NASA, just like the rest of us, must balance a checkbook. Sometimes the unexpected occurs, requiring adjustments. A lot of input goes into deciding the finances for science missions. Scientists construct plans that span 10 years. NASA must balance its priorities and come up with realistic costs for the missions. Then Congress enters the act, placing constraints. Recently, the Bush administration mandated an exploration program, and the space shuttle program experienced a tragedy and numerous related problems. Budgeting became particularly complex. Earlier this year, NASA submitted a budget to Congress that eliminated the Stratospheric Observatory for Infrared Astronomy (SOFIA), a telescope mounted in a plane. On July 7, NASA Administrator Mike Griffin announced SOFIA would be restored, but at the cost of the Space Interferometry Mission (SIM), designed to measure the distances between stars.
The presence of two disks of dust around the star Beta Pictoris signals the possible existence of a Jupiter-sized planet around the distant star. A picture of disk galaxy NGC 5866 shows a crisp dust lane dividing the galaxy in two halves. Hubble's Advanced Camera for Surveys is back on track after a power failure took it out of service for two weeks. One of its latest images will help astronomers study the mysterious force known as dark energy. Get the details on these topics in this month?s HubbleWatch, your roundup of the latest Hubble Space Telescope science and discoveries.
Schedule some time outside on the evening of Aug. 12 to catch the annual Perseid meteor shower. The most-watched annual shower features 100 meteors per hour, but the light of this year?s full Moon will probably cut that down to 20 to 30 meteors per hour. Meteorites are bits of comet dust that burn up as they enter the Earth?s atmosphere.
Meteorites crash into the Moon all the time. NASA is trying to find out more about the impacts. Astronomers at Marshall Space Flight Center have monitoring the Moon?s nighttime side. The nighttime side is visible when the Moon is almost in its new moon phase that is, when the sunlit side of the Moon faces away from Earth. The observations are not easy. They can only be taken about 10 times per month. But the astronomers were lucky enough to observe a meteoroid strike in November 2005. They were also able to record a movie of another strike in May 2006.
Hubble?s Advanced Camera for Surveys, out of commission for almost two weeks after its primary power supply failed, is back to normal. NASA engineers were able to switch the camera to a backup power supply. The Advanced Camera for Surveys, or ACS, is Hubble?s newest instrument, installed in 2002. Its expanded wavelength range allows it to see in light ranging from ultraviolet to infrared. It was designed to study some of the earliest activity in the universe.
Astronomers combing through the archives of x-ray observations taken by the XMM-Newton telescope have found the most distant cluster of galaxies ever seen. The objects, embedded in hot gas that glows with x-rays, are located nearly 10 billion light years away. They offer a tantalizing glimpse of what galaxy clusters would have been like at the earliest stages of their formation. Strangely, though the cluster named XMM 2215-1738 must have formed when the universe was relatively young, its galaxies' colors indicate old age.
So what is a planet, exactly? Sure, we're familiar with Earth and Mars, Jupiter and Saturn. But recently astronomers have been discovering strange, small worlds at the far edges of our solar system. Some are close to Pluto in size - one is actually bigger. Do they all get to be called planets? If so, improving detection techniques could leave us with hundreds, even thousands, of "planets." At an upcoming meeting, astronomers hope to finally decide the definition of "planet."
Pluto's two newly discovered moons now boast the names of Nix and Hydra, after the goddess of the night and the nine-headed snake that guards the entrance of Hades. The gravitational power of a group of galaxies magnifies the light of a distant quasar and multiplies it into five distinct images. All the lights are on in the region of Arp 220, where a merger between two galaxies has birthed a multitude of new stars. Get the details on these topics in this month?s HubbleWatch, your roundup of the latest Hubble Space Telescope science and discoveries.
A rock carving discovered in Arizona might depict an ancient star explosion seen by Native Americans a thousand years ago. The carving, or "petroglyph" by the Hohokam people was discovered in White Tanks Regional Park just outside Phoenix. It could be the only known American record of the famed supernova of 1006 A.D., seen by stargazers in Asia, the Middle East and Europe. The 1006 supernova was possibly the brightest stellar event in human history, though little remains visible today.
Astronomers like to see galaxies at various angles, since certain angles present better views of galaxies' structures. Recently, Hubble took a picture of NGC 5866, an "edge-on" galaxy. Our view of the galaxy is almost level with its edge. The galaxy was imaged in a variety of filters so that its tight, dark dust lane, flattened disk of blue stars and extended halo can be identified. Close examination of the image shows a small red bulge surrounding the nucleus of NGC 5866 and numerous globular clusters in an extended region around the halo. Had the galaxy been seen face-on, it would have revealed little more detail than a flat disk. NGC 5866 is a spectacular example of an "S0" galaxy. S0 galaxies have features of both smooth, uniform elliptical galaxies and complex spiral galaxies. They were originally thought to be transition objects between the two types of galaxies. Scientists now believe they may actually form in a variety of ways.
