Posted on by Fraser Cain

The Universe Used to Be More Blue

Image credit: ESO

Although the Universe is currently a beige colour overall, it used to be more blue, according to astronomers with the European Southern Observatory. This was caused by the predominantly hot, young blue stars in the most distant galaxies – astronomers are seeing them when the Universe was only 2.5 billion years old. The astronomers worked out the distance and colour to 300 galaxies which were contained within the Hubble Deep Sky survey, which took a deep look at a region of sky in the southern constellation of Tuscanae.

An international team of astronomers [1] has determined the colour of the Universe when it was very young. While the Universe is now kind of beige, it was much bluer in the distant past, at a time when it was only 2,500 million years old.

This is the outcome of an extensive and thorough analysis of more than 300 galaxies seen within a small southern sky area, the so-called Hubble Deep Field South. The main goal of this advanced study was to understand how the stellar content of the Universe was assembled and has changed over time.

Dutch astronomer Marijn Franx, a team member from the Leiden Observatory (The Netherlands), explains: “The blue colour of the early Universe is caused by the predominantly blue light from young stars in the galaxies. The redder colour of the Universe today is caused by the relatively larger number of older, redder stars.”

The team leader, Gregory Rudnick from the Max-Planck Institut f?r Astrophysics (Garching, Germany) adds: “Since the total amount of light in the Universe in the past was about the same as today and a young blue star emits much more light than an old red star, there must have been significantly fewer stars in the young Universe than there is now. Our new findings imply that the majority of stars in the Universe were formed comparatively late, not so long before our Sun was born, at a moment when the Universe was around 7,000 million years old.”

These new results are based on unique data collected during more than 100 hours of observations with the ISAAC multi-mode instrument at ESO’s Very Large Telescope (VLT), as part of a major research project, the Faint InfraRed Extragalactic Survey (FIRES). The distances to the galaxies were estimated from their brightness in different optical near-infrared wavelength bands.

Observing the early Universe
It is now well known that the Sun was formed some 4.5 billion years ago. But when did most of the other stars in our home Galaxy form? And what about stars in other galaxies? These are some of the key questions in present-day astronomy, but they can only be answered by means of observations with the world’s largest telescopes.

One way to address these issues is to observe the very young Universe directly – by looking back in time. For this, astronomers take advantage of the fact that light emitted by very distant galaxies travels a long time before reaching us. Thus, when astronomers look at such remote objects, they see them as they appeared long ago.

Those remote galaxies are extremely faint, however, and these observations are therefore technically difficult. Another complication is that, due to the expansion of the Universe, light from those galaxies is shifted towards longer wavelengths [2], out of the optical wavelength range and into the infrared region.

In order to study those early galaxies in some detail, astronomers must therefore use the largest ground-based telescopes, collecting their faint light during very long exposures. In addition they must use infrared-sensitive detectors.

Telescopes as giant eyes
The “Hubble Deep Field South (HDF-S)” is a very small portion of the sky in the southern constellation Tucanae (“the Toucan”). It was selected for very detailed studies with the Hubble Space Telescope (HST) and other powerful telescopes. Optical images of this field obtained by the HST represent a total exposure time of 140 hours. Many ground-based telescopes have also obtained images and spectra of objects in this sky area, in particular the ESO telescopes in Chile.

A sky area of 2.5 x 2.5 arcmin2 in the direction of HDF-S was observed in the context of a thorough study (the Faint InfraRed Extragalactic Survey; FIRES, see ESO PR 23/02). It is slightly larger than the field covered by the WFPC2 camera on the HST, but still 100 times smaller than the area subtended by the full moon.

Whenever this field was visible from the ESO Paranal Observatory and the atmospheric conditions were optimal, ESO astronomers pointed the 8.2-m VLT ANTU telescope in this direction, taking near-infrared images with the ISAAC multi-mode instrument. Altogether, the field was observed for more than 100 hours and the resulting images (see ESO PR 23/02), are the deepest ground-based views in the near-infrared Js- and H-bands. The Ks-band image is the deepest ever obtained of any sky field in this spectral band, whether from the ground or from space.

These unique data provide an exceptional view and have now allowed unprecedented studies of the galaxy population in the young Universe. Indeed, because of the exceptional seeing conditions at Paranal, the data obtained with the VLT have an excellent image sharpness (a “seeing” of 0.48 arcsec) and can be combined with the HST optical data with almost no loss of quality.

A bluer colour
The astronomers were able to detect unambiguously about 300 galaxies on these images. For each of them, they measured the distance by determining the redshift [2]. This was done by means of a newly improved method that is based on the comparison of the brightness of each object in all the individual spectral bands with that of a set of nearby galaxies.

