Picture of the moon

In this photograph can be seen lunar craters on the moon, and seas of the moon, the darker and flat areas of the Moon. The seas of the moon can be seen with the naked eye, especially when the moon is full and that has the name of seas such as the famous "sea of tanquilo" in which the astronaut Neil A. Armstrong landed on the moon in 1969, never have hosted water inside, are actually lava fields that have been formed at the origin of the Moon. At the bottom left of the picture, you can see these seas. At the top of the picture we can observe craters more clearly.

Note: photo of the Moon property of the author obtained from Madrid with a Newtonian reflector telescope 114 mm.

Image Credits: Astrofotos

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Hubble Images of Asteroids Vesta and Ceres

These Hubble Space Telescope images of Vesta and Ceres show two of the most massive asteroids in the asteroid belt, a region between Mars and Jupiter. The images are helping astronomers plan for the Dawn spacecraft’s tour of these hefty asteroids.

On July 7, NASA is scheduled to launch the spacecraft on a four-year journey to the asteroid belt. Once there, Dawn will do some asteroid-hopping, going into orbit around Vesta in 2011 and Ceres in 2015. Dawn will be the first spacecraft to orbit two targets. At least 100,000 asteroids inhabit the asteroid belt, a reservoir of leftover material from the formation of our solar-system planets 4.6 billion years ago.

Dawn also will be the first satellite to tour a dwarf planet. The International Astronomical Union named Ceres one of three dwarf planets in 2006. Ceres is round like planets in our solar system, but it does not clear debris out of its orbit as our planets do.

To prepare for the Dawn spacecraft’s visit to Vesta, astronomers used Hubble’s Wide Field Planetary Camera 2 to snap new images of the asteroid. The image at right was taken on May 14 and 16, 2007. Using Hubble, astronomers mapped Vesta’s southern hemisphere, a region dominated by a giant impact crater formed by a collision billions of years ago. The crater is 285 miles (456 kilometers) across, which is nearly equal to Vesta's 330-mile (530-kilometer) diameter. If Earth had a crater of proportional size, it would fill the Pacific Ocean basin. The impact broke off chunks of rock, producing more than 50 smaller asteroids that astronomers have nicknamed “vestoids.” The collision also may have blasted through Vesta’s crust. Vesta is about the size of Arizona.

Hubble’s view reveals extensive global features stretching longitudinally from the northern hemisphere to the southern hemisphere. The image also shows widespread differences in brightness in the east and west, which probably reflect compositional changes. Both of these characteristics could reveal volcanic activity throughout Vesta. The size of these different regions varies. Some are hundreds of miles across.

The brightness differences could be similar to the effect seen on the Moon, where smooth, dark regions are more iron-rich than the brighter highlands that contain minerals richer in calcium and aluminum. When Vesta was forming 4.5 billion years ago, it was heated to the melting temperatures of rock. This heating allowed heavier material to sink to Vesta’s center and lighter minerals to rise to the surface.

Astronomers combined images of Vesta in two colors to study the variations in iron-bearing minerals. From these minerals, they hope to learn more about Vesta’s surface structure and composition. Astronomers expect that Dawn will provide rich details about the asteroid’s surface and interior structure.

The Hubble image of Ceres on the left reveals bright and dark regions on the asteroid’s surface that could be topographic features, such as craters and/or areas containing different surface material. Large impacts may have caused some of these features and potentially added new material to the landscape. The Texas-sized asteroid holds about 30 to 40 percent of the mass in the asteroid belt. Ceres’ round shape suggests that its interior is layered like those of terrestrial planets such as Earth. The asteroid may have a rocky inner core, an icy mantle and a thin, dusty outer crust. The asteroid may even have water locked beneath its surface. It is approximately 590 miles (950 kilometers) across and was the first asteroid discovered in 1801.

The observations were made in visible and ultraviolet light between December 2003 and January 2004 with the Advanced Camera for Surveys. The color variations in the image show either a difference in texture or composition on Ceres’ surface. Astronomers need the close-up views of the Dawn spacecraft to determine the characteristics of these regional differences.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The Space Telescope Science Institute conducts Hubble science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington.

Credits for Vesta: NASA; ESA; L. McFadden and J.Y. Li (University of Maryland, College Park); M. Mutchler and Z. Levay (Space Telescope Science Institute, Baltimore); P. Thomas (Cornell University); J. Parker and E.F. Young (Southwest Research Institute); and C.T. Russell and B. Schmidt (University of California, Los Angeles).

Credits for Ceres: NASA; ESA; J. Parker (Southwest Research Institute); P. Thomas (Cornell University); L. McFadden (University of Maryland, College Park); and M. Mutchler and Z. Levay (Space Telescope Science Institute).

Source: NASA

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Weather Without Water

Bright mid-latitude clouds near the bottom of this view hint at the ongoing cycling of methane on Titan. These cloud streaks are near the same latitude as similar clouds observed above different longitudes on Titan.

