Posted on by Fraser Cain

Asteroids Change Colour With Age

Image credit: NASA
In an article published today in the journal Nature, a team led by Robert Jedicke of the University of Hawaii?s Institute for Astronomy provides convincing evidence that asteroids change color as they age.

David Nesvorny, a team member from the Southwest Research Institute in Boulder, CO, used a variety of methods to estimate asteroid ages that range from 6 million up to 3 billion years. Accurate color measurements for over 100,000 asteroids were obtained by the Sloan Digital Sky Survey (SDSS), and catalogued by team members Zeljko Ivezic from the University of Washington and Mario Juric from Princeton University.

Robert Whiteley, a team member from the USAF Space and Missile Systems Center in Los Angeles, points out that ?the age-color correlation we found explains a long-standing discrepancy between the colors of the most numerous meteorites known as ordinary chondrites (OC) and their presumed asteroid progenitors.? Meteorites are chips of asteroids and comets that have fallen to Earth?s surface.

According to Jedicke, ?If you were given a piece of rock from the Grand Canyon, you might expect that it would be red, like the colorful pictures in travel magazines. You?d be forgiven for questioning its origin if the rock had a bluish color. But if you were then told that the rocks turn from blue to Grand Canyon red because of the effects of weather, then everything might make sense. Your gift is simply a fresh piece of exposed rock, whereas the pictures you?ve seen show weathered cliff faces millions of years old.?

Nesvorny explains that this is similar to the situation experienced by asteroid astronomers. ?The meteorites are gifts of the solar system to scientists on Earth?pieces of asteroids delivered to their own backyard. The mystery is that the OC meteorites have a bluish color relative to the reddish color of the asteroids from which they were supposedly released.? Jedicke asks, ?How could they possibly be related??

About thirty years ago, a ?space weathering? effect was proposed to explain the color change. Meteorites, whose surface is affected by their fall through Earth?s atmosphere, are usually studied in laboratories by observing their freshly cut and exposed interiors. Billions of years of exposure of the same material on the surface of an asteroid to solar and cosmic radiation and the heating effect of impacts of tiny asteroids might alter the surface color of asteroids in exactly the manner required to match the color of asteroids.

Jedicke said that they found that ?asteroids get more red with time in exactly the right manner and at the right rate to explain the mystery of the color difference between them and OC meteorites.? He added, ?Even though we have found a link between the two types of objects, we still don?t know what causes space weathering.?

Once these researchers refine their analysis by obtaining more colors of the youngest-known asteroid surfaces, it will be possible to determine the age of any asteroid from its surface color. They are currently searching for a space weathering effect on other types of asteroids in the solar system.

The Institute for Astronomy at the University of Hawaii conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Mauna Kea. Refer to http://www.ifa.hawaii.edu/ for more information about the Institute.

Funding for the creation and distribution of the SDSS Archive has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. The SDSS Web site is http://www.sdss.org/.

The SDSS is managed by the Astrophysical Research Consortium (ARC) for the Participating Institutions. The Participating Institutions are The University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, University of Pittsburgh, Princeton University, the United States Naval Observatory, and the University of Washington.

Original Source: University of Hawaii News Release

Posted on by Fraser Cain

Japanese Spacecraft Images Earth and Moon on Flyby

Image credit: JAXA
The Space Engineering Spacecraft “Hayabusa” (MUSES-C) launched on May 9, 2003, by the Japan Aerospace Exploration Agency (JAXA) has been flying smoothly in a heliocentric orbit for about a year using its ion engines.
On May 19, Hayabusa came close to the Earth, and successfully carried out an earth swing-by to place it in a new elliptical orbit toward the asteroid “ITOKAWA”.

The earth swing-by is a technique to significantly change direction of an orbit and/or speed by using the Earth’s gravity without consuming onboard propellant. Hayabusa came closest to the Earth at 3:22 p.m. on May 19 (Japan Standard Time) at an altitude of approximately 3700 km.

The combination of acceleration by the ion engines and the earth swing-by performed this time was the first technological verification in the world, both in the sense of plot and implementation.
After its precise orbit is determined in a week, Hayabusa will restart its ion engines to fly toward “ITOKAWA”.
Hayabusa acquired earth images using its onboard optical navigation camera (which is for detecting a relative position to an asteroid and for scientific observations) as it neared the Earth. You can find these images at the following websites:

Institute of Space and Astronautical Science (ISAS)
http://www.isas.jaxa.jp/e/index.shtml

Original Source: JAXA News Release

Posted on by Fraser Cain

Atlas II Launches AMC-11 Satellite

Image credit: ILS
International Launch Services (ILS) marked another successful mission tonight, after its Atlas IIAS rocket placed the AMC-11 satellite into orbit for SES AMERICOM.