In this way, galaxies were found in the field with redshifts as high as z = 3.2, corresponding to distances around 11,500 million light-years. In other words, the astronomers were seeing the light of these very remote galaxies as they were when the Universe was only about 2.2 billion year old.

The astronomers next determined the amount of light emitted by each galaxy in such a way that the effects of the redshift were “removed”. That is, they measured the amount of light at different wavelengths (colours) as it would have been recorded by an observer near that galaxy. This, of course, only refers to the light from stars that are not heavily obscured by dust.

Summing up the light emitted at different wavelengths by all galaxies at a given cosmic epoch, the astronomers could then also determine the average colour of the Universe (the “cosmic colour”) at that epoch. Moreover, they were able to measure how that colour has changed, as the Universe became older.

They conclude that the cosmic colour is getting redder with time. In particular, it was much bluer in the past; now, at the age of nearly 14,000 million years, the Universe has a kind of beige colour.

When did stars form ?
The change of the cosmic colour with time may be interesting in itself, but it is also an essential tool for determining how rapidly stars were assembled in the Universe.

Indeed, while the star-formation in individual galaxies may have complicated histories, sometimes accelerating into true “star-bursts”, the new observations – now based on many galaxies – show that the “average history” of star-formation in the Universe is much simpler. This is evident by the observed, smooth change of the cosmic colour as the Universe became older.

Using the cosmic colour the astronomers were also able to determine how the mean age of relatively unobscured stars in the Universe changed with time. Since the Universe was much bluer in the past than it is now, they concluded that the Universe is not producing as many blue (high mass, short-lived) stars now as it was earlier, while at the same time the red (low mass, long-lived) stars from earlier generations of star formation are still present. Blue, massive stars die more quickly than red, low-mass stars, and therefore as the age of a group of stars increases, the blue short-lived stars die and the average colour of the group becomes redder. So did the Universe as a whole.

This behaviour bears some resemblance with the ageing trend in modern Western countries where less babies are born than in the past and people live longer than in the past, with the total effect that the mean age of the population is rising.

The astronomers determined how many stars had already formed when the Universe was only about 3,000 million years old. Young stars (of blue colour) emit more light than older (redder) stars. However, since there was just about as much light in the young Universe as there is today – although the galaxies are now much redder – this implies that there were fewer stars in the early Universe than today. The present study inidcates that there were ten times fewer stars at that early time than there is now.

Finally, the astronomers found that roughly half of the stars in the observed galaxies have been formed after the time when the Universe was about half as old (7,000 million years after the Big Bang) as it is today (14,000 million years).

Although this result was derived from a study of a very small sky field, and therefore may not be completely representative of the Universe as a whole, the present result has been shown to hold in other sky fields.

Original Source: ESO News Release

Posted on by Fraser Cain

Is Mars Coming Out of An Ice Age?

Image credit: NASA/JPL

Data gathered by NASA’s Mars Global Surveyor and Mars Odyssey spacecraft show evidence that the Red Planet might be coming out of a recent ice age. Unlike on Earth, an ice age on Mars happens when the poles warm up and water vapour can escape to lower latitudes on the planet. Scientists examined global patterns of landscape shapes and near-surface ice levels and found that a covering of ice and dust covered the surface to latitudes as low as 30 degrees – and it’s currently on the retreat. They believe this ice age happened just 400,000 to 2.1 million years ago.

NASA’s Mars Global Surveyor and Mars Odyssey missions have provided evidence of a relatively recent ice age on Mars. In contrast to Earth’s ice ages, a Martian ice age waxes when the poles warm, and water vapor is transported toward lower latitudes. Martian ice ages wane when the poles cool and lock water into polar icecaps.

The “pacemakers” of ice ages on Mars appear to be much more extreme than the comparable drivers of climate change on Earth. Variations in the planet’s orbit and tilt produce remarkable changes in the distribution of water ice from Polar Regions down to latitudes equivalent to Houston or Egypt. Researchers, using NASA spacecraft data and analogies to Earth’s Antarctic Dry Valleys, report their findings in Thursday’s edition of the journal Nature.

“Of all the solar system planets, Mars has the climate most like that of Earth. Both are sensitive to small changes in orbital parameters,” said planetary scientist Dr. James Head of Brown University, Providence, R.I., lead author of the study. “Now we’re seeing that Mars, like Earth, is in a period between ice ages,” he said.

Discoveries on Mars, since 1999, of relatively recent water- carved gullies, glacier-like flows, regional buried ice and possible snow packs created excitement among scientists who study Earth and other planets. Information from the Mars Global Surveyor and Odyssey missions provided more evidence of an icy recent past.

