Posted on by Fraser Cain

Ancient Impact Craters Reveal Mars’ First Equator

Since the time billions of years ago when Mars was formed, it has never been a spherically symmetric planet, nor is it composed of similar materials throughout, say scientists who have studied the planet. Since its formation, it has changed its shape, for example, through the development of the Tharsis bulge, an eight kilometer [five mile] high feature that covers one-sixth of the Martian surface, and through volcanic activity. As a result of these and other factors, its polar axis has not been stable relative to surface features and is known to have wandered through the eons as Mars rotated around it and revolved around the Sun.

Now, a Canadian researcher has calculated the location of Mars’ ancient poles, based upon the location of five giant impact basins on the planet’s surface. Jafar Arkani-Hamed of McGill University in Montreal, Quebec, has determined that these five basins, named Argyre, Hellas, Isidis, Thaumasia, and Utopia, all lie along the arc of a great circle. This suggests that the projectiles that caused the basins originated with a single source and that the impacts trace the Martian equator at the time of impact, which was prior to the development of the Tharsis bulge, he says.

Writing in the Journal of Geophysical Research (Planets), Arkani-Hamed calculates that the source of the five projectiles was an asteroid that had been circling the Sun in the same plane as Mars and most of the other planets. At one point, it passed close to the planet, until the force of Martian gravity surpassed the tensile strength of the asteroid, at which point it fragmented. The five large fragments would have remained in the same plane, that of Mars’ then-equator. They hit in different spots around the Martian globe, due to Mars’ rotation on its then-axis and the differing lengths of time the fragments took before impacting on Mars.

Arkani-Hamed describes the locations of the resulting basins, only three of which are well preserved. The two others have been detected by analysis of Martian gravitational anomalies. The great circle they describe on the Martian surface has its center at latitude -30 and longitude 175. By realigning the map of Mars with that spot as the south pole, the great circle marks the ancient equator.

Arkani-Hamed estimates that the mass of the asteroid captured by Mars was about one percent of that of Earth’s Moon. Its diameter was in the range of 800 to 1,000 kilometers [500 to 600 miles], depending upon its density, which cannot be determined.

The significance of Arkani-Hamed’s findings, if borne out by further research, is that the extent of presumed underground water on Mars would have to be reassessed. “The region near the present equator was at the pole when running water most likely existed,” he said in a statement. “As surface water diminished, the polar caps remained the main source of water that most likely penetrated to deeper strata and has remained as permafrost, underlain by a thick groundwater reservoir. This is important for future manned missions to Mars.”

Original Source: AGU News Release

Posted on by Fraser Cain

Fundamental Aspect of the Universe has Remained Unchanged

A fundamental number that affects the color of light emitted by atoms as well as all chemical interactions has not changed in more than 7 billion years, according to observations by a team of astronomers charting the evolution of galaxies and the universe.

The results are being reported today (Monday, April 18) at the annual meeting of the American Physical Society (APS) by astronomer Jeffrey Newman, a Hubble Fellow at Lawrence Berkeley National Laboratory representing DEEP2, a collaboration led by the University of California, Berkeley, and UC Santa Cruz. Newman is presenting the data and an update on the DEEP2 project at a 1 p.m. EDT press conference at the Marriott Waterside Hotel in Tampa, Fla.

The fine structure constant, one of a handful of pure numbers that occupy a central role in physics, pops up in nearly all equations involving electricity and magnetism, including those describing the emission of electromagnetic waves – light – by atoms. Despite its fundamental nature, however, some theorists have suggested that it changes subtly as the universe ages, reflecting a change in the attraction between the atomic nucleus and the electrons buzzing around it.

Over the past few years, a group of Australian astronomers has reported that the constant has increased over the lifetime of the universe by about one part in 100,000, based on its measurements of the absorption of light from distant quasars as the light passes through galaxies closer to us. Other astronomers, however, have found no such change using the same technique.

The new observations by the DEEP2 survey team use a more direct method to provide an independent measure of the constant, and show no change within one part in 30,000.

“The fine structure constant sets the strength of the electromagnetic force, which affects how atoms hold together and the energy levels within an atom. At some level, it is helping set the scale of all ordinary matter made up of atoms,” Newman said. “This null result means theorists don’t need to find an explanation for why it would change so much.”

