A weak magnetic field saved life on Earth


The early Solar System was a much different place than it is now.

Chaos reigned supreme before things settled down into their present state.

solar flare

New research shows that the young Sun was more chaotic and expressive than it is now, and that Earth’s magnetic field was key for the development of life on Earth.

Researchers at the Harvard Smithsonian Centre for Astrophysics have been studying a star called Kappa Ceti, about 30 light years away in the Cetus constellation.

Kappa Ceti is in many ways similar to our own Sun, but it’s estimated to be between 400 million to 600 million years old, about the same age as our Sun when life appeared on Earth.

Studying Kappa Ceti gives scientists a good idea of the type of star that early life on Earth had to contend with.

Kappa Ceti, at its young age, is much more magnetically active than our 4.6 billion year old Sun, according to this new research.

It emits a relentless solar wind, which the research team at Harvard says is 50 times as powerful as the solar wind from our Sun.

It’s surface is also much more active and chaotic. Rather than the sunspots that we can see on our Sun, Kappa Ceti displays numerous starspots, the larger brother of the sunspot.

And the starspots on Kappa Ceti are much more numerous than the sunspots observed on the Sun.

We’re familiar with the solar flares that come from the Sun periodically, but in the early life of the Sun, the flares were much more energetic too.

The early Solar System was a much different place than it is now.

Chaos reigned supreme before things settled down into their present state.

New research shows that the young Sun was more chaotic and expressive than it is now, and that Earth’s magnetic field was key for the development of life on Earth.

Researchers at the Harvard Smithsonian Centre for Astrophysics have been studying a star called Kappa Ceti, about 30 light years away in the Cetus constellation.

Kappa Ceti is in many ways similar to our own Sun, but it’s estimated to be between 400 million to 600 million years old, about the same age as our Sun when life appeared on Earth.

Studying Kappa Ceti gives scientists a good idea of the type of star that early life on Earth had to contend with.

Kappa Ceti, at its young age, is much more magnetically active than our 4.6 billion year old Sun, according to this new research.

It emits a relentless solar wind, which the research team at Harvard says is 50 times as powerful as the solar wind from our Sun.

It’s surface is also much more active and chaotic. Rather than the sunspots that we can see on our Sun, Kappa Ceti displays numerous starspots, the larger brother of the sunspot.

And the starspots on Kappa Ceti are much more numerous than the sunspots observed on the Sun.

We’re familiar with the solar flares that come from the Sun periodically, but in the early life of the Sun, the flares were much more energetic too.

Researchers have found evidence on Kappa Ceti of what are called super-flares. These monsters are similar to the flares we see today, but can release 10 to 100 million times more energy than the flares we can observe on our Sun today.

So if early life on Earth had to contend with such a noisy neighbor for a Sun, how did it cope? What prevented all that solar output from stripping away Earth’s atmosphere, and killing anything alive? Then, as now, the Earth’s electromagnetic field protected it.

But in the same way that the Sun was so different long ago, so was the Earth’s protective shield. It may have been weaker than it is now.

The researchers found that if the Earth’s magnetic field was indeed weaker, then the magnetosphere may have been only 34% to 48% as large as it is now.

The conclusion of the study says “…the early magnetic interaction between the stellar wind and the young Earth planetary magnetic field may well have prevented the volatile losses from the Earth exosphere and created conditions to support life.”

Or, in plain language: “The early Earth didn’t have as much protection as it does now, but it had enough,” says Do Nascimento.

Evidently.

Researchers have found evidence on Kappa Ceti of what are called super-flares. These monsters are similar to the flares we see today, but can release 10 to 100 million times more energy than the flares we can observe on our Sun today.

So if early life on Earth had to contend with such a noisy neighbor for a Sun, how did it cope? What prevented all that solar output from stripping away Earth’s atmosphere, and killing anything alive? Then, as now, the Earth’s electromagnetic field protected it.

But in the same way that the Sun was so different long ago, so was the Earth’s protective shield. It may have been weaker than it is now.