Both the rocket and the satellite were built by Lockheed Martin Corp. (NYSE:LMT), which is also a partner in the ILS joint venture. This was the fifth launch for ILS in 2004, four of which have been on Atlas rockets. This also was the 72nd consecutive successful launch for the Atlas vehicle family.

The Atlas IIAS rocket lifted of from Cape Canaveral?s Launch Complex 36B at 6:22 p.m. EDT (2222 GMT). The satellite, an A2100 model, was injected into a transfer orbit 28 minutes later. The AMC-11 spacecraft is a twin to AMC-10, launched in February, and together they form SES AMERICOM?s premier cable neighborhood and the platform for its HD-PRIME service.

?We?re proud to deliver another satellite on target for SES AMERICOM,? said ILS President Mark Albrecht. ?We look forward to the same success with our two Proton launches this summer with WORLDSAT 2 and AMC-15, and the AMC-16 mission scheduled for an Atlas V at the end of this year. You could say SES AMERICOM is an ILS Frequent Flyer.?

Albrecht noted the long-standing relationship shared by ILS, SES AMERICOM and its parent company, SES GLOBAL. To date ILS has launched 16 satellites for companies affiliated with SES GLOBAL, including seven for the SES AMERICOM fleet. Last month, the companies announced that three additional satellites for SES AMERICOM and SES ASTRA will be launched on ILS vehicles.

Dean Olmstead, president and CEO of SES AMERICOM, said: ?We have great confidence in ILS, as evidenced by our recent experience with the Atlas IIAS and Proton launch vehicles. We are optimistic that the two Proton launches scheduled for August and October, as well as our first Atlas V launch in December, will be just as flawless as tonight?s AMC-11 Atlas IIAS launch.?

ILS has established itself as the indisputable leader of launch services worldwide and offers the industry’s two best launch systems: Atlas and Proton. With a remarkable launch rate of 63 missions during the past three years, the Atlas and Proton launch vehicles have consistently demonstrated the reliability and flexibility that have made them the vehicles of choice. Further demonstrating ILS as the industry leader, ILS has signed more new contracts than its competitors combined over the same three-year period. By any measure, ILS is truly the global leader.

ILS is a joint venture of Lockheed Martin and Russian rocket builder Khrunichev State Research and Production Space Center. ILS markets and manages the missions on the Atlas rocket in the United States and on the Proton rocket at the Baikonur Cosmodrome, Kazakhstan. ILS was formed in 1995, and is based in McLean, Va., a suburb of Washington, D.C.

Original Source: ILS News Release

Posted on by Fraser Cain

Cassini Gets Another Look at Titan

Image credit: NASA/JPL/Space Science
Cassini continues its ground-breaking observations of Saturn’s mysterious moon Titan, stealing another early peek at its haze-enshrouded surface.

The spacecraft was 29.3 million kilometers (18.2 million miles) from Titan on May 5, 2004 when the image on the left was taken through one of the narrow angle camera’s spectral filters (centered at 938 nanometers) specifically designed to penetrate the moon’s thick atmosphere. The image scale is 176 kilometers (109 miles) per pixel, an improvement in resolution of 30% over the images released on May 6. Cassini’s view of Titan now surpasses Earth-based observations in its ability to show detail.

The image has been magnified 10 times using a procedure which smoothly interpolates between pixels to create intermediate pixel values, and has been enhanced in contrast to bring out details. The mottled pattern is an artifact of the processing. The larger scale brightness variations are real. No further processing to remove the effects of the overlying atmosphere has been performed.

The superimposed coordinate system grid in the accompanying image on the right illustrates the geographical regions of the moon that are illuminated and visible, as well as the orientation of Titan — north is up and rotated 25 degrees to the left. The yellow curve marks the position of the boundary between day and night on Titan.

