Posted on by Nicholos Wethington

Paper Boomerang will be Tested on Space Station

boomerang-led.thumbnail.jpg

You know this is a burning question on the minds of eight-year olds everywhere: if you threw a boomerang in zero-gravity, would it come back to you? Japanese astronaut Takao Doi plans to test this very premise when he travels to the International Space Station in March 2008.

Doi plans to bring a paper boomerang to the ISS to test whether it will perform the trick of returning to the thrower in zero-gravity. He reportedly decided to test the boomerang at the behest of Yasuhiro Togai, a world boomerang champion from Osaka, Japan. With the announcement that a paper airplane will be launched from the ISS, space is beginning to look like an unruly high school classroom. But these experiments aren’t all fun and games, as there are underlying physical principles that can be explored by such simple tests.

A returning boomerang – when thrown properly – will travel in a circular path which brings it back around to the thrower. The two (or three) fins of a boomerang are shaped like an airplane wing, so when thrown the shape provides lift and causes the boomerang to fly.

Boomerangs fly in a circle because of the lift provided by the leading fin of the boomerang. Because it is spinning around a central axis, one fin provides lift in the direction of travel, then the other does the same. This force in the same direction makes the path of the boomerang form a circle, and as it loses energy because of the pull of gravity the boomerang comes back down to the ground.

Now, the question remains as to what will happen if the force of gravity is not present. The zero-gravity environment of the ISS is a perfect place to test this. The atmosphere of the ISS will still allow the boomerang to generate lift, but will it return to the sender, bounce off the walls, or just spin in place?

Source: Space Travel report

Posted on by Ian O'Neill

Scientists Designing “Ion Shield” To Protect Astronauts From Solar Wind

bubblechamber.thumbnail.jpg

British scientists are working to build an invisible magnetic “Ion Shield” to be used during missions in space. A minature solar wind has been created in an Oxfordshire laboratory to simulate the highly charged particles emitted from the Sun and a magnetic “bubble” is being conceived to surround future spaceships. The magnetic field should have sufficient deflecting strength to redirect cancer-causing energetic particles away from future astronauts. Useful, especially during the proposed long-haul flights to Mars should the Sun begin launching flares at the wrong time…

The protection of astronauts in space from being bathed in damaging solar radiation is paramount to mission planners. Preventing exposure to high-energy particles is essential for the short-term success of the mission, and for the long-term health of the astronaut. Generally, humans in Earth orbit are protected from the ravages of the solar wind as they are within the protective blanket surrounding our planet. The protection is supplied by Earth’s magnetosphere, a powerful magnetic shield that deflects charged particles and channels them to the north and south poles, allowing life to thrive down here on the surface. The particles injected into the poles react with our atmosphere generating light, the Aurora.

So, the UK team are looking to create a small-scale “magnetosphere” of their own. If a spaceship can generate its own magnetic field, then perhaps the majority of solar particles can be deflected, creating a protective bubble the ship can travel in during solar storms. This may sound like science fiction, but the physics is sound, magnetic fields are used every day to deflect charged particles. Why not try to build a spaceship-sized magnetic particle deflector?

“We now have actual measurements that show a ‘hole’ in the solar wind could be created in which a spacecraft could sit, affording some protection from ‘ion storms’, as they would call them on Star Trek.” – Dr Ruth Bamford, physicist at the Rutherford Appleton Laboratory (RAL) in Chilton, Oxfordshire.

Firing a jet of charged particles into a strong magnetic field was attempted in the laboratory and the results were excellent. Observing the particles “hit” the leading edge of the field, a protected volume was made within the synthetic solar wind, arcing the particles around the void.

These are very early results however, and development on any large-scale system will take some work. Lots of energy would be required to create a spaceship-sized magnetic bubble, so there will be energy optimization issues to work into the design. Whether this exciting form of protection is possible or not, the pressure will be on to build a prototype before plans for the international Global Exploration Strategy to send man back to the Moon and beyond come into action. The US is now committed to a manned mission to Mars by 2020, so it would be useful to have the solar wind, high-energy particle problem solved by then.