The researchers found that if the Earth’s magnetic field was indeed weaker, then the magnetosphere may have been only 34% to 48% as large as it is now.

The conclusion of the study says “…the early magnetic interaction between the stellar wind and the young Earth planetary magnetic field may well have prevented the volatile losses from the Earth exosphere and created conditions to support life.”

Or, in plain language: “The early Earth didn’t have as much protection as it does now, but it had enough,” says Do Nascimento.

Evidently.

Magnetic Field May Be a Map for Migratory Birds .


If you’re lost, you need a map and a compass. The map pinpoints where you are, and the compass orients you in the right direction.Migratory birds, on the other hand, cantraverse entire hemispheres and end up just a couple miles from where they bred last year, using their senses alone. Their compass is the sun, the stars and the Earth’s magnetic field. But their map is a little more mysterious. One theory goes that they use olfactory cues—how a place smells. Another is that they rely on their sense of magnetism.

Researchers in Russia investigated the map issue in a past study by capturing Eurasian reed warblers on the Baltic Sea as they flew northeast towards their breeding grounds near Saint Petersburg. They moved the birds 600 miles east, near Moscow. And the birds just reoriented themselves to the northwest—correctly determining their new position.

Trumpeter swans at the Riverlands Migratory Bird Sanctuary in Illinois. 

Now the same scientists have repeated that experiment—only this time, they didn’t move the birds at all. They just put them in cages that simulated the magnetic field of Moscow, while still allowing the birds to experience the sun, stars and smells of the Baltic. Once again, the birds re-oriented themselves to the northwest—suggesting that the magnetic field alone—regardless of smells or other cues, is enough to alter the birds’ mental map. The study is in the journal Current Biology. [Dmitry Kishkinev et al, Eurasian reed warblers compensate for virtual magnetic displacement]

And if you’re envious of that sixth sense—keep in mind that since the Earth’s magnetic field fluctuates, the researchers say magnetic route-finding is best for crude navigation. Meaning for door-to-door directions—you’re still better off with your GPS.

Stellar discovery: Massive binary star with unique properties


The first massive binary star, epsilon Lupi, in which both stars have magnetic fields has been discovered by a PhD candidate. A binary star is a star system consisting of two or more stars, orbiting around their common center of mass.

The polarity of the star’s surface magnetic field, north or south, is indicated by red and blue respectively. Yellow lines indicate the magnetic field lines running from the stellar surfaces.

PhD candidate Matt Shultz has discovered the first massive binary star, epsilon Lupi, in which both stars have magnetic fields. A binary star is a star system consisting of two or more stars, orbiting around their common centre of mass.

For the past few years, the BinaMIcS (Binarity and Magnetic Interactions in various classes of Stars) collaboration, formed to study the magnetic properties of close binaries, has been trying to find such an object. They have now discovered one using the Canada-France-Hawaii Telescope.

“The origin of magnetism amongst massive stars is something of a mystery,” says Mr. Shultz (Physics, Engineering Physics and Astronomy), “and this discovery may help to shed some light on the question of why these stars have magnetic fields.”

In cool stars, such as the Sun, magnetic fields are generated by a convection in the outer portion of the star. However, there is no convection in the outer layers of massive star, so there is no support for a magnetic dynamo. Nevertheless, approximately 10 per cent of massive stars have strong magnetic fields.

Two explanations have been proposed for the origin of massive star magnetic fields, both variants on the idea of a so-called “fossil” magnetic field, which is generated at some point in the star’s past and then locked in to the star’s outer portion.

The first hypothesis is that the magnetic field is generated while the star is being formed; the second is that the magnetic field originates in dynamos driven by the violent mixing of stellar plasma when the two stars in a close binary merge.

“This discovery doesn’t change the basic statistics that the BinaMIcS collaboration has assembled,” says Mr. Shultz, “and we still don’t know why there are so few magnetic, massive stars in close binaries.”

The research shows the strengths of the magnetic fields are similar in the two stars, however, their magnetic axes are anti-aligned, with the south pole of one star pointing in approximately the same direction as the north pole of the other.

