No fruits were harmed in the making of this video.
Here on Universe Today we often discuss things that exist on the atomic and sub-atmonic scale. Even though astronomy is concerned with very big things that happen over very, very large distances and time spans, the reality is that our Universe is driven by events occurring on the tiny atomic scale.
We all know atoms are really small (and the particles inside them are even smaller.) But… how small are they, really? To help answer that question, here’s a neat little animation from TEDEducation, presented by Jonathan Bergmann and Cognitive Media.
The Apollo Light Flash Moving Emulsion Detector (ALFMED), an experiment to record of incidents cosmic ray particles hitting astronauts. Credit: NASA
Astronauts have long reported the experience of seeing flashes while they are in space, even when their eyes are closed. Neil Armstrong and Buzz Aldrin both reported these flashes during the Apollo 11 mission, and similar reports during the Apollo 12 and 13 missions led to subsequent Apollo missions including experiments specifically looking at this strange phenomenon. These experiments involved blindfolding crewmembers and recording their comments during designated observation sessions, and later missions had a special device, the Apollo Light Flash Moving Emulsion Detector (ALFMED), which was worn by the astronauts during dark periods to record of incidents of cosmic ray hits.
It was determined the astronauts were ‘seeing’ cosmic rays zipping through their eyeballs. Cosmic rays are high-energy charged subatomic particles whose origins are not yet known. Fortunately, cosmic rays passing through Earth are usually absorbed by our atmosphere. But astronauts outside the atmosphere can find themselves “seeing things that aren’t there,” wrote current International Space Station astronaut Don Pettit, who told about his experience of seeing these flashes on his blog:
“In space I see things that are not there. Flashes in my eyes, like luminous dancing fairies, give a subtle display of light that is easy to overlook when I’m consumed by normal tasks. But in the dark confines of my sleep station, with the droopy eyelids of pending sleep, I see the flashing fairies. As I drift off, I wonder how many can dance on the head of an orbital pin.”
In a report on the Apollo experiment, astronauts described the types of flashes they saw in three ways: the ‘spot’, the ‘streak’, and the ‘cloud’; and all but one described the flashes as ‘white’ or ‘colorless.’ One crewmember, Apollo 15 Commander David Scott, described one flash as “blue with a white cast, like a blue diamond.”
Pettit described the physics/biology of what takes place:
“When a cosmic ray happens to pass through the retina it causes the rods and cones to fire, and you perceive a flash of light that is really not there. The triggered cells are localized around the spot where the cosmic ray passes, so the flash has some structure. A perpendicular ray appears as a fuzzy dot. A ray at an angle appears as a segmented line. Sometimes the tracks have side branches, giving the impression of an electric spark. The retina functions as a miniature Wilson cloud chamber where the recording of a cosmic ray is displayed by a trail left in its wake.”
Pettit said that the rate or frequency at which these flashes are seen varies with orbital position.
“There is a radiation hot spot in orbit, a place where the flux of cosmic rays is 10 to 100 times greater than the rest of the orbital path. Situated southeast of Argentina, this region (called the South Atlantic Anomaly) extends about halfway across the Atlantic Ocean. As we pass through this region, eye flashes will increase from one or two every 10 minutes to several per minute.
A cosmic ray hit on a camera appears as a segmented line in the image. Credit: NASA/Don Pettit..
During the Apollo missions, astronauts saw these flashes after their eyes had become dark-adapted. When it was dark, they reported a flash every 2.9 minutes on average. Only one Apollo crewmember involved in the experiments did not report seeing the phenomenon, Apollo 16’s Command Module Pilot Ken Mattingly, who stated that he had poor night vision.
