Universe Today

May 22, 2011April 13, 2022 by Ken Kremer

Ultimate ISS + Shuttle + Earth Photo Op Coming on May 23 from Soyuz and Paolo Nespoli

First ever Photos of Shuttle-Space Station Stack coming on May 23. This still image from a NASA computer generated animation shows three different views of how the Soyuz TMA-20 crew will undock from the ISS on Monday May 23, 2011. Astronaut Paolo Nespoli will capture first ever photos and video of a space shuttle [Endeavour] docked to International Space Station from his departing Russian Soyuz capsule . photographs the setup after undocking.. CREDIT: NASA TV. Watch Video simulation below

KENNEDY SPACE CENTER: Get ready for the ultimate photo op in space – set for the International Space Station joined to Space Shuttle Endeavour and topped off by Planet Earth as the backdrop.

And it’s coming up momentarily because of an unexpected and “unique opportunity” that’s also taking place at nearly the last possible moment in the life of the soon to be retired Space Shuttle program.

On Monday, May 23, Italian Astronaut Paolo Nespoli will snap the first ever photos and video of a US Space Shuttle orbiter while it is simultaneously still docked to the International Space Station, NASA officials just announced on Friday, May 19.

Video Caption: This computer generated animation depicts the view the Soyuz crew will see as they depart from the International Space Station (upper left) on May 23, 2011 at 5:32 p.m. EDT. Italian Astronaut Paolo Nespoli will capture an incredible and first ever imagery of the stacked station/shuttle complex with a space shuttle orbiter; the Endeavour. Bottom view shows side view of the Soyuz departing the ISS. Credit: NASA

Nespoli will capture the dramatic and historic imagery – in a newly devised plan – while he is departing the “Shuttle- Station stack” aboard a Russian Soyuz spacecraft and heading for a landing back on Earth with two crewmates barely 4 hours later in Kazakhstan.

“We have a unique opportunity. We are calling this Soyuz undock with imagery,” said Kenneth Todd, chair of NASA’s space station mission management team. “We are not calling this a Soyuz flyaround or flyabout.”

“This is going to be a great opportunity for the spaceflight community.”

After months of high level international negotiations since the STS-133 mission, NASA and Russian space officials from the space shuttle and space station teams have finally agreed on a arrangement for utilizing a crewed Soyuz vehicle to record the first ever photos showing a shuttle while still docked to the massive orbiting outpost in the same field of view.

The chance to do the shuttle- station photo documentation in this way only became possible when the launch of Space Shuttle Endeavour was scrubbed on April 29 and the resulting delayed launch of the STS-134 mission on May 16 fortuitously afforded an overlapping time period that coincided with the Soyuz TMA-20 crew departure.

Space Shuttle Endeavour launches from Pad 39 A on May 16, 2011 on the STS-134 mission.
View from the countdown clock at NASA’s Kennedy Space Center. Endeavour has delivered the $2 Billion Alpha Magnetic Spectrometer to the International Space Station. The AMS will search for dark matter, dark energy and antimatter to determine the origin and evolution of the Universe. Credit: Ken Kremer

The photo opportunity will take place under what’s called a dual docked operations scenario whereby the Soyuz is undocked while a shuttle is still attached to the ISS.

“With 100 percent consensus, we approved this change to the baseline mission to go add this photo documentation task as part of the Soyuz TMA-20 undock,” Todd explained.

In order to accommodate the extra time required to accomplish the photo shoot, the Soyuz TMA-20 capsule will undock from the ISS one orbit earlier than originally scheduled, about 90 minutes, at 5:32 p.m. EDT.

Space Shuttle Atlantis docked to Russian Mir Space Station
on 29 June 1995.
Check out this perspective of what a space shuttle looks like when docked to an Earth orbiting space station. Atlantis is docked to the Mir Space Station on 29 June 1995 during the STS-71 mission. The shuttle has never before been photographed while attached to the Internalional Space Station. The photos of the Shuttle Endeavou and ISS Space Station stack are expected on May 23, 2010. Credit: Roscosmos

Nespoli is departing with ISS Expedition 27 commander and Russian cosmonaut Dimitry Kondratyev and NASA astronaut Catherine “Cady” Coleman. They will be completing a nearly six month stint in space aboard the ISS.”