“We’re not sure why that is yet, but it probably points to something significant about how the stars are interacting with one another. We’ll need to collect more data.”

Magnetic field discovery gives clues to galaxy-formation processes


Astronomers making a detailed, multi-telescope study of a nearby galaxy have discovered a magnetic field coiled around the galaxy’s main spiral arm. The discovery, they said, helps explain how galactic spiral arms are formed. The same study also shows how gas can be funneled inward toward the galaxy’s center, which possibly hosts a black hole.

“This study helps resolve some major questions about how form and evolve,” said Rainer Beck, of the Max-Planck Institute for Radio Astronomy (MPIfR), in Bonn, Germany.

The scientists studied a galaxy called IC 342, some 10 million light-years from Earth, using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA), and the MPIfR’s 100-meter Effelsberg radio telescope in Germany. Data from both radio telescopes were merged to reveal the magnetic structures of the galaxy.

The surprising result showed a huge, helically-twisted loop coiled around the galaxy’s main spiral arm. Such a feature, never before seen in a galaxy, is strong enough to affect the flow of gas around the .

“Spiral arms can hardly be formed by gravitational forces alone,” Beck said. “This new IC 342 image indicates that magnetic fields also play an important role in forming spiral arms.”

The new observations provided clues to another aspect of the galaxy, a bright central region that may host a black hole and also is prolifically producing new stars. To maintain the high rate of star production requires a steady inflow of gas from the galaxy’s outer regions into its center.

“The magnetic field lines at the inner part of the galaxy point toward the galaxy’s center, and would support an inward flow of gas,” Beck said.

Large-scale Effelsberg radio image of IC 342. Lines indicate orientation of magnetic fields. Credit: R. Beck, MPIfR.

The scientists mapped the galaxy’s magnetic-field structures by measuring the orientation, or polarization, of the radio waves emitted by the galaxy. The orientation of the radio waves is perpendicular to that of the magnetic field. Observations at several wavelengths made it possible to correct for rotation of the waves’ polarization plane caused by their passage through interstellar magnetic fields along the line of sight to Earth.

The Effelsberg telescope, with its wide field of view, showed the full extent of IC 342, which, if not partially obscured to visible-light observing by dust clouds within our own Milky Way Galaxy, would appear as large as the full moon in the sky. The high resolution of the VLA, on the other hand, revealed the finer details of the galaxy. The final image, showing the , was produced by combining five VLA images made with 24 hours of observing time, along with 30 hours of data from Effelsberg.

Scientists from MPIfR, including Beck. were the first to detect polarized radio emission in galaxies, starting with Effelsberg observations of the Andromeda Galaxy in 1978. Another MPIfR scientist, Marita Krause, made the first such detection with the VLA in 1989, with observations that included IC 342, which is the third-closest spiral galaxy to Earth, after the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33).

NASA Discovers Hidden Portals In Earth’s Magnetic Field.


Our planet has come a long way in scientific breakthroughs and discoveries. Mainstream science is beginning to discover new concepts of reality that have the potential to change our perception about our planet and the extraterrestrial environment that surrounds it forever. Star gates, wormholes, and portals have been the subject of conspiracy theories and theoretical physics for decades, but that is all coming to an end as we continue to grow in our understanding about the true nature of our reality.

 

In physics, a wormhole was a hypothetical feature of space time that would be a shortcut through space-time. We often wonder how extraterrestrials could travel so far and this could be one of many explanations. Although scientists still don’t really understand what they have found, it does open the mind to many possibilities.

NASA Discovers Hidden Portals In Earth’s Magnetic FieldTurning science fiction into science fact seems to happen quite often these days and NASA did it by announcing the discovery of hidden portals in Earth’s magnetic field.

NASA calls them X-points or electron diffusion regions. They are places where the magnetic field of Earth connects to the magnetic field of the Sun, which in turn creates an uninterrupted path leading from our own planet to the sun’s atmosphere which is 93 million miles away.

