Posted on by Steve Nerlich

Astronomy Without A Telescope – Doubly Special Relativity

The Large Hadron Collider - destined to deliver fabulous science data, but uncertain if these will include an evidence basis for quantum gravity theories. Credit: CERN.

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General relativity, Einstein’s theory of gravity, gives us a useful basis for mathematically modeling the large scale universe – while quantum theory gives us a useful basis for modeling sub-atomic particle physics and the likely small-scale, high-energy-density physics of the early universe – nanoseconds after the Big Bang – which general relativity just models as a singularity and has nothing else to say on the matter.

Quantum gravity theories may have more to say. By extending general relativity into a quantized structure for space-time, maybe we can bridge the gap between small and large scale physics. For example, there’s doubly special relativity.

With conventional special relativity, two different inertial frames of reference may measure the speed of the same object differently. So, if you are on a train and throw a tennis ball forward, you might measure it moving at 10 kilometers an hour. But someone else standing on the train station platform watching your train pass by at 60 kilometers an hour, measures the speed of the ball at 60 + 10 – i.e. 70 kilometers an hour. Give or take a few nanometers per second, you are both correct.

However, as Einstein pointed out, do the same experiment where you shine a torch beam, rather than throw a ball, forward on the train – both you on the train and the person on the platform measure the torch beam’s speed as the speed of light – without that additional 60 kilometers an hour – and you are both correct.

It works out that for the person on the platform, the components of speed (distance and time) are changed on the train so that distances are contracted and time dilated (i.e. slower clocks). And by the math of Lorenz transformations, these effects become more obvious the faster than train goes. It also turns out that the mass of objects on the train increase as well – although, before anyone asks, the train can’t turn into a black hole even at 99.9999(etc) per cent of the speed of light.

Now, doubly special relativity, proposes that not only is the speed of light always the same regardless of your frame of reference, but Planck units of mass and energy are also always the same. This means that relativistic effects (like mass appearing to increase on the train) do not occur at the Planck (i.e. very small) scale – although at larger scales, doubly special relativity should deliver results indistinguishable from conventional special relativity.

The Planck spacecraft - an observatory exploring the universe and named after the founder of quantum theory. Coincidence? Credit: ESA.

Doubly special relativity might also be generalized towards a theory of quantum gravity – which, when extended up from the Planck scale, should deliver results indistinguishable from general relativity.

It turns out that at the Planck scale e = m, even though at macro scales e=mc2. And at the Planck scale, a Planck mass is 2.17645 × 10-8 kg – supposedly the mass of a flea’s egg – and has a Schwarzschild radius of a Planck length – meaning that if you compressed this mass into such a tiny volume, it would become a very small black hole containing one Planck unit of energy.

To put it another way, at the Planck scale, gravity becomes a significant force in quantum physics. Although really, all we are saying that is that there is one Planck unit of gravitational force between two Planck masses when separated by a Planck length – and by the way, a Planck length is the distance that light moves within one unit of Planck time!

And since one Planck unit of energy (1.22×1019 GeV) is considered the maximal energy of particles – it’s tempting to consider that this represents conditions expected in the Planck epoch, being the very first stage of the Big Bang.

It all sounds terribly exciting, but this line of thinking has been criticized as being just a trick to make the math work better, by removing important information about the physical systems under consideration. You also risk undermining fundamental principles of conventional relativity since, as the paper below outlines, a Planck length can be considered an invariable constant independent of an observer’s frame of reference while the speed of light does become variable at very high energy densities.

Nonetheless, since even the Large Hadron Collider is not expected to deliver direct evidence about what may or may not happen at the Planck scale – for now, making the math work better does seem to be the best way forward.

Further reading: Zhang et al. Photon Gas Thermodynamics in Doubly Special Relativity.

Posted on by Nancy Atkinson

Carnival of Space #189

This week’s Carnival of Space is hosted by Steve Tilford over at Steve’s Astro Corner.

Click here to read the Carnival of Space #189.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

Posted on by Ken Kremer

Robo Trek Debuts … Robonaut 2 Unleashed and joins First Human-Robot Space Crew

For a moment we had 2 @AstroRobonaut. ISS Commander Scott Kelly and Robonaut 2 pose together in the Destiny laboratory module. Credit: ESA/NASA

Star Trek’s Data must be smiling.

