Astronomers using NASA's Hubble Space Telescope have solved a 40-year mystery on the origin of the Magellanic Stream, a long ribbon of gas stretching nearly halfway around our Milky Way galaxy.
The Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way, are at the head of the gaseous stream. Since the stream's discovery by radio telescopes in the early 1970s, astronomers have wondered whether the gas comes from one or both of the satellite galaxies. Now, new Hubble observations reveal that most of the gas was stripped from the Small Magellanic Cloud about 2 billion years ago, and a second region of the stream originated more recently from the Large Magellanic Cloud. (More at Hubble Site)
Hubble Sees True Shapes of Galaxies 11 Billion Years Back in Time
Looking 11 billion years back in time to when the universe was very young, astronomers have found that the anatomy of distant galaxies is not that different from galaxies seen in the nearby universe today. The results come from the Hubble Space Telescope Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). The largest project in the history of Hubble, it aims to explore galactic evolution in the early universe, and the very first seeds of cosmic structure at less than 1 billion years after the Big Bang.
Previous studies of this early epoch were inconclusive because they were limited to visible light. Because of the stretching of light by the expansion of the universe the visible light detected in distant galaxies actually maps only the ultraviolet emissions of the galaxies. Because this radiation only comes from regions of active star formation the galaxies appeared to be clumpy and messy, with no resemblance to the galaxy shapes we see around us today. By observing the galaxies in infrared light with Hubble's Wide Field Camera 3, astronomers could observe how these distant galaxies would appear normally in visible light if their radiation were not stretched to infrared wavelengths by the expanding universe. For more information about this study, visit: Hubble explores the origins of modern galaxies - Astronomers see true shapes of galaxies 11 billion years back in time . (More at Hubble Site)
The universe is so big, and it takes so long for most celestial objects to change, that it is rare a telescope can catch something in motion. It helps if the target is moving at nearly the speed of light, and that the Hubble Space Telescope's crystal-clear view can catch subtle changes in one-tenth the time it might take for a ground-based telescope. Astronomers collected 500 Hubble pictures, taken over 13 years to make a movie flipbook of a blowtorch-like jet of gas blasted from the vicinity of a supermassive black hole. The black hole resides in the center of the galaxy M87. The jet has been known about for nearly a century. But the new Hubble movie provides a look at the jet's dynamics. The movie shows that the hot plasma is spiraling along magnetic field lines generated by the 7-billion-solar-mass black hole. These so-called extragalactic jets are seen elsewhere in the universe, but this comparatively nearby jet is offering a detailed look at what powers and aligns them. When Lick Observatory astronomer Heber Curtis first saw the jet in 1918 he described it as "a curious straight ray." Little might Curtis have imagined that we'd someday follow it blazing across space. (More at Hubble Site)
This light-year-long knot of interstellar gas and dust resembles a caterpillar on its way to a feast. But the meat of the story is not only what this cosmic caterpillar eats for lunch, but also what's eating it. Harsh winds from extremely bright stars are blasting ultraviolet radiation at this 'wanna-be' star and sculpting the gas and dust into its long shape. (More at Hubble Site)
Some Planetary Nebulae Have Bizarre Alignment to Our Galaxy
Hubble astronomers have found an unexpected surprise while surveying more than 100 planetary nebulae in the central bulge of our Milky Way galaxy. Those nebulae that are butterfly-shaped or hourglass-shaped tend to be mysteriously aligned such that their rotation axis is perpendicular to the plane of our galaxy.
Planetary nebulae are the expanding gaseous shrouds encircling dying stars. A subset of this population has bipolar outflows that align to the star's rotation axis. Such nebulae formed in different places and have different characteristics and so it is a puzzle why they should always point on the same sky direction, like bowling pins set up in an alley.
Researchers suggest that there is something bizarre about star systems within the central hub of our galaxy. They would all have to be rotating perpendicular to the interstellar clouds from which they formed. At present, the best guess is that the alignment is caused by strong magnetic fields that were present when the galactic bulge formed billions of years ago.