NASA used its THEMIS spacecraft, as well as a European Cluster probe, to examine this phenomenon. They found that these portals open and close dozens of times each day. It’s funny, because there is a lot of evidence that points toward the sun being a giant star gate for the ‘gods’ to pass back and forth from other dimensions and universes. The portals that NASA has discovered are usually located tens of thousands of kilometres from Earth and most of them are short-lived; others are giant, vast and sustained.

As far as scientists can determine, these portals aid in the transfer of tons of magnetically charged particles that flow from the Sun causing the northern and southerns lights and geomagnetic storms. They aid in the transfer of the magnetic field from the Sun to the Earth. In 2014, the U.S. space agency will launch a new mission called Magnetospheric Multi scale Mission (MMS) which will include four spacecraft that will circle the Earth to locate and then study these portals. They are located where the Earth and the Sun’s magnetic fields connect and where the unexplained portals are formed.

NASA funded the University of Iowa for this study, and they are still unclear as to what these portals are. All they have done is observed charged particles flowing through them that cause electro-magnetic phenomenon in Earth’s atmosphere.

Magnetic portals are invisible, unstable and elusive. they open and close without warming and there are no signposts to guide is in – Dr Scudder, University of Iowa

Mainstream science continues to grow further, but I often get confused between mainstream science, and science that is formed in the black budget world. It seems that information and discovery isn’t information and discovery without the type of ‘proof’ that the human race requires. Given that the human race requires, and has a certain criteria for ‘proof’, which has been taught to us by the academic world, information can easily be suppressed by concealing that ‘proof’.

It’s no secret that the department of defence receives trillions of dollars that go unaccounted for and everything developed within the United States Air Force Space Agency remains classified. They are able to classify information for the sake of ‘national security’. Within the past few years, proof has been emerging for a number of phenomenon that would suggest a whole other scientific world that operates separately from mainstream science.

We have the technology to take ET home, anything you can imagine we already have the technology to do, but these technologies are locked up in black budget projects. It would take an act of God to ever get them out to benefit humanity – Ben Rich, Fmr CEO of LockHeed Skunk Works

– See more at: http://www.thinkinghumanity.com/2013/07/nasa-discovers-hidden-portals-in-earths-magnetic-field.html#sthash.OC80fQgY.Q3YXr2hL.dpuf

Dot Physics The Physics of Wireless Charging


What if you could charge your phone (or device) without having to worry about the charging cable? Well, you can. This is the idea behind wireless charging. In short, you place your device on some type of pad and then phone gets power without a wire (as long as the phone also supports wireless charging). That’s where they get the term “wireless charging” – you know…because there are no wires.

Magnets and Wires

Let’s start with a very simple demonstration. Here I have a coil of wire connected to a Galvanometer. I could write a whole post on just the Galvanometer, but for now I will just say that it measures electric current. Inside the red coil I am holding a very strong magnet.

Summer 14 Sketches key

If I just hold the magnet inside the coil, nothing happens. However, if I move the magnet either in or out of the coil I get a current.

Wireless

This is all about changing magnetic flux. Yes, just like a “flux capacitor” even though that isn’t a real thing. You can have flux for all sorts of things. My favorite flux to use as an example is rain flux. This is simply the rate that falling rain hits some area – let’s say it’s a sheet of paper.

Summer 14 Sketches key

There are three things you could change that would also change this “rain flux”. First, you could change how much it rains. If the rain comes down faster of course more water will hit the paper (note – real rain drops aren’t shaped like that). Second, you could change the angle between the paper and the rain. Third, you could change the area of paper. That’s rain flux.

We can do the exact same thing with the magnetic field. Guess what we call this? Yes, it’s called the magnetic flux. This magnetic flux depends on the strength of the magnetic field, the angle between the field and the area and the size of the area.

Summer 14 Sketches key

The curved lines are representations of the magnetic field from the magnet.

