Posted on by Ken Kremer

Era of Space Shuttle Endeavour Ends with June 1 landing at the Kennedy Space Center

Space Shuttle Endeavour landed safely at the Kennedy Space Center on June 1, 2011 at 2:35 a.m. EDT. During the 16 day STS-134 mission, Endeavour delivered the $2 Billion Alpha Magnetic Spectrometer to the International Space Station and journeyed more than sixteen million miles. Endeavour was towed back to the Orbiter Processing Facility in preparation for display at her new retirement home at the California Science Center. Credit: Ken Kremer

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KENNEDY SPACE CENTER – Space Shuttle Endeavour and her six man crew landed safely today at the Kennedy Space Center in Florida at 2:35 a.m. EDT following a 16 day journey of more than sixteen million miles.

The STS-134 mission marked the end of Endeavour’s space exploration career. It was the 25th and last space mission by NASA’s youngest orbiter. Altogether, Endeavour has logged 299 days in space, orbited Earth 4,671 times and traveled 122,883,151 miles.

The crew was led by Shuttle Commander Mark Kelly. Also aboard were Pilot Greg H. Johnson and Mission Specialists Mike Fincke, Drew Feustel, Greg Chamitoff and the European Space Agency’s Roberto Vittori. Vittori is the last non NASA astronaut to fly on a shuttle mission.

The night landing capped a highly productive flight highlighted by the delivery of the $2 Billion Alpha Magnetic Spectrometer (AMS) to the International Space Station. AMS is a cosmic ray detector that seeks to unveil the invisible universe and search for evidence of dark matter, strange matter and antimatter.

5 of 6 crew members of STS-134 mission of Space Shuttle Endeavour at post landing press briefing. Credit: Ken Kremer

“What a great ending to this really wonderful mission,” said Bill Gerstenmaier, associate administrator for Space Operation at a briefing today for reporters “They’re getting great data from their instrument on board the space station. It couldn’t have gone any better for this mission.”

Mike Leinbach, the Space Shuttle Launch Director, said, “It’s been a great morning at the Kennedy Space Center. Commander Kelly and his crew are in great spirits.”

Four members of the crew conducted 4 spacewalks during the flight, which were the last by shuttle crew members during the space shuttle era. Simultaneously they completed the construction of the US portion of the ISS.

During the flight, Mike Fincke established a new record of 382 days for time a U.S. astronaut has spent in space. He broke the record on May 27, his 377th day on May 27, by surpassing previous record holder Peggy Whitson.

STS-134 was the 134th space shuttle mission and the 36th shuttle mission dedicated to ISS assembly and maintenance.

“You know, the space shuttle is an amazing vehicle, to fly through the atmosphere, hit it at Mach 25, steer through the atmosphere like an airplane, land on a runway, it is really, really an incredible ship,” said Kelly.

“On behalf of my entire crew, I want to thank every person who’s worked to get this mission going and every person who’s worked on Endeavour. It’s sad to see her land for the last time, but she really has a great legacy.”

After the landing at the Shuttle Landing Facility (SLF) , Endeavour was towed back into the Orbiter Processing Facility (OPF) where she will be cleaned and “safed” in preparation for her final resting place – Retirement and public display at the California Science Center in Los Angelos, California.

With the successful conclusion of Endeavour’s mission, the stage is now set for blastoff of the STS-135 mission on July 8, the very final flight of the three decade long shuttle Era.

“We’ve had a lot going on here,” said Mike Moses, space shuttle launch integration manager, “Being able to send Atlantis out to the pad and then go out and land Endeavour was really a combination I never expected to have.

It’s been a heck of a month in the last 4 hours !”

Shuttle Endeavour Landing Photos by Mike Deep for Universe Today

STS-134 Space Shuttle Commander Mark Kelly. Credit: Ken Kremer
STS-134 Endeavour Post Landing Press Briefing.
Bill Gerstenmaier, NASA Associate Administrator for Space Operations, Mike Moses, Space Shuttle launch integration manager at NASA KSC, Mike Leinbach, Space Shuttle Launch Director at NASA KSC, laud the hard work and dedication of everyone working on the Space Shuttle program. Credit: Ken Kremer

Read my related stories about the STS-134 mission here:

Amazing Photos and Milestone Tributes Mark Last Space Shuttle Spacewalk
Awesome Hi Def Launch Videos from Endeavour
Spectacular Soyuz Photo Gallery shows Unprecedented View Of Shuttle Docked at Station
Ultimate ISS + Shuttle + Earth Photo Op Coming on May 23 from Soyuz and Paolo Nespoli
Endeavour Blasts Off on Her 25th and Final Mission
Endeavour Unveiled for Historic Final Blastoff
Looking to the Heavens with Endeavour; Launch Pad Photo Special
Endeavour Astronauts Arrive at Cape for May 16 Launch
NASA Sets May 16 for Last Launch of Endeavour; Atlantis Slips to July
Endeavour’s Final Launch further delayed another Week or more
On the Cusp of Endeavour’s Final Flight
Brush Fires Erupt at Kennedy Space Center during Endeavour’s Last Countdown
Commander Mark Kelly and STS-134 Crew Arrive at Kennedy for Endeavour’s Final Flight
President Obama to Attend Endeavour’s Last Launch on April 29
Shuttle Endeavour Photo Special: On Top of Pad 39A for Final Flight
Endeavour Mated to Rockets for Last Flight Photo Album
Endeavour Rolls to Vehicle Assembly Building for Final Flight