One of his kind has finally made it to the High Frontier. The voyages of Robo Trek have begun !

Robonaut 2, or R2, was finally unleashed from his foam lined packing crate by ISS crewmembers Cady Coleman and Paolo Nespoli on March 15 and attached to a pedestal located inside its new home in the Destiny research module. R2 joins the crew of six human residents as an official member of the ISS crew. See the video above and photos below.

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The fancy shipping crate goes by the acronym SLEEPR, which stands for Structural Launch Enclosure to Effectively Protect Robonaut. R2 had been packed inside since last summer.

Robonaut 2 is the first dexterous humanoid robot in space and was delivered to the International Space Station by Space Shuttle Discovery on STS-133.

”Robonaut is now onboard as the newest member of our crew. We are happy to have him onboard. It’s a real good opportunity to help understand the interface of humans and robotics here in space.” said Coleman. “We want to see what Robonaut can do. Congratulations to the team of engineers [at NASA Johnson Space center] who got him ready to fly.”

ISS Flight Engineer Cady Coleman and Robonaut 2

Discovery blasted off for her historic final mission on Feb. 24 and made history to the end by carrying the first joint Human-Robot crew to space.

The all veteran human crew of Discovery was led by Shuttle Commander Steve Lindsey. R2 and SLEEPR were loaded aboard the “Leonardo” storage and logistics module tucked inside the cargo bay of Discovery. Leonardo was berthed at the ISS on March 1 as a new and permanent addition to the pressurized habitable volume of the massive orbiting outpost.

“It feels great to be out of my SLEEPR, even if I can’t stretch out just yet. I can’t wait until I get to start doing some work!” tweeted R2.

The 300-pound R2 was jointly developed in a partnership between NASA and GM at a cost of about $2.5 million. It consists of a head and a torso with two arms and two hands. It was designed with exceptionally dexterous hands and can use the same tools as humans.

ISS Flight Engineer Paolo Nespoli and Robonaut 2

R2 will function as an astronaut’s assistant that can work shoulder to shoulder alongside humans and conduct real work, ranging from science experiments to maintenance chores. After further upgrades to accomplish tasks of growing complexity, R2 may one day venture outside the ISS to help spacewalking astronauts.

“It’s a dream come true to fly the robot to the ISS,” said Ron Diftler in an interview at the Kennedy Space Center. Diftler is the R2 project manager at NASA’s Johnson Space Center.

President Obama called the joint Discovery-ISS crew during the STS-133 mission and said he was eager to see R2 inside the ISS and urged the crew to unpack R2 as soon as possible.

“I understand you guys have a new crew member, this R2 robot,” Obama said. “I don’t know whether you guys are putting R2 to work, but he’s getting a lot of attention. That helps inspire some young people when it comes to science and technology.”

Commander Lindsey replied that R2 was still packed in the shipping crate – SLEEPR – and then joked that, “every once in a while we hear some scratching sounds from inside, maybe, you know, ‘let me out, let me out,’ we’re not sure.”

Robonaut 2 is free at last to meet his destiny in space and Voyage to the Stars.

“I don’t have a window in front of me, but maybe the crew will let me look out of the Cupola sometime,” R2 tweeted from the ISS.

Read my earlier Robonaut/STS-133 stories here, here, here and here.

This isn’t an animation or computer graphics.
I’m in space, says Robonaut 2 from inside the Destiny module at the ISS. Credit: NASA
Robonaut 2 unveiled at the ISS.
Robonaut 2, the dexterous humanoid astronaut helper, is pictured in the Destiny laboratory of the International Space Station.
Flight Engineer Oleg Skripochka and Robonaut 2 inside the ISS
R2A waving goodbye.
Robonaut R2A waving goodbye as Robonaut R2B launches into space aboard STS-133 from the Kernnedy Space Center. R2 is the first humanoid robot in space. Credit: Joe Bibby
R2A waving goodbye to twin brother R2B launching aboad Space Shuttle Discovery on Feb 14, 2011. Credit: Joe Bibby
Discovery launched on Feb. 14 with crew of six human astronauts and R2 Robonaut on STS-133 mission.
First joint Human – Robot crew. Credit: Ken Kremer
The twin brother of the R2 Robonaut and their NASA/GM creators at KSC.
Robonaut 2 and the NASA/GM team of scientists and engineers watched the launch of Space Shuttle Discovery and the first joint Human-Robot crew on the STS-133 mission on Feb. 24, 2011 from the Kennedy Space Center. Credit: Ken Kremer
Posted on by Nancy Atkinson

Hopes Dim for Contacting Spirit Rover

A composite image of how the Spirit rover probably looks, stuck in Gusev Crater. Credit: NASA, image editing by Stu Atkinson.