The fine structure constant, designated by the Greek letter alpha, is a ratio of other “constants” of nature that, in some theories, could change over cosmic time. Equal to the square of the charge of the electron divided by the speed of light times Planck’s constant, alpha would change, according to one recent theory, only if the speed of light changed over time. Some theories of dark energy or grand unification, in particular those that involve many extra dimensions beyond the four of space and time with which we are familiar, predict a gradual evolution of the fine structure constant, Newman said.

DEEP2 is a five-year survey of galaxies more than 7-to-8-billion-light years distant whose light has been stretched out or redshifted to nearly double its original wavelength by the expansion of the universe. Though the collaborative project, supported by the National Science Foundation, was not designed to look for variation in the fine structure constant, it became clear that a subset of the 40,000 galaxies so far observed would serve that purpose.

“In this gigantic survey, it turns out that a small fraction of the data seems to be perfect for answering the question Jeff’s asking,” said DEEP2 principal investigator Marc Davis, professor of astronomy and of physics at UC Berkeley. “This survey is really general purpose and will serve a million uses.”

Several years ago, astronomer John Bahcall of the Institute for Advanced Study pointed out that, in the search for variations in the fine structure constant, measuring emission lines from distant galaxies would be more direct and less error-prone that measuring absorption lines. Newman quickly realized that DEEP2 galaxies containing oxygen emission lines were perfectly suited to provide a precise measure of any change.

“When the contradictory results from absorption lines starting showing up, I had the idea that, since we have all these high redshift galaxies, maybe we can do something not with absorption lines, but with emission lines within our sample,” Newman said. “Emission lines would be very slightly different if the fine structure constant changed.”

The DEEP2 data allowed Newman and his colleagues to measure the wavelength of emission lines of ionized oxygen (OIII, that is, oxygen that has lost two electrons) to a precision of better than 0.01 Angstroms out of 5,000 Angstroms. An Angstrom, about the width of a hydrogen atom, is equivalent to 10 nanometers.

“This is a precision surpassed only by people trying to look for planets,” he said, referring to detection of faint wobbles in stars due to planets tugging on the star.

The DEEP2 team compared the wavelengths of two OIII emission lines for 300 individual galaxies at various distances or redshifts, ranging from a redshift of about 0.4 (approximately 4 billion years ago) to 0.8 (about 7 billion years ago). The measured fine structure constant was no different from today’s value, which is approximately 1/137. There also was no upward or downward trend in the value of alpha over this 4-billion-year time period.

“Our null result is not the most precise measurement, but another method (looking at absorption lines) that gives more precise results involves systematic errors that cause different people using the method to come up with different results,” Newman said.

Newman also announced at the APS meeting the public release of the first season of data (2002) from the DEEP2 survey, which represents 10 percent of the 50,000 distant galaxies the team hopes to survey. DEEP2 uses the DEIMOS spectrograph on the Keck II telescope in Hawaii to record redshift, brightness and color spectrum of these distant galaxies, primarily to compare galaxy clustering then versus now. The survey, now more than 80 percent complete, should finish observations this summer, with full data release by 2007.

“This is really a unique data set for constraining both how galaxies have evolved and how the universe has evolved over time,” Newman said. “The Sloan Digital Sky Survey is making measurements out to about redshift 0.2, looking back the last 2-3 billion years. We really start at redshift 0.7 and peak at 0.8 or 0.9, equivalent to 7-8 billion years ago, a time when the universe was half as old as it is today.”

The survey also has completed measurements that could shed light on the nature of dark energy – a mysterious energy that permeates the universe and seems to be causing the universe’s expansion to accelerate. The team now is modeling various theories of dark energy to compare theoretical predictions with the new DEEP2 measurements.

As Davis explained it, the amount of dark energy, now estimated to be 70 percent of all the energy in the universe, determines the evolution of galaxies and clusters of galaxies. By counting the number of small groups and massive clusters of galaxies in a distant volume of space as a function of their redshift and mass, it is possible to measure the amount by which the universe has expanded to the present day, which depends on the nature of dark energy.

“Basically, you count the clusters and ask, ‘Are there a lot, or a few?'” Davis said. “That’s all it amounts to. If there are very few clusters, that means the universe expanded quite a ways. And if there are a lot of clusters the universe didn’t expand as much.”

Davis currently is comparing DEEP2 measurements with predictions of the simplest dark energy theory, but hopes to collaborate with other theoreticians to test more exotic dark energy theories.