Posted on by Steve Nerlich

Astronomy Without A Telescope – Holographic Dark Information Energy

The bubble nebula NGC 7635 - it doesn't have a lot to do with Holographic Dark Information Energy, but you always have to start these articles with an image. Credit: Croman/APOD Nov 7 2005.

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Holographic Dark Information Energy gets my vote for the best mix of arcane theoretical concepts expressed in the shortest number of words – and just to keep it interesting, it’s mostly about entropy.

The second law of thermodynamics requires that the entropy of a closed system cannot decrease. So drop a chunk of ice in a hot bath and the second law requires that the ice melts and the bath water cools – moving the system from a state of thermal disequilibrium (low entropy) towards a state of thermal equilibrium (high entropy). In an isolated system (or an isolated bath) this process can only move in one direction and is irreversible.

A similar idea exists within information theory. Landauer’s principle has it that any logically irreversible manipulation of information, such as erasing one bit of information, equates to an increase in entropy.

So for example, if you keep photocopying the photocopy you just made of an image, the information in that image degrades and is eventually lost. But Landauer’s principle has it that the information is not so much lost, as converted into energy that is dissipated away by the irreversible act of copying a copy.

Translating this thinking into a cosmology, Gough proposes that as the universe expands and density declines, information-rich processes like star formation also decline. Or to put it in more conventional terms – as the universe expands, entropy increases since the energy density of the universe is being steadily dissipated across a greater volume. Also, there are less opportunities for gravity to generate low entropy processes like star formation.

The link between entropy and information - more interesting and information-rich things occur in low entropy states than in high entropy states.

So in an expanding universe there is a loss of information – and by Landauer’s principle this loss of information should release dissipated energy – and Gough claims that this dissipated energy accounts for the dark energy component of the current standard model of universe.

There are rational objections to this proposal. Landauer’s principle is really an expression of entropy in information systems – which can be mathematically modeled as though they were thermodynamic systems. It’s a bold claim to say this has a physical reality and a loss of information actually does release energy – and since Landauer’s principle expresses this as heat energy, wouldn’t it then be detectable (i.e. not dark)?

There is some experimental evidence of information loss releasing energy, but arguably it is just conversion of one form of energy to another – the information loss aspect of it just representing the transition from low to high entropy, as required by the second law of thermodynamics. Gough’s proposal requires that ‘new’ energy is introduced into the universe out of nowhere – although to be fair, that is pretty much what the current mainstream dark energy hypothesis requires as well.

Nonetheless, Gough alleges that the math of information energy does a much better job of accounting for dark energy than the traditional quantum vacuum energy hypothesis which predicts that there should be 120 orders of magnitude more dark energy in the universe than there apparently is.

Gough calculates that the information energy in the current era of the universe should be about 3 times its current mass-energy contents – which closely aligns with the current standard model of 74% dark energy + 26% everything else.

Invoking the holographic principle doesn’t add a lot to the physics of Gough’s argument – presumably it’s in there to make the math easier to manage by removing one dimension. The holographic principle has it that all the information about physical phenomena taking place within a 3D region of space can be contained on a 2D surface bounding that region of space. This, like information theory and entropy, is something that string theorists spend a lot of time grappling with – not that there’s anything wrong with that.

Further reading:
Gough Holographic Dark Information Energy.

Posted on by Tammy Plotner

Australian Student Uncovers the Universe’s Missing Mass

Comic Microwave Background Courtesy of NASA / WMAP Science Team

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Not since the work of Fritz Zwicky has the astronomy world been so excited about the missing mass of the Universe. His evidence came from the orbital velocities of galaxies in clusters, rotational speeds, and gravitational lensing of background objects. Now there’s even more evidence that Zwicky was right as Australian student – Amelia Fraser-McKelvie – made another breakthrough in the world of astrophysics.

Working with a team at the Monash School of Physics, the 22-year-old undergraduate Aerospace Engineering/Science student conducted a targeted X-ray search for the hidden matter and within just three months made a very exciting discovery. Astrophysicists predicted the mass would be low in density, but high in temperature – approximately one million degrees Celsius. According to theory, the matter should have been observable at X-ray wavelengths and Amelia Fraser-McKelvie’s discovery has proved the prediction to be correct.

