In the year 2001 Davis Disnes and his colligues detected VIRG0H121 in the virgo culster about 5 million light years away - an invisible galaxy made almost entirely of dark matter - the first ever detected. A dark galaxy is an area in the universe containing a large amount of mass that rotates like a galaxy, but contains no stars. Without any stars to give light, it could only be found using radio telescopes. The big Question is does a Dark Galaxy really exist? Devoid of light and gas? The question is associated with understanding how the universe bloosomed from the big bang as we consider. According to increasingly refined story 85% of the matter in the universe is not ordinary baryonic matter-that makes up galaxies and stars and planets. Rather it is dark matter. As the universe grew from its infancy, the dark matter condensed in to enormous filaments like tubes, clumps and haloes. These weighty objects pooled in hydrogen gas which formed the galaxies and stars. Simulations show that dark matter should have myriad clumps between 1/1000 and 1/1000,000 as massive as our milky way galaxy. At first these small haloes should have accumulated gas and lit up as small dwarf galaxies thousands of which should whiz around Milky Way. So far astronomy could have few near by. Various factors kept the small halos dark. So space should have many dark galaxies.
Rocky planets, possibly with conditions suitable for life, may be more common than previously thought in our galaxy, a study has found. New evidence suggests more than half the Sun-like stars in the Milky Way could have similar planetary systems. There may also be hundreds of undiscovered worlds in outer parts of our Solar System, astronomers believe. If there are hundreds of planets and dwarf planets waiting to be discovered in the outer reaches of our own solar system, untold billions in the rest of the milky way.
http://news.bbc.co.uk/1/hi/sci/tech/7249884.stm
Astronomers using the Hubble Space Telescope are examining one of the largest structures in the universe as part of a quest to understand the violent lives of galaxies. Hubble is providing evidence of unseen dark matter tugging on galaxies in the crowded, rough-and-tumble environment of a massive supercluster of hundreds of galaxies. Dark matter is an invisible form of matter that accounts for most of the universe’s mass. Hubble’s Advanced Camera for Surveys has mapped the invisible dark matter scaffolding superclusters as well as the detailed structure of individual galaxies embedded in it.
The dark matter map was constructed by measuring the distorted shapes of over 60,000 faraway galaxies. To reach Earth, the galaxies’ light traveled through the dark matter that surrounds the supercluster galaxies and was bent by the massive gravitational field. Heymans used the observed, subtle distortion of the galaxies’ shapes to reconstruct the dark matter distribution in the supercluster using a method called weak gravitational lensing. The dark matter map is 2.5 times sharper than a previous ground-based survey of the supercluster.
Supernova explosions pose a threat to human life, however small. When a star explodes, most of its energy will be absorbed in the vast emptiness of space. Cosmic rays would be diffused by magnetic fields, and most of the damaging light would not affect life on Earth. But it is believed long-term exposure to blue-enhanced light could interfere with life. Those who study chronobiology, or the effects of biological timing, have found that low levels of blue light can strongly affect the endocrine systems of mammals by causing physiological and alerting responses. Blue-enhanced light is associated with reduced levels of melatonin production and affects circadian rhythms. For these reasons, it is sometimes prescribed to counteract seasonal affective disorder (SAD) or winter depression. Blue light can increase insomnia, reduce resistance to infection and is being studied as a possible risk of cancer.
Mysterious ‘Blue Lights’ discovered about 12 million light-years away are clusters of orphan stars that formed in an unlikely part of the universe. An analysis of archived high-resolution images from the Hubble Space Telescope have revealed that the stars were clusters of mostly young stars. Scientists were surprised by the find, because the clusters of massive stars sit along a wispy bridge of gases it collided with 200 million years ago. This means that the stars are in the middle of a great void.
Astronomers have now found new evidence of matter that spirals outward from a young star like a jetstream. Due to this spiral motion, the jets help the star to grow by drawing momentum from the surrounding disk. Angular momentum is the tendency for a spinning object to continue spinning. It applies to star formation because a star forms at the center of a rotating disk of hydrogen gas. A star grows by gathering material from the disk. However, gas cannot fall inward toward the star until that gas sheds its excess angular momentum. As hydrogen nears the star, a fraction of the gas is ejected outward perpendicular to the disk in opposite directions, like water from a fire hose, in a bipolar jet. If the gas spirals around the axis of the jet, then it will carry angular momentum with it away from the star.