“What they are really trying to get at is how the dark energy density is changing as the universe is expanding,” said UC Berkeley theoretical physicist Martin White, a professor of astronomy and of physics who has worked with Davis. “If the dark energy density is Einstein’s cosmological constant, then the theoretical prediction is that it doesn’t change. The holy grail now is to get some evidence that it’s not the cosmological constant, that it is in fact changing.”

Original Source: UC Berkeley

Posted on by Fraser Cain

Audio: Oldest Star Discovered

Image credit: ANU
Listen to the interview: Oldest Star Discovered (2.5 mb)

Or subscribe to the Podcast: universetoday.com/audio.xml

Fraser Cain: How old is this star that you’ve found?

Anna Frebel: Well, that’s a bit of a problem because we cannot actually place an exact age on the star. You would need to measure radioactive elements in the star and if you said already that the star if very primitive, it is mint condition, so we don’t see any radioactive elements and hence we can only make a good guess on how old it is.

Fraser: How does it look different from our own sun?

Frebel: It’s very different from our Sun. We found the star because it had very low iron as compared to the Sun and this is also the reason why we think it is the oldest star because it has the lowest iron ever observed, and not only the iron, but also many other elements; carbon and nitrogen are very low as compared to the Sun.

Fraser: Why does our Sun have larger amounts of iron and this one doesn’t?

Frebel: If you consider the chemical evolution of the galaxy, and the entire universe, and you might know that after the Big Bang, the universe started out only with hydrogen and helium, and a little bit of lithium, and all the time, the heavy elements were synthesized in the stars themselves, now, certain elements such as carbon, nitrogen, oxygen and iron were synthesized during the lifetime of stars, but other elements, especially the heavy ones, were produced in supernova explosions; the death of a big star. So over time, the stars got enriched more and more in heavy elements; the Sun is not very old by astronomical standards, hence it has much more heavy elements than the star 183027, which was what we found.

Fraser: So you are saying that normal stars like our Sun have been through the wash cycle several times, and they have had their matter recycled through several stars, and that’s why they have some of the higher elements in them. How can a star remain untouched from such a long period?

Frebel: Well the density of stars in some areas is rather low and others, it’s higher; this star is a field halo star, so it’s in an area of our galaxy which is not very populated, so it’s just been sitting there for many, many, many years, and because it’s a low mass star, it is still very unevolved, so it’s just waiting there for us to find it.

Fraser: What kind of star is it, because I understand that our Sun is several billion years old, but definitely not the age of the universe, so what kind of star is it that it could be as old as the Big Bang?

Frebel: The star is a low mass star, it’s a bit lighter than the Sun and that means that it evolved very very slowly. I mean the Sun, well, it’s still in its teenage years, so it hasn’t burned much. High mass stars burn very very fast, and they explode quickly as a supernova enriching the surrounding gas; the interstellar medium with heavy elements, but this star, because it is so low in mass has just been sitting there and burning its hydrogen slowly and we think the hydrogen has just finished burning. So helium should be the next stage.

Fraser: How early on do you think it actually formed? How long after the Big Bang?

Frebel: Well, we have 2 scenarios; one would be that it formed in the second generation of stars and the first generation formed within one billion years after the Big Bang. So that star should have formed very quickly, probably about one billion years after the Big Bang. And the second theory which we cannot exclude, although I personally don’t favor it, is that the star indeed is a first star itself, meaning that it formed as one of the very, very first stars in the universe and presumably that happened then within the first billion years.

Fraser: Do you think that there are many of these types of stars in the Milky Way?

Frebel: Good question; probably not because they are very old and hence they are very rare because it seems that there is a certain type of these low mass stars which are actually able to survive that long and astronomers have been searching for these types of stars for the last 30-40 years and so far, we’ve only found 2 in huge efforts, so we are really looking for the needle in the haystack I would say.

Fraser: In the last couple of years, I have been covering the fires at Mount Stromlo. How is the observatory doing?

Frebel: It’s doing very well. We haven’t been affected from a science point of view. We have been very much productive since the fires. The reconstruction has now started; we are getting an new advanced, technological instrumentation building so we have a lot of noise here, but that also means things are progressing. Everyone is doing very well and we’ve, I think psychologically, we’ve put the fires way behind us.