These cosmic rays don’t just hit people, but things in space, too, and sometimes cause problems. Pettit wrote:
“Free from the protection offered by the atmosphere, cosmic rays bombard us within Space Station, penetrating the hull almost as if it was not there. They zap everything inside, causing such mischief as locking up our laptop computers and knocking pixels out of whack in our cameras. The computers recover with a reboot; the cameras suffer permanent damage. After about a year, the images they produce look like they are covered with electronic snow. Cosmic rays contribute most of the radiation dose received by Space Station crews. We have defined lifetime limits, after which you fly a desk for the rest of your career. No one has reached that dose level yet.”
The Phantom Torso experiment, AKA, Fred. Credit: NASA
There are experiments on board the ISS to monitor how much radiation the crew is receiving. One experiment is the Phantom Torso, a mummy-looking mock-up of the human body which determines the distribution of radiation doses inside the human body at various tissues and organs.
There’s also the Alpha Magnetic Spectrometer experiment, a particle physics experiment module that is mounted on the ISS. It is designed to search for various types of unusual matter by measuring cosmic rays, and hopefully will also tell us more about the origins of both those crazy flashes seen in space, and also the origins of the Universe.
IceCube team poses for a picture in front of deployment tower after the completion of the IceCube Neutrino Detector in December of 2010. Photo by: Chad Carpenter/NSF
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The origin of cosmic rays has been one of the most enduring mysteries in physics, and it looks like it’s going to stay that way for a while longer. One of the leading candidates for where cosmic rays come from is gamma ray bursts, and physicists were hoping a huge Antarctic detector called the IceCube Neutrino Observatory would confirm that theory. But observations of over 300 GRB’s turned up no evidence of cosmic rays. In short, cosmic rays aren’t what we thought they were.
But, just like Thomas Edison who said that “every wrong attempt discarded is another step forward,” physicists view this latest finding as progress.
“Although we have not discovered where cosmic rays come from, we have taken a major step towards ruling out one of the leading predictions,” said IceCube principal investigator and University of Wisconsin–Madison physics professor Francis Halzen.
Cosmic rays are electrically charged particles, such as protons, that strike Earth from all directions, with energies up to one hundred million times higher than those created in man-made accelerators. The intense conditions needed to generate such energetic particles have focused physicists’ interest on two potential sources: the massive black holes at the centers of active galaxies and gamma ray bursts (GRBs), flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies.
IceCube is using neutrinos, which are believed to accompany cosmic ray production, to explore these two theories. In a paper published in the April 19 issue of the journal Nature, IceCube scientists describe a search for neutrinos emitted from 300 gamma ray bursts observed, most recently in coincidence with the SWIFT and Fermi satellites, between May 2008 and April 2010. Surprisingly, they found none – a result that contradicts 15 years of predictions and challenges one of the two leading theories for the origin of the highest energy cosmic rays.
Aurora seen behind the IceCube Lab. Photo by: Sven Lidstrom/NSF
The detector searches for high-energy (teraelectronvolt; 1012-electronvolt) neutrinos, and in their paper the team said they found an upper limit on the flux of energetic neutrinos associated with GRBs that is at least a factor of 3.7 below the predictions. This implies that either GRBs are not the only sources of cosmic rays with energies greater than 1018More info on IceCube.
The 10-meter South Pole Telescope in Antarctica at the Amundsen-Scott Station. (Daniel Luong-Van, National Science Foundation)
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Located at the southermost point on Earth, the 280-ton, 10-meter-wide South Pole Telescope has helped astronomers unravel the nature of dark energy and zero in on the actual mass of neutrinos — elusive subatomic particles that pervade the Universe and, until very recently, were thought to be entirely without measureable mass.
The NSF-funded South Pole Telescope (SPT) is specifically designed to study the secrets of dark energy, the force that purportedly drives the incessant (and apparently still accelerating) expansion of the Universe. Its millimeter-wave observation abilities allow scientists to study the Cosmic Microwave Background (CMB) which pervades the night sky with the 14-billion-year-old echo of the Big Bang.