Here is the physics part. When you change the magnetic flux, you create an electric field inside the wire. This electric field then makes an electric current and electric currents can recharge your phone. Remember, CHANGE in flux is the important part. Actually, you could just use a spinning magnet and a coil of wire and make as much electricity as you want. In fact, this is exactly what happens with a gasoline powered generator. Oh, it’s also how a nuclear power plant makes electricity (the nuclear reactions just turn water to steam and the steam turns a turbine).

Magnetic Flux Without Magnets

The wireless chargers don’t have magnets in them. If you place a wire with current over a magnetic compass you can see that these currents also make magnetic fields.

The Physics of the Railgun   Science Blogs   Wired

If you replace a moving magnet with a wire that has alternating current, you are all set. The changing electric current in one wire makes a changing magnetic field. This changing magnetic field then induces an electric current in another loop. Also, the more loops you have (in both coils of wires) the greater the effect. Here is simplest version of wireless charging.

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On the bottom is a huge coil of wire. This wire is then attached to a household style plug. Yes, it’s just a loop of wire with a plug on the end. When you plug this thing into the outlet, electric current runs through the wire. All the outlets in your house have alternating current. This means the current oscillates with a 60 Hz frequency and provides the changing current needed to make a changing magnetic field. On top of this large coil is a smaller coil (in my hand). This coil is just connected to a small lightbulb. When this small lightbulb-coil is near the changing magnetic field, you get an induced current. The current is large enough to light up the lightbulb.

Of course, an actual wireless charger is a little bit smaller – but same idea.

Last question. Previously, I looked at the possibility of charging a smartwatch just by shaking it. Could you power a smartwatch with a wireless charger? Yes, you could. However, the smart watch would have to be right on the charger. It wouldn’t work over a long distance – at least not with this type of wireless charger.

Researchers build first 3D magnetic logic gate.


The integrated circuits in virtually every computer today are built exclusively from transistors. But as researchers are constantly trying to improve the density of circuits on a chip, they are looking at alternative ways to build circuits. One alternative method uses nano-sized magnets, in which the magnets possess two stable magnetic states that represent the logic states “0” and “1.”

3D magnetic computing 1

Until now, nanomagnetic logic (NML) has been implemented only in two dimensions. Now for the first time, a new study has demonstrated a 3D programmable magnetic logic gate, where the magnets are arranged in a 3D manner. In comparison to the 2D gate, the 3D arrangement of the magnets allows for an increase in the field interaction between neighboring magnets and offers higher integration densities.

The researchers, Irina Eichwald, et al., at the Technical University of Munich in Munich, Germany; and the University of Notre Dame in Notre Dame, Indiana, US, have published their paper on the 3D magnetic logic gate in a recent issue of Nanotechnology.

“We showed for the first time that magnetic field coupling can be exploited in all three dimensions in order to realize magnetic logic computing circuitry, and therefore paves the way for new technologies, where high integration densities combined with low power consumption can be achieved,” Eichwald told Phys.org.

The 3D magnetic logic gate consists of three input magnets that influence the magnetic state of one output magnet. To prepare the output magnet, the researchers used a focused ion beam to irradiate a 40 x 40-nm area of the magnet to destroy its crystalline structure, creating a domain wall. When the magnetic fields from the three input magnets are placed within 100 nm of the irradiated spot, the domain wall’s magnetic state can be controlled. As a result, the output magnet can be switched between the “0” and “1” states.

3D magnetic computing 2
SEM image of the 3D magnetic logic gate. The input magnet I3 is located in a different layer than the rest of the magnets, making the gate three-dimensional. Credit: Eichwald, et al. ©2014 IOP

One important feature of the 3D magnetic logic gate is that one of the input magnets is arranged in an extra layer in comparison to 2D gates. Adding a third dimension enhances the amount of magnetic area surrounding the output magnet by 1/3, and also increases the influence of each input magnet by 1/6. These stronger magnetic effects reduce the error rate and improve the functionality of the gate. The input magnet in the third dimension also programs the gate to operate as either a NOR or NAND gate.

NML has several potential advantages compared to transistors. One is that there is no need for electrical wiring or interconnects because the computation is performed entirely by magnetic interactions between neighboring magnets. NML also operates with , which in turn enables the combination of logic and memory functionality in a single device.