The view is centered on Titan's trailing hemisphere, over the 1,700 kilometer (1,050 mile) wide bright region known as Adiri. North on Titan (5,150 kilometers, or 3,200 miles across) is up and rotated 15 degrees to the right.

This view was created by combining multiple images taken using a combination of spectral filters sensitive to wavelengths of infrared light centered at 939 and 742 nanometers.

The images were taken with the Cassini spacecraft wide-angle camera on May 13, 2007 at a distance of approximately 104,000 kilometers (65,000 miles) from Titan. Image scale is 12 kilometers (8 miles) per pixel. Due to scattering of light by Titan's hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale.

Credit: NASA/JPL/Space Science Institute

Source: JPL

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New Science on the Moon

NASA has selected proposals, including two from the Jet Propulsion Laboratory in Pasadena, Calif., for future lunar science activities. In addition, the agency has established two new programs that will enhance research made possible by the Vision for Space Exploration.

The proposals and programs are part of an effort by NASA to develop new opportunities to conduct important science investigations during the planned renewal of human exploration of the moon.

The seven selected proposals will result in advanced development for simple, autonomous instrument packages deployed on the lunar surface by astronauts. Such "suitcase science" packages could open up a wide variety of research applications regarding the moon and the lunar environment.

Some of the funded efforts will help scientists better understand the lunar dust that creates problems for astronauts on the moon. Other studies will provide a better understanding of the moon's interior, look for natural resources on the lunar surface and use lasers to provide precise information about the position of the moon and its features.

"The proposals we received show that the scientific community is excited about the opportunity to capitalize on the nation's planned lunar outpost. The moon has much to teach us about itself, the history of our solar system, and even the history of the sun. In the future, more and more scientists will be able to participate in lunar research as we focus attention on Earth's fascinating satellite," said Alan Stern, associate administrator for NASA's Science Mission Directorate.

The two selected proposals from JPL are:

"Autonomous Lunar Geophysical Experiment Package"--William Banerdt, principal investigator".

"Lunar Laser Transponder and Retroreflector Science"--Slava Turyshev, principal investigator".

The other selected proposals are:

Goddard Space Flight Center, Greenbelt, Md., "Volatile Analysis by Pyrolysis of Regolith on the Moon using Mass Spectrometry"-- Daniel Glavin, principal investigator.

Goddard Space Flight Center, "Seismology and Heat flow instrument package for Lunar Science and Hazards"-- Patrick Taylor, principal investigator.

Southwest Research Institute, Boulder, Colo., "Lunar Radiation Environment and Regolith Shielding Experiment"-- Donald Hassler, principal investigator.

U.S. Army Engineer Research and Development Center, Fort Wainwright, Alaska, "Lunar Suitcase Science: A Lunar Regolith Characterization Kit" --Jerome Johnson, principal investigator.

Ball Aerospace and Technologies Corp., Boulder, Colo., "Autonomous Lunar Dust Observer" -- Christian Grund, principal investigator.

Under the planned Lunar Advanced Science and Exploration Research program, proposals will be solicited for investigations to increase knowledge of the moon while also providing necessary information for humans to live and work there. Studies may include simulations and laboratory work to better understand the lunar environment and its hazards, such as dust and radiation. The program also will support analysis of existing lunar data, including the Apollo and robotic mission data archives, and work to understand the origin and evolution of the moon.

In the upcoming Lunar Reconnaissance Orbiter Participating Scientist Program, NASA will select researchers to perform detailed investigations using instruments aboard the spacecraft during its first years in lunar orbit. Proposals for both programs are due Sept. 7, 2007.

Lunar Reconnaissance Orbiter is NASA's next orbital mission to the moon. Launch is planned in late 2008. It will orbit the moon for at least one year, providing data to accelerate opportunities for future science missions and human exploration.

More information: http://www.nasa.gov/exploration

Image credit: USGS

Source: NASA

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Messenger Flies By Venus

The MESSENGER spacecraft snapped a series of images as it approached Venus on June 5. The planet is enshrouded by a global layer of clouds that obscures its surface to the MESSENGER Dual Imaging System (MDIS) cameras.

This single frame is part of a color sequence taken to help the MESSENGER team calibrate the camera in preparation for the spacecraft’s first flyby of Mercury on January 14, 2008. Over the next several months the camera team will pore over the 614 images taken during this Venus encounter to ascertain color sensitivity and other optical properties of the instrument. These tasks address two key goals for the camera at Mercury: understanding surface color variations and their relation to compositional variations in the crust, and ensuring accurate cartographic placement of features on Mercury’s surface.

Preliminary analysis of the Venus flyby images indicates that the cameras are healthy and will be ready for next January’s close encounter with Mercury.

After acquiring hundreds of high-resolution images during close approach to Venus, MESSENGER turned its wide-angle camera back to the planet and acquired a departure sequence. These images provide a spectacular good-bye to the cloud-shrouded planet while also providing valuable data to the camera calibration team.