Overlaid upon the imprint of the CMB are the silhouettes of distant galaxy clusters — some of the most massive structures to form within the Universe. By locating these clusters and mapping their movements with the SPT, researchers can see how dark energy — and neutrinos — interact with them.
“Neutrinos are amongst the most abundant particles in the universe,” said Bradford Benson, an experimental cosmologist at the University of Chicago’s Kavli Institute for Cosmological Physics. “About one trillion neutrinos pass through us each second, though you would hardly notice them because they rarely interact with ‘normal’ matter.”
If neutrinos were particularly massive, they would have an effect on the large-scale galaxy clusters observed with the SPT. If they had no mass, there would be no effect.
The SPT collaboration team’s results, however, fall somewhere in between.
Even though only 100 of the 500 clusters identified so far have been surveyed, the team has been able to place a reasonably reliable preliminary upper limit on the mass of neutrinos — again, particles that had once been assumed to have no mass.
Previous tests have also assigned a lower limit to the mass of neutrinos, thus narrowing the anticipated mass of the subatomic particles to between 0.05 – 0.28 eV (electron volts). Once the SPT survey is completed, the team expects to have an even more confident result of the particles’ masses.
“With the full SPT data set we will be able to place extremely tight constraints on dark energy and possibly determine the mass of the neutrinos,” said Benson.
“We should be very close to the level of accuracy needed to detect the neutrino masses,” he noted later in an email to Universe Today.
The South Pole Telescope's unique position allows it to watch the night sky for months on end. (NSF)
Such precise measurements would not have been possible without the South Pole Telescope, which has the ability due to its unique location to observe a dark sky for very long periods of time. Antarctica also offers SPT a stable atmosphere, as well as very low levels of water vapor that might otherwise absorb faint millimeter-wavelength signals.
“The South Pole Telescope has proven to be a crown jewel of astrophysical research carried out by NSF in the Antarctic,” said Vladimir Papitashvili, Antarctic Astrophysics and Geospace Sciences program director at NSF’s Office of Polar Programs. “It has produced about two dozen peer-reviewed science publications since the telescope received its ‘first light’ on Feb. 17, 2007. SPT is a very focused, well-managed and amazing project.”
The team’s findings were presented by Bradford Benson at the American Physical Society meeting in Atlanta on April 1.
Inside the LHC's underground tunnel. (Credit: CERN)
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Neutrinos have been cleared of allegations of speeding, according to an announcement issued today by CERN and the ICARUS experiment at Italy’s Gran Sasso National Laboratory. Turns out they travel exactly as fast as they should, and not a nanosecond more.
The initial announcement in September 2011 from the OPERA experiment noted a discrepancy in the measured speed of neutrinos traveling in a beam sent to the detectors at Gran Sasso from CERN in Geneva. If their measurements were correct, it would have meant that the neutrinos had arrived 60 nanoseconds faster than the speed of light allows. This, understandably, set the world of physics a bit on edge as it would effectually crumble the foundations of the Standard Model of physics.
As other facilities set out to duplicate the results, further investigations by the OPERA team indicated that the speed anomaly may have been the result of bad fiberoptic wiring between the detectors and the GPS computers, although this was never officially confirmed to be the exact cause.
Now, a a statement from CERN reports the results of the ICARUS experiment — Imaging Cosmic and Rare Underground Signals — which is stationed at the same facilities as OPERA. The ICARUS data, in measuring neutrinos from last year’s beams, show no speed anomaly — further evidence that OPERA’s measurement was very likely a result of error.
The full release states:
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The ICARUS experiment at the Italian Gran Sasso laboratory has today reported a new measurement of the time of flight of neutrinos from CERN to Gran Sasso. The ICARUS measurement, using last year’s short pulsed beam from CERN, indicates that the neutrinos do not exceed the speed of light on their journey between the two laboratories. This is at odds with the initial measurement reported by OPERA last September.