Head and co-authors from Brown (Drs. John Mustard and Ralph Milliken), Boston University (Dr. David Marchant) and Kharkov National University, Ukraine (Dr. Mikhail Kreslavsky) examined global patterns of landscape shapes and near-surface water ice the orbiters mapped. They concluded a covering of water ice mixed with dust mantled the surface of Mars to latitudes as low as 30 degrees, and is degrading and retreating. By observing the small number of impact craters in those features and by backtracking the known patterns of changes in Mars’ orbit and tilt, they estimated the most recent ice age occurred just 400 thousand to 2.1 million years ago, very recent in geological terms. “These results show Mars is not a dead planet, but it undergoes climate changes that are even more pronounced than on Earth,” Head said.

Marchant, a glacial geologist, who spent 17 field seasons in the Mars-like Antarctic Dry Valleys, said, “These extreme changes on Mars provide perspective for interpreting what we see on Earth. Landforms on Mars that appear to be related to climate changes help us calibrate and understand similar landforms on Earth. Furthermore, the range of microenvironments in the Antarctic Dry Valleys helps us read the Mars record.”

Mustard said, “The extreme climate changes on Mars are providing us with predictions we can test with upcoming Mars missions, such as Europe’s Mars Express and NASA’s Mars Exploration Rovers. Among the climate changes that occurred during these extremes is warming of the poles and partial melting of water at high altitudes. This clearly broadens the environments in which life might occur on Mars.”

According to the researchers, during a Martian ice age, polar warming drives water vapor from polar ice into the atmosphere. The water comes back to ground at lower latitudes as deposits of frost or snow mixed generously with dust. This ice-rich mantle, a few meters thick, smoothes the contours of the land. It locally develops a bumpy texture at human scales, resembling the surface of a basketball, and also seen in some Antarctic icy terrains. When ice at the top of the mantling layer sublimes back into the atmosphere, it leaves behind dust, which forms an insulating layer over remaining ice. On Earth, by contrast, ice ages are periods of polar cooling. The buildup of ice sheets draws water from liquid- water oceans, which Mars lacks. The age of the Earth, like Mars, is 4.6 billion years.

“This exciting new research really shows the mettle of NASA’s ‘follow-the-water’ strategy for studying Mars,” said Dr. Jim Garvin, NASA’s lead scientist for Mars exploration. “We hope to continue pursuing this strategy in January, if the Mars Exploration Rovers land successfully. Later, the 2005 Mars Reconnaissance Orbiter and 2007 Phoenix near-polar lander will be able to directly follow up on these astounding findings by Professor Head and his team.”

Global Surveyor has been orbiting Mars since 1997, Odyssey since 2001. NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages both missions for the NASA Office of Space Science, Washington. Information about NASA’s Mars missions is available on the Internet at: http://mars.jpl.nasa.gov

Original Source: NASA News Release

Posted on by Fraser Cain

NASA Tests New Rocket and Parachute Systems

Image credit: NASA

NASA has tested out rocket engines and parachutes that could help astronauts escape from the Orbital Space Plane (OSP) if there’s a problem on the launch pad. The RS-88 engines, which would launch the astronauts away from the OSP, were fired 14 times for a total of 15 seconds of operation. The parachutes were tested at the US Army’s Yuma Proving Grounds and verified that the four main and single drogue parachutes were working as expected. NASA has several Pad Abort Demonstration tests planned for the future, which should give astronauts a better chance of surviving if there’s a problem with the spacecraft.

NASA has tested rocket engines and parachutes that could be instrumental in developing the first spacecraft crew launch escape system in almost 30 years.

The tests pave the way for a series of integrated Pad Abort Demonstration (PAD) test flights to support NASA’s Orbital Space Plane (OSP) program. Launch pad abort tests support development of a system that could pull a crew safely away from danger during liftoff. Knowledge gained from the testing will reduce the future design and development risks of a launch escape system that could be used for the OSP.

“PAD is the first launch pad crew escape system NASA has developed since Apollo,” said Chuck Shaw, PAD Project Manager at the Johnson Space Center (JSC), Houston. “The engine and parachute tests followed successful vehicle wind tunnel tests in September.”

The engines were fired in tests at the Marshall Space Flight Center (MSFC) in Huntsville, Ala., in November and December. A series of 14 hot-fire tests of a 50,000-pound thrust RS-88 rocket engine were conducted, resulting in a total of 55 seconds of successful engine operation. The final test was completed Dec. 11. The engine is being designed and built by the Rocketdyne Propulsion & Power unit of The Boeing Company.

The parachutes were tested at the Army’s Yuma Proving Grounds in Yuma, Ariz., Dec. 9. The tests verify the function, performance and stability of an 80-foot drogue parachute and four 156-foot main parachutes. A 12.5-ton pallet, simulating the size and weight of a crewed vehicle, was dropped from 10,000 feet. The pallet descended to a soft landing under almost two acres of parachutes. A second set of parachute tests will be conducted at Yuma in spring 2004.