Dr Kevin Pimbblet from the School of Astrophysics explains: “It was thought from a theoretical viewpoint that there should be about double the amount of matter in the local Universe compared to what was observed. It was predicted that the majority of this missing mass should be located in large-scale cosmic structures called filaments – a bit like thick shoelaces.”

Up until this point in time, theories were based solely on numerical models, so Fraser-McKelvie’s observations represent a true break-through in determining just how much of this mass is caught in filamentary structure. “Most of the baryons in the Universe are thought to be contained within filaments of galaxies, but as yet, no single study has published the observed properties of a large sample of known filaments to determine typical physical characteristics such as temperature and electron density.” says Amelia. “We examine if a filament’s membership to a supercluster leads to an enhanced electron density as reported by Kull & Bohringer (1999). We suggest it remains unclear if supercluster membership causes such an enhancement.”

Still a year away from undertaking her Honors year (which she will complete under the supervision of Dr Pimbblet), Ms Fraser-McKelvie is being hailed as one of Australia’s most exciting young students… and we can see why!

Posted on by Nancy Atkinson

GALEX Confirms Nature of Dark Energy

New results from NASA's Galaxy Evolution Explorer and the Anglo-Australian Telescope atop Siding Spring Mountain in Australia confirm that dark energy (represented by purple grid) is a smooth, uniform force that now dominates over the effects of gravity (green grid). The observations follow from careful measurements of the separations between pairs of galaxies (examples of such pairs are illustrated here).Image credit: NASA/JPL-Caltech

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From a JPL press release:

A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds. The survey used data from NASA’s space-based Galaxy Evolution Explorer and the Anglo-Australian Telescope on Siding Spring Mountain in Australia.

The findings offer new support for the favored theory of how dark energy works — as a constant force, uniformly affecting the universe and propelling its runaway expansion. They contradict an alternate theory, where gravity, not dark energy, is the force pushing space apart. According to this alternate theory, with which the new survey results are not consistent, Albert Einstein’s concept of gravity is wrong, and gravity becomes repulsive instead of attractive when acting at great distances.

“The action of dark energy is as if you threw a ball up in the air, and it kept speeding upward into the sky faster and faster,” said Chris Blake of the Swinburne University of Technology in Melbourne, Australia. Blake is lead author of two papers describing the results that appeared in recent issues of the Monthly Notices of the Royal Astronomical Society. “The results tell us that dark energy is a cosmological constant, as Einstein proposed. If gravity were the culprit, then we wouldn’t be seeing these constant effects of dark energy throughout time.”

Dark energy is thought to dominate our universe, making up about 74 percent of it. Dark matter, a slightly less mysterious substance, accounts for 22 percent. So-called normal matter, anything with atoms, or the stuff that makes up living creatures, planets and stars, is only approximately four percent of the cosmos.

The idea of dark energy was proposed during the previous decade, based on studies of distant exploding stars called supernovae. Supernovae emit constant, measurable light, making them so-called “standard candles,” which allows calculation of their distance from Earth. Observations revealed dark energy was flinging the objects out at accelerating speeds.

his diagram illustrates two ways to measure how fast the universe is expanding -- the "standard candle" method, which involves exploded stars in galaxies, and the "standard ruler" method, which involves pairs of galaxies. Image credit: NASA/JPL-Caltech

Dark energy is in a tug-of-war contest with gravity. In the early universe, gravity took the lead, dominating dark energy. At about 8 billion years after the Big Bang, as space expanded and matter became diluted, gravitational attractions weakened and dark energy gained the upper hand. Billions of years from now, dark energy will be even more dominant. Astronomers predict our universe will be a cosmic wasteland, with galaxies spread apart so far that any intelligent beings living inside them wouldn’t be able to see other galaxies.

The new survey provides two separate methods for independently checking the supernovae results. This is the first time astronomers performed these checks across the whole cosmic timespan dominated by dark energy. The team began by assembling the largest three-dimensional map of galaxies in the distant universe, spotted by the Galaxy Evolution Explorer. The ultraviolet-sensing telescope has scanned about three-quarters of the sky, observing hundreds of millions of galaxies.

“The Galaxy Evolution Explorer helped identify bright, young galaxies, which are ideal for this type of study,” said Christopher Martin, principal investigator for the mission at the California Institute of Technology in Pasadena. “It provided the scaffolding for this enormous 3-D map.”

The astronomers acquired detailed information about the light for each galaxy using the Anglo-Australian Telescope and studied the pattern of distance between them. Sound waves from the very early universe left imprints in the patterns of galaxies, causing pairs of galaxies to be separated by approximately 500 million light-years.

This “standard ruler” was used to determine the distance from the galaxy pairs to Earth — the closer a galaxy pair is to us, the farther apart the galaxies will appear from each other on the sky. As with the supernovae studies, this distance data were combined with information about the speeds at which the pairs are moving away from us, revealing, yet again, the fabric of space is stretching apart faster and faster.

