New Scientist has the story, including this video.
Launched in September of 2007, and propelled by any one of a trio of hyper-efficient ion engines, NASA's Dawn spacecraft passed the orbit of Mars last summer. At that time, the asteroid belt (where Dawn's two targets, asteroid Vesta and the dwarf planet Ceres reside), had never been closer. In early July the spacecraft began to lose altitude, falling back towards the inner solar system. Then on October 31, 2008, after 270 days of almost continuous thrusting, the ion drive turned off.
"Not only are our thrusters off and we are dropping in altitude, we are plunging toward Mars," said Marc Rayman, the Dawn project's chief engineer from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "And everybody here on Dawn could not be happier."
The team's joy at plummeting towards a planet named for the Roman god of war is not unfounded. Mars, the final stop for many a NASA spacecraft, was always an important, and weighty, waypoint for the Dawn mission. It all has to do with one of the heavy subjects of rocket science, gravity assists.
A gravity assist is the use of the relative movement and gravity of a planet or other celestial body to alter the path and speed of a spacecraft, typically in order to save fuel, time and expense. A spacecraft traveling to an outer planet (or in this case asteroid) will decelerate because the incessant tug of the sun's gravity slows it down. By flying a spacecraft close by a large planet and its large gravity field, some of the planet's speed as it orbits the sun is transferred to the spacecraft. In Dawn's case, it is using the Red Planet's tremendous angular momentum (the speed at which Mars orbits the sun) to give it a little extra oomph.
"A big oomph actually," said Rayman. "The gravity of Mars will change Dawn's path about the sun, enlarging its elliptical orbit and sending the probe farther from the sun. It will also change Dawn's orbital plane by more than 5 degrees. This is important because Dawn has to maneuver into the same plane in which Vesta orbits the sun."
Here's the rest of the story. Thanks, Will.
Explanation: A jewel of the southern sky, the Great Carina Nebula, aka NGC 3372, spans over 300 light-years, one of our Galaxy's largest star forming regions. Like the smaller, more northerly Great Orion Nebula, the Carina Nebula is easily visible to the unaided eye, though at a distance of 7,500 light-years it is some 5 times farther away. This stunning telescopic view from the 2.2-meter ESO/MPG telescopeLa Silla Observatory in Chile reveals remarkable details of the region's glowing filaments of interstellar gas and dark cosmic dust clouds. The Carina Nebula is home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun. Eta Carinae is the bright star left of the central dark notch in this field and near the dusty Keyhole Nebula (NGC 3324).
Albert Einstein may have written his last scientific theory more than half a century ago, but he's still honing his emotional intelligence in a laboratory at the University of California, San Diego.
Scientists at UC San Diego's California Institute for Telecommunications and Information Technology (Calit2) have equipped a robot modeled after the famed theoretical physicist with specialized software that allows it to interact with humans in a relatively natural, conversational way. The so-called "Einstein Robot," which was designed by Hanson Robotics of Dallas, Texas, recognizes a number of human facial expressions and can respond accordingly. Scientists consider it an unparalleled tool for understanding how both robots and humans perceive emotion, as well as a potential platform for teaching, entertainment, fine arts and even cognitive therapy.
"In the short-term, Einstein is being used to develop computer vision so we can see how computers perceive facial expressions and develop hardware to visually react," says Javier Movellan, a research scientist in the Calit2-based UCSD Machine Perception Laboratory (MPL). "This robot is a scientific instrument that we hope will tell us something about human-robot interaction, but also human-to-human interaction.
The Einstein Robot — a head-and-shoulders automaton complete with unruly white hair and bushy mustache — made its public debut at the Technology, Entertainment and Design (TED) conference in Long Beach last week. David Hanson, the robot's primary designer and owner of Hanson Robotics, amazed a crowd of 1,500 with Einstein's capacity to understand and mimic expressions. Several graduate students from the MPL accompanied Hanson to the conference, which was established to facilitate creative collaborations among scientists, entrepreneurs and designers.
Click here for more information, including a video of the Einstein robot.
Data from the Mars Reconnaissance Orbiter (MRO) suggest the discovery of ancient springs in the Vernal Crater, sites where life forms may have evolved on Mars, according to a report in Astrobiology, a peer-reviewed journal.
Hot springs have great astrobiological significance, as the closest relatives of many of the most ancient organisms on Earth can thrive in and around hydrothermal springs. If life forms have ever been present on Mars, hot spring deposits would be ideal locations to search for physical or chemical evidence of these organisms and could be target areas for future exploratory missions.
In the research paper entitled, "A Case for Ancient Springs in Arabia Terra, Mars," Carlton C. Allen and Dorothy Z. Oehler, from the Astromaterials Research and Exploration Science Directorate at the NASA Johnson Space Center, Houston, Texas, propose that new image data from the High Resolution Imaging Science Experiment (HiRISE) on MRO depict structures in Vernal Crater that appear to have arisen as part of a major area of ancient spring activity. The data suggest that the southern part of Vernal Crater has experienced episodes of water flow from underground to the surface and may be a site where martian life could have developed.