10. CONSTELLATION BUILDS SYSTEMS FOR RETURN TO MOON
NASA began laying the foundation for the future of space exploration in 2007. Construction projects across the agency supported the Constellation Program, which is developing next-generation spacecraft and systems to return astronauts to the moon by 2020.
9. AN HISTORIC HANDSHAKE BETWEEN WOMEN COMMANDERS
Space Shuttle Commander Pam Melroy and the International Space Station’s Expedition 16 Commander Peggy Whitson made history Oct. 25 when shuttle Discovery and the station docked, and the hatches between the two ships were opened. As the two women shook hands 200 miles above Earth, they became the first female spacecraft commanders to lead shuttle and station missions simultaneously.
8. RISE OF THE PHOENIX
NASA’s Phoenix mission launched Aug. 4 from Cape Canaveral Air Force Station in Florida on a nine-month trek to Mars. The robotic lander is scheduled to arrive at the Red Planet May 25, 2008, and begin a close examination of Mars’ northern polar region.
7. INTERNATIONAL SPACE STATION KEEPS ON GROWING
NASA launched three successful space shuttle missions in June, August and October to deliver pieces of the International Space Station, allowing it to grow in size, volume and power production in 2007. The electricity generated by the station and used aboard the outpost more than doubled this year.
6. COLD AS ICE
Scientists using NASA satellites discovered an extensive network of waterways beneath a fast-moving Antarctic ice stream. The waterways provide clues as to how “leaks” in the system affect sea level and the world’s largest ice sheet. Data from the Moderate Resolution Imaging Spectroradiometer instrument aboard NASA’s Aqua satellite and data from the Geoscience Laser Altimeter System on NASA’s Ice Cloud and Land Elevation Satellite provided a multi-dimensional view of changes in the elevation of the icy surface above a large subglacial lake and surrounding areas during a three-year period.
5. CIRCUIT CHIP BREAKTHROUGH
NASA researchers designed and built a new silicon carbide differential amplifier integrated circuit chip that has exceeded 4,000 hours of continuous operation at 500 degrees Celsius - a breakthrough that represents a 100-fold increase in what had been achieved previously. Prior to this development, such integrated circuit chips had operated at these high temperatures for only a few hours or less before degrading or failing.
4. NEW HUMAN SPACEFLIGHT RECORDS
Two new human spaceflight milestones were set by NASA astronauts in 2007. Sunita Williams, the International Space Station’s Expedition 14 and Expedition 15 flight engineer, broke the record for the longest duration single spaceflight by a woman, spending 195 consecutive days in orbit. She also completed the most spacewalks by a woman, logging 29 hours and 17 minutes during four spacewalks, and was the first astronaut to run a marathon while in orbit.
3. STAR POWER
The brightest stellar explosion ever recorded was seen by NASA’s Chandra X-ray Observatory and ground-based optical telescopes. The discovery indicates that violent explosions of extremely massive stars were relatively common in the early universe, and a similar explosion in our own galaxy could be imminent. This new supernova may offer a rare glimpse of how the first stars died. It is unprecedented to find such a massive star and witness its death.
2. ADVANCED NEW AIRCRAFT DESIGN FLIES SUCCESSFULLY
NASA’s Aeronautics Research Mission Directorate, with the Air Force Research Lab and Boeing Phantomworks, successfully completed flight experiments for the X-48B Blended Wing Body advanced aircraft at NASA’s Dryden Flight Research Center this year. The aircraft is a hybrid configuration combining the best attributes of a conventional tube-and-wing aircraft with a flying wing.
1. GLOBAL EXPLORATION STRATEGY UNVEILED
NASA and 13 space agencies from around the world released the framework for a global exploration strategy in May 2007. The document, “The Global Exploration Strategy: The Framework for Coordination,” reflects a shared vision of space exploration focused on solar system destinations where humans may someday live and work. It represents an important step in an evolving process toward a comprehensive global approach.
Astronomers have discovered a cluster of orphan stars which are forming in a tail of gas far from its parent galaxy. The discovery of these stars suggests that ‘orphan’ stars may be more common than first thought. The tail extends more than 210,000 light years and was created as gas was stripped from a galaxy called ESO 137-001. The gas in the tail has formed millions of stars. Because of the large amount of gas and dust required to form stars astronomers have previously thought it was unlikely for a large numbers of stars to form outside a galaxy.