The team also used the galaxy map to study how clusters of galaxies grow over time like cities, eventually containing many thousands of galaxies. The clusters attract new galaxies through gravity, but dark energy tugs the clusters apart. It slows down the process, allowing scientists to measure dark energy’s repulsive force.

“Observations by astronomers over the last 15 years have produced one of the most startling discoveries in physical science; the expansion of the universe, triggered by the Big Bang, is speeding up,” said Jon Morse, astrophysics division director at NASA Headquarters in Washington. “Using entirely independent methods, data from the Galaxy Evolution Explorer have helped increase our confidence in the existence of dark energy.”

For more information see the Australian Astronomical Observatory

Posted on by Ken Kremer

President Obama to Attend Endeavour’s Last Launch on April 29

President Obama plans to attend the last launch of Endeavour on April 29, 2011 at the Kennedy Space Center. President Obama last visited the Kennedy Space Center in Florida on April 15, 2010 and outlined the new course his administration is charting for NASA and the future of U.S. human spaceflight. Credit: NASA/Kim Shiflett

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President Barack Obama and the entire First Family apparently plan to attend the final launch of Space Shuttle Endeavour, according to government officials and multiple news outlets. Endeavour is slated to blast off on the STS-134 mission next Friday, April 29 from the Kennedy Space Center (KSC) in Florida at 3:47 p.m. EDT.

There has already been intense drama surrounding the STS-134 mission because it is being commanded by Mark Kelly. Kelly is the husband of U.S. Congresswoman Gabrielle Giffords of Arizona who was critically wounded by gunshots to her head at point blank range during an assassination attempt while attending a meet and greet with her constituents on Jan. 8, 2011. Six people – including a nine year old girl and a federal judge – were killed and a dozen more were wounded that awful day.

Space Shuttle Endeavour awaits her final launch on April 29, 2011 from Pad 39A at the Kennedy Space Center, FL Credit: Ken Kremer

The Presidents appearance at the STS-134 launch will almost certainly lead to skyrocketing interest, but has not yet been officially announced by NASA and the White House. The event is not yet listed on the presidents official schedule.

However, a tweet by the staff of Congresswoman Giffords on her official website states Obama will attend; “We are very happy that Pres. Obama is coming to Mark’s launch! This historic mission will be #Endeavours final flight.”

NASA spokesman Allard Beutel told me today, “I cannot confirm whether the president will be coming to launch next week. If he’s coming, which I can’t confirm, we are a White House agency.”

“We always welcome a visit from the President,” Beutel said.

Security is always tight at KSC during a shuttle launch. A visit by President Obama will certainly lead to even tighter security controls and even more massive traffic jams.

Giant crowds were already expected for this historic final spaceflight of Space Shuttle Endeavour, NASA’s youngest Orbiter, on her 25th mission to space.

Endeavour is carrying the $2 Billion Alpha Magnetic Spectrometer (AMS) ) on a 14-day flight to the International Space Station, a premier science instrument that will collect cosmic rays, search for dark energy, dark matter and anti matter and seeks to determine the origin of the Universe. See my photo below of the AMS from inside the Space Station Processing Facility (SSPF) at KSC with the principal investigator, Nobel Prize winner Prof. Sam Ting of MIT.

NASA Administrator Charles Bolden just announced that Endeavour will be displayed at the California Science Museum following her retirement from active flight service upon landing.

President Obama last visited KSC on April 15, 2010 and gave a major policy speech outlining his radical new human spaceflight goals for NASA. Obama decided to cancel NASA’s Project Constellation ‘Return to the Moon’ Program and the Ares 1 and Ares 5 rockets. He directed NASA to plan a mission for astronauts to visit an Asteroid by 2025 and one of the moons of Mars in the 2030’s. Obama also decided to revive the Orion crew module built by Lockheed Martin, which is now envisaged for missions beyond low earth orbit (LEO), and invest in development of new commercial space taxis such as the Dragon spacecraft by SpaceX for transporting astronaut crews to the ISS.

Spokesman Beutel said that during the April 2010 visit, “The President met with space workers.” He could not comment on details of the president’s plans for the STS-134 visit and said information would have to come from the White House.

The last time a sitting president watched a live human space launch was in 1998 when then President Bill Clinton attended the blastoff of the return to space of Astronaut and Senator John Glenn. Glenn was the first American to orbit the Earth back in 1962. Glenn’s first flight took place a little over a year after the historic first human spaceflight by Soviet Cosmonaut Yuri Gagarin on April 12, 1961- which occurred exactly 50 years ago last week.

Congresswoman Giffords is recovering from her wounds and Shuttle Commander Kelly has said that she would like to attend the STS-134 launch. But no official announcement about her attendance has been made by NASA and depends on many factors including decisions by the doctors treating her in a Houston area hospital.