Integrated launch abort demonstration tests in 2005 will use four RS-88 engines to separate a test vehicle from a test platform, simulating pulling a crewed vehicle away from an aborted launch. Four 156-foot parachutes will deploy and carry the vehicle to landing. Lockheed Martin Corporation is building the vehicle for the PAD tests. “The separate subsystem tests will allow NASA and Lockheed Martin to begin integration of the test vehicle, its engines and parachutes over the next year,” Shaw said.

Seven integrated PAD test flights are planned during 2005/06. For the initial PAD flight test in mid-2005, a representative crew escape module will be mounted on a pusher propulsion module. Instrumented mannequins will represent a spacecraft crew during the tests.

NASA awarded a contract to Lockheed Martin in November 2002, to design and build a crew escape and survivability system demonstrator and to establish a flexible test bed for use in support of the OSP program.

The OSP program will support U.S. International Space Station requirements for crew transport, rescue and contingency cargo. The OSP will initially launch on an expendable vehicle and provide rescue capability for at least four crewmembers. OSP could launch as early as 2008. Crew transfer for the Station is planned as soon as practical, but no later than 2012. The PAD project is managed at JSC for the OSP Program. The OSP Program is managed at MSFC.

Original Source: NASA News Release

Posted on by Fraser Cain

Atlas Launches Navy Communications Satellite

Image credit: Boeing

A Lockheed Martin Atlas III rocket carried a Navy communications satellite onto orbit on Thursday morning. The Atlas III lifted off at 0230 UTC (9:30 pm EST), and it placed the UHF Follow-On (UFO) satellite into an elliptical transfer orbit approximately 32 minutes later. The launch was delayed from Monday because a boltcutter on a liquid oxygen valve needed to be replaced. This was the 68th consecutive successful launch for the Atlas rocket.

A Lockheed Martin-built Atlas III rocket carried a Navy communications satellite into orbit tonight, ending the year on a high note for International Launch Services (ILS), with six successful missions.

The Atlas III launch vehicle left the pad at 9:30 p.m. EST (02:30 Dec. 18 GMT), depositing the satellite into an elliptical transfer orbit about 32 minutes later. The satellite is the 11th in the series called UHF Follow-On (UFO), based on the 601 model built by Boeing Satellite Systems (BSS). Atlas vehicles have launched all 11 UFO satellites, beginning in 1993. The program is managed by the Navy Space and Naval Warfare Systems Command (SPAWAR).

Mark Albrecht, president of McLean-Va.,-based ILS, said: ?Through the UFO program, we have developed a long-standing synergy among the three partners ? BSS as the prime contractor, building the satellites and contracting with ILS for the launches, on behalf of the Navy. ILS and the Lockheed Martin Atlas launch team are proud to have played a part in providing vital communications capabilities worldwide to America?s military.?

Albrecht added: ?SPAWAR had the foresight 15 years ago to model its acquisition of the satellites and launches on largely commercial terms. The UHF Follow-On contract is the largest single contract for the commercial Atlas launch program. It was a tremendous boost to establish Atlas in the early days of its commercial launch business.?

A follow-on program could reunite some of the partners. Lockheed Martin (NYSE:LMT) is leading a team that includes Boeing and General Dynamics, competing to develop the follow-on to UFO called Mobile User Objective System.

Tonight?s rocket, the Atlas III, is one of three Atlas models currently being flown. It is a transitional vehicle between the Atlas II series that has been flying since 1991, and the powerful Atlas V, which made its debut successfully in 2002. The Atlas II, III and V families have achieved 100 percent success through 68 consecutive launches. Just two weeks ago, on Dec. 2, an Atlas IIAS rocket successfully launched another military payload. That mission was for the National Reconnaissance Office, and was launched from Vandenberg Air Force Base, Calif.

The Atlas III builds upon the pressure-stabilized booster design of the Atlas II, but uses the Russian RD-180 main engine with variable thrust control. The Atlas V also uses the RD-180, with a structurally stabilized Common Core Booster. Up to five solid rocket boosters can be strapped on for additional lift capability. Lockheed Martin (NYSE: LMT) developed the Atlas V series for both commercial missions and the U.S. Air Force?s Evolved Expendable Launch Vehicle (EELV) program. ILS? Atlas rockets and their Centaur upper stages are built by Lockheed Martin Space Systems Co. ? Space & Strategic Missiles Operations, at facilities in Denver, Colo.; Harlingen, Texas; and San Diego, Calif.

ILS is a joint venture of Lockheed Martin Corp. and Khrunichev State Research and Production Space Center of Russia. ILS, based in McLean, Va., markets and manages the missions for the Atlas rockets and the Russian Proton launch vehicles. ILS offers the broadest range of launch services in the world along with products with the highest reliability in the industry.