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Still no response from Spirit, the Mars Exploration Rover that became stuck in a sand trap on the Red Planet, and went into hibernation without sufficient solar power. March 10 was the point at which the rover should have received its maximum amount of sunshine – i.e. power — for this Martian year, and with the passage of that date, optimism is dimming for being able to revive Spirit. But, the rover teams have not yet given up all hope and have a few unique strategies up their sleeves to try and wake the sleeping rover.

Over the past few months, engineers at JPL said they used strategies to contact Spirit based on the possibility that increasing energy availability might wake the rover from hibernation. Now, the team has switched to communication strategies designed to address more than one problem on the rover.

“The commands we are sending starting this week should work in a multiple-fault scenario where Spirit’s main transmitter is no longer working and the mission clock has lost track of time or drifted significantly,” said JPL’s John Callas, project manager for Spirit and Opportunity.

No one probably wants to hear this, but if no signal is heard from Spirit in the next month or two, the rover will officially be declared as lost, and the rover teams will shift to single-rover operations, continuing to operate Spirit’s active twin, Opportunity.

The Spirit rover, as seen by the HiRISE camera on the Mars Reconnaissance Orbiter. Credit: NASA, image enhanced by Stu Atkinson.

Spirit has not communicated for almost one Earth year — since March 22, 2010. Being stuck as the Martian winter approached, the rover could not move into a favorable position for its solar panels to gather enough energy from the Sun to keep the rover completely “alive,” and it eventually went into a low-power hibernation mode.

Officials from JPL said that during the Martian winter with most heaters turned off, Spirit experienced colder internal temperatures than in any of its three previous winters on Mars. The cold could have damaged any of several electronic components that, if damaged, would prevent reestablishing communication with Spirit.

But the rover teams have worked for more than 8 months to try and regain contact, just in case the increased solar power available would have awoken Spirit. NASA’s Deep Space Network of antennas in California, Spain and Australia has been listening for Spirit daily. The rover team has also sent commands to elicit a response from the rover even if the rover has lost track of time, or if its receiver has degraded in frequency response.

With the available solar energy at Spirit’s site estimated to peak on March 10, revised commanding then began March 15, including instructions for the rover to be receptive over UHF relay to hailing from the Mars orbiters for extended periods of time and to use a backup transmitter on the rover.

We’ll wait patiently, and hope to hear from Spirit.

She landed on Mars waaaay back on Jan. 4, 2004, for a mission originally designed to last for three months.

Spirit and Opportunity both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Opportunity landed three weeks after Spirit.

Posted on by Nancy Atkinson

How to Recover a Solid Rocket Booster

NASA shot some very unique high-definition footage of teams recovering the space shuttle’s solid rocket booster segments, including under-water shots of divers working on the recovery in the Atlantic Ocean. Seeing the divers and other recovery team members around the boosters helps give a sense of scale of how big these SRBs are. This is from shuttle Discovery’s final mission, STS-133, and comes complete with underwater breathing sounds!

The video also includes HD video footage from the recovery ships, showing how the teams keep track of and locate the boosters, as well as time-lapse footage of recovery efforts on the Freedom Star ship.
Continue reading “How to Recover a Solid Rocket Booster”

Posted on by Nancy Atkinson

New Horizons Flies by Uranus

An 'overhead' view of New Horizons' location. Credit: NASA

The Pluto-bound New Horizons spacecraft will fly by another planet today (March 18, 2011). However, the robotic craft won’t be taking any images as it zooms past Uranus’ orbit at about 6 p.m. EDT, 3.8 billion kilometers (2.4 billion miles) away from the gas giant (and 2.0 billion km (1.8 billion miles) from Earth). New Horizons is currently in hibernation mode, and the great distance from Uranus means any observations wouldn’t provide much as far as data and images. But, even so, this event is a ‘landmark’ so to speak in New Horizon’s gauntlet across the solar system.