Posted on by Fraser Cain

What’s Up This Week – Apr 18 – Apr 24, 2005

Image credit: NOAO/AURA/NSF
Monday, April 18 – Tonight let’s use two bright celestial objects to our advantage to help you locate an outstanding galactic cluster – M44. Because this great gathering of stars is located near the ecliptic plane, you will find it easily tonight in binoculars by scanning the area mid-point between Saturn and the Moon. Also known as the “Beehive”, this wonderful open cluster is sufficiently bright enough to be seen unaided under darker conditions. In ancient times it was used as a weather predicting tool – if it was not visible under otherwise clear skies – a major storm was on the way. This easy collection of bright pairs was known and recorded as far back as 260 B.C. – but in 1610 Galileo was the first to resolve it into individual stars with his newly invented telescope. Enjoy its stellar “swarm” tonight…

Continue on to the lunar surface to explore the very fine appearance of crater Copernicus located about mid-way along the terminator. It is not the largest, the deepest, the oldest, the most bright, nor the most unusual of lunar features – but it definitely holds the record at being the most spectacular!

Tuesday, April 19 – A little more than 35 years ago, the Apollo 13 crew was on a mission to land on the Moon in the Fra Mauro highlands. Although disaster kept them from completion, Apollo 14 carried out the plan a little less than a year later – and tonight we will be able to see this landing area on the lunar surface. Along the terminator to the south, you will see a dark expanse known as Mare Nubium. On its northern shore and nearing the terminator’s center, you will see a inlet of small shallow craters. The brightest of these small rings is crater Parry with Fra Mauro appearing larger and more shallow to its north. Power up! Fra Mauro has a long fissure that runs between its north and south borders. At the northern crater edge you will see the ruins of an ancient impact. Known as X, it definitely marks the spot of this successful lunar landing.

Wednesday, April 20 – Tonight the most prominent lunar feature will be the ancient and graceful Gassendi. Its bright ring stands on the north shore of Mare Humorum – an area about the size of the state of Arkansas. Around 113 km in diameter and 2012 meters deep, you will see a triple mountain peak in its center and the south wall eroded by lava flows. Gassendi offers a wealth of details to telescopic observers on its ridge and rille covered floor.

When you have finished with your lunar observations, let’s travel on to a fascinating double star. A little less than a handspan south of the last star in the handle of the “Big Dipper”, you will see a fairly bright star that is on the edge of unaided eye detection thanks to tonight’s gibbous Moon. Aim your telescopes or steady binoculars there for a real treat! Alpha Canum is more commonly known as Cor Caroli – or the “heart of Charles” – and is a true jewel easily split by the most modest of instruments. Although some observers may not be able to distinguish a color difference between the magnitude 2.8 and 5.6 companions, it has been my experience that most will see a faded blue primary (a magnetic spectrum variable) and pale orange secondary on this 120 light year distant pair. If you are equatorially aligned, turn off the drive and wait for 150 seconds. Widely separated Struve 1702 will be coming into view…

Thursday, April 21 – Tonight’s lunar observing will be a challenging one – worthy of the larger scope. Start by identifying past study craters, Hansteen and Billy. Due west of Hansteen you will find a small crater near the terminator known as Sirsalis. It will appear as a small, dark ellipse with a bright west wall with its twin, Sirsalis B on the edge. The feature you will be looking for is the Sirsalis Rille – the longest presently known. Stretching northeast of Sirsalis and extending for 459 kilometers south to the bright rays of Byrgius, this major “crack” in the lunar surface will show several branches – like a long dry river bed.

Tonight let’s go from one navigational extreme to another as viewers in the northern hemisphere try their hand at Polaris. As guide star for north, Polaris is also a wonderful double with an easily resolved, faint blue companion for the mid-sized telescope. But what about the south? Viewers in the southern hemisphere can never see Polaris – is there a matching star for the south? The answer is yes – Sigma Octantis – but at magnitude 5, it doesn’t make a very good unaided eye guide. Ancient navigators found better success with the constellation of Crux, better known as the “Southern Cross”. While Crux has many wonderful double stars, if southern hemispere viewers would like to see a star very similar to Polaris, then try your luck with Lambda Centauris. The magnitude difference between components and separation are about the same!