“After the Soyuz undocks, they will back out to about 200 meters,” explained Courtney McMillan, STS-134 Station Team 4 Flight Director. “You will see they are a little bit above the velocity vector, above the station, and that is to keep the sun out of the pilot’s eyes.”

“After they get to the station keeping point, ISS will begin to maneuver, turning 130 degrees at 0.2 degrees per second.” The attitude was designed to provide the best perspective of the ISS and Endeavour.

“It will take 15 minutes to bring the whole stack around to get a side view and a really good view of Endeavour. This is an unusual attitude for the station to fly during a mated mission and people have done a lot of work to make sure this is a good thing to be doing. They have scrutinized the issue and are very comfortable with the plan.”

The station move will be done using thrusters on the Russian Segment service module – named Zvezda – and the thrusters on the docked Progress 42P vehicle, an unmanned Russian cargo ship. See diagram below.

Nespoli will have to float into the Soyuz vehicles forward habitation module – from his seat in the central descent module – and then snap the photo and video imagery through the modules windows. He will have a direct line of sight to the stack.

Paolo will have roughly 30 minutes time to collect all the imagery of the combined space complex during the photo survey, starting at about 5:50 p.m. EDT.

Then he will float back out of the habitation module, carefully seal the hatches in between and take his seat in the descent module.

The habitation module burns up in Earth orbit after the modules separate in preparation for the Soyuz’s deorbit and scorching reentry into Earth’s atmosphere.

Since the Soyuz will be pitched up during the undocking sequence, breathtaking views of Earth in the background of the “Shuttle-
Station stack” are expected.

The goal is to get good archival imagery of the space station stack with the shuttle attached. In addition to the gee whiz factor there are good reasons from an engineering perspective to record this imagery to assess the condition of the orbiting complex, NASA managers said.

“Future generations will look back on their history and look back at what we accomplished between these two very, very large programs – the shuttle and the space station – and realize it was amazing what we accomplished with the technology available at the time.”

“These pictures will be in textbooks to show what we did”, said Todd.

Exactly when the digital photos and video will be available for all to see is still to be determined. NASA and Russian space officials are discussing the details of when and how to distribute the imagery. The Soyuz is not equipped to transmit the imagery in real time.

“We hope to start seeing the photos and videos within a day of landing”, said Todd.

Paolo has snapped many gorgeous shots during his stay in space, including these of an Ariane V launching the European ATV cargo craft from French Guiana.

Go Paolo !

Read my story about the Final Shuttle mission, STS-135, here:
Atlantis Rolls to Vehicle Assembly Building with Final Space Shuttle Crew for July 8 Blastoff

Diagram of Russian Zvezda Service Module

May 21, 2011April 26, 2016 by Steve Nerlich

Astronomy Without A Telescope – Small Bangs

Gamma ray bursts - have we really figured out all the science here? Credit: NASA.

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Most gamma-ray bursts come in two flavors. Firstly, there are long duration bursts which form in dense star-forming regions and are associated with supernovae – which would understandably generate a sustained outburst of energy. The technical definition of a long duration gamma-ray burst is one that is more than two seconds in duration – but bursts lasting over a minute are not unusual.

Short duration gamma-ray bursts more often occur in regions of low star formation and are not associated with supernovae. Their duration is technically less than 2 seconds, but a duration of only a few milliseconds is not unusual. These are assumed to result from collisions between massive compact objects – perhaps neutron stars or black holes – producing a short, sharp outburst of energy.

But there are also rare instances of gamma-ray bursts that don’t really fill either category. GRB 060614 is such a beast – and has been referred to as a hybrid burst. It had a long duration (102 seconds) but was not associated with a supernova. This finding was significant enough to warrant an article in Nature – with the lead author Gehrels stating ‘This is brand new territory; we have no theories to guide us.’

We should be grateful that no-one decided to call it a dark burst. And we are yet to see another such confirmed hybrid gamma-ray burst that might verify whether these are hybrid bursts are really something extraordinary.