There is also the advantage of high densities using NML, which is possible in part due to the small size of the 3D magnetic gates (here, about 700 x 550 nm). Although high densities lead to the problem of stray magnetic fields interfering with magnets other than their nearest neighbors, the researchers note that previous research has already begun discussing and proposing solutions to these problems. Overall, NML could have a variety of applications.

“The main aspect of 3D nanomagnetic logic is that you can build up circuits, in which a huge number of the computing processes is done simultaneously (the keyword is systolic architecture), while the is kept at a minimum (as you only need to generate a global magnetic field and then you can clock the whole circuitry),” Eichwald said. “Applications are digital filtering, decoding and cryptography. Here all computing processes should be done by magnets.”

The results here pave the way for the development of other 3D architectures of NML circuits in the future.

“The future research plans are to investigate a 3D full adder structure, with the lowest possible number of magnets and the smallest area consumption,” Eichwald said.

MAGNETS MAY ACT AS WIRELESS COOLING AGENTS.


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The magnets cluttering the face of your refrigerator may one day be used as cooling agents, according to a new theory formulated by MIT researchers.

The theory describes the motion of magnons — quasi-particles in magnets that are collective rotations of magnetic moments, or “spins.” In addition to the magnetic moments, magnons also conduct heat; from their equations, the MIT researchers found that when exposed to a magnetic field gradient, magnons may be driven to move from one end of a magnet to another, carrying heat with them and producing a cooling effect.

“You can pump heat from one side to the other, so you can essentially use a magnet as a refrigerator,” says Bolin Liao, a graduate student in MIT’s Department of Mechanical Engineering. “You can envision wireless cooling where you apply a magnetic field to a magnet one or two meters away to, say, cool your laptop.”

In theory, Liao says, such a magnetically driven refrigerator would require no moving parts, unlike conventional iceboxes that pump fluid through a set of pipes to keep things cool.

Liao, along with graduate student Jiawei Zhou and Department of Mechanical Engineering head Gang Chen, have published a paper detailing the magnon cooling theory in Physical Review Letters.

“People now have a new theoretical playground to study how magnons move under coexisting field and temperature gradients,” Liao says. “These equations are pretty fundamental for magnon transport.”

A cool effect

In a ferromagnet, the local magnetic moments can rotate and align in various directions. At a temperature of absolute zero, the local magnetic moments align to produce the strongest possible magnetic force in a magnet. As temperature increases, a magnet becomes weaker as more local magnetic moments spin away from the shared alignment; a magnon population is created with this elevated temperature.

In many ways, magnons are similar to electrons, which can simultaneously carry electrical charge and conduct heat. Electrons move in response to either an electric field or a temperature gradient — a phenomenon known as the thermoelectric effect. In recent years, scientists have investigated this effect for applications such as thermoelectric generators, which can be used to convert heat directly into electricity, or to deliver cooling without any moving parts.

Liao and his colleagues recognized a similar “coupled” phenomenon in magnons, which move in response to two forces: a temperature gradient or a magnetic field. Because magnons behave much like electrons in this aspect, the researchers developed a theory of magnon transport based on a widely established equation for electron transport in thermoelectrics, called the Boltzmann transport equation.

From their derivations, Liao, Zhou, and Chen came up with two new equations to describe magnon transport. With these equations, they predicted a new magnon cooling effect, similar to the thermoelectric cooling effect, in which magnons, when exposed to a magnetic field gradient, may carry heat from one end of a magnet to the other.

Motivating new experiments

Liao used the properties of a common magnetic insulator to model how this magnon cooling effect may work in existing magnetic materials. He collected data for this material from previous literature, and plugged the numbers into the group’s new model. He found that while the effect was small, the material was able to generate a cooling effect in response to a moderate magnetic field gradient. The effect was more pronounced at cryogenic temperatures.

The theoretical results suggest to Chen that a first application for magnon cooling may be for scientists working on projects that require wireless cooling at extremely low temperatures.