Source: Guardian.co.uk

Posted on by Ian O'Neill

Will Time be Replaced by Another Space Dimension?

world_line.thumbnail.png

What if time disappeared? Yes, it sounds like a silly question – and if the cosmos sticks to the current laws of physics – it’s a question we need never ask beyond this article. Writing this article would in itself be a waste of my time if the cosmos was that simple. But I’m hedging my bets and continuing to type, as I believe we have only just scratched the surface of the universal laws of physics; the universe is anything but simple. There may in fact be something to this crazy notion that the nature of the universe could be turned on its head should the fundamental quantity of time be transformed into another dimension of space. An idea like this falls out of the domain of classical thought, and into the realms of “braneworlds”, a view that encapsulates the 4-dimensional universe we know and love with superstrings threaded straight through…

Brane theory is a strange idea. In a nutshell, a brane (short for “membrane”) can be viewed as a sheet floating in a fifth dimension. As we can only experience three dimensional space along one dimension of time (four dimensional space-time, a.k.a. a Lorentzian universe), we cannot understand what this fifth dimension looks like, but we are fortunate to have mathematics to help us out. Mathematics can be used to describe as many dimensions as we like. Useful, as branes describe the cumulative effect of “strings” threading through many dimensions and the forces interacting to create the universe we observe in boring old three dimensional space. According to the “braneworld” view, our four dimensional cosmos may actually be embedded within a multidimensional universe – our cosmic version only uses four of the many possible dimensions.

Theorists contemplating braneworlds, such as Marc Mars at the University of Salamanca in Spain, now believe they have stumbled on an implication that could, quite literally, stop cosmologists in their tracks. The time dimension could soon be disappearing to be replaced by a fourth space dimension. Our familiar Lorentzian universe could turn Euclidean (i.e. four spatial dimensions, no time) and Mars believes the evidence for the change is staring us in the face.

“One of the interesting, and intriguing, properties of these signature-changing branes is that, even though the change of signature may be conceived as a dramatical event within the brane, both the bulk and the brane can be fully smooth. In particular, observers living in the brane but assuming that their Universe is Lorentzian everywhere may be misled to interpret that a curvature singularity arises precisely at the signature change” – Marc Mars, from Is the accelerated expansion evidence of a forthcoming change of signature on the brane?.

The observed expansion of the universe (as discovered by Edwin Hubble in 1925) may in fact be a symptom of a “signature changing” brane. If our brane is mutating from time-like to space-like, observers in the Lorentzian universe should observe an expanding and accelerating universe, exactly as we are observing presently. Mars goes on to detail that this theory can explain this ever increasing expansion, whilst keeping the physical characteristics of the cosmos as we observe today, without assuming any form of dark matter or dark energy is responsible.

It is doubtful that we can ever perceive a time-less cosmos, and what would happen to the universe should time go space-like is beyond our comprehension. So, enjoy your four dimensions while they last, time could soon be running out.

Source: arXiv blog

Posted on by Ian O'Neill

Forget Black Holes, How Do You Find A Wormhole?

An artists impression of what it would look like inside a wormhole. Pretty. (credit: Space.com)

Finding a black hole is an easy task… compared with searching for a wormhole. Suspected black holes have a massive gravitational effect on planets, stars and even galaxies, generating radiation, producing jets and accretion disks. Black holes will even bend light through gravitational lensing. Now, try finding a wormhole… Any ideas? Well, a Russian researcher thinks he has found an answer, but a highly sensitive radio telescope plus a truckload of patience (I’d imagine) is needed to find a special wormhole signature…

A wormhole connecting two points within spacetime.
Wormholes are a valid consequence of Einstein’s general relativity view on the universe. A wormhole, in theory, acts as a shortcut or tunnel through space and time. There are several versions on the same theme (i.e. wormholes may link different universes; they may link the two separate locations in the same universe; they may even link black and white holes together), but the physics is similar, wormholes create a link two locations in space-time, bypassing normal three dimensional travel through space. Also, it is theorized, that matter can travel through some wormholes fuelling sci-fi stories like in the film Stargate or Star Trek: Deep Space Nine. If wormholes do exist however, it is highly unlikely that you’ll find a handy key to open the mouth of a wormhole in your back yard, they are likely to be very elusive and you’ll probably need some specialist equipment to travel through them (although this will be virtually impossible).

Alexander Shatskiy, from the Lebedev Physical Institute in Moscow, has an idea how these wormholes may be observed. For a start, they can be distinguished from black holes, as wormhole mouths do not have an event horizon. Secondly, if matter could possibly travel through wormholes, light certainly can, but the light emitted will have a characteristic angular intensity distribution. If we were viewing a wormhole’s mouth, we would be witness to a circle, resembling a bubble, with intense light radiating from the inside “rim”. Looking toward the center, we would notice the light sharply dim. At the center we would notice no light, but we would see right through the mouth of the wormhole and see stars (from our side of the universe) shining straight through.

For the possibility to observe the wormhole mouth, sufficiently advanced radio interferometers would be required to look deep into the extreme environments of galactic cores to distinguish this exotic cosmic ghost from its black hole counterpart.