Original Source: ILS News Release

Posted on by Fraser Cain

SpaceShipOne Goes Supersonic

Image credit: Scaled

Scaled Composites’ SpaceShipOne achieved an important milestone this week when it broke the sound barrier on a test flight. The suborbital prototype was carried to 14,600 metres by the White Knight carrier plane, and then released. It fired up its hybrid rocket engine and flew up to an altitude of 20,700 metres, breaking the sound barrier in the process. There was a slight problem with the plane’s landing gear, which caused some minor damage on its landing; it’s going to be easily repaired and there were no injuries. SpaceShipOne is considered the frontrunner to win the $10 million X-Prize.

Today, a significant milestone was achieved by Scaled Composites: The first manned supersonic flight by an aircraft developed by a small company’s private, non-government effort.

In 1947, fifty-six years ago, history’s first supersonic flight was flown by Chuck Yeager in the Bell X-1 rocket under a U.S. Government research program. Since then, many supersonic aircraft have been developed for research, military and, in the case of the recently retired Concorde, commercial applications. All these efforts were developed by large aerospace prime companies, using extensive government resources.

Our flight this morning by SpaceShipOne demonstrated that supersonic flight is now the domain of a small company doing privately-funded research, without government help. The flight also represents an important milestone in our efforts to demonstrate that truly low-cost space access is feasible.

Our White Knight turbojet launch aircraft, flown by Test Pilot Peter Siebold, carried research rocket plane SpaceShipOne to 48,000 feet altitude, near the desert town of California City. At 8:15 a.m. PDT, Cory Bird, the White Knight Flight Engineer, pulled a handle to release SpaceShipOne. SpaceShipOne Test Pilot, Brian Binnie then flew the ship to a stable, 0.55 mach gliding flight condition, started a pull-up, and fired its hybrid rocket motor. Nine seconds later, SpaceShipOne broke the sound barrier and continued its steep powered ascent. The climb was very aggressive, accelerating forward at more than 3-g while pulling upward at more than 2.5-g. At motor shutdown, 15 seconds after ignition, SpaceShipOne was climbing at a 60-degree angle and flying near 1.2 Mach (930 mph). Brian then continued the maneuver to a vertical climb, achieving zero speed at an altitude of 68,000 feet. He then configured the ship in its high-drag “feathered” shape to simulate the condition it will experience when it enters the atmosphere after a space flight. At apogee, SpaceShipOne was in near-weightless conditions, emulating the characteristics it will later encounter during the planned space flights in which it will be at zero-g for more than three minutes. After descending in feathered flight for about a minute, Brian reconfigured the ship to its conventional glider shape and flew a 12-minute glide to landing at Scaled’s home airport of Mojave. The landing was not without incident as the left landing gear retracted at touchdown causing the ship to veer to the left and leave the runway with its left wing down. Damage from the landing incident was minor and will easily be repaired. There were no injuries.

The milestone of private supersonic flight was not an easy task. It involved the development of a new propulsion system, the first rocket motor developed for manned space flights in several decades. The new hybrid motor was developed in-house at Scaled with first firings in November 2002. The motor uses an ablative nozzle supplied by AAE and operating components supplied by SpaceDev. FunTech teamed with Scaled to develop a new Inertial Navigation flight director. The first flight of the White Knight launch aircraft was in August 2002 and SpaceShipOne began its glide tests in August 2003.

Scaled does not pre-announce the specific flight test plans for its manned space program, however completed accomplishments are updated as they happen at our website:
http://www.scaled.com/projects/tierone/index.htm. The website also provides downloadable photos and technical descriptions of the rocket motor system and motor test hardware.

Scaled Composites, LLC, is an aerospace research company located on the Mojave Airport:

Original Source: Scaled Composites

Posted on by Fraser Cain

SIRTF is Now the Spitzer Space Telescope

Image credit: NASA

NASA announced today that the Spitzer Space Telescope will be their new name for the Space Infrared Telescope Facility, which was launched a few months ago. The space observatory was named after the late Dr. Lyman Spitzer Jr., who was an influential scientist and one of the first to propose building space-based telescopes. As part of the announcement, NASA also released a series of new images taken by the observatory, including a glowing stellar nursery, a dusty galaxy, and a disc of planet-forming debris.

A new window to the universe has opened with today’s release of the first dazzling images from NASA’s newly named Spitzer Space Telescope, formerly known as the Space Infrared Telescope Facility.

The first observations, of a glowing stellar nursery; a swirling, dusty galaxy; a disc of planet-forming debris; and organic material in the distant universe, demonstrate the power of the telescope’s infrared detectors to capture cosmic features never before seen.

The Spitzer Space Telescope was also officially named today after the late Dr. Lyman Spitzer, Jr. He was one of the 20th century’s most influential scientists, and in the mid-1940s, he first proposed placing telescopes in space.