What neutrinos look like to ICARUS. (LNGS)
“The evidence is beginning to point towards the OPERA result being an artefact of the measurement,” said CERN Research Director Sergio Bertolucci, “but it’s important to be rigorous, and the Gran Sasso experiments, BOREXINO, ICARUS, LVD and OPERA will be making new measurements with pulsed beams from CERN in May to give us the final verdict. In addition, cross-checks are underway at Gran Sasso to compare the timings of cosmic ray particles between the two experiments, OPERA and LVD. Whatever the result, the OPERA experiment has behaved with perfect scientific integrity in opening their measurement to broad scrutiny, and inviting independent measurements. This is how science works.”
The ICARUS experiment has independent timing from OPERA and measured seven neutrinos in the beam from CERN last year. These all arrived in a time consistent with the speed of light.
“The ICARUS experiment has provided an important cross check of the anomalous result reports from OPERA last year,” said Carlo Rubbia, Nobel Prize winner and spokesperson of the ICARUS experiment. “ICARUS measures the neutrino’s velocity to be no faster than the speed of light. These are difficult and sensitive measurements to make and they underline the importance of the scientific process. The ICARUS Liquid Argon Time Projection Chamber is a novel detector which allows an accurate reconstruction of the neutrino interactions comparable with the old bubble chambers with fully electronics acquisition systems. The fast associated scintillation pulse provides the precise timing of each event, and has been exploited for the neutrino time-of-flight measurement. This technique is now recognized world wide as the most appropriate for future large volume neutrino detectors”.
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An important note is that, although further research points more and more to neutrinos behaving as expected, the OPERA team had proceeded in a scientific manner right up to and including the announcement of their findings.
“Whatever the result, the OPERA experiment has behaved with perfect scientific integrity in opening their measurement to broad scrutiny, and inviting independent measurements,” the ICARUS team reported. “This is how science works.”
3D printing of a microscopic race car. Image credit: TU Vienna
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3D printers let you manufacture any 3-dimensional object out of plastic. You just download the design, fire up the old 3D printer, fill the hopper with plastic, and it’ll slowly print out the object. It sounds cool, and hackers are having a great time playing around with them, but it still doesn’t compare to the scale, quality and cost of traditional manufacturing. It’s still a toy for hackers… right?
As you know, technology has a way of creeping up and then dramatically changing everything. And once you watch this mind-bending video of an ultra-high-resolution 3D printer creating a tiny race car, I think you’ll agree with me that 3D printing technology is improving in leaps and bounds.
Researchers at the Vienna University of Technology recently demonstrated a new kind of 3D printer that can create objects orders of magnitude faster than previous devices, at much finer scales; just a few hundred nanometers wide.
Check out this amazing video of the new 3D printer technology quickly creating a microscopic model of a race car.
Their printer uses a liquid resin which is hardened at exactly the right spots by a focused laser beam (rule 1, everything cool is done with lasers). The lasers can be redirected by mirrors and can harden a line of this liquid resin just a few hundred nanometers wide, giving it a very high resolution.
But it’s also fast. In the past, 3D printers were clocked at millimetres per second. Well, this TU Vienna printer can harden a 5-meter line of resin in 1 second.
There were two discoveries that pushed this advance forward:
They improved the control mechanism of the mirrors so they’re in continuous motion, accelerating and decelerating at the precise times to get the high resolution printing.
They used photoactive molecules to harden the resin. When the laser light hits the resin, it induces a chain reaction that turns it from a liquid to a solid; only at the point of highest intensity.
What would you use a 3D printer like this for? If it’s this fast and accurate, the mind boggles with the possiblities. The researchers proposed medical applications, like building scaffolding for living cells to attach, allowing you to grow organs in the lab. But the imagination really breaks down trying to imagine the implications for this kind of technology.
What matter and antimatter might look like annihilating one another. Credit: NASA/CXC/M. Weiss
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We live in a universe made of matter. But at the moment of the Big Bang, matter and antimatter existed in equal amounts. That antimatter has all but disappeared suggests that nature, for some reason, has a strong preference for matter. Physicists want to know why matter has replaced its antimatter twin, and this week the ALPHA collaboration at CERN got a step closer to unraveling the mystery.