This image shows about one quarter of Titan’s surface, from 180 to 250 degrees West longitude, and overlaps part of the surface shown in the previous Cassini image release (PIA 05390). (That release also included a map of relative surface brightness variations on Titan as measured from images taken with the Hubble Space Telescope.) The dark northwest-southeast trending southern hemisphere feature extending from 210 degrees to 250 degrees West longitude, and the bright region to the east (right) and southeast of it at -50 degrees latitude and 180 to 230 degrees West longitude on the Hubble map, are visible again in today’s release.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Posted on by Fraser Cain

Second Interim Return to Flight Report Released

Image credit: NASA
2004-0519shuttle-sm.jpg view insert

Image credit: NASA
There have been several significant changes in NASA?s Space Shuttle return to flight effort since the last plenary meeting of the Return to Flight Task Group (RTF TG) in December. First, and most immediately, the schedule for the next launch was moved from September 2004 to March-April 2005. See Figure 1 below. This schedule change was prompted by three developments:

1. additional testing of the susceptibility of the Thermal Protection System (TPS), especially the Reinforced Carbon-Carbon, coupled with advanced analysis of the airflows around the Orbiter, External Tank (ET) and Solid Rocket Boosters indicated that the foam on a larger area of the ET should be stripped and reapplied;

2. some rudder speed brake actuators were discovered to have been incorrectly assembled during the original assembly over 20 years ago. Further, the gears in the actuators have generally suffered some damage with use and time. Therefore, all the actuators are being replaced or refurbished; and

3. design and building of a new camera/laser boom that would be used by the Space Shuttle?s robotic arm to help inspect for possible damage while in orbit.

This change in schedule means that NASA will have additional time to implement the Columbia Accident Investigation Board (CAIB) return to flight recommendations before return to flight. In many cases this change also allows expected plans to be at least partially implemented. For example, the CAIB called for a detailed plan to, among other things, establish an Independent Technical Engineering Authority?it is expected those plans will now be implemented, at least for the Office of Space Flight, before next year.

The expanded time before the next launch also allows NASA additional time to select and perfect methods of, for example, inspecting the TPS for damage. Since the loss of Columbia, NASA has been engaged in a wide-ranging search for corrective and preventive measures of all types. In some cases, the time is approaching when decisions must be made as to the most promising alternatives and resources focused on this smaller set of possibilities?the garden must be thinned. In this sense, the additional time until launch can be seductive and leadership will need to be exercised to sort the many options under consideration.

The second major change since December is the announcement of President Bush?s initiative, or vision, for the future of human space flight. The President proposed to utilize the Space Shuttle to finish the International Space Station (ISS) and then retire the Shuttle. In its place would be continued reliance on international partners to service the ISS as well as the possibility of private sector development of launch vehicles. During the next decade, NASA would also begin to develop the capability to return astronauts to the moon, establish a presence, and move on to explore Mars within the next 20 years.

While the President?s vision has obvious implications for the long-run use of the Shuttle, its effects on the return to flight efforts have not been fully examined. However, no matter how long the Shuttle is used in the future, it must first be safely returned to flight. Therefore, except for potential competition for human resources, the new program should have minimal impact on the actual return to flight activities and the implementation of CAIB recommendations. Third, the Task Group determined that the contingency of utilizing the ISS as a shelter for Shuttle Crew Contingency Support in the event of potentially catastrophic damage on the next flight, is becoming increasingly important in NASA?s decision making for return to flight. Therefore, the Task Group formally notified NASA of its intent to assess this capability much as if it were a CAIB recommendation.

Finally, the Task Group instituted a ?sub-panel? to examine the implications of the increased flow of data resulting from many of the CAIB recommendations and other return to flight initiatives.

The Task Group is encouraged by NASA?s progress since its last plenary in December. Throughout the organization, the people of NASA are engaged and dedicated to correcting the deficiencies that led to the demise of Columbia.

The RTF TG is conditionally closing out three CAIB recommendations. ?Closing out? a recommendation means that NASA has responded adequately to a specific CAIB return to flight recommendation. ?Conditionally? means that the close out is dependent on the delivery of final information and the assurance of NASA that it will keep the RTF TG up-to-date on any new developments pertaining to those recommendations. The three recommendations being conditionally closed out with this second interim report are:

3.3-1: Reinforced Carbon-Carbon Non-Destructive Inspection;
4.2-3: Closeout Inspection; and
6.3-2: NASA/National Imagery and Mapping Agency Memorandum of Agreement.

The Task Group will continue to monitor the implementation of these recommendations and NASA has agreed to notify the Task Group if there is any material change in status.