Nonetheless, Retter and Heller have suggested we should consider the possibility that GRB 060614 might have been a white hole. A white hole is a theoretical entity – and arguably just an artifact of the mathematics of general relativity. Assuming a black hole is an object from which nothing can escape – then its symmetrical opposite would be a white hole into which nothing can enter – but which can radiate light and from which matter can and does escape.

Arguably the whole idea just arises because general relativity abhors sharp edges. So the argument goes that the space-time continuum should ideally extend indefinitely – being curved by massive objects, but never brought to an edge. However, black holes represent a pinch in space-time where everything is supposedly dragged into a point-like singularity. So, one solution to this problem is to suggest that a black hole is not an interruption to the continuum, but instead the space-time around a black hole is drawn into a narrow-necked funnel – essentially a wormhole – which then feeds through to a white hole somewhere else.

**Left image:** The mysterious hybrid gamma ray burst GRB 060614. **Right image:** The 'what goes in must come out' model of white holes - where a black hole is connected to a white hole - and the white hole is time-reversed so that it expels material in the past. This was an initially proposed as a solution to explain quasars in the early universe, but better explanations have come along since (e.g. supermassive black holes with jets).

Being opposites, a black hole in the present would be connected to a white hole in the past – perhaps a white hole that existed in the early universe, emitting light and matter for a period and then exploding – kind of like a film of the formation of a black hole run backwards. It’s been suggested that such white holes might have created the first anisotropies in the early isotropic universe – creating the ‘clumpiness’ that later led to galaxies and galaxy clusters.

Alternatively, the Big Bang might be seen as the ultimate white hole which expelled a huge amount of mass/energy in one go – and any subsequent white holes might then be ‘lagging cores’ or Small Bangs.

There are substantial theoretical problems with white hole physics though – for example, the matter it ejects should immediately collapse back down on itself through self-gravity – meaning it just becomes a black hole anyway, or perhaps it explodes. If the latter possibility is correct, maybe this is one possible explanation of GRB 060614 seen back in 2006. But it’s probably best to wait for another hybrid burst to appear and get some more data before getting too carried away here.

Further reading:
Retter and Heller The Revival of White Holes as Small Bangs.
The mysterious GRB 060614.
You can apparently create a white hole in your kitchen sink.

May 20, 2011January 18, 2016 by Nancy Atkinson

Friday Special: Two Rocket Launches in Less Than Two Hours

It was a busy launch day around the world on Friday. Above, the Ariane 5 rocket carrying the ST-2 and GSAT-8 communications satellites launched from Kourou, French Guiana, and below, about an hour and a half earlier, a Proton rocket blasted off from the Baikonur Cosmodrome in Kazakhstan bringing a Telstar 14R satellite to orbit. The Telstar satellite will provide communications services over the United States, Brazil and other parts of South America for Telesat of Canada, and the ST 2 will provide fixed and mobile voice and Internet to Asia and the Middle East.

Thanks to Chris Calubquib on Twitter for the updates and posting the launch videos on You Tube.

Continue reading “Friday Special: Two Rocket Launches in Less Than Two Hours”

May 20, 2011April 26, 2016 by Nancy Atkinson

New Movie Revives Old Voyager Data of Jupiter’s Clouds

I remember, some time after Voyager 1 flew past Jupiter, of seeing a television show that played a movie of Jupiter’s bands of rolling clouds. I was mesmerized. Now, UnmannedSpaceflight.com member Bjorn Jonsson has re-mastered that data into a crisp, clear video. I find it just as mesmerizing! In his description, Jonsson says, “The movie is based on 58 orange-green-blue color composites obtained on every Jovian rotation from January 6 to January 29, 1979. Over this period Voyager 1’s distance from Jupiter dropped from 58 to 36 million km so the resolution and sharpness of the frames increases from start to finish. The 58 frames were tweened, increasing the number of frames by a factor of 8 (that is, 7 synthetic frames are inserted between each real frame).”

You can see more of Jonsson’s work at his website.