The Alpha Magnetic Spectrometer (AMS) and Nobel Prize Winner and Principal Investigator Sam Ting of MIT - inside the Space Station Processing Facility at KSC. The STS-134 mission of shuttle Endeavour will deliver the AMS to the ISS. The AMS purpose is to try and determine the origin of the Universe. . Credit: Ken Kremer
Close up of Endeavour crew cabin, ET, SRB and astronaut walkway to the White Room. Credit: Ken Kremer
Posted on by Vanessa Janek

Cosmology 101: The End

A1689-zD1, one of the brightest and most distant galaxies, is 12.8 billion light years away - an extremely far distance in our expanding universe. Image credit: NASA/ESA/JPL-Caltech/STScI

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Welcome back to the third, and last, installment of Cosmology 101. So far, we’ve covered the history of the universe up to the present moment. But what happens next? How will our universe end? And how can we be so sure that this is how the story unfolded?

Robert Frost once wrote, “Some say the world will end in fire; some say in ice.” Likewise, some scientists have postulated that the universe could die either a dramatic, cataclysmic death – either a “Big Rip” or a “Big Crunch” – or a slower, more gradual “Big Freeze.” The ultimate fate of our cosmos has a lot to do with its shape. If the universe were open, like a saddle, and the energy density of dark energy increased without bound, the expansion rate of the cosmos would eventually become so great that even atoms would be torn apart – a Big Rip. Conversely, if the universe were closed, like a sphere, and gravity’s strength trumped the influence of dark energy, the outward expansion of the cosmos would eventually come to a halt and reverse, collapsing on itself in a Big Crunch.

Despite the poetic beauty of fire, however, current observations favor an icy end to our universe – a Big Freeze. Scientists believe that we live in a spatially flat universe whose expansion is accelerating due to the presence of dark energy; however, the total energy density of the cosmos is most likely less than or equal to the so-called “critical density,” so there will be no Big Rip. Instead, the contents of the universe will eventually drift prohibitively far away from each other and heat and energy exchange will cease. The cosmos will have reached a state of maximum entropy, and no life will be able to survive. Depressing and a bit anti-climactic? Perhaps. But it probably won’t be perceptible until the universe is at least twice its current age.

At this point you might be screaming, “How do we know all this? Isn’t it all just rampant speculation?” Well, first of all, we know without a doubt that the universe is expanding. Astronomical observations consistently demonstrate that light from distant stars is always redshifted relative to us; that is, its wavelength has been stretched due to the expansion of the cosmos. This leads to two possibilities when you wind back the clock: either the expanding universe has always existed and is infinite in age, or it began expanding from a smaller version of itself at a specific time in the past and thus has a fixed age. For a long time, proponents of the Steady State Theory endorsed the former explanation. It wasn’t until Arno Penzias and Robert Wilson discovered the cosmic microwave background in 1965 that the big bang theory became the most accepted explanation for the origin of the universe.

Why? Something as large as our cosmos takes quite a while to cool completely. If the universe did, in fact, began with the kind of blistering energies that the big bang theory predicts, astronomers should still see some leftover heat today. And they do: a uniform 3K glow evenly dispersed at every point in the sky. Not only that – but WMAP and other satellites have observed tiny inhomogeneities in the CMB that precisely match the initial spectrum of quantum fluctuations predicted by the big bang theory.

What else? Take a look at the relative abundances of light elements in the universe. Remember that during the first few minutes of the cosmos’ young life, the ambient temperature was high enough for nuclear fusion to occur. The laws of thermodynamics and the relative density of baryons (i.e. protons and neutrons) together determine exactly how much deuterium (heavy hydrogen), helium and lithium could be formed at this time. As it turns out, there is far more helium (25%!) in our current universe than could be created by nucleosynthesis in the center of stars. Meanwhile, a hot early universe – like the one postulated by the big bang theory – gives rise to the exact proportions of light elements that scientists observe in the universe today.

But wait, there’s more. The distribution of large-scale structure in the universe can be mapped extremely well based solely on observed anisotropies in the CMB. Moreover, today’s large-scale structure looks very different from that at high redshift, implying a dynamic and evolving universe. Additionally, the age of the oldest stars appears to be consistent with the age of the cosmos given by the big bang theory. Like any theory, it has its weaknesses – for instance, the horizon problem or the flatness problem or the problems of dark energy and dark matter; but overall, astronomical observations match the predictions of the big bang theory far more closely than any rival idea. Until that changes, it seems as though the big bang theory is here to stay.

Posted on by Nancy Atkinson

Hubble Rules Out One Alternative to Dark Energy

NGC 5584. Credit: NASA, ESA, A. Riess (STScI/JHU), L. Macri (Texas A&M University), and Hubble Heritage Team (STScI/AURA)

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From a NASA press release:

Astronomers using NASA’s Hubble Space Telescope have ruled out an alternate theory on the nature of dark energy after recalculating the expansion rate of the universe to unprecedented accuracy.