Friday, April 22 – Today celebrates the birthday of Sir Harold Jeffreys, who was born in 1891. Jeffreys was an astrogeophysicist and the first person to envision Earth’s fluid core. He also helped in our understanding of tidal friction, general planetary structure, and the origins of our solar system. Start your morning off before dawn with a chance to view the peak of the Lyrid meteor shower. Since the radiant is near Vega, you will improve your chances of spotting them when the constellation of Lyra is as high as possible and the Moon far to the west. This stream comes from parent Comet Thatcher and produces around 15 bright, long-lasting meteors per hour. (UPDATE: The current projected peak time has been upgraded to 10:30 UT.)

But what about later?

The Moon will be very busy tonight… On this universal date it will occult Jupiter in regions across mid-to-south Africa. Since we have many readers from that area, please watch! This IOTA webpage will give you precise universal times for your location. As the Earth turns, a wide swath across the southeast, central and western portions of both North and South America, will enjoy the Moon occulting Eta Viriginis. Be sure to visit this IOTA webpage for a list of universal times in your area.

Saturday, April 23 – Pioneer quantum physicist, Max Planck was born on this day in 1858. In 1900, Max developed the quantum – known as the Planck equation- to explain the shape of blackbody spectra (a function of temperature and wavelength of emission). A “blackbody” is any object that absorbs all incident radiation – regardless of wavelength. For example, a heated metal has blackbody properties because the energy it radiates is thermal. The blackbody spectrum’s shape remains a constant and the peak and height of an emitter can be measured against it – be it cosmic background radiation or our own bodies.

Now, let’s put this knowledge into action. Stars themselves approximate blackbody radiators, because their temperature directly controls the color we see. A prime example of a “hot” star is Alpha Viginis, better known as Spica. Compare its color to the cooler Arcturus… What colors do you see? There are other astronomical delights that radiate like blackbodies over some or all parts of the spectrum as well. You can observe a prime example in a nebulae, such as the M42 in Orion. By examining the radio portion of the spectrum, we find the temperature properly matches that of electrons involved in the process of flourescence. Much like a common household fixture, this process is what produces the visible light we can observe.

Sunday, April 24 – For central and western North America, this would be an excellent morning to set the alarm for the early hours as the Moon undergoes a penumbral eclipse – reaching its deepest at 09:55 UT. The effects of the shading of a penumbral eclipse are not as dramatic as the umbral portion, but it’s still fun! For viewers in Central America and western South America, the event will happen before dawn. Hawaii will catch the action around local midnight, while Australia, New Zealand and Japan will have their opportunity in the early evening.

Just because we have full Moon doesn’t mean we can’t have any fun. Tonight let’s explore the star in the middle of the handle of the “Big Dipper”. Its name is Mizar, but if you have exceptional eyes you may also see its companion Alcor as well! The ancient Arabs used this star as an “eye test” for their warriors – if you could see both components, you were given a horse. The name Mizar and Alcore literally translates to “the horse and rider”. If it’s not clear to you, even the slightest optical aid will separate the two, but a treat is in store for telescope users. Mizar itself is a double star! As the very first to be discovered and photographed, you will enjoy this pair. In the eyepiece, Alcor will appear to the east of Mizar A and B, but look for a faint star in between. It has the very impressive name of Sidus Ludovicianum and was once believed to be a planet.

Until next week? Ask for the Moon – but keep reaching for the stars! Light speed…. ~Tammy Plotner

Posted on by Fraser Cain

DART Mission Ends Prematurely

The Demonstration of Autonomous Rendezvous Technology (DART) spacecraft that was successfully launched Friday at 10:25 a.m. PDT from Vandenberg Air Force Base, Calif., experienced an on orbit anomaly late Friday.

After a successful rendezvous, acquisition of the target spacecraft, and approach to within approximately 300 feet, DART placed itself in the retirement phase before completing all planned proximity operations, ending the mission prematurely.

NASA is convening a mishap investigation board to determine the reason for the DART spacecraft anomaly.

A teleconference with DART project managers is scheduled for 11 a.m. PDT. Media who want to participate must register by calling the DART Newsroom at 805/605-3051.

The DART spacecraft was a flight experiment attempting to establish autonomous rendezvous capabilities for the U.S. space program. While previous rendezvous and docking efforts have been piloted by astronauts, the DART spacecraft completed the rendezvous and acquisition with no human intervention, relying on a variety of sensors and analyses to complete these functions.

For more information about DART on the Internet, visit:

http://www.nasa.gov/

Original Source: NASA News Release

Posted on by Fraser Cain

Iceberg Smashes Off a Chunk of Antarctica

Maps of Antarctica need to be amended. The long-awaited collision between the vast B-15A iceberg and the landfast Drygalski ice tongue has taken place. This Envisat radar image shows the ice tongue ? large and permanent enough to feature in Antarctic atlases – has come off worst.