“New Horizons is all about delayed gratification, and our 9 1/2-year cruise to the Pluto system illustrates that,” said Principal Investigator Alan Stern, of the Southwest Research Institute. “Crossing the orbit of Uranus is another milepost along our long journey to the very frontier of exploration.”

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New Horizons is now well over halfway through its journey to Pluto. Motoring along at 57,900 km/hr (36,000 mph), it will travel more than 4.8 billion km (3 billion miles) to fly past Pluto and its moons Nix, Hydra and Charon in July 2015.

But the journey doesn’t end there. After that, New Horizons will head off to a post-Pluto encounter with other objects within the Kuiper Belt, some event(s) which might take place even into the 2020’s. The planetary science community is working on the selection of potential targets.

The mission still has more than 4 years to go to get to Pluto; it will take 9 nine months to send all the data back to Earth.

The next planetary milestone for New Horizons will be the orbit of Neptune, which it crosses on Aug. 25, 2014, exactly 25 years after Voyager 2 made its historic exploration of that giant planet.

“This mission is a marathon,” says Project Manager Glen Fountain, of the Johns Hopkins University Applied Physics Laboratory. “The New Horizons team has been focused on keeping the spacecraft on course and preparing for Pluto. So far, so good, and we are working to keep it that way.”

Source: New Horizons

Posted on by Anne Minard

Success! MESSENGER First Spacecraft to Orbit Mercury

Artist's concept of MESSENGER in orbit around Mercury. Courtesy of NASA
Artist's concept of MESSENGER in orbit around Mercury. Courtesy of NASA

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After more than a dozen laps through the inner solar system, NASA’s MESSENGER spacecraft appears to have moved into orbit around Mercury tonight. Although Mariner in the 1970s and MESSENGER in the past several years have done flybys, MESSENGER is the first spacecraft to orbit the innermost planet in our solar system. NASA is stopping short of saying the spacecraft has achieved its planned orbit, but the clapping and hand-shaking in the control room looked highly optimistic.

“Preliminary results show that the burn went just as expected,” said a jubilant Ken Hibbard, an engineer at John Hopkins University’s Applied Physics Lab (APL), in a live report on NASA TV.

UPDATE, 9:50 p.m. EDT: NASA has abandoned all its cautionary language. MESSENGER is confirmed in orbit!

MESSENGER — which stands for MErcury Surface, Space ENvironment, GEochemistry and Ranging — launched Aug. 3, 2004 from Cape Canaveral. The orbit insertion places the spacecraft into a 12-hour orbit about Mercury with a 200 kilometer (124 mile) minimum altitude. The durable spacecraft is carrying seven science instruments and is fortified against the blistering environs near the sun.

The mission is an effort to study the geologic history, magnetic field, surface composition and other mysteries of the planet. The findings are expected to broaden our understanding of rocky planets, more and more of which are being discovered in other solar systems. One of the most compelling enigmas surrounds Mercury’s magnetic field. At a diameter only slightly larger than that of the moon (about 4,800 kilometers or 2,983 miles), Mercury should have solidified to the core. However, the presence of a magnetic field suggests to some researchers that the planet’s insides could be partially molten.

During its journey toward Mercury, MESSENGER passed the planet several times, filling in the imaging gaps left by Mariner 10. Now, the entire planet with the exception of about five percent has been observed. MESSENGER will focus its cameras on getting the best possible images of the remaining portions, mostly in the polar regions.

The MESSENGER mission is led by NASA, APL and the Carnegie Institution and includes a highly dedicated team of engineers, and many scientists.

“I’ve waited 36 years for this, and I’m about as excited as a person could get right now,” said Robert Strom, a MESSENGER team member from the University of Arizona’s Lunar and Planetary Lab.

Source: NASA’s MESSENGER mission website and NASA TV.

Posted on by Jon Voisey

The Universe Verse Continues – It’s Alive!