The universe appears to be expanding at an increasing rate. Some believe that is because the universe is filled with a dark energy that works in the opposite way of gravity. One alternative to that hypothesis is that an enormous bubble of relatively empty space eight billion light-years across surrounds our galactic neighborhood. If we lived near the center of this void, observations of galaxies being pushed away from each other at accelerating speeds would be an illusion.

This hypothesis has been invalidated because astronomers have refined their understanding of the universe’s present expansion rate. Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University in Baltimore, Md., led the research. The Hubble observations were conducted by the SHOES (Supernova H0 for the Equation of State) team that works to refine the accuracy of the Hubble constant to a precision that allows for a better characterization of dark energy’s behavior. The observations helped determine a figure for the universe’s current expansion rate to an uncertainty of just 3.3 percent. The new measurement reduces the error margin by 30 percent over Hubble’s previous best measurement in 2009. Riess’s results appear in the April 1 issue of The Astrophysical Journal.

“We are using the new camera on Hubble like a policeman’s radar gun to catch the universe speeding,” Riess said. “It looks more like it’s dark energy that’s pressing the gas pedal.”

Riess’ team first had to determine accurate distances to galaxies near and far from Earth. The team compared those distances with the speed at which the galaxies are apparently receding because of the expansion of space. They used those two values to calculate the Hubble constant, the number that relates the speed at which a galaxy appears to recede to its distance from the Milky Way. Because astronomers cannot physically measure the distances to galaxies, researchers had to find stars or other objects that serve as reliable cosmic yardsticks. These are objects with an intrinsic brightness, brightness that hasn’t been dimmed by distance, an atmosphere, or stellar dust, that is known. Their distances, therefore, can be inferred by comparing their true brightness with their apparent brightness as seen from Earth.

To calculate longer distances, Riess’ team chose a special class of exploding stars called Type 1a supernovae. These stellar explosions all flare with similar luminosity and are brilliant enough to be seen far across the universe. By comparing the apparent brightness of Type 1a supernovae and pulsating Cepheid stars, the astronomers could measure accurately their intrinsic brightness and therefore calculate distances to Type Ia supernovae in far-flung galaxies.

Using the sharpness of the new Wide Field Camera 3 (WFC3) to study more stars in visible and near-infrared light, scientists eliminated systematic errors introduced by comparing measurements from different telescopes.

“WFC3 is the best camera ever flown on Hubble for making these measurements, improving the precision of prior measurements in a small fraction of the time it previously took,” said Lucas Macri, a collaborator on the SHOES Team from Texas A&M in College Station.

Knowing the precise value of the universe’s expansion rate further restricts the range of dark energy’s strength and helps astronomers tighten up their estimates of other cosmic properties, including the universe’s shape and its roster of neutrinos, or ghostly particles, that filled the early universe.

“Thomas Edison once said ‘every wrong attempt discarded is a step forward,’ and this principle still governs how scientists approach the mysteries of the cosmos,” said Jon Morse, astrophysics division director at NASA Headquarters in Washington. “By falsifying the bubble hypothesis of the accelerating expansion, NASA missions like Hubble bring us closer to the ultimate goal of understanding this remarkable property of our universe.”

Science Paper by: Adam G. Riess et al. (PDF document)

Posted on by Anne Minard

Continent-Wide Telescope Array Now Seeing 450 Million Light-Years Into Space

Artist's conception of Milky Way, showing locations of star-forming regions whose distances were recently measured. CREDIT: M. Reid, Harvard-Smithsonian CfA; R. Hurt, SSC/JPL/Caltech, NRAO/AUI/NSF

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Kitt Peak. Los Alamos. St. Croix. Pie Town.

What do these places have in common? They each house one of 10 giant telescopes in the Very Large Baseline Array, a continent-spanning collection of telescopes that’s flexing its optical muscles, reaching farther into space — with more precision — than any other telescope in the world.

And today, at the 177th annual meeting of the American Association for the Advancement of Science in Washington, DC, VLBA researchers announced an amazing feat: They’ve used the VLBA to peer, with stunning accuracy, three times as far into the universe as they had just two years ago. New measurements with the VLBA have placed a galaxy called NGC 6264 (coordinates below) at a distance of 450 million light-years from Earth, with an uncertainty of no more than 9 percent. This is the farthest distance ever directly measured, surpassing a measurement of 160 million light-years to another galaxy in 2009.

VLBA telescope locations, courtesy of NRAO/AUI

Previously, distances beyond our own Galaxy have been estimated through indirect methods. But the direct seeing power of the VLBA scraps the need for assumptions, noted James Braatz, of the National Radio Astronomy Observatory.