Credit: NASA/JPL/Processed by Bjorn Jonsson

May 20, 2011December 24, 2015 by Nancy Atkinson

Best-Ever Radio Image of Black Hole Jets

The giant elliptical galaxy NGC 5128 is the radio source known as Centaurus A. Vast radio-emitting lobes (shown as orange in this optical/radio composite) extend nearly a million light-years from the galaxy. Credit: Capella Observatory

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A new image taken by an array of radio telescopes is the best resolution view ever of particle jets erupting from a supermassive black hole in a nearby galaxy. An international team of astronomers targeted Centaurus A (Cen A), and the image shows a region less than 4.2 light-years across — less than the distance between our sun and the nearest star. Radio-emitting features as small as 15 light-days can be seen, making this the most detailed image yet of black hole jets.

“These jets arise as infalling matter approaches the black hole, but we don’t yet know the details of how they form and maintain themselves,” said Cornelia Mueller, the study’s lead author and a doctoral student at the University of Erlangen-Nuremberg in Germany.

The data was gathered by the TANAMI project (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry), an intercontinental array of nine radio telescopes.

While not completely understood, black hole particle jets typically escape the confines of their host galaxies and flow for hundreds of thousands of light years. They are somewhat a paradox, because while black holes are known for pulling matter in, they also produce these jets which accelerate matter at near light speed.

They are a primary means of redistributing matter and energy in the universe, and understanding them will be key to understanding galaxy formation and other cosmic mysteries such as the origin of ultrahigh-energy cosmic rays.

While the black hole is invisible, the jets are seen in great detail in the new image. Cen A is located about 12 million light-years away in the constellation Centaurus and is one of the first celestial radio sources identified with a galaxy.

Seen in radio waves, Cen A is one of the biggest and brightest objects in the sky, nearly 20 times the apparent size of a full moon. This is because the visible galaxy lies nestled between a pair of giant radio-emitting lobes, each nearly a million light-years long.

Merging X-ray data (blue) from NASA’s Chandra X-ray Observatory with microwave (orange) and visible images reveals the jets and radio-emitting lobes emanating from Centaurus A's central black hole. Credit: ESO/WFI (visible); MPIfR/ESO/APEX/A.Weiss et al. (microwave); NASA/CXC/CfA/R.Kraft et al. (X-ray)

These lobes are filled with matter streaming from particle jets near the galaxy’s central black hole. Astronomers estimate that matter near the base of these jets races outward at about one-third the speed of light.

The new study will appear in the June issue of Astronomy and Astrophysics and is available online.

Source: NASA

May 20, 2011December 24, 2015 by Ken Kremer

Atlantis Rolls to Vehicle Assembly Building with Final Space Shuttle Crew for July 8 Blastoff

Final shuttle crew greets the media and shuttle workers during Atlantis rollover from the OPF-1 processing hanger to the VAB at KSC. From left: Rex Walheim Shuttle Commander Christopher Ferguson, Douglas Hurley and Sandra Magnus. The all veteran crew will deliver the Raffaello multipurpose logistics module (MPLM), science supplies, provisions and space parts to the International Space Station (ISS). Credit: Ken Kremer

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KENNEDY SPACE CENTER – The end of NASA’s shuttle era has begun as pre-launch preparations for the final shuttle flight by Space Shuttle Atlantis kicked into high gear. The STS-135 mission is set to launch on July 8 at about 11:40 a.m. EDT on a 12 day flight.

Shuttle Atlantis has been moved about a quarter of a mile from its pre-launch processing hanger – known as Orbiter Processing Facility-1 (OPF-1) – to the Vehicle Assembly Building (VAB) at the Kennedy Space Center in Florida. Check out our eyewitness photo album herein.

Atlantis rolls over from the Orbiter Processing Facility (OPF-1, at right) processing hanger to the Vehicle Assembly Building (VAB, at left) at KSC for the STS-135 mission. Credit: Ken Kremer

The four person crew of STS-135 was on hand to meet and greet and thank the big crowd of NASA managers and shuttle workers who are preparing Atlantis for the final spaceflight of the Space Shuttle Program after three decades of flight.