However, just because wormholes are possible does not mean they do exist. They could simply be the mathematical leftovers of general relativity. And even if they do exist, they are likely to be highly unstable, so any possibility of traveling through time and space will be short lived. Besides, the radiation passing through will be extremely blueshifted, so expect to burn up very quickly. Don’t pack your bags quite yet…

Source: arXiv publication

Posted on by Ian O'Neill

A Possible Answer to Flyby Anomalies

galileo_earth.thumbnail.jpg
Artist's impression of the Galileo mission above Earth - which spent seven years (1995–2003) orbiting Jupiter. Credit: NASA

Strange things are happening to our robotic space explorers. Also known as the “Pioneer effect“ (the unexpected and sudden alterations to Pioneer 10 and Pioneer 11 trajectories measured as they continue their journey into the outer solar system), similar anomalies are being seen in flybys by modern space probes. Earth flybys by Galileo, Rosetta, NEAR and Cassini have all experienced a sudden boost in speed. After cancelling out all possible explanations, including leakage of fuel and velocity measurement error, a new study suggests the answer may lie in a bizarre characteristic of universal physics…

Planetary flybys are an essential aid to interplanetary missions to gain energy as they accelerate on their merry way to their destination. Gravity assists are accurately calculated by mission scientists so the time of arrival can be calculated down to the minute. Considering most missions take years to complete, this degree of accuracy is amazing, but essential.

So, when Galileo completed gravity assist past Earth on December 8, 1990, to speed it toward Jupiter, you can imagine NASA’s surprise to find that Galileo had accelerated suddenly, and for no apparent reason. This small boost was tiny, but through the use of the Deep Space Network, extremely accurate measurements of the speeding craft could be made. Galileo had accelerated 3.9 mm/s.

This isn’t an isolated case. During Earth flybys by the space probes NEAR, Cassini-Huygens and Rosetta, all experienced a unexplained boosts of 13 mm/s, 0.11 mm/s and 2 mm/s respectively. Once technical faults, observational errors, radiation pressure, magnetic instabilities and electrical charge build-up could be ruled out, focus is beginning to turn to more exotic explanations.

A recent study by Magic McCulloch suggests that “Unruh radiation” may be the culprit. The Unruh effect, put simply, suggests that accelerating bodies experience a type of electromagnetic radiation. At very low acceleration, the wavelength emitted will be so large that a whole wavelength will be longer than the dimensions of the Universe (otherwise known as the Hubble Distance). Low acceleration would therefore generate waves that have no effect on the body. However, should the accelerating body (i.e. Galileo getting accelerated by Earth’s gravity during the 1990 flyby) slowly exceed an acceleration threshold, the Unruh radiation will decrease in wavelength (smaller than the Hubble Distance), causing a tiny, but measurable “boost” to its increasing velocity.

Although complex, this theory is very interesting and proves that although we can calculate the arrival time of space probes down to the nearest minute, the Universe will continue to throw up some perplexing issues for a long time yet.

Sources: arXiv Blog, arXiv abstract and paper download

Posted on by Ian O'Neill

Our Virtual Reality Universe

virtual_world_ioneill.thumbnail.jpg

What if the Universe was in fact a simulation? A product of some information processor, creating space and time, energy and matter? What if the Big Bang was the whole simulation booting up, beginning billions of years of space and time calculations? Can we possibly understand our consciousness as a subroutine in an advanced number crunching machine? A new paper published by the Centre for Discrete Mathematics and Theoretical Computer Science, University of Auckland, asks us to keep an open mind and suggests if we look at the complexity of physical laws of our known universe, many paradoxes may be explained if we view our physical reality as a virtual reality.

Virtual reality is a term that has been used frequently in sci-fi novels and movies since the early 1980’s but the term artificial reality can be traced back to the 1970’s. Movies such as Tron, The Matrix and Lawnmower Man centre around the possibility of fully immersible virtual realities. It is only very recently however, with advanced interactive gaming systems and the design of complex virtual worlds online and on home computers, that we can experience worlds of sufficient detail that we can be fooled into believing what we are experiencing approximates physical reality. Additional systems have been engineered to provide the user with feedback from the virtual world they are interacting with (whether it is a rumble in the joypad or wired gloves giving the user a sense of touch), enhancing the experience beyond purely a visual one.

Taking a look at physics in our universe, many paradoxes and uncertainties exist. Quantum physics is one such field highlighted in Brian Whitworth’s research and considered to be “strange” physics, giving some justification to his theory we might actually be immersed in a virtual reality world:

“While virtual reality theory seems strange, so do other current theories of physics, e.g. the many-world view of quantum physics proposes that each quantum choice divides the universe into parallel universes. […] Even relatively main-stream physics theories are quite strange.” – The Physical World as a Virtual Reality.

Although this research pushes the envelope of the most outlandish physics theories, it is not so hard to imagine that advanced information processing may be complex enough to govern the dynamics of an entire universe (if the information processor was advanced enough). Our physical universe, after all, is approximated through physical equations and mathematical reasoning, why can’t the laws of our “physical” reality be approximated by virtual reality? If this can be done, do we actually exist in a virtual world?