ALPHA, an international collaborative experiment established in 2005, was designed to trap and measure antihydrogen particles with a specially designed experiment. It’s picking up where its antimatter-searching predecessor, ATHENA, left off. The focus is on antihydrogen because hydrogen is the most prevalent element in the universe and its structure is extremely well known to scientists.
Each hydrogen atom has one electron orbiting its nucleus. Firing light at the atoms excites the electron, causing it to jump into an orbit further away from the nucleus before it relaxes and returns to its resting orbit emitting light in the process. The frequency distribution of this emitted light is known; it has been precisely measured and, in our universe made of matter, is unique to hydrogen.
An illustration of hydrogen and antihydrogen. Credit: USAF
Basic physics dictates that hydrogen’s antimatter twin, antihydrogen, should be equally recognizable by having an identical spectrum. That is, if everything we know about particle physics is right. Capturing and measuring antihydrogen’s spectrum is the main goal of the ALPHA group.
ALPHA has taken the first modest measurements of antihydrogen. In the ALPHA apparatus, antihydrogen is trapped by an arrangement of magnets that affect the magnetic field of the atoms. Microwaves tuned to a specific frequency aimed on these antihydrogen atoms flips their magnetic orientation, liberating them. The freed antihydrogen meets hydrogen as it escapes and the two annihilate one another, leaving a well known pattern in particle detectors surrounding the apparatus.
The apparatus captured evidence of the electron jumping orbits in an antihydrogen atom after microwave radiation changed its internal state. The result further proves the validity of ALPHA’s approach, demonstrating that the apparatus has enough control and sensitivity to successfully carry out the experiment it was designed for. In the future, ALPHA will focus on improving the precision of its microwave measurements to uncover the antihydrogen spectrum using lasers.
The exciting results were hard to come by as antihydrogen does not exist in nature. It’s made in the ALPHA apparatus from antiprotons that are themselves made in the Antiproton Decelerator and positrons from a radioactive source. And it has to have a low enough energy level to stay trapped for measurements. But it’s working, and it just might give physicists the key they need to understand the mystery of the early universe.
An atomic clock; a relic of a bygone age? Image credit: NIST
[/caption] Do you find that you’re always having to adjust the clocks in your house? Why can’t someone just make a clock that’s accurate? How about a clock that would never lose time in, say, the entire age of the Universe? Well, that’s just what researchers from the University of New South Wales are proposing.
According to their calculations, a neutron orbiting around the atomic nucleus of an atom would do the trick. In fact, this “atomic clock” would be so accurate, it wouldn’t gain or lose 1/20th of a second in 14 billion years – that’s the age of the Universe.
Obviously a clock like this wouldn’t have any value for home use, but in science, accurate clocks are everything. And this single atom clock would be 100 times more accurate than anything scientists have access to right now. They’d be able to record time down to 19 decimal places: 0.0000000000000000001 of a second.
One of the most important places that clocks are used is GPS. The Global Positioning System uses clocks to time how long signals take to reach your GPS unit from various satellites. The satellites are broadcasting very accurate times, which can then be used to triangulate your position. More accurate clocks mean more accurate position.
So how exactly would they do it? Lasers, of course. All the cool science is done with lasers. According the researchers:
“Atomic clocks use the orbiting electrons of an atom as the clock pendulum. But we have shown that by using lasers to orient the electrons in a very specific way, one can use the orbiting neutron of an atomic nucleus as the clock pendulum, making a so-called nuclear clock with unparalleled accuracy.”
Here’s the trick. The neutron of an atom is so tightly bound to the nucleus that it’s almost completely unaffected by outside forces. Electrons, on the other hand, can be affected and so the clocks can be less accurate.