Atlantis’ crew comprises of Shuttle Commander Christopher Ferguson, pilot Douglas Hurley and mission specialists Rex Walheim and Sandra Magnus.

Atlantis atop 78 wheeled transporter during rollover from OPF-1 to the VAB. Credit: Ken Kremer

More than a hundred photo journalists representing media worldwide gathered to watch this historic event – known as “rollover”. I had a chance to briefly speak and shake hands with Shuttle Commander Chris Ferguson and wish the crew good luck.

Under a gorgeous clear blue sky, Atlantis was hauled to the VAB – while bolted atop a 78 wheeled transporter – a key milestone setting a clear path to blastoff. Inside the VAB, the orbiter is mated to the external fuel tank and solid rocket boosters before rolling out to Launch Pad 39 A in about two weeks.

Atlantis Up Close on the path to the VAB. Credit: Ken Kremer

Midway through the road trip, Atlantis was parked for several hours to allow KSC employees to pose for photo opportunities with the flight ready orbiter for the last time.

The goal of Atlantis mission is to carry the Raffaello multipurpose logistics module (MPLM) to the International Space Station (ISS) and stock up the orbiting outpost with science equipment, crew supplies, food, water, logistics, gear and spare parts before the shuttles are retired forever at the prime of their lifetime.

Check back later for more photos

The all veteran STS-135 crew poses with Atlantis during rollover to the VAB. Credit: Ken Kremer

Atlantis heads to the VAB for the last time in preparation for the STS-135 mission. Credit: Ken Kremer

Atlantis approaches the VAB for the final time. Credit: Ken Kremer

The Space Shuttle Program will be prematurely stopped after the STS-135 flight.
Lack of NASA funding from the US Federal Government is causing the retirement of the Space Shuttles although the orbiters are operating at peak performance. Credit: Ken Kremer

Ken Kremer and Space Shuttle Atlantis on the road to the VAB. Credit: Ken Kremer

May 20, 2011December 24, 2015 by Nancy Atkinson

DARPA Wants Your Ideas for a 100-Year Starship

Will humanity one day boldly go... somewhere? Credit: Paramount.

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The idea for a 100-year starship has been tossed around recently, and now DARPA the Defense Advanced Research Projects Agency, has put out a Request for Information (RFI) looking for ideas about how a long-term human mission to boldly go out to the stars could possibly happen. It’s been estimated that such a mission would cost over $10 billion, and the idea has gotten $100,000 from NASA and $ 1 million from DARPA – which means that as of now it is just that, an idea.

Pete Worden, the Director of NASA’s Ames Research Center announced the idea last fall, and it received plenty of coverage, but not much publicized research on how the idea could possibly come to fruition. Worden optimistically said he expected to see the first prototype of a new propulsion system within the next few years, but that seem unlikely given NASA’s frozen budget and a Congress that doesn’t seem very forward-looking in their vision for what NASA should be doing. But perhaps DARPA’s input could have some leverage.

There would be several technological obstacles to overcome, such as how to create an artificial gravity so that those aboard the ship wouldn’t experience the muscle and bone loss that astronauts on the ISS have after just six months in space. Then there’s how to manufacture food, and create other things the crew might need while they are out in the middle of nowhere. Those are just a few examples of what would need to be dealt with.

But anyway, a journey starts with a single step, and so if you’ve got any ideas, here’s DARPA’s RFI (hurry, you’ve only got until June 3, 2011!):

DARPA is seeking ideas for an organization, business model and approach appropriate for a self-sustaining investment vehicle in support of the 100 Year StarshipTM Study. The 100 Year StarshipTM Study is a project seeded by DARPA to develop a viable and sustainable model for persistent, long-term, private-sector investment into the myriad of disciplines needed to make long-distance space travel practicable and feasible. The genesis of this study is to foster a rebirth of a sense of wonder among students, academia, industry, researchers and the general population to consider “why not” and to encourage them to tackle whole new classes of research and development related to all the issues surrounding long duration, long distance spaceflight. DARPA contends that the useful, unanticipated consequences of such research will have benefit to the Department of Defense and to NASA, and well as the private and commercial sector. The information obtained will be used for planning and acquisition strategy development. DARPA will use the information obtained as a result of this RFI on a non-attribution basis. Providing data and information that is limited or restricted for use by the Government for that purpose would be of very little value and the inclusion of such restricted/limited data/information is discouraged. Responses as a single file in Adobe PDF electronic format can be submitted to [email protected] by 12:00 pm (noon) Eastern Time, Friday, June 3, 2011. For complete details of this notice, please refer to the attachment, “RFI – 100 Year Starship Study“.

