA designation is the result of a sustained, three-year campaign by the Kerry Dark Sky Group. Organization members dedicated countless hours educating local citizens, civic organizations and municipalities on the importance of dark-sky protection.
“The granting of this award will provide new opportunities to enjoy and experience the beauty of South West Kerry’s night sky,” says Julie Ormonde, Chairperson of the Kerry Dark Sky Group and Project Manager of the Reserve. “It will encourage other areas in Kerry, and in Ireland as a whole, to take positive action to protect their own dark-sky areas.”
Read the press release here (PDF).