In a 2008 interview by TIME magazine, astrophysicist Neil deGrasse Tyson was asked what he thought the “most astounding fact” about the Universe was. Never at a loss for words, the famed scientist gave his equally astounding answer. His response is in the video above, set to images and music by Max Schlickenmeyer.
It’s the best three minutes and thirty-three seconds you’ll spend all day.
Dropping out of warp speed could have deadly results. (Image: Paramount Pictures/CBS Studios)
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Planning a little space travel to see some friends on Kepler 22b? Thinking of trying out your newly-installed FTL3000 Alcubierre Warp Drive to get you there in no time? Better not make it a surprise visit — your arrival may end up disintegrating anyone there when you show up.
“Warp” technology and faster-than-light (FTL) space travel has been a staple of science fiction for decades. The distances in space are just so vast and planetary systems — even within a single galaxy — are spaced so far apart, such a concept is needed to make casual human exploration feasible (and fit within the comforts of people’s imagination as well… nobody wants to think about Kirk and Spock bravely going to some alien planet while everyone they’ve ever known dies of old age!)
While many factors involving FTL travel are purely theoretical — and may remain in the realm of imagination for a very long time, if not ever — there are some concepts that play well with currently-accepted physics.
Warp field according to the Alcubierre drive. (AllenMcC.)
The Alcubierre warp drive is one of those concepts.
Proposed by Mexican theoretical physicist Miguel Alcubierre in 1994, the drive would propel a ship at superluminal speeds by creating a bubble of negative energy around it, expanding space (and time) behind the ship while compressing space in front of it. In much the same way that a surfer rides a wave, the bubble of space containing the ship and its passengers would be pushed at velocities not limited to the speed of light toward a destination.
Of course, when the ship reaches its destination it has to stop. And that’s when all hell breaks loose.
Researchers from the University of Sydney have done some advanced crunching of numbers regarding the effects of FTL space travel via Alcubierre drive, taking into consideration the many types of cosmic particles that would be encountered along the way. Space is not just an empty void between point A and point B… rather, it’s full of particles that have mass (as well as some that do not.) What the research team — led by Brendan McMonigal, Geraint Lewis, and Philip O’Byrne — has found is that these particles can get “swept up” into the warp bubble and focused into regions before and behind the ship, as well as within the warp bubble itself.
When the Alcubierre-driven ship decelerates from superluminal speed, the particles its bubble has gathered are released in energetic outbursts. In the case of forward-facing particles the outburst can be very energetic — enough to destroy anyone at the destination directly in front of the ship.
“Any people at the destination,” the team’s paper concludes, “would be gamma ray and high energy particle blasted into oblivion due to the extreme blueshifts for [forward] region particles.”
In other words, don’t expect much of a welcome party.
Another thing the team found is that the amount of energy released is dependent on the length of the superluminal journey, but there is potentially no limit on its intensity.
“Interestingly, the energy burst released upon arriving at the destination does not have an upper limit,” McMonigal told Universe Today in an email. “You can just keep on traveling for longer and longer distances to increase the energy that will be released as much as you like, one of the odd effects of General Relativity. Unfortunately, even for very short journeys the energy released is so large that you would completely obliterate anything in front of you.”
So how to avoid disintegrating your port of call? It may be as simple as just aiming your vessel a bit off to the side… or, it may not. The research only focused on the planar space in front of and behind the warp bubble; deadly postwarp particle beams could end up blown in all directions!
Luckily for Vulcans, Tatooinians and any acquaintances on Kepler 22b, the Alcubierre warp drive is still very much theoretical. While the mechanics work with Einstein’s General Theory of Relativity, the creation of negative energy densities is an as-of-yet unknown technology — and may be impossible.
Which could be a very good thing for us, should someone out there be planning a surprise visit our way!
Read more about Alcubierre warp drives here, and you can download the full University of Sydney team’s research paper here.
Thanks to Brendan McMonigal and Geraint Lewis for the extra information!