“NASA’s newest Great Observatory is open for business, and it is beginning to take its place at the forefront of science,” said NASA’s Associate Administrator for Space Science, Dr. Ed Weiler. “Like Hubble, Compton and Chandra, the new Spitzer Space Telescope will soon be making major discoveries, and, as these first images show, should excite the public with views of the cosmos like we’ve never had before.”

“The Spitzer Space Telescope is working extremely well. The scientists who are starting to use it deeply appreciate the ingenuity and dedication of the thousands of people devoted to development and operations of the mission,” said Dr. Michael Werner, project scientist for the Spitzer Space Telescope at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Launched Aug. 25 from Cape Canaveral, Fla., the Spitzer Space Telescope is the fourth of NASA’s Great Observatories, a program designed to paint a more comprehensive picture of the cosmos using different wavelengths of light.

While the other Great Observatories have probed the universe with visible light (Hubble Space Telescope), gamma rays (Compton Gamma Ray Observatory) and X-rays (Chandra X-ray Observatory), the Spitzer Space Telescope observes the cosmos in the infrared. Spitzer’s unprecedented sensitivity allows it to sense infrared radiation, or heat, from the most distant, cold and dust-obscured celestial objects. Today’s initial images revealed the versatility of the telescope and its three science instruments. The images:

— Resembling a creature on the run with flames streaming behind it, the Spitzer image of a dark globule in the emission nebula IC 1396 is in spectacular contrast to the view seen in visible light. Spitzer’s infrared detectors unveiled the brilliant hidden interior of this opaque cloud of gas and dust for the first time, exposing never-before-seen young stars.

— The dusty, star-studded arms of a nearby spiral galaxy, Messier 81, are illuminated in a Spitzer image. Red regions in the spiral arms represent infrared emissions from dustier parts of the galaxy where new stars are forming. The image shows the power of Spitzer to explore regions invisible in optical light, and to study star formation on a galactic scale.

— Spitzer revealed, in its entirety, a massive disc of dusty debris encircling the nearby star Fomalhaut. Such debris discs are the leftover material from the building of a planetary system. While other telescopes have imaged the outer Fomalhaut disc, none was able to provide a full picture of the inner region. Spitzer’s ability to detect dust at various temperatures allows it to fill in this missing gap, providing astronomers with insight into the evolution of planetary systems.

— Data from Spitzer of the young star HH 46-IR, and from a distant galaxy 3.25 billion light-years away, show the presence of water and small organic molecules not only in the here and now, but, for the first time, far back in time when life on Earth first emerged.

JPL manages the Spitzer Space Telescope mission for NASA’s Office of Space Science, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Major partners are Lockheed Martin Corporation, Sunnyvale, Calif.; Ball Aerospace & Technologies Corporation, Boulder, Colo.; NASA’s Goddard Space Flight Center, Greenbelt, Md.; Boeing North America (now DRS Technologies, Inc.) Anaheim, Calif.; the University of Arizona, Tucson; and Raytheon Vision Systems, Goleta, Calif. The instrument principal investigators are Dr. Giovanni Fazio, Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.; Dr. James Houck, Cornell University, Ithaca, N.Y.; and Dr. George Rieke, University of Arizona, Tucson.

The images are available at http://www.spitzer.caltech.edu and http://photojournal.jpl.nasa.gov . Additional information about the Spitzer Space Telescope is available at http://www.spitzer.caltech.edu .

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

New Research Confirms Einstein

Image credit: NASA

Einstein’s General Theory of Relativity got another confirmation this week thanks to research by an astronomer from NASA. Some theorists believed that particles popping into and out of existence in space would slow light down, as if it was moving through air or water. Scientists measured the total energy of gamma rays emitted by a distant gamma ray bursts and found that they were interacting with particles on their way to the Earth in such a way that precisely matched predictions by Einstein.

Scientists say that Albert Einstein’s principle of the constancy of the speed of light holds up under extremely tight scrutiny, a finding that rules out certain theories predicting extra dimensions and a “frothy” fabric of space.

The finding also demonstrates that basic ground- and space-based observations of the highest-energy gamma-rays, a form of electromagnetic energy like light, can provide insight into the very nature of time, matter, energy and space at scales extremely far below the subatomic level — something that few scientists thought possible.

Dr. Floyd Stecker of NASA’s Goddard Space Flight Center in Greenbelt, Md., discusses the implications of these findings in a recent issue of Astroparticle Physics. His work is based partly on an earlier collaboration with Nobel laureate Sheldon Glashow of Boston University.

“What Einstein worked out with pencil and paper nearly a century ago continues to hold up to scientific scrutiny,” said Stecker. “High-energy observations of cosmic gamma rays don’t rule out the possibility of extra dimensions and the concept of quantum gravity, but they do place some strict constraints on how scientists can go about finding such phenomena.”