Source: arXiv.org publication (abstract and full paper download)

Posted on by Astronomy Cast

Podcast: The Large Hadron Collider and the Search for the Higgs-Boson

cms_higgs-event.thumbnail.jpg

When it was first developed, the standard model predicted a collection of particles, and thanks to more and more powerful colliders, physicsists have been able to find them all except one: the Higgs-Boson. It’s an important one because it should explain how objects have mass. The European Large Hadron Collider should have the power and sensitivity to find the Higgs-Boson.

Click here to download the episode

The Large Hadron Collider and the Search for the Higgs-Boson – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Posted on by Nicholos Wethington

Could Antimatter Be Powering Super-Luminous Supernovae?

2007-1126supernova.thumbnail.jpg

Explosions are almost always cool, and supernovae are some of the most spectacular and violent explosions in the Universe. In 2006, the supernova SN 2006gy wowed scientists with a light show that was 10 times as luminous as the average supernova, challenging the traditional model of exactly how an exploding star creates a supernova. Astronomers suspect that the cause is the repeated production of antimatter in the core of the star.

Supernovae occur when a star nears the end of its life, and the nuclear processes that fuel the star push outward more powerfully than the force of gravity can hold the star together; the type of supernova created depends on the mass of the star. In stars with masses between 95-130 times the Sun, this process can occur more than once, creating a “pulsational” supernova which can happen as many as seven times.

The cause for the multiple explosions may have to do with the production of antimatter particles in the core, which then recombine and release large amounts of energy.

“The pair instability is encountered when, late in the star’s life, a large amount of thermal energy goes into making the masses of an increasing abundance of electron-positron pairs rather than providing pressure,” wrote Dr. Stan Woosley, of the Department of Astronomy and Astrophysics, USCS Santa Cruz.

What happens is this: the first supernova occurs, powered by the antimatter explosions in the core, and ejects a large amount of the star’s material out into space; however, there still remains enough matter near the core for the star to reignite and begin nuclear processes once again. After between a few hundred days and a few years, another supernova occurs by the same mechanism, and when the ejected material collides with the previous shell of ejected material, the interaction gives off enormous amounts of light.

This process only occurs with stars in the 95-130 solar mass range. Stars with solar masses under 95 undergo typical, non-repeating supernovae, while those over 130 solar masses are subject to the pair instability but explode with such force as to leave nothing near the core to recombine and start the process again.

The production of antimatter in the core, as well as the large amount of light given off by the repeated collision of the shells of ejected matter explains very well the otherwise puzzling luminosity of SN 2006gy.

“The model existed before 2006gy happened as well as the prediction of a possible bright supernova of this sort. When we learned of the supernova, we carried out much more detailed calculations specific to 2006gy and found, to our satisfaction, that many of the observed facts were in the model results,” Dr. Woosley said.

There are other possible candidates for this type of repeating supernova, including Eta Carinae, though they unfortunately may not all be as spectacular as SN 2006gy.

Source: Arxiv paper

Posted on by Fraser Cain

Podcast: The Important Numbers in the Universe

numbers.thumbnail.jpg

This week we wanted to give you a basic physics lesson. This isn’t easy physics, this is a lesson on the basic numbers of the Universe. Each of these numbers define a key aspect of our Universe. If they had different values, the Universe would be a changed place, and life here on Earth would never have arisen.

Click here to download the episode

The Important Numbers in the Universe – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Posted on by Fraser Cain

Creating the Conditions Inside Supergiant Planets

2007-0504laser.thumbnail.jpg

We won’t be visiting a supergiant planet any time soon. But physicists are about to do the next best thing, and creat the conditions that exist inside the most dense planets right here on Earth. What used to require a nuclear explosion should now be possible with diamond anvils and powerful lasers.

Researchers from the Lawrence Livermore National Laboratory (LLNL), New Mexico State University and France’s Atomic Energy Commission announced this week that they have achieved pressures of 10 million atmospheres using a 30 kilojoule ultraviolet laser. The next step will be to use a 2 megajoule laser to achieve more than a billion atmospheres of pressure. Just for comparison, the centre of the Earth squeezes with a little less than 4 to 5 million atmospheres, and the centre of Jupiter is 70 million atmospheres.

Half of the apparatus uses diamond anvils, which can squeeze liquids and solids under high pressures. The researchers then blast the material with a laser-induced shock wave, and compressing it even more. Of course, you need a laser the size of a building, and half the diamond anvil is vapourized.

Once they reached pressures this high, scientists are discovering entirely new realms of chemistry. The just need to work quickly. The high pressure is only maintained for 1 or 2 nanoseconds.

Original Source: UC Berkeley News Release