The first image was taken June 6 at 12:58 UTC (8:58 p.m. EDT on June 5), and the final image on June 7 at 02:18 UTC (10:18 p.m. EDT on June 6). During this 25 hour, 20 minute period the spacecraft traveled 833,234 kilometers (517,748 miles—more than twice the distance from the Earth to the moon) with respect to Venus at an average speed of 9.13 kilometers per second (5.67 miles per second).

Credit: NASA

Source: NASA

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Crews to Fold Arrays, Prep for Spacewalk Repair Tasks

As Space Shuttle Atlantis and the International Space Station sail above Earth today, the STS-117 and Expedition 15 crews will continue retracting solar arrays and preparing for repair work during Friday’s spacewalk.

STS-117 Mission Specialists Jim Reilly and Danny Olivas will review procedures and practice techniques they will use during the spacewalk set to begin at 1:38 p.m. EDT Friday. The first task of the extravehicular activity is the repair of a thermal blanket that pulled away from the orbital maneuvering system pod on the rear of the shuttle.

This afternoon, the STS-117 crew will resume retraction of the starboard P6 solar array. Almost half of the 31½ array bays were retracted Wednesday. If the arrays are not fully retracted today, efforts will resume Friday with the assistance of the spacewalkers.

About an hour and 20 minutes before this morning’s scheduled wakeup call, the crews were awakened by a false alarm on the station. The alarm was triggered by the restart of Russian navigation computers that provide backup attitude control and orbital altitude adjustments. For now, the station’s control moment gyroscopes are handling attitude control, with the shuttle’s propulsion system providing backup.

Credit: NASA

Source: NASA

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ESA takes steps toward quantum communications

A team of European scientists has proved within an ESA study that the weird quantum effect called 'entanglement' remains intact over a distance of 144 kilometres. The experiment allows ESA to take a step closer to exploiting entanglement as a way of communicating with satellites with total security.

Quantum entanglement is one of the many non-intuitive features of quantum mechanics. If two photons of light are allowed to properly interact with one another, they can become entangled. One can even directly create pairs of entangled photons using a non-linear process called Spontaneous Parametric Down Conversion (SPDC).

Those two entangled photons can then be separated but as soon as one of them interacts with a third particle, the other photon of the pair will change its quantum state instantaneously. This happens according to the random outcome of the interaction, even though this photon never did interact with a third particle.

Such behaviour has the potential to allow messages to be swapped with complete confidence. This is because, if an eavesdropper listens into the message, the act of detecting the photons will change the entangled partner. These changes would be obvious to the legitimate receiving station and the presence of the eavesdropper would be instantly detected.

A quantum communications system would be a valuable way to transmit banking information, or military communications, or even to distribute feature films without the fear of piracy.

Even though entanglement has been known about for decades, no one has known whether the entanglement decays over long distance. For example, would a beam of entangled photons remain entangled if it passed through the atmosphere of the Earth? On their journey, the photons could interact with atoms and molecules in the air. Would this destroy the entanglement?

If so, entanglement would be useless as a means of communicating with satellites in orbit, because all signals would have to pass through the Earth's atmosphere. Now, an Austrian-German led team have proved conclusively that photons remain entangled over a distance of 144 kilometres through the atmosphere. That means that entangled signal will survive the journey from the surface of the Earth into space, and vice versa.

In September 2005, the European team aimed ESA's one-metre telescope on the Canary Island of Tenerife toward the Roque de los Muchachos Observatory on the neighbouring island of La Palma, 144 kilometres away. On La Palma, a specially built quantum optical terminal generated entangled photon pairs, using the SPDC process, and then sent one photon towards Tenerife, whilst keeping the other for comparison.

Upon comparing the results from Tenerife with those from La Palma, it was obvious that the photons had remained entangled. "We were sending the single-photon beam on a 144 kilometres path through the atmosphere, so this horizontal quantum link can be considered a 'worst case scenario' for a space to ground link," says Josep Perdigues, ESA's Study Manager.

Additional tests with a quantum communication source that generated faint laser pulses instead of entangled photon pairs were performed in 2006. Faint laser pulse sources emulate single photon sources by attenuating the optical power of a standard laser down to single photon regime. Attenuated lasers are technologically much simpler than entangled photon sources or 'true' single photon sources.

The price you have to pay is the unwanted opportunity for information leakage, due to the non-zero probability of having more than one photon per pulse. In practice, this limits the maximum link distance for exchanging securely a key. By implementing a decoy-state protocol in the experiments using a faint laser pulse source, the maximum link distance (yet secure against an eavesdropper’s action) was extended to values representative of a space to ground experiment.

The team are now studying ways to take the experiment into space. "Being in space will mean that we can test entanglement over lines of sight longer than 1 000 kilometres, unfeasible on Earth, thereby extending the validity of Quantum Physics theory to macroscopic scales," says Perdigues. One option is to use the external pallet on the Columbus module of the International Space Station. Another would be to put the quantum optical terminal on a dedicated satellite of its own. The quantum optical terminal is about 100 kg in mass and fits into a one-cubic-metre box.

Credits: ESA

Source: ESA

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