Hubble Space Telescope on Track for Measuring the Expansion Rate of the Universe
Using the Hubble telescope, two international teams of astronomers are reporting major progress in converging on an accurate measurement of the universe's rate of expansion - a value that has been debated for over half a century.
These new results yield ranges for the age of the universe from 9-12 billion years and 11-14 billion years, respectively. The black and white photograph from a ground-based telescope shows the entire galaxy. The color image from the Hubble telescope shows a region in NGC 1365, a barred spiral galaxy located in a cluster of galaxies called Fornax. A barred spiral galaxy is characterized by a "bar" of stars, dust, and gas across its center. Astronomers used Cepheid variable stars in Fornax to estimate the cluster's distance from Earth, about 60 million light-years. Cepheids are bright, young stars that are used as milepost markers to calculate distances to nearby galaxies. Galaxy distances are important in calculating the universe's expansion rate and age.
Hubble Astronomers Unveil "Crab Nebula - The Movie"
Probing the mysterious heart of the Crab Nebula, the tattered remains of an exploding star, astronomers have found this object to be even more dynamic than previously understood. These findings are based on a cosmic "movie" assembled from a series of Hubble telescope observations.
The sequence of pictures is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab pulsar - the collapsed core of the exploding star - and the vast nebula of dust and gas that it powers. This picture, which reveals the inner parts of the Crab, represents one frame from the movie. The Crab pulsar is the star on the left [white dot] near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features.
Hubble Space Telescope Captures First Direct Image of a Star
This is the first direct image of a star other than the Sun. Called Alpha Orionis, or Betelgeuse, the star is a red super giant, a Sun-like star nearing the end of its life.
The Hubble picture reveals a huge ultraviolet atmosphere with a mysterious hot spot on the stellar behemoth's surface. The enormous bright spot, twice the diameter of the Earth's orbit, is at least 2,000 degrees Kelvin hotter than the star's surface.
Analyzing the pictures of some of the most distant galaxies in the universe, astronomers are uncovering intriguing new evidence that the Big Bang was followed by a stellar "baby boom."
Hubble's unprecedented measurement of the rate of star birth in remote galaxies, which existed when the cosmos was less than 10 percent its current age, supports the emerging view that the early universe had an active, dynamic youth where stars formed out of dust and gas at a ferocious rate. The graph is based on observations of distant galaxies made by the Hubble telescope and ground-based observatories. Hubble shows a steep rise in star birth that happened shortly after the Big Bang. The ground-based data show a precipitous decline in the star formation rate, beginning about 9 billion years ago and continuing to the present.
Though the brightest supernova in four centuries lit up the southern sky almost exactly 10 years ago on Feb. 23, 1987, astronomers have waited a decade for the ballooning fireball to become large enough ? about one-sixth of a light-year ? to be resolved from Earth's orbit with the Hubble telescope.
Hubble's sharp "eyes" have resolved a dumbbell-shaped structure ? one-tenth of a light-year long ? that consists of two blobs of debris expanding apart at nearly 6 million mph from each other. This Hubble picture shows the supernova, designated 1987A, and its neighborhood. The four frames follow the evolution of the supernova debris.
The Egg Nebula, also known as CRL 2688, is shown on the left as it appears in visible light and on the right as it looks in infrared light. Both Hubble views recount the last gasps of a dying, Sun-like star.
Objects like the Egg Nebula are helping astronomers understand how stars like our Sun expel carbon and nitrogen – elements crucial for life – into space. Studies on the Egg Nebula show that these dying stars eject matter at high speeds along a preferred axis and may even have multiple jet-like outflows. The signature of the collision between this fast-moving material and the slower, out-flowing shells is the glow of hydrogen molecules [the red material] captured in the right-hand image.
Hubble Reveals Invisible High-Speed Collision around Supernova 1987A
The highest velocity material expelled in a cataclysmic, stellar explosion 10 years ago has been detected for the first time by the Hubble telescope's imaging spectrograph.
The top image, taken with Hubble's visible-light camera, shows the orange-red rings surrounding Supernova 1987A in the Large Magellanic Cloud. The glowing debris of the supernova explosion, which occurred in February 1987, is at the center of the inner ring. The small, white square indicates the location of the imaging spectrograph aperture. The Hubble data in the middle panel [and a schematic representation in the bottom panel] shows the presence of glowing hydrogen expanding at a speed of 33 million mph (15,000 kilometers per second) coming from an extended area inside the inner ring.
Probing the heart of the active galaxy NGC 6251, the Hubble telescope has provided a never-before-seen view of a warped disk or ring of dust caught in a blazing torrent of ultraviolet light from a suspected massive black hole.