The VLBA provides the greatest ability to see fine detail, called resolving power, of any telescope in the world. It can produce images hundreds of times more detailed than those from the Hubble Space Telescope, at a power equivalent to sitting in New York and reading a newspaper in Los Angeles. VLBA sites include Kitt Peak, Arizona; Los Alamos and Pie Town, New Mexico; St. Croix in the Virgin Islands, Mauna Kea, Hawaii; Brewster, Washington; Fort Davis, Texas; Hancock, New Hampshire; North Liberty, Iowa; and Owens Valley in California. Sure, I could include pictures of the scopes in Hawaii or the Virgin Islands. But Pie Town, besides hosting the Very Large Array, also has two fun restaurants (the Daily Pie and the Pie-O-Neer) with really amazing pie. And an annual pie-eating festival. So it wins:

The VLBA site at Pie Town, N.M., courtesy of NRAO/AUI.

Tripling the visible “yardstick” into space bears favorably on numerous areas of astrophysics, including determining the nature of dark energy, which constitutes 70 percent of the Universe. The VLBA is also redrawing the map of the Milky Way and is poised to yield tantalizing new information about extrasolar planets, the NRAO points out.

Fine-tuning the measurement of ever-greater distances is vital to determining the expansion rate of the Universe, which helps theorists narrow down possible explanations for the nature of dark energy. Different models of Dark Energy predict different values for the expansion rate, known as the Hubble Constant.

“Solving the Dark Energy problem requires advancing the precision of cosmic distance measurements, and we are working to refine our observations and extend our methods to more galaxies,” Braatz said. Measuring more-distant galaxies is vital, because the farther a galaxy is, the more of its motion is due to the expansion of the Universe rather than to random motions.

As for the map of our own galaxy, the direct VLBA measurements are improving on earlier estimates by as much as a factor of two. The clearer observations have already revealed the Milky Way has four spiral arms, not two as previously thought.

Mark Reid, of the Harvard-Smithsonian Center for Astrophysics led an earlier VLBA study revealing that the Milky Way is also rotating faster than previously believed — and that it’s as massive as Andromeda.

Reid’s team is now observing the Andromeda Galaxy in a long-term project to determine the direction and speed of its movement through space. “The standard prediction is that the Milky Way and Andromeda will collide in a few billion years. By measuring Andromeda’s actual motion, we can determine with much greater accuracy if and when that will happen,” Reid said.

The VLBA is also being used for a long-term, sensitive search of 30 stars to find the subtle gravitational tug that will reveal orbiting planets. That four-year program, started in 2007, is nearing its completion. The project uses the VLBA along with NRAO’s Green Bank Telescope in West Virginia, the largest fully-steerable dish antenna in the world. Early results have ruled out any companions the size of brown dwarfs for three of the stars, and the astronomers are analyzing their data as the observations continue.

Ongoing upgrades in electronics and computing have enhanced the VLBA’s capabilities. With improvements now nearing completion, the VLBA will be as much as 5,000 times more powerful as a scientific tool than the original VLBA of 1993.

NGC 6264 Coordinates, from DOCdb: 16<sup>h</sup> 57<sup>m</sup> 16.08<sup>s</sup>; +27° 50′ 58.9″

Source: A press release from the National Radio Astronomy Observatory, via the American Astronomical Society (AAS). Not to be confused with the American Association for the Advancement of Science (AAAS), which now conducting its annual meeting in Washington, DC — and where the VLBA results were presented.

Posted on by Nancy Atkinson

Astronomers Find Giant Structures From the Early Universe

An infrared/optical representative-color image of a massive galaxy cluster located 7 billion light-years from Earth. Credit: Infrared Image: NASA/JPL-Caltech/M. Brodwin (Harvard-Smithsonian CfA) Optical Image: CTIO Blanco 4-m telescope/J. Mohr (LMU Munich)

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Looking back to when our Universe was about half the age it is now, astronomers have discovered the most massive galaxy cluster yet seen at so great a distance. The researchers say that if we could see it as it appears today, it would be one of the most massive galaxy clusters in the universe. The cluster, modestly named SPT-CL J0546-5345, weighs in at around 800 trillion Suns, and holds hundreds of galaxies. “This galaxy cluster wins the heavyweight title,”said Mark Brodwin, from the Harvard-Smithsonian Center for Astrophysics. “This cluster is full of ‘old’ galaxies, meaning that it had to come together very early in the universe’s history – within the first two billion years.”


Using the new South Pole Telescope, Brodwin and his colleagues are searching for giant galaxy clusters using the Sunyaev-Zel’dovich effect – a small distortion of the cosmic microwave background, a pervasive all-sky glow left over from the Big Bang. Such distortions are created as background radiation passes through a large galaxy cluster.

They found the heavyweight cluster in some of their first observations with the new telescope.
Located in the southern constellation Pictor (the Painter), the cluster has a redshift of z=1.07, putting it at a distance of about 7 billion light-years, meaning we see it as it appeared 7 billion years ago, when the universe was half as old as now and our solar system didn’t exist yet.