Einstein stated that space and time were actually two aspects of a single entity called spacetime, a four-dimensional concept. This is the foundation to his theories of special and general relativity. For example, general relativity posits that the force of gravity is the result of mass distorting spacetime, like a bowling ball on a mattress.

General relativity is the theory of gravity on a large scale, while quantum mechanics, developed independently in the early 20th century, is the theory of the atom and subatomic particles on a very small scale. Theories based on quantum mechanics do not describe gravity, but rather the other three fundamental forces: electromagnetism (light), strong forces (binding atomic nuclei), and weak forces (seen in radioactivity).

Scientists have long hoped to meld these theories into one “theory of everything” to describe all aspects of nature. These unifying theories — such as quantum gravity or string theory — may involve the invocation of extra dimensions of space and also violations of Einstein’s special theory of relativity, such as the speed of light being the maximum attainable velocity for all objects.

Stecker’s work involves concepts called the uncertainty principle and Lorentz invariance. The uncertainty principle, derived from quantum mechanics, implies that at the subatomic level virtual particles, also called quantum fluctuations, pop in and out of existence. Many scientists say that spacetime itself is made up of quantum fluctuations which, when viewed up close, resemble a froth or “quantum foam.” Some scientists think a quantum foam of spacetime can slow the passage of light — much as light travels at a maximum speed in a vacuum but at slower speeds through air or water.

The foam would slow higher-energy electromagnetic particles, or photons — such as X rays and gamma rays — more than lower energy photons of visible light or radio waves. Such a fundamental variation in the speed of light, different for photons of different energies, would violate Lorentz invariance, the basic principle of the special theory of relativity. Such a violation could be a clue that would help point us on the road to unification theories.

Scientists have hoped to find such Lorentz invariance violations by studying gamma rays coming from far outside the Galaxy. A gamma-ray burst, for example, is at such a great distance that the differences in the speeds of photons in the burst, depending on their energy, might be measurable — as the quantum foam of space may act to slow light which has been traveling to us for billions of years.

Stecker looked much closer to home to find that Lorentz invariance is not being violated. He analyzed gamma rays from two relatively nearby galaxies about half a billion light years away with supermassive black holes at their centers, named Markarian (Mkn) 421 and Mkn 501. These black holes generate intense beams of gamma-ray photons that are aimed directly at the Earth. Such galaxies are called blazars. (Refer to Image 4 for a picture of Mkn 421. Images 1 – 3 are artist’s concepts of supermassive black holes powering quasars which, when pointed directly at Earth, are called blazars. Image 5 is a Hubble Space Telescope photo of a blazar.)

Some of the gamma rays from Mkn 421 and Mkn 501 collide with infrared photons in the Universe. These collisions result in the destruction of the gamma rays and infrared photons as their energy is converted into mass in the form of electrons and positively charged antimatter-electrons (called positrons), according to Einstein’s famous formula E=mc^2. Stecker and Glashow have pointed out that evidence of the annihilation of the highest-energy gamma rays from Mkn 421 and Mkn 501, obtained from direct observations of these objects, demonstrates clearly that Lorentz invariance is alive and well and not being violated. If Lorentz invariance were violated, the gamma rays would pass right through the extragalactic infrared fog without being annihilated.

This is because annihilation requires a certain amount of energy in order to create the electrons and positrons. This energy budget is satisfied for the highest-energy gamma rays from Mkn 501 and Mkn 421 in interacting with infrared photons if both are moving at the well-known speed of light according to the special theory of relativity. However, if the gamma rays in particular were moving at a slower velocity because of Lorentz invariance violation, the total energy available would be inadequate and the annihilation reaction would be a “no go.”

“The implications of these results,” Stecker said “is that if Lorentz invariance is violated, it is at such a small level — less than one part in a thousand trillion — that it is beyond the ability of our present technology to find. These results may also be telling us that the correct form of string theory or quantum gravity must obey the principle of Lorentz invariance.”

For more information, refer to “Constraints on Lorentz Invariance Violating Quantum Gravity and Large Extra Dimensions Models using High Energy Gamma Ray Observations” online at:

http://xxx.lanl.gov/abs/astro-ph/0308214

Original Source: NASA News Release

Posted on by Fraser Cain

Stardust is Set for Comet Encounter

Image credit: NASA

NASA’s Stardust spacecraft has nearly arrived at its first destination, Comet Wild 2. On January 2, 2004, the spacecraft will buzz through the comet’s tail and collect interstellar particles and dust. The particles will be captured on a tennis racket-shaped grid that will ensure they aren’t damaged. Stardust will return the sample to Earth in 2006 so that scientists can analyze it on the ground. It’s believed that comets are as old as the solar system, so analyzing these particles will reveal valuable information about our origins.