An image acquired by Envisat on 15 April 2005 shows that a five-kilometre-long section at the seaward end of Drygalski has broken off following a collision with the drifting B-15A. The iceberg itself appears so far unaffected. With more than half the iceberg still to clear the floating pier of ice, Drygalski may undergo more damage in coming days.

It is an old philosophical paradox: what happens when an irresistible force meets an immovable object? For the past few months, ESA’s Envisat satellite has been watching an answer play out in ice, as the B-15A iceberg converged on the Drygalski ice tongue.

The sheer scale of B-15A is best appreciated from space. The bottle-shaped Antarctic iceberg is around 115 kilometres long, with an area exceeding 2500 square kilometres, making it about as large as the entire country of Luxembourg.

From January the iceberg has been drifting towards, then past, the 70-kilometre-long Drygalski ice tongue in McMurdo Sound on the Ross Sea. In the last month prevailing currents have been slowly edging B-15A along past the northern edge of Drygalski.

Envisat’s Advanced Synthetic Aperture Radar (ASAR) instrument has been monitoring events since the start of the year, gathering the highest frequency weather-independent satellite dataset of this area ever.

Ice in opposition
B-15A is the largest remaining section of the even larger B-15 iceberg that calved from the Ross Ice Shelf in March 2000. Equivalent in size to Jamaica, B-15 had an initial area of 11 655 square kilometres but subsequently broke up into smaller pieces.

Since then, the largest piece – B-15A – has found its way to McMurdo Sound, where its presence has blocked ocean currents and led to a build-up of sea ice. With the Antarctic summer now at an end and in-situ observations therefore limited, the ASAR instrument aboard Envisat becomes even more useful for monitoring changes in polar ice and tracking icebergs.

Its radar signals pass freely through the thickest polar storm clouds or local darkness. And because ASAR is sensitive to surface texture as well as physical and chemical properties, the sensor is extremely sensitive to different types of ice ? for example clearly delineating the older rougher surface of the Drygalski ice tongue and iceberg B15A from the surrounding sea ice pack.

The Drygalski ice tongue is located at the opposite end of McMurdo Sound from the US and New Zealand bases. The long narrow tongue stretches out to sea as an extension of the land-based David Glacier, which flows through coastal mountains of Victoria Land.

Twin-mode ASAR Antarctic observations
Envisat’s ASAR instrument monitors Antarctica in two different modes: Global Monitoring Mode (GMM) provides 400-kilometre swath one-kilometre resolution images, enabling rapid mosaicking of the whole of Antarctica to monitor changes in sea ice extent, ice shelves and iceberg movement.

Wide Swath Mode (WSM) possesses the same swath but with 150-metre resolution for a detailed view of areas of particular interest.

ASAR GMM images are routinely provided to a variety of users including the US National Oceanic and Atmospheric Administration (NOAA) National Ice Centre, responsible for tracking icebergs worldwide.

ASAR imagery is also being used operationally to track icebergs in the Arctic by the Northern View and ICEMON consortia, which provide ice monitoring services as part of the Global Monitoring for Environment and Security (GMES) initiative, jointly backed by ESA and the European Union.

This year also sees the launch of CryoSat, a dedicated ice-watching mission designed to precisely map changes in the thickness of polar ice sheets and floating sea ice.

CryoSat, in connection with regular Envisat ASAR GMM mosaics and SAR interferometry ? a technique used to combine radar images to measure tiny centimetre-scale shifts between acquisitions – should answer the question of whether the kind of ice-shelf calving that gave rise to B-15 and its descendants are a consequence of ice sheet dynamics or other factors.

Together they will provide insight into whether such iceberg calving occurrences are becoming more common, as well as improving our understanding of the relationship between the Earth’s ice cover and the global climate.

Original Source: ESA News Release

Posted on by Fraser Cain

Expedition 11’s Soyuz Docks

Image credit: NASA
New residents arrived at the International Space Station tonight to begin a six-month mission and to prepare for the arrival of the first Space Shuttle crew to visit the complex since November 2002.

With Expedition 11 Commander Sergei Krikalev at the controls, the Soyuz TMA-6 spacecraft automatically linked up to the Pirs Docking Compartment at 9:20 p.m. CDT as the Soyuz and the Station flew over eastern Asia. Within minutes, hooks and latches between the two vehicles joined together to form a tight seal.