May 19, 2011December 24, 2015 by Jason Major

Studying Saturn’s Super Storm

Three views of Saturn's northern storm. ESO/University of Oxford/L. N. Fletcher/T. Barry

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First seen by amateur astronomers back in December, the powerful seasonal storm that has since bloomed into a planet-wrapping swath of churning clouds has gotten some scrutiny by Cassini and the European Southern Observatory’s Very Large Telescope array situated high in the Chilean desert.

The image above shows three views of Saturn acquired on January 19: one by amateur astronomer Trevor Barry taken in visible light and the next two by the VLT’s infrared VISIR instrument – one taken in wavelengths sensitive to lower atmospheric structures one sensitive to higher-altitude features.

Cassini image showing dredged-up ammonia crystals in the storm. NASA/JPL/Univ. of Arizona.

While the storm band can be clearly distinguished in the visible-light image, it’s the infrared images that really intrigue scientists. Bright areas can be seen along the path of the storm, especially in the higher-altitude image, marking large areas of upwelling warmer air that have risen from deep within Saturn’s atmosphere.

Normally relatively stable, Saturn’s atmosphere exhibits powerful storms like this only when moving into its warmer summer season about every 29 years. This is only the sixth such storm documented since 1876, and the first to be studied both in thermal infrared and by orbiting spacecraft.

The initial vortex of the storm was about 5,000 km (3,000 miles) wide and took researchers and astronomers by surprise with its strength, size and scale.

“This disturbance in the northern hemisphere of Saturn has created a gigantic, violent and complex eruption of bright cloud material, which has spread to encircle the entire planet… nothing on Earth comes close to this powerful storm.”

– Leigh Fletcher, lead author and Cassini team scientist at the University of Oxford in the United Kingdom.

The origins of Saturn’s storm may be similar to those of a thunderstorm here on Earth; warm, moist air rises into the cooler atmosphere as a convective plume, generating thick clouds and turbulent winds. On Saturn this mass of warmer air punched through the stratosphere, interacting with the circulating winds and creating temperature variations that further affect atmospheric movement.

The temperature variations show up in the infrared images as bright “stratospheric beacons”. Such features have never been seen before, so researchers are not yet sure if they are commonly found in these kinds of seasonal storms.

“We were lucky to have an observing run scheduled for early in 2011, which ESO allowed us to bring forward so that we could observe the storm as soon as possible. It was another stroke of luck that Cassini’s CIRS instrument could also observe the storm at the same time, so we had imaging from VLT and spectroscopy of Cassini to compare. We are continuing to observe this once-in-a-generation event.”

– Leigh Fletcher

A separate analysis using Cassini’s visual and infrared mapping spectrometer confirmed the storm is very violent, dredging up larger atmospheric particles and churning up ammonia from deep in the atmosphere. Other Cassini scientists are studying the evolving storm and a more extensive picture will emerge soon.

Read the NASA article here, or the news release from ESO here.

The leading edge of Saturn's storm in visible RGB color from Cassini raw image data taken on February 25, 2011. (The scale size of Earth is at upper left.) NASA / JPL / Space Science Institute. Edited by J. Major.

May 19, 2011April 26, 2016 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

May 19, 2011April 26, 2016 by Nancy Atkinson

Miles O’Brien Talks Live with Shuttle/Station Crew

Miles O’Brien, now with PBS NewHour did a live interview with a few members of the STS-134 crew, along with Ron Garan of the ISS crew this morning (Thursday). The webcast was part of a collaboration between Google/PBS/You Tube where the public has the chance to ask questions via video. Miles starts about 2 minutes into the video.

Transcript is available here.