On January 2nd 2004 the NASA space mission, STARDUST, will fly through comet Wild 2, capturing interstellar particles and dust and returning them to Earth in 2006. Space scientists from the Open University and University of Kent have developed one of the instruments which will help tell us more about comets and the evolution of our own solar system and, critical for STARDUST, its survival in the close fly-by of the comet.

Launched in February 1999, STARDUST is the first mission designed to bring samples back from a known comet. The study of comets provides a window into the past as they are the best preserved raw materials in the Solar System. The cometary and interstellar dust samples collected will help provide answers to fundamental questions about the origins of the solar system.

Scientists from the Open University and University of Kent have developed one set of sensors for the Dust Flux Monitor Instrument (DFMI) built by the University of Chicago, and the software to analyse the data. The DFMI, part funded by the Particle Physics and Astronomy Research Council (PPARC) will record the distribution and sizes of particles on its journey through the centre, or coma, of the comet.

Professor Tony McDonnell and Dr Simon Green from the Open Universitys Planetary and Space Science Research Institute (PSSRI), will be at the mission command centre, the Jet Propulsion Laboratory in California, when the encounter with Wild 2 begins.

Dr Green explains By combining the information about each of the tiny grains of dust captured by STARDUST we will discover more about the formation of stars, planets and our solar system.

Professor Tony McDonnell said The information derived from the signals will tell us on the night if the dust shield has been critically punctured.

Cometary particles will be captured on a tennis racket like grid which contains a substance called aerogel the lightest solid in the Universe! This is a porous material that allows the particles to become embedded with minimum damage. This means that on their return to Earth they will be as near as possible to their original state.

Once the samples are captured a clam-like shell closes around them. The capsule then returns to Earth in January 2006 where it will land at the US Air Force Utah Test and Training Range. Once collected, the samples will be taken to the planetary material curatorial facility at NASAs Johnson Space Centre, Houston, where they will be carefully stored and examined.

The Open University team hope to be involved in analysing the samples that return to Earth in January 2006.

UK scientists, including a team from the Open University, are also involved with the European Space Agencys Rosetta Mission which will follow and land on Comet Churyumov-Gerasimenko. This mission is due to be launched on 26th February 2004.

Original Source: PPARC News Release

Posted on by Fraser Cain

Mars Express Needs to Aim Carefully

Image credit: ESA

Mars Express has got just one chance to get this right. In two days the Beagle 2 lander will separate from the spacecraft; next stop, Mars. Beagle 2 has to be traveling at exactly the right trajectory so that it hits the Martian atmosphere at the right angle so that it doesn’t burn up or skip off into deep space. This trajectory would crash Mars Express into the Red Planet, so after it lets go of Beagle 2, it has to change its own trajectory to go into a safe orbit.

Any football or rugby fan knows that when a player kicks the ball, there is no longer anything they can do to influence its path. The player must trust to their own skill for the ball to reach its intended destination.

What has all this to do with Mars Express? Three days from now, on 19 December 2003, Mars Express must, like an expert rugby player, ?pass? Beagle 2 on to the next player, Mars. The problem is that Beagle 2 has no thrusters on board, so cannot influence its own trajectory.

Right place at the right time
To equip the lander with rockets would have made it far too heavy to transport on Mars Express. Instead, engineers at the European Space Operations Centre (ESOC) in Darmstadt, Germany, will precisely orientate the Mars Express spacecraft to point Beagle 2 at Mars. Everything relies on dropping Beagle 2 in the right place at the right time.

Collision course…
In order to do this, Mars Express has been following a trajectory that will lead to Beagle 2?s touchdown point. That puts the whole mission in danger, because it means that Mars Express is effectively on a collision course with the planet.

If nothing is done to alter its trajectory, instead of falling into orbit, Mars Express will slam into Mars on 25 December. Yet nothing can be done to avert this impending catastrophe until Beagle 2 has been released, since to move the spacecraft beforehand would ruin the landing.

At ejection, the spacecraft simply lets go of the lander. Beagle 2 will be spun to keep it stable and pushed away with the gentlest of forces; nothing dramatic like a ‘blast off’ at launch. Then, and only then, can engineers send the necessary commands for Mars Express to fire its engine and alter its course to avoid destruction on the surface of Mars.

Original Source: ESA News Release

Posted on by Fraser Cain

No Moon Announcement Today

United States President George Bush disappointed space optimists today when he failed to announce any grand plans to return to the Moon or send humans to Mars. Some believed that Bush would announce a revitalized goal as part of the 100th anniversary celebrations for the first flight of the Wright Flyer at Kitty Hawk, North Carolina. Some believe that the 2004 budget deficit of $500 billion makes any additional spending difficult for the President to justify. Some are hopeful that Bush will still make an announcement at the State of the Union address in January 2004.