Aboard the Soyuz with Krikalev were NASA Expedition 11 Flight Engineer and Science Officer John Phillips and European Space Agency (ESA) Astronaut Roberto Vittori of Italy.

Hatches between the Soyuz and the Station were opened at 11:45 p.m. Saturday. The two crews greeted one another with handshakes and hugs. The first activity scheduled for the five crewmembers was a safety briefing to familiarize the newly arrived trio with emergency escape procedures.

Krikalev and Phillips will remain on board the Station until October. Vittori will return to Earth next week after eight days of scientific experiments on the complex under a commercial agreement between ESA and the Russian Federal Space Agency. The trio launched at dawn Friday from the Baikonur Cosmodrome in Kazakhstan for their two-day journey to the outpost.

Aboard the Station at the time of docking were Expedition 10 Commander and NASA Science Officer Leroy Chiao and Flight Engineer Salizhan Sharipov, who are wrapping up their six-month mission and who will ride home on their Soyuz TMA-5 capsule with Vittori on April 25 for a pre-dawn landing in central Kazakhstan. Saturday marked the 185th day in space for Chiao and Sharipov and their 183rd day on the Station.

Krikalev and Phillips will relocate the new Soyuz from Pirs to the Zarya module docking port this summer.

On hand for the docking activities at the Russian Mission Control Center outside Moscow were NASA Deputy Administrator Fred Gregory, NASA Deputy Associate Administrator for Space Station and Space Shuttle Programs Michael Kostelnik, NASA Deputy Associate Administrator for Exploration Systems Craig Steidle and ISS Program Manager William Gerstenmaier along with Russian and European space officials.

On Sunday before they begin an extended sleep period, the new crew will transfer their custom-made Soyuz seatliners as well as cargo carried aloft on the Soyuz for the complex. Later in the day, initial briefings on the handover from the current residents to their replacements will be conducted and the new Soyuz? systems will be deactivated.

Over the next week, Krikalev and Phillips will familiarize themselves with Station systems and stowed equipment, conduct robotics training with the Canadarm2 robot arm, and receive detailed briefings on scientific payloads. Phillips and Chiao will also continue the maintenance and repair work on the cooling systems in the U.S. airlock Quest for the resumption of spacewalk capability from the Station this summer.

In addition, they will pack discarded gear and equipment for return to Earth on the Raffaello cargo module that will be brought to the Station on the Space Shuttle?s Return to Flight mission, STS-114, targeted to arrive next month on the Shuttle Discovery.

Information on the crew’s activities aboard the Space Station, future launch dates, as well as Station sighting opportunities from anywhere on the Earth, is available on the Internet at:


http://spaceflight.nasa.gov/

Original Source: NASA News Release

Posted on by Fraser Cain

Podcast: Oldest Star Discovered

Let’s say you’re browsing around the comic book store and happened to notice a perfect copy of Action Comics #1 on the rack mixed in with the current stuff. It’s in mint condition, untouched since it was first printed almost 70 years ago. Now imagine the same situation… except with stars. Anna Frebel is a PhD student at the Research School of Astronomy & Astrophysics at the Australian National University. She’s working with a team of astronomers who have found the oldest star ever seen – possibly untouched since shortly after the Big Bang.
Continue reading “Podcast: Oldest Star Discovered”

Posted on by Fraser Cain

Matter is Incinerated When it Falls into a Black Hole

Image credit: ESA
Contrary to established scientific thinking, you’d be roasted and not “spaghettified” if you stumbled into a supermassive black hole. New research being presented at the Institute of Physics conference Physics 2005 in Warwick will take a new look at the diet of the universe’s most intriguing object, black holes.

Black holes stand at the very edge of scientific theory. Most scientists believe they exist, although many of their theories break down under the extreme conditions within. But Professor Andrew Hamilton of the University of Colorado says he knows what you would find inside, and challenges the traditional idea that gravity would cause you death by “spaghettification”.

Most people have heard of the event horizon of a black hole, as the point of no return. But astronomically realistic black holes are more complex and should have two horizons, an outer and an inner. In the bizarre physics of black holes, time and space are exchanged when you cross an event horizon, but at a second horizon they would switch back again.