There has been substantial progress on virtually all of the 12 remaining return to flight recommendations. It is anticipated that several more recommendations will be substantially met by the time of the next RTF TG plenary in the summer.

One universal concern of the Task Group is the personnel requirements to meet the CAIB recommendations and return to flight. The various new organizations, from the NASA Engineering and Safety Center, to the Independent Technical Authority, to the Space Shuttle System Engineering and Integration Office all require talented staff drawn largely from the current NASA and contractor pool. At some point, the ability of the Space Shuttle Program to carry out its mission may be hampered by personnel shortages.

The most important work remains to be efforts to eliminate critical ascent debris. If it could be guaranteed that no critical debris would come from the ET, the immediate cause of the loss of Columbia would be rectified. But such a guarantee is impossible short of extensive testing in flight. Analytical and testing techniques will allow a level of comfort before launch and advances in Non-Destructive Inspection techniques may add to confidence. However, statistically significant results verifying ET debris conditions may not be accomplished even by the end of the Shuttle Program.

As such, on-orbit inspection and repair remain necessary to reduce the risk to future flights. Should one or both of these capabilities not be fully developed by the anticipated date of return to flight, the ability for the crew to await a rescue mission at the ISS will become an important consideration for the next launch.

Original Source: Stafford-Covey Second Interim Report (PDF)

Posted on by Fraser Cain

Japanese Celebrity Will Visit the Space Station

Image credit: Space Adventures
Space Adventures, Ltd., the world’s leading space experiences company, announced today it has begun working with Dentsu, the world’s largest advertising agency, to send a prominent Japanese figure to the International Space Station (ISS) within the next several years.

As part of the agreement with Dentsu, Space Adventures will dedicate one of the four seats the company has available on the Russian Soyuz TMA spacecraft. Space Adventures currently has a contract with the Federal Space Agency of Russia that provides them with the sole rights to transport the next four private space explorers to the ISS. The first of the four seats has already been contracted by American technology entrepreneur, Greg Olsen, Ph.D., who is currently training at the Yuri Gargarin Training Center in Star City, Russia. His expedition is currently planned for April 2005. With two of the four seats committed, Space Adventures has two seats remaining on the Soyuz.

“I welcome the opportunity to work with Dentsu. They are the world’s premier advertising agency and we are delighted to embark on such an exciting opportunity with them,” said Eric Anderson, president and CEO of Space Adventures. “As Dentsu has cultivated unique artistic designs and opportunities for advertising in today’s marketplace, we, at Space Adventures, are using the same enthusiasm and innovative techniques to open the space frontier to private citizens. Together, we will make history by sending the first Japanese private explorer to space.”

About Space Adventures: The world’s leading space flight experiences and space tourism company offers a wide range of programs from Zero-Gravity and Edge of Space flights, cosmonaut training and space flight qualification programs to reservations on future suborbital spacecraft. Headquartered in Arlington, Va., with an office in Moscow, Space Adventures is the only company to have successfully launched private individuals to the ISS. The company’s advisory board comprises Apollo 11 moonwalker Buzz Aldrin, shuttle astronauts Kathy Thornton, Robert (Hoot) Gibson, Charles Walker, Norm Thagard, Sam Durrance and Byron Lichtenberg and Skylab astronaut Owen Garriott.

About Dentsu Inc.: Founded in 1901, Dentsu is the largest advertising agency brand and the fifth largest marketing and communications organization in the world. Based in Tokyo, Dentsu offers national, multinational and global clients the most comprehensive range of advertising and marketing services through its unique “Total Communications Services” approach. Dentsu has pioneered and set global standards for integrated communications, which in latter years have been adopted by a number of major international networks. The group has more than 6,000 clients and 14,245 full-time employees in both Japan and in its offices overseas. Consolidated billings (net sales) for fiscal term 03/04 were recorded at 1,749 billion yen. Dentsu is publicly quoted on the Tokyo Stock Exchange. For more information, please visit www.dentsu.com.

Original Source: Space Adventures News Release

Posted on by Fraser Cain

How to Avoid Space Madness

Image credit: Mars Society
Defiance, detachment, disagreement ? harmful emotions in any small group situation, but in Outer Space these feelings are particularly damaging and possibly life endangering.

ANU psychologists are preparing to gather unique insights into the duress of space travel as part of a ?Mars expedition? to be staged in the Australian desert later this year.