"Hot spring deposits are key target areas for future Mars missions," says Sherry L. Cady, PhD, Editor of Astrobiology and Associate Professor in the Department of Geology at Portland State University. "Such deposits on Earth preserve evidence of the fossilized remains of the microbial communities that inhabited the hot springs over a wide range of spatial scales. The potential to find key evidence indicative of life––biofabrics, microbial remains, chemical fossils in minerals––is high when sedimentary deposits form from hydrothermal fluids. Hot spring fluids are typically laden with dissolved mineral ions that, when they precipitate out and create the hydrothermal deposit, enhance fossilization of all types of biosignatures."
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The light reflected off of vegetation could be a signal of life on an alien planet. Researchers have now shown that this plant life signal can be seen even if a world is in the midst of an ice age.
Could an alien astronomer have detected life on Earth during an ice age? Recent work has calculated how past climate extremes affected the light reflected from vegetation out into space. The results could give hope to our own search for life on distant worlds.
From far away, our planet is a single faint speck of light in the sky. Although we have sent radio messages out to potential extraterrestrial listeners, none of these signals have traveled more than a few tens of light years.
However, Earthlings have been broadcasting their presence to the galaxy for millions of years. Terrestrial plants reflect strongly in the infrared, resulting in a distinctive feature (called the vegetation red edge or VRE) in the light bouncing off the Earth's surface.
Although sonic boom research has progressed rapidly since the early 1950's, the complete suppression of sonic booms at ground level by means of present technology does not appear imminent. This does not mean that sonic booms are always heard in conjunction with supersonic flight. Some meteorological factors occasionally could reduce sonic boom intensities or, even more rarely, prevent sonic booms from reaching the ground at all. However, the reported total absence of sonic booms from UFOs in supersonic flight and undergoing rapid accelerations or intricate maneuvers, particularly near the earth's surface, cannot be explained on the basis of current knowledge. On the contrary, intense sonic booms are expected under such conditions.
NASA has completed a delicate set of flight tests to measure how modifications to an F-15 jet can affect the way shock waves form. The results could help turn sonic booms into distant rumbles.
The measurements will be used to calibrate a computer model of shock wave propagation which will be a crucial aid for engineers designing a new generation of quieter supersonic aircraft. "We're pretty close to being able to control sonic booms," says Peter Coen of NASA's Langley Research Center in Virginia, principal investigator for the agency's supersonic research programme.
"Skeptic does not mean him who doubts, but him who investigates or researches as opposed to him who asserts and thinks that he has found." [Miguel de Unamuno, "Essays and Soliloquies," 1924]
Quite simply, the "skeptics" of today suffer a poverty of both imagination and curiosity
"I am Locutus of Borg. Resistance is futile. Your life as it has been is over. From this time forward, you will service us." - Locutus of Borg.
"Strength is irrelevant. Resistance is futile...Your culture will adapt to service ours." -- The Borg.
This spectacular new image of an unusual spiral galaxy in the Coma galaxy cluster has been created from data obtained by the Advanced Camera for Surveys on the Hubble Space Telescope. It reveals fine details of the galaxy, NGC 4921, and an extraordinary rich background of more remote galaxies stretching back to the early Universe.
The Coma galaxy cluster, in the northern constellation of Coma Berenices, the hair of Queen Berenice, is one of the closest, very rich collections of galaxies in the nearby Universe. The cluster, also known as Abell 1656, is about 320 million light-years from Earth and contains more than 1000 members. The brightest galaxies, including NGC 4921 shown here, were discovered back in the late 18th century by William Herschel.
The galaxies in rich clusters undergo many interactions and mergers that tend to gradually turn gas-rich spirals into elliptical systems without much active star formation. As a result, there are far more ellipticals and fewer spirals in the Coma Cluster than are found in quieter corners of the Universe.
NGC 4921 is one of the rare spirals in Coma, and a rather unusual one — it is an example of an ‘anaemic spiral’ where the normal vigorous star formation that creates a spiral galaxy’s familiar bright arms is less intense. As a result there is just a delicate swirl of dust in a ring around the galaxy, accompanied by some bright young blue stars that are clearly separated out by Hubble’s sharp vision. Much of the pale spiral structure in the outer parts of the galaxy is unusually smooth and gives the whole galaxy the ghostly look of a vast translucent jellyfish.
Read more here.
"The claim that it is the 'smallest exoplanet' found to date is not correct. . . . It is the smallest mass exoplanet found to date that transits, but other hot super-Earths have been found that do not transit but have lower masses."And over at Cosmic Log on MSNBC.com, Alan Boyle added a similar cautionary note, pointing out one has to question the use of terms like "smallest" and "Earth-like."
"If the universe is teeming with advanced civilizations capable of communicating over interstellar distances, then surely we ought to have seen them by now. That's the gist of a paradoxical line of reasoning put forward by the physicist Enrico Fermi in 1950. The so-called Fermi Paradox has haunted SETI researchers ever since. Not least because if the number of intelligent civilizations capable of communication in our galaxy is greater than 1, then we should eventually hear from them. Now one astrophysicist says this thinking fails to take into account the limit to how far a signal from ET can travel before it becomes too faint to hear. Factor that in and everything changes. Assuming the average communicating civilization has a lifetime of 1,000 years, ten times longer than Earth has been broadcasting, and has a signal horizon of 1,000 light-years, you need a minimum of over 300 communicating civilizations in the Milky Way to ensure that you'll see one of them. Any less than that and the chances are that they'll live out their days entirely ignorant of each other's existence. Paradox solved, right?"