Back in 2009, I was given an odd book. It was the Universe Verse: Book One. In it, the author illustrates the formation of the universe, from the Big Bang, to the formation of stars and galaxies in rich detail and painstaking attention to the tiniest of scientific facts. And to top it off, it’s all done in rhyme as if Carl Sagan met Dr. Seuss. But as the title indicates, it was just the first of the series. In total, the author, James Lu Dunbar, is planning three books and at long last, the second in the Universe Verse trilogy is ready for release. And we’ve got a sneak peek!

The previous book (available to preview on the author’s website) ended with the formation of heavy atoms in the cores of stars and supernovae. “It’s Alive!” begins with the formation of planets from these elements. It explains the formation of primordial oceans and the atmosphere and introduces abiogenesis. It takes the reader through the fundamentals of random mutations leading to natural selection, formation of amino acids, and biodiversity.

This chapter in the saga leaves off with life still quite simple, still at the bacterial level, but with hints at what it will become (the province of the next book). As with the previous book, this one is lavishly illustrated, but unlike its predecessor, it’s in color. This was all thanks to a series of pledges James received to continue his project, netting him six times more than the amount requested!

Like the last book, this one can be previewed free online, but to go even further, James is releasing the book as a free eBook. All you have to do is send him an Email (address on his website) for a high resolution .pdf copy! He encourages anyone interested to request it since “Everyone, especially children, should have the opportunity to read this story.” For even more behind the scenes with this book, James chronicled the making of the book, complete with rough draft pages on his blog.

For those interested in purchasing the book, it will available for purchase in paperback on April 3rd of this year. Preorders are available here.

Posted on by Anne Minard

Titan’s Spring Showers Bring Torrents of Methane, Maintain ‘Dry’ Gullies

NASA’s Cassini spacecraft chronicles the change of seasons as it captures clouds concentrated near the equator of Saturn’s largest moon, Titan, on 18 October 2010. Credit: NASA/JPL/Space Science Institute

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Titan’s skies dump methane rain on the bizarre moon a quarter of the year, which collects in northern methane lakes and maintains gullies and washes once presumed to have been sculpted in a wetter age.

Elizabeth Turtle from the Johns Hopkins University Applied Physics Laboratory (APL) is lead author on the new Science paper reporting that Cassini seems to have caught a storm in action last year: “We report the detection by Cassini’s Imaging Science Subsystem of a large low-latitude cloud system early in Titan’s northern spring and extensive surface changes,” write Turtle and her co-authors in the new paper, which appears today. “The changes are most consistent with widespread methane rainfall reaching the surface, which suggests that the dry channels observed at Titan’s low latitudes are carved by seasonal precipitation.”

While Saturn’s largest moon has methane lakes at high latitudes, its equatorial regions are mostly arid, with vast expanses of dunes. Researchers first observed dry, riverbed-like channels in these regions in Huygens probe images, but generally believed them to be remnants of a past wetter climate.

Turtle and her colleagues observed sudden decreases in the brightness of the surface near Titan’s equator after a cloud outburst. The authors consider several possible explanations for these changes, including wind storms and volcanism, but they conclude that rainfall from a large methane storm over the region is most likely responsible for the darkening they observed. The surface changes they noted after the storm spanned more than 500,000 square kilometers, about the size of California.

Simplified global atmospheric circulation and precipitation pattern on Titan and Earth. Most precipitation occurs at the intertropical convergence zone, or ITCZ, where air ascends as a result of convergence of surface winds from the northern and southern directions. Titan’s ITCZ was previously near the south pole (A) but is currently on its way to the north pole (B). The seasonal migration of the ITCZ on Earth is much smaller (C and D). Credit: P. Huey/Science © 2011 AAAS

In a related Perspectives piece, Tetsuya Tokan from the Universität zu Köln in Köln, Germany wrote that Titan’s precipitation climatology “is clearly different from that of Earth, and exotic climate zones unknown in Köppen’s classification may exist.” He was referring to a widely-used climate classification system coined by Wladimir Köppen in 1884.

Tokan writes that while Earth’s global circulation patterns concentrate precipitation in rainy belts along the equatorial regions, Titan’s “convergence zone” appears migrate north and south over time, distributing precipitation more equitably across the moon.

Source: “Rapid and Extensive Surface Changes Near Titan’s Equator: Evidence of April Showers,” by Elizabeth Turtle et al. and the related Perspectives piece, “Precipitation Climatology on Titan,” by Tetsuya Tokan. Both articles appear today in the journal Science.