The way that small groups of astronauts interact in the extreme, unfamiliar and isolating conditions of space travel will be closely scrutinised by Dr Rachael Eggins, Dr Kate Reynolds and PhD student Mr Phill Krins, from the Psychology Department in the ANU Faculty of Science.

The researchers are set to record the interactions of participants of an expedition into the South Australian outback in August organised by the Mars Society of Australia. This follows on from an initial study of participants in a planetary simulation in the United States last year.

?The rigorous personality testing astronauts undergo in their relatively cosy, comfortable labs can not measure how their personality might change in a confined, socially stifling and unfamiliar space,? Dr Eggins says.

?In everyday life we are very socially dynamic and belong to a number of groups, such as family, work and friends. There are a number of psychological advantages to having such a dynamic social environment, which will be absent when people spend long periods of time in isolation.?

Mr Krins and Dr Steve Dawson, a research psychologist with the Mars Society of Australia, will travel into the desert with the expedition and ask participants ? who try and replicate as closely as possible what it would be like living and working on Mars ? to complete questionnaires designed to monitor social dynamics.

Participants will undergo a daily cortisol (a hormone produced by the body in reaction to stress) measurement test and cognitive testing to gauge stress and performance levels.

Mr Krins will also keep a daily journal to record important social events, such as leadership changes, likely to affect the social dynamics of the expedition.

?One thing we are interested in is the question of whether or not groups are good or bad for your health,? Dr Eggins says. ?We know that in cohesive groups people perform better, work harder and are more cooperative than in loose-knit groups.

?But do cohesive groups make us work too hard and what does that do to our stress levels??

There are also other issues relating to the wrong sort of cohesion in a group, and small sub-groups forming within larger groups.

?There is a danger groups may become too cohesive,? Mr Krins says.

?When this occurs there may be intense pressure for individual crew members to behave in accordance with ?group norms?. For example, if there is a group norm to not report safety breaches, this could put the entire crew in danger.?

Also, past research on groups (whether isolated or not) has shown that it is common for the larger group to splinter into smaller subgroups.

?A number of problems can occur when large groups split off into these smaller groups,? Dr Eggins says. ?Polarisation can lead to infighting and poor decision-making.

?But there are advantages ? subgroups can become an important source of creative new ideas benefiting the larger group. Subgroups are also an important source of identity and pride for people. They then work hard to achieve its goals, improving the mission as a whole.?

With unmanned Mars missions underway and intensifying research interest in the red planet, the ANU researchers believe the human element of space exploration should be taken just as seriously as the technological or scientific. The team?s research will focus on developing guiding principles to avoid problems associated with groups in such stressful circumstances.

?It is important that group differences are managed properly and don?t become a source of conflict or feelings of disenfranchisement,? Dr Eggins says.

?These principles will ensure that individuals maintain commitment to the whole, have avenues for input into decision making and follow leadership guidelines.?

Original Source: ANU News Release

Posted on by Fraser Cain

Unmanned Amateur Rocket Reaches Space

A team of amateur rocket builders accomplished a major feat this week; the first privately built rocket to reach the edge of space. The 6.5-metre (21 foot) unmanned rocket blasted off from its Nevada launch pad, and reached a speed of 6500 km/h (4000 m/h) in only 9 seconds. Based on this velocity, the Civilian Space Exploration Team (CSXT) calculated that it would have reached the official edge of space at 100 km (62.5 m). The CSXT team has detected the rocket’s landing telemetry information, but hasn’t been able to locate it on the ground yet.

Posted on by Fraser Cain

Chandra Furthers Understanding About Dark Energy

Image credit: Chandra
Dark energy. Does it exist, and what are its properties? Using galaxy-cluster images from NASA’s Chandra X-ray Observatory, astronomers have applied a powerful, new method for detecting and probing dark energy. The results offer intriguing clues about the nature of dark energy and the fate of the Universe. The Marshall Center manages the Chandra program.
Photo: Composite image of the galaxy cluster Abell 2029 (Optical: NOAO/Kitt Peak/J.Uson, D.Dale; X-ray: NASA/CXC/IoA/S.Allen et al.)

Astronomers have detected and probed dark energy by applying a powerful, new method that uses images of galaxy clusters made by NASA’s Chandra X-ray Observatory. The results trace the transition of the expansion of the Universe from a decelerating to an accelerating phase several billion years ago, and give intriguing clues about the nature of dark energy and the fate of the Universe.