Traveling into a black hole, you would therefore pass through a strange region where space is falling inward faster than light, before finally entering a zone of normal space at the core. It’s this core of normal space which Professor Hamilton has been working on.

A so-called singularity sits at the centre of the core, swallowing up matter. But according to Professor Hamilton, the strange laws of general relativity temper its appetite. If the singularity ate too quickly, it would become gravitationally repulsive, so instead, matter piles up in a hot, dense plasma filling the core of the black hole and siphoning gradually into the singularity.

Depending on the size of the black hole, this plasma could be the cause of a space traveller’s demise. Most books will tell you that under the extreme gravitational conditions of a black hole, your feet would experience gravity more strongly than your head, and your body would be stretched out like spaghetti.

For a small black hole with the mass of several suns, this should still be true. But for a supermassive black hole weighing millions or billions of suns, explains Professor Hamilton, the tidal forces which cause spaghettification are relatively weak. You would instead be roasted by the heat of the plasma.

Professor Andrew Hamilton is Professor of Astrophysics at the Department of Astrophysical and Planetary Sciences, University of Colorado.

Original Source: Institute of Physics News Release

Posted on by Fraser Cain

Michael Griffin Takes the Helm at NASA

Michael Griffin is returning to NASA as the Agency’s 11th Administrator.

He reported to work at NASA Headquarters in Washington on Thursday, April 14, the same day the Expedition 11 crew launched to the International Space Station.

“I have great confidence in the team that will carry out our nation’s exciting, outward-focused, destination-oriented program,” said Griffin. “I share with the agency a great sense of privilege that we have been given the wonderful opportunity to extend humanity’s reach throughout the solar system.”

Administrator Griffin, who served as NASA’s Chief Engineer earlier in his career, takes the helm of the Agency as it’s charting a new course. The Space Shuttle fleet is poised to Return to Flight, the first step in fulfilling the Vision for Space Exploration — a bold plan to return humans to the Moon, journey to Mars and beyond.

In his first address to NASA employees, Griffin said he would focus immediately on Return to Flight efforts, and noted that the Agency has much on its plate right now. “It’s going to be difficult, it’s going to be hectic, but we will do it together,” he said.

He also told employees that he saw “nothing but cheers” in the public reaction to the Vision. “People want a space program that goes somewhere and does something,” he said.

Griffin was nominated by President George W. Bush on March 14, 2005, and confirmed by the United States Senate on April 13, 2005. At his confirmation hearing on April 12, he made clear that the “strategic vision for the U.S. manned space program is of exploration beyond low Earth orbit.”

In his statement to the committee, Griffin said, “It is a daring move at any time for a national leader to call for the bold exploration of unknown worlds, a major effort at the very limit of the technical state of the art,” adding later, “in the twenty-first century and beyond, for America to continue to be preeminent among nations, it is necessary for us also to be the preeminent spacefaring nation.”

A holder of five master’s degrees and a Ph.D., Griffin also made clear that, despite limited resources, “NASA can do more than one thing at a time.”

“My conclusion is that we as a nation can clearly afford well-executed, vigorous programs in both robotic and human space exploration as well as in aeronautics. We know this. We did it,” he said, referring back to the Agency’s accomplishments during the Apollo era.

He closed his statement with a call for exploration: “I believe that, if money is to be spent on space, there is little doubt that the huge majority of Americans would prefer to spend it on an exciting, outward-focused, destination-oriented program. And that is what the President’s Vision for Space Exploration is about.”

Prior to his appointment, Griffin was serving as Space Department Head at Johns Hopkins University Applied Physics Laboratory. Prior to that, he was President and Chief Operating Officer of In-Q-Tel, Inc. He also served in several positions within Orbital Sciences Corporation, including Chief Executive Officer of Magellan Systems, Inc.

Earlier in his career, Griffin served as chief engineer and associate administrator for exploration at NASA Headquarters and also worked at NASA’s Jet Propulsion Laboratory. He also served as Deputy for Technology at the Strategic Defense Initiative Organization.

Griffin received a bachelor’s degree in Physics from Johns Hopkins University; a master’s degree in Aerospace Science from Catholic University of America; a Ph.D. in Aerospace Engineering from the University of Maryland; a master’s degree in Electrical Engineering from the University of Southern California; a master’s degree in Applied Physics from Johns Hopkins University; a master’s degree in Business Administration from Loyola College; and a master’s degree in Civil Engineering from George Washington University.

Original Source: NASA News Release