This discovery suggests that the environments around black holes may be more varied than thought previously and may provide a new link in the evolution of black holes in the centers of galaxies. This composite picture of the galaxy's core of the galaxy combines visible- and ultraviolet-light observations. While the visible-light image shows a dark dust disk, the ultraviolet image [color-coded blue] reveals a bright feature along one side of the disk. Because Hubble sees ultraviolet light reflected from only one side of the disk, astronomers conclude it must be warped like the brim of a hat. The bright white spot at the image's center is light from the vicinity of the black hole, which is illuminating the disk.
Astronomers using the Hubble telescope have taken their first direct look in visible light at a lone neutron star. This view offers a unique opportunity to pinpoint the star's size and to narrow theories about the composition and structure of this bizarre class of gravitationally collapsed, burned out stars.
The Hubble results show that the star [marked by white arrow] is very hot and can be no larger than 16.8 miles (28 kilometers) across. These findings prove that the object must be a neutron star, for no other known type of object can be this hot, small, and dim.
Astronomers have long been mystified by observations of a few hot, bright, apparently young stars residing in well-established communities where most of their neighbors are much older.
With the help of the Hubble telescope, astronomers now have evidence that may eventually help solve the 45-year-old mystery of how these enigmatic stars, called blue stragglers, were formed. For the first time, astronomers have confirmed that a blue straggler in the core of a globular cluster (a very dense community of stars) is a massive, rapidly rotating star that is spinning 75 times faster than the Sun. This finding provides proof that blue stragglers are created by collisions or other intimate encounters in an overcrowded cluster core. A ground-based telescope image
shows the crowded core of the globular cluster 47 Tucanae, which is teeming with blue stragglers. Peering into the heart of the cluster's brilliant core, Hubble separated the dense clump of stars into many individual stars
Hubble Witnesses the Final Blaze of Glory of Sun-Like Stars
The end of a Sun-like star's life was once thought to be simple: the star gracefully casts off a shell of glowing gas and then settles into a long retirement as a burned-out white dwarf.
Now, a dazzling collection of detailed views from the Hubble telescope reveals surprisingly intricate, glowing patterns spun into space by aging stars: pinwheels, lawn sprinkler-style jets, elegant goblet shapes, and even some that look like a rocket engine's exhaust. In this picture of M2-9, twin lobes of material emanate from a central, dying star. Astronomers have dubbed this object the "Twin Jet Nebula" because of the shape of the lobes. If the nebula is sliced across the star, each side appears much like a pair of exhausts from jet engines. Indeed, because of the nebula's shape and the measured velocity of the gas, in excess of 200 miles per second, astronomers believe that the description as a super-super-sonic jet exhaust is quite apt.
Astronomers Have Found a New Twist in a Suspected Proto-Planetary Disk
A telltale new warp uncovered in a vast, thin disk of dust encircling the star Beta Pictoris may be caused by the gravitational tug of a bypassing star or companion brown dwarf.
These conclusions are based on Hubble telescope pictures that reveal the dim outermost reaches of the disk, which are 7 billion miles from the central star. The top image presents the entire disk, which spans 140 billion miles edge-to-edge. An unusual flaring at the top of the right side of the disk reveals that dust has been pulled above the dense plane of the disk beyond what is observed on the left side. A detailed close-up view of the inner region of the disk [bottom picture] shows a warp in the disk. These new details support the presence of one or more planets orbiting the star.
Astronomers Discover an Infrared Background Glow in the Universe
Astronomers have assembled the first definitive detection of a background infrared glow across the sky produced by dust warmed by all the stars that have existed since the beginning of time. For scientists, the discovery of this "fossil radiation" is akin to turning out all the lights in a bedroom only to find the walls, floor, and ceiling aglow with an eerie luminescence.
The telltale infrared radiation puts a limit on the total amount of energy released by all the stars in the universe. Astronomers say this will greatly improve development of models explaining how stars and galaxies were born and evolved after the Big Bang. These three pictures are maps of the full sky as seen in infrared light. The top picture represents the brightness of the full sky as seen in infrared light. The middle picture is a view of the sky after the foreground glow of the solar system dust has been extracted. After the infrared light from our solar system and galaxy has been removed, what remains is a uniform, cosmic, infrared background.
The Hubble telescope is giving astronomers a ringside seat to a never-before-seen titanic collision of an onrushing stellar shock wave with an eerie glowing gas ring encircling a nearby stellar explosion, called supernova 1987A.