“Dark energy is perhaps the biggest mystery in physics,” said Steve Allen of the Institute of Astronomy (IoA) at the University of Cambridge in England, and leader of the study. “As such, it is extremely important to make an independent test of its existence and properties.”

Allen and his colleagues used Chandra to study 26 clusters of galaxies at distances corresponding to light travel times of between one and eight billion years. These data span the time when the Universe slowed from its original expansion, before speeding up again because of the repulsive effect of dark energy.

“We’re directly seeing that the expansion of the Universe is accelerating by measuring the distances to these galaxy clusters,” said Andy Fabian also of the IoA, a co-author on the study. The new Chandra results suggest that the dark energy density does not change quickly with time and may even be constant, consistent with the “cosmological constant” concept first introduced by Albert Einstein. If so, the Universe is expected to continue expanding forever, so that in many billions of years only a tiny fraction of the known galaxies will be observable.

If the dark energy density is constant, more dramatic fates for the Universe would be avoided. These include the “Big Rip,” where dark energy increases until galaxies, stars, planets and eventually atoms are eventually torn apart. The “Big Crunch,” where the Universe eventually collapses on itself, would also be ruled out.

Chandra’s probe of dark energy relies on the unique ability of X-ray observations to detect and study the hot gas in galaxy clusters. From these data, the ratio of the mass of the hot gas and the mass of the dark matter in a cluster can be determined. The observed values of the gas fraction depend on the assumed distance to the cluster, which in turn depends on the curvature of space and the amount of dark energy in the universe.

Because galaxy clusters are so large, they are thought to represent a fair sample of the matter content in the universe. If so, then relative amounts of hot gas and dark matter should be the same for every cluster. Using this assumption, Allen and colleagues adjusted the distance scale to determine which one fit the data best. These distances show that the expansion of the Universe was first decelerating and then began to accelerate about six billion years ago.

Chandra’s observations agree with supernova results including those from the Hubble Space Telescope (HST), which first showed dark energy’s effect on the acceleration of the Universe. Chandra’s results are completely independent of the supernova technique – both in wavelength and the objects observed. Such independent verification is a cornerstone of science. In this case it helps to dispel any remaining doubts that the supernova technique is flawed.

“Our Chandra method has nothing to do with other techniques, so they’re definitely not comparing notes, so to speak,” said Robert Schmidt of University of Potsdam in Germany, another coauthor on the study.

Better limits on the amount of dark energy and how it varies with time are obtained by combining the X-ray results with data from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), which used observations of the cosmic microwave background radiation to discover evidence for dark energy in the very early Universe. Using the combined data, Allen and his colleagues found that dark energy makes up about 75% of the Universe, dark matter about 21%, and visible matter about 4%.

Allen and his colleagues stress that the uncertainties in the measurements are such that the data are consistent with dark energy having a constant value. The present Chandra data do, however, allow for the possibility that the dark energy density is increasing with time. More detailed studies with Chandra, HST, WMAP and with the future mission Constellation-X should provide much more precise constraints on dark energy.

“Until we better understand cosmic acceleration and the nature of the dark energy we cannot hope to understand the destiny of the Universe,” said independent commentator Michael Turner, of the University of Chicago.

The team conducting the research also included Harald Ebeling of the University of Hawaii and the late Leon van Speybroeck of the Harvard-Smithsonian Center for Astrophysics. These results will appear in an upcoming issue of the Monthly Notices of the Royal Astronomy Society.

NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA’s Office of Space Science, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Additional information and images are available at:

http://chandra.harvard.edu/
and
http://chandra.nasa.gov/

Original Source: NASA News Release

Posted on by Fraser Cain

New Photo of Comet NEAT

Astrophotographer John Chumack sent in this image of Comet Neat which he took last night. He used a Canon 10D digital SLR and 4″ F8 refractor telescope, ISO 400, 9 minute exposure. If you want to see the comet for yourself, just head outside and look to the West. It’s a fuzzy blur that you can just make out with the unaided eye, even in the city. You can make it out much better with a pair of binoculars. Skymaps.com has conveniently put positions of Comet’s NEAT and LINEAR for the month of May in its current sky chart, so head there and grab a free map to help you orient yourself. Get some friends and make an evening of it.

Good luck!

Fraser Cain
Publisher
Universe Today