Hubble Uncovers Largest Known Population of Star Clusters
Ten years ago, astronomer John Blakeslee spotted dots of light peppered throughout images of a giant cluster of galaxies, called Abell 1689. Each dot was not one star, but hundreds of thousands of stars crowded together in groupings called globular clusters. Blakeslee counted 500 such clusters, the brightest members of a teeming population of globular clusters.
Now, a new Hubble census of globular clusters in Abell 1689 reveals that an estimated 160,000 such groupings are huddled near the galaxy cluster's core. The Hubble observations break the record for the farthest and the most globular clusters ever seen. Globular clusters are the homesteaders of galaxies, containing some of the oldest surviving stars in the universe. These stellar relics are important to study because they help reveal the story of galaxy formation in the early universe. By comparison, only 150 globular clusters orbit the Milky Way galaxy. (More at Hubble Site)
Hubble and Chandra Find Evidence for Densest Galaxy in Nearby Universe
Astronomers may have found the densest galaxy in the nearby universe. The galaxy, known as M60-UCD1, is located near a massive elliptical galaxy NGC 4649, also called M60, about 54 million light-years from Earth. This composite image shows M60 and the region around it, where data from NASA's Chandra X-ray Observatory are pink and data from NASA's Hubble Space Telescope are red, green, and blue. The Chandra image shows hot gas and double stars containing black holes and neutron stars, and the Hubble image reveals stars in M60 and neighboring galaxies including M60-UCD1. The arrow points to M60-UCD1.
Packed with an extraordinary number of stars, M60-UCD1 is an "ultra-compact dwarf galaxy." It is one of the most massive galaxies of its kind, weighing 200 million times more than our Sun, based on observations with the Keck 10-meter telescope in Hawaii. Remarkably, about half of this mass is found within a radius of only about 80 light-years. This would make the density of stars about 15,000 times greater than found in Earth's neighborhood in the Milky Way, meaning that the stars are about 25 times closer. For more information about M60-UCD1, visit Chandra Press Room :: NASA's Hubble and Chandra Find Evidence for Densest Nearby Galaxy :: 24 September 13 . (More at Hubble Site)
Water-rich Planetary Building Blocks Found Around White Dwarf
If you go walking along the beach or take an ocean cruise, it's hard to believe that Earth is essentially a "dry" planet. Barely 0.02 percent of our home planet's mass is surface water. In fact, our oceans came along a few hundred million years after Earth formed 4.6 billion years ago. Though still debated, astronomers think that the primeval Earth was most likely irrigated when water-rich asteroids in the solar system crashed into our planet.
Now astronomers have found that the same water "delivery system" could have occurred in a dying star's planetary system. Hubble Space Telescope spectroscopic observations have found forensic evidence for the same kind of water-rich asteroids that may have once brought water to Earth. Observations made with Hubble's Cosmic Origins Spectrograph (COS) allowed the team of astronomers to do a robust chemical analysis of debris falling into the white dwarf star GD 61, located 150 light-years from Earth. They didn't detect planets but the building blocks of planets. The asteroids are plummeting deep into the gravitational field of the white dwarf, presumably due to gravitational perturbations from a surviving Jupiter-sized planet in the system. This is circumstantial evidence that potentially habitable planets once existed in this star system. However, the star burned out 200 million years ago. (More at Hubble Site)
Dr. Jason Kalirai Selected as One of Baltimore's Future Visionaries
Astronomer Dr. Jason Kalirai of the Space Telescope Science Institute (STScI) has been cited by Baltimore Magazine as one of the "top 40 under 40" up-and-comers in the Baltimore metropolitan region. The selection, which the magazine does every five years, looks at young Baltimore professionals in a diversity of fields who in the editor's opinion are an exceptional selection of people that will have an important impact on the future. The 35-year-old Kalirai was selected from several hundred potential candidates to be highlighted in the magazine's October issue. (More at Hubble Site)
Most Distant Gravitational Lens Helps Weigh Galaxies and Deepens a Galactic Mystery
An international team of astronomers has found the most distant gravitational lens yet a galaxy that, as predicted by Albert Einstein's general theory of relativity, deflects and intensifies the light of an even more distant object. The discovery provides a rare opportunity to directly measure the mass of a distant galaxy. The observation also poses a mystery: lenses of this kind should be exceedingly rare. Given this and other recent finds, astronomers either have been phenomenally lucky or, more likely, they have underestimated substantially the number of small, very young galaxies in the early universe.