Though the star's self-destruction was first seen nearly 11 years ago on Feb. 23, 1987, astronomers are just now beginning to witness its tidal wave of energy reaching the "shoreline" of the immense light-year-wide ring. Shocked by the 40-million-mile-per-hour sledgehammer blow, a 100-billion-mile-wide knot of gas in a piece of the ring has already begun to "light up," as its temperature surges from a few thousand degrees to a million degrees Fahrenheit. For comparison, the Hubble image on the left was taken before the collision. The picture on the right shows a glowing ball of gas [denoted by arrow].
Gamma-Ray Burst Found to be Most Energetic Event in Universe
A team of astronomers has announced that a recently detected gamma-ray burst was as bright as the rest of the universe, releasing a hundred times more energy than previously theorized.
The team measured the distance to a faint galaxy from which the burst, designated GRB 971214, originated. It is about 12 billion light-years from Earth. The astronomers used a suite of satellites and ground-based telescopes to follow the burst. This Hubble image of the GRB 971214 field was taken about four months after the burst, well after the afterglow had faded away. The extremely faint and distant object marked with an arrow is the host galaxy of the gamma-ray burst.
Hubble Provides Multiple Views of How to Feed a Black Hole
Astronomers have obtained an unprecedented look at the nearest example of galactic cannibalism - a massive black hole hidden at the center of a nearby giant galaxy that is feeding on a smaller galaxy in a spectacular collision. Such fireworks were common in the early universe, as galaxies formed and evolved, but are rare today.
The Hubble telescope offers a stunning unprecedented close-up view of a turbulent firestorm of star birth along a nearly edge-on dust disk girdling Centaurus A, the nearest active galaxy to Earth. The picture at upper left shows the entire galaxy. The blue outline represents Hubble's field of view. The larger, central picture is Hubble's close-up view of the galaxy. Brilliant clusters of young blue stars lie along the edge of the dark dust lane. Outside the rift the sky is filled with the soft hazy glow of the galaxy's much older resident population of red giant and red dwarf stars.
Hubble Takes First Image of a Possible Planet around Another Star and Finds a Runaway World
The Hubble telescope has given astronomers their first direct look at what is possibly a planet outside our solar system - one apparently that has been ejected into deep space by its parent stars.
The discovery further challenges conventional theories about the birth and evolution of planets, and offers new insights into the formation of our own solar system. Located within a star-forming region in the constellation Taurus, the object, called TMR-1C, appears to lie at the end of a strange filament of light, suggesting it has apparently been flung away from the vicinity of a newly forming pair of binary stars.
A Bright Ring of Star Birth around a Galaxy's Core
This Hubble telescope snapshot reveals clusters of infant stars that formed in a ring around the core of the barred-spiral galaxy NGC 4314. This stellar nursery, whose inhabitants were created within the past 5 million years, is the only place in the entire galaxy where new stars are being born.
This close-up view also illustrates other interesting details in the galaxy's core: dust lanes, a smaller bar of stars, dust and gas embedded in the stellar ring, and an extra pair of spiral arms packed with young stars. These details make the center resemble a miniature version of a spiral galaxy. The black-and-white image on the left, taken by a ground-based telescope, shows the entire galaxy.
Hubble Space Telescope Helps Find Evidence that Neptune's Largest Moon Is Warming Up
Observations obtained by the Hubble telescope and ground-based instruments reveal that Neptune's largest moon, Triton, seems to have heated up significantly since the Voyager spacecraft visited it in 1989.
Even with the warming, no one is likely to plan a summer vacation on Triton, which is a bit smaller than Earth's moon. Since 1989 Triton's temperature has risen from about 37 on the absolute (Kelvin) temperature scale (-392 degrees Fahrenheit) to about 39 Kelvin (-389 degrees Fahrenheit). The scientists are basing a rise in Triton's surface temperature on the Hubble telescope's detection of an increase in the moon's atmospheric pressure, which has at least doubled in bulk since the time of the Voyager encounter. When Triton passed in front of a star known as "Tr180" in the constellation Sagittarius, Hubble measured the star's gradual decrease in brightness. The starlight became fainter as it traveled through Triton's thicker atmosphere, alerting astronomers to changes in the moon's air pressure.
Hubble Goes to the Limit In Search Of Farthest Galaxies
Stretching the Hubble telescope's vision farther across space and further back into time than ever before, astronomers have peered into a previously unseen realm of the universe.
A "long-exposure" infrared image has uncovered the faintest galaxies ever seen. Astronomers believe some of these galaxies could be the farthest objects ever seen. A powerful new generation of telescopes will be needed to confirm the suspected distances. The picture on the left contains over 300 galaxies, which have spiral, elliptical, and irregular shapes. The two images on the right represent close-up views of objects that may be over 12 billion light-years away, the farthest galaxies ever seen. Each faraway galaxy is centered in the frame.