Our Milky Way belongs to a cluster of about a dozen galaxies known as the Local Group. New discoveries keep increasing that cluster's number. Astronomers are finding more of the small dwarf galaxies that hover around our Milky Way. These dwarf galaxies, hidden among the stars, gas and dust of our own galaxy, are difficult to detect. But a new survey of the sky is helping astronomers pick out more of our galaxy's little companions.
An international team of professional and amateur astronomers, using simple, off-the-shelf equipment to search the skies for planets outside our solar system, has struck gold. The astronomers discovered a Jupiter-sized planet, named XO-1b, orbiting a Sun-like star 600 light-years from Earth in the constellation Corona Borealis. Using modest telescopes to search for extrasolar planets could create a collaboration between professional and amateur astronomers that would accelerate the quest to find extrasolar planets.
A comet the size of a city shatters into house-sized fragments under the Sun's caress. Supernova-sparked gamma ray bursts have the power to fry planets, but don't panic yet - our galaxy seems an unlikely candidate for such an explosion. Amateur astronomers, break out those telescopes; you can help locate planets beyond our solar system. Jupiter's renowned Great Red Spot has company - Red Spot Junior, another hurricane-like storm roaring through the atmosphere. Get the details on these topics in this month's HubbleWatch, your roundup of the latest Hubble Space Telescope science and discoveries.
A new meteorite the size of a beach ball has been discovered a half-mile below a giant crater in South Africa. The meteorite fragment has unusual qualities. First, it's largely unchanged by the extreme heat from its impact, while most giant meteorites are believed to vaporize or melt seconds after striking the Earth. Second, its chemical makeup is different from any other meteorite collected on Earth in the past. This new meteorite had to have been much larger when it crashed into Earth. At 10 inches, it would have created a crater only three miles across, but it was found in a crater 43 miles across.
A single, distant quasar can be seen five times in a recent Hubble Space Telescope picture, thanks to an effect called "gravitational lensing." The gravity of a cluster of foreground galaxies bends and amplifies the light from the more-distant quasar. Light from the quasar, the core of a galaxy powered by a supermassive black hole, is both magnified and bent, creating the five separate images.
Sunspots are dark regions, cooler than the rest of the Sun's surface, that appear and disappear. Every 11 years, the Sun cycles from spotty to clear and then back again. Sunspots bring increased solar storms, which can harm Earth satellites, communications and power, so understanding their cycles and strengths would be beneficial. But the Sun's 11 year cycle of sunspots and solar storms has always been difficult to predict accurately. Now scientists using new technology and new models may have done just that. Helioseismology, for instance, is a new technique that tracks sound waves reverberating inside the Sun to reveal details about its interior.
Ten billion miles away lies an object officially called 2003 UB313, but commonly known as Xena. Xena was discovered a few years ago, and since then, it's been carefully observed by a variety of telescopes. The Hubble Space Telescope recently nailed down the diameter of Xena at 1,490 miles, larger than Pluto's 1,422 miles. Xena is very reflective, almost like a mirror. From detailed observations of the reflected sunlight, it looks like Xena has a methane surface. It's possible that methane froze out of Xena's atmosphere, since it is so far away from the Sun. Xena also has a moon in orbit around it. The moon may help astronomers figure out the density of the object and draw further comparisons with Pluto.
Astronomers have discovered a tiny galaxy that appears to have an extremely energetic black hole at its center. It's not unusual for black holes to inhabit galactic centers, but this one is generating as much energy as those found in much larger galaxies. This rare find may help us better understand how galaxies evolve.
- A story from the National Radio Astronomy Observatory.
- The Very Large Array and the Apache Point Observatory?s 3.5 meter telescope studied the galaxy.
- Apache Point is home to the Sloan Digital Sky Survey, which also studied the tiny galaxy.
The Sun will be around for about another 5 billion years. After that, the Sun will have exhausted the hydrogen fuel it uses for fusion. Its outer atmosphere will swell, vaporizing the Earth's atmosphere and boiling the seas. Scientists wonder if there is a way to extend the Sun's life. Hydrogen is converted to helium during fusion, releasing energy in the Sun's core. This energy is transported through the surface. When the fuel is exhausted, a lot of hydrogen will still be left throughout the structure of the Sun. Perhaps scientists could figure out how to transport that unused hydrogen into the Sun's core. Alternately, smaller-mass stars burn their fuel more slowly. Is there a way to remove mass from the sun? Both ideas are pretty tricky since the Sun is comprised of hot plasma.
How small can an object be and still be called a star? Or, how big can an object be and still be considered a planet? Stars form from large, swirling clouds of gas and dust that have so much mass that they collapse. As the star forms, its interior becomes so hot that fusion begins. The star shines with its own fuel. Planets seem to form around stars. They seem to coalesce from the clumps of the material left over from the star formation process. Planets shine by reflecting light from their parent star. Somewhere in between planets and stars are brown dwarfs. Astronomers are trying to find these objects to help them better understand how stars and planets form. Current theory suggests that brown dwarfs form like stars, but never obtain enough mass to ignite the fusion process. New observations of two brown dwarfs orbiting together allowed scientists to measure the masses of the objects. The observations confirm the theory that brown dwarfs start out as star-sized objects, but shrink and cool, becoming increasingly planet-sized as they age.