The team is composed of Arjen van der Wel, Glenn van de Ven, Michael Maseda, and Hans-Walter Rix (Max Planck Institute for Astronomy [MPIA]), Gregory Rudnick (University of Kansas and MPIA), Andrea Grazian (INAF), Steven Finkelstein (University of Texas at Austin), David Koo and Sandra M. Faber (University of California, Santa Cruz), Henry Ferguson, Anton Koekemoer, and Norman Grogin (STScI), and Dale Kocevski (University of Kentucky). For more information about this study, visit Max-Planck-Institut für Astronomie and Most distant gravitational lens helps weigh galaxies - but deepens a galactic mystery. (More at Hubble Site)
A new image of the sunward plunging Comet ISON taken by NASA's Hubble Space Telescope on October 9, 2013, suggests that the comet is intact despite some predictions that the fragile icy nucleus might disintegrate as the Sun warms it. The comet will pass closest to the Sun on November 28.
Galaxy Found in Hubble Survey Has Farthest Confirmed Distance
A team of astronomers has discovered a galaxy that sets the current distance record for galaxies whose distance has been definitively measured by spectroscopic redshift. The galaxy is seen as it was at a time just 700 million years after the Big Bang, when the universe was only about 5 percent of its current age of 13.8 billion years. This galaxy and dozens of others were selected for follow-up observations from the approximately 100,000 galaxies discovered in the Hubble Space Telescope CANDELS survey (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey). The team used the Keck I Telescope in Hawaii to measure the redshift of the CANDELS galaxy, designated z8_GND_5296, at 7.51. This is the highest galaxy redshift ever confirmed. The spectral redshift of galaxies is caused by the expansion of space from the Big Bang.
NASA's Great Observatories Begin Deepest Ever Probe of the Universe
NASA's Great Observatories are teaming up to look deeper into the universe than ever before. With a boost from natural "zoom lenses" found in space, they should be able to uncover galaxies that are as much as 100 times fainter than what the Hubble, Spitzer, and Chandra space telescopes can typically see.
This ambitious collaborative program is called The Frontier Fields. Astronomers will spend the next three years peering at six massive clusters of galaxies. Researchers are interested not only as to what's inside the clusters, but also what's behind them. The gravitational fields of the clusters brighten and magnify distant background galaxies that are so faint they would otherwise be unobservable.
Despite several deep field surveys, astronomers realized that a lot is still to be learned about the distant universe. And, such knowledge will help in planning the observing strategy for the next-generation space observatory, the James Webb Space Telescope.
Join several members of the Frontier Fields collaboration during the live Hubble Hangout event at 4:00pm (EDT) on Thursday, October 24 to discuss more on what's to come from these observations, how the clusters were chosen, and what we hope to learn from them. Visit:https://plus.google.com/u/0/events/cpl8pr6rjvls7en3c9ltrgelc80 . (More at Hubble Site)
Hubble's New Shot of Proxima Centauri, Our Nearest Neighbor
Proxima Centauri lies in the constellation of Centaurus (the Centaur), just over four light-years from Earth. Although it looks bright through the eye of the Hubble Space Telescope, as you might expect from the nearest star to the solar system, Proxima Centauri is not visible to the naked eye. Its average luminosity is very low, and it is quite small compared to other stars, at only about an eighth of the mass of the Sun. These observations were taken using Hubble's Wide Field and Planetary Camera 2 (WFPC2) in 1996. Proxima Centauri is actually part of a triple star system – its two companions, Alpha Centauri A and B, lie out of frame.