Even at that young age, the cluster was almost as massive as the nearby Coma cluster. Since then, it should have grown about four times larger.

This optical image of the newfound galaxy cluster highlights how faint and reddened these galaxies are due to their great distance. Credit: CTIO Blanco 4-m telescope/J. Mohr (LMU Munich)

Galaxy clusters like this can be used to study how dark matter and dark energy influenced the growth of cosmic structures. Long ago, the universe was smaller and more compact, so gravity had a greater influence. It was easier for galaxy clusters to grow, especially in areas that already were denser than their surroundings.

“You could say that the rich get richer, and the dense get denser,” quipped Harvard astronomer Robert Kirshner, commenting on the study.

As the universe expanded at an accelerating rate due to dark energy, it grew more diffuse. Dark energy now dominates over the pull of gravity and chokes off the formation of new galaxy clusters.

The main goal of the SPT survey is to find a large sample of massive galaxy clusters in order to measure the equation of state of the dark energy, which characterizes cosmic inflation and the accelerated expansion of the universe. Additional goals include understanding the evolution of hot gas within galaxy clusters, studying the evolution of massive galaxies in clusters, and identifying distant, gravitationally lensed, rapidly star-forming galaxies.

The team expects to find many more giant galaxy clusters lurking in the distance once the South Pole Telescope survey is completed.

Follow-up observations on the cluster were done using the Infrared Array Camera on the Spitzer Space Telescope and the Magellan telescopes in Chile. A paper announcing the discovery has been published in the Astrophysical Journal.

The team’s paper is available at arXiv.

For more information on the South Pole Telescope, see this link.

Source: Harvard Smithsonian Center for Astrophysics

Posted on by Steve Nerlich

Astronomy Without A Telescope – Dark Denial

The University of Chicago's Sunyaev-Zeldovich Array - searching for the point in time when dark energy became an important force in the evolution of the universe. Credit: Erik Leitch, University of Chicago.

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A recent cosmological model seeks to get around the sticky issue of dark energy by jury-rigging the Einstein field equation so that the universe naturally expands in an accelerated fashion. In doing so, the model also eliminates the sticky issue of singularities – although this includes eliminating the singularity from which the Big Bang originated. Instead the model proposes that we just live in an eternal universe that kind of oscillates geometrically.

As other commentators have noted, this model hence fails to account for the cosmic microwave background. But hey, apart from that, the model is presented in a very readable paper that tells a good story. I am taking the writer’s word for it that the math works – and even then, as the good Professor Einstein allegedly stated: As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.

Like a number of alternate cosmological models, this one also requires the speed of light in a vacuum to vary over the evolution of the universe. It is argued that time is a product of universe expansion – and hence time and distance are mutually derivable – the conversion factor between the two being c – the speed of light. So, an accelerating expansion of the universe is just the result of a change in c – such that a unit of time converts to an increasing greater distance in space.

Yes, but…

The speed of light in a vacuum is the closest thing there is to an absolute in general relativity – and is really just a way of saying that electromagnetic and gravitational forces act instantaneously – at least from the frame of reference of a photon (and perhaps a graviton, if such a hypothetical particle exists).

It’s only from subluminal (non-photon) frames of reference that it becomes possible to sit back and observe, indeed even time with a stopwatch, the passage of a photon from point A to point B. Such subluminal frames of reference have only become possible as a consequence of the expansion of the universe, which has left in its wake an intriguingly strange space-time continuum in which we live out our fleetingly brief existences.

As far as a photon is concerned the passage from point A to point B is instantaneous – and it always has been. It was instantaneous around 13.7 billion years ago when the entire universe was much smaller than a breadbox – and it still is now.

But once you decide that the speed of light is variable, this whole schema unravels. Without an absolute and intrinsic speed for relatively instantaneous information transfer, the actions of fundamental forces must be intimately linked to the particular point of evolution that the universe happens to be at.

For this to work, information about the evolutionary status of the universe must be constantly relayed to all the constituents of the universe – or otherwise those constituents must have their own internal clock that refers to some absolute cosmic time – or those constituents must be influenced by a change in state of an all-pervading luminiferous ether.

In a nutshell, once you start giving up the fundamental constants of general relativity – you really have to give it all up.

The basic Einstein field equation. The left hand side of the equation describes space-time geometry (of the observable universe, for example) and the right hand side describes the associated mass-energy responsible for that curvature. If you want to add lambda (which these days we call dark energy) - you add it to the left hand side components.

The cosmological constant, lambda – which these days we call dark energy – was always Einstein’s fudge factor. He introduced it into his nicely balanced field equation to allow the modeling of a static universe – and when it became apparent the universe wasn’t static, he realized it had been a blunder. So, if you don’t like dark energy and you can do the math, this might be a better place to start.

Further reading: Wun-Yi Shu Cosmological Models with No Big Bang.