NASA's Hubble Sees Asteroid Spout Six Comet-like Tails
It's not often that astronomers stumble across a celestial interloper that they can only describe as "weird and freakish." Hubble researchers say they were "literally dumbfounded" when they took a close-up look at an object that lives in the asteroid belt but superficially looks like a comet. It has no less than six dust tails that seem to be forming sequentially. The entire structure rotates like a bicycle wheel with spokes on one side.
One explanation is that the tails formed through a series of impulsive dust-ejection events. These could have been triggered when the gentle nudge of sunlight spun up the asteroid to the point where dust is falling off the surface and into space. Solar radiation stretches the dust into finger-like streamers. (More at Hubble Site)
Hubble Reveals First Scrapbook Pictures of Milky Way's Formative Years
According to new Hubble Space Telescope observations of our Milky Way's siblings, which existed long ago, the night sky must have looked much emptier in the distant past, when our galaxy was still under construction. The vast majority of our Milky Way's stars had not yet been born. Yet the heavens were ablaze with a firestorm of new star formation.
By tracing the Milky Way's siblings, astronomers find that our galaxy built up most of its stars between 11 billion and 7 billion years ago. The Hubble telescope's superb resolving power allowed the researchers to study how the structure of Milky Way-like galaxies changed over time. The observations suggest that our galaxy's flat disk and central bulge grew simultaneously into the majestic spiral galaxy of today. (More at Hubble Site)
Dr. Jason Kalirai Honored as 2013 Outstanding Young Scientist
Dr. Jason Kalirai, James Webb Space Telescope Project Scientist at the Space Telescope Science Institute and associate researcher at the Center for Astrophysical Sciences at the Johns Hopkins University in Baltimore, Md., will be presented the 2013 Annual Outstanding Young Scientist (OYS) award by the Maryland Academy of Sciences and the Maryland Science Center on Nov. 20.
The OYS award program was established in 1959 and recognizes Maryland residents who have distinguished themselves early in their careers for accomplishments in science. Award recipients are chosen by members of the Maryland Academy of Sciences' Scientific Advisory Council, which provides expertise and content review to the Maryland Science Center in Baltimore, Md. Kalirai will share this year's award with Dr. Claire E. Cramer of the National Institute of Standards and Technology. (More at Hubble Site)
Astronomers using the combined power of NASA's Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA) telescope have discovered a far-flung trio of primitive galaxies nestled inside an enormous blob of primordial gas. The rare triple system existed when the universe was only 800 million years old. The trio may eventually merge into a single massive galaxy, researchers predict. The researchers state that the system provides key insights into the earliest stages of galaxy formation.
Hubble Traces Subtle Signals of Water on Hazy Worlds
Astronomers continue to tally up how many planets are orbiting other stars. But finding out what their atmospheres are made of is another story. Two teams of scientists using the Hubble Space Telescope have found faint signatures of water in the atmospheres of five distant exoplanets. The planets are not the size of Earth, but rather massive worlds known as hot Jupiters because they orbit so close to their stars. Hubble's instruments can deduce the types of gases in the atmospheres of these monsters by determining which colors of a star's light are transmitted and which are partially absorbed as the planet passes in front of its star. The observations demonstrate Hubble's continuing exemplary performance in exoplanet research.
Hubble Space Telescope Sees Evidence of Water Vapor Venting off Jovian Moon
Though it's five times farther from the Sun than Earth, and therefore so cold that ice becomes as hard as rock, Jupiter's moon Europa may be the first place to go to look for extraterrestrial life. Ever since the moon, which superficially resembles a cracked eggshell, was photographed close-up by the Voyager space probe, scientists have been intrigued by its potential as a niche for life.
For over the past 30 years it has been hypothesized that the icy crust covers a subsurface ocean. Where there is water there could be life. Now NASA's Hubble Space Telescope has found something the Jovian probes may have missed, plumes of water vapor leaking off into space near the moon's south pole. Astronomers do not know yet if these gas plumes are connected to subsurface liquid water or not. This venting doesn't seem unique. In 2005, NASA's Cassini orbiter discovered similar water vapor plumes spewing off of the tiny moon Enceladus, 1 billion miles away. (More at Hubble Site)