“At this stage, potential applications are in cryogenics — for example, cooling infrared detectors,” Chen says.  “However, we need to confirm the effect experimentally and look for better materials. We hope this will motivate new experiments.”

Li Shi, a professor of mechanical engineering at the University of Texas at Austin who was not involved in the research, says the magnetic cooling effect identified by the group is “a highly useful theoretical framework for studying the coupling between spin and heat, and can potentially stimulate ideas of utilizing magnons as a working ‘fluid’ in a solid-state refrigeration system.”

Liao points out that magnons also add to the arsenal of tools for improving existing thermoelectric generators — which, while potentially innovative in their ability to generate electricity from heat, are also relatively inefficient.

“There’s still a long way to go for thermoelectrics to compete with traditional technologies,” Liao says. “Studying the magnetic degree of freedom could potentially help optimize existing systems and improve the thermoelectric efficiency.”

Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by Jennifer Chu. Note: Materials may be edited for content and length.

Sun has ‘flipped upside down’ .


The sun has fully “flipped upside down”, with its north and south poles reversed to reach the midpoint of Solar Cycle 24, Nasa has said.

Now, the magnetic fields have once again started moving in opposite directions to begin the completion of the 22 year long process which will culminate in the poles switching once again.

The Sun. Photo / Getty Images

“A reversal of the sun’s magnetic field is, literally, a big event,” said Nasa’s Dr. Tony Phillips.

“The domain of the sun’s magnetic influence (also known as the ‘heliosphere’) extends billions of kilometers beyond Pluto. Changes to the field’s polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space.”

To mark the event, Nasa has released a visualisation of the entire process.

At the beginning, in 1997, the video shows the sun with its positive polarity on the top (the green lines), and the negative polarity on the bottom (the purple lines).

Over the next 11 years, each set of lines gradually move toward the opposite pole, eventually showing a complete flip.

By the end, both set of lines representing the opposing magnetic fields begin to work their way back, which will eventually culminate in the completion of the full 22 year magnetic solar cycle in approximately 11 years, before the whole process starts over again.

“At the height of each magnetic flip, the sun goes through periods of more solar activity, during which there are more sunspots, and more eruptive events such as solar flares and coronal mass ejections,” said Nasa’s Karen C. Fox.

“Cosmic rays are also affected,” added Dr. Phillips. “These are high-energy particles accelerated to nearly light speed by supernova explosions and other violent events in the galaxy.”

Source:NASA

Space radiation: Should frequent flyers worry?


We’re bombarded with the radiation of supernovae and other cosmic sources when we fly – how concerned should we be?

Plane surrounded by sun flare (Getty Images)

One day, shortly before boarding a flight from Paris to Montreal, I began to think about the risks of flying for the first time. It was not the fear of engine failure or crashing into a mountain that worried me. Rather I realised I was about to make my 39th plane journey of the year, and as a result was exposing myself to higher than normal levels of radiation from space.

Like most holidaymakers, I had checked the weather forecast. But now, as I waited to board the plane, I wondered whether I and other frequent flyers should be more concerned with checking the space weather before we take off.

The Earth is constantly being bombarded by high speed, sub-atomic particles. These interact with the atmosphere and our planet’s magnetic field to generate cosmic radiation which rains down on us. Our exposure levels rise when we travel by plane, especially at higher altitudes and latitudes.

What do scientists know about the dangers that cosmic radiation might pose during regular flights, and is there anything that aviation authorities or passengers can do to minimise risk?

Cosmic radiation consists mainly of protons and helium nuclei that originate outside our galaxy. Scientists have long speculated over their origins, with likely candidates being powerful events such as star collisions, gamma ray bursts, black holes and supernovae – explosions that mark the death of large stars. Earlier this year US astronomers concluded supernovae were indeed a significant source of cosmic radiation hitting Earth. Particles thrown out by our Sun are another source.

These sub-atomic particles can be both low- and high-energy. Many are deflected by the Earth’s magnetosphere, without which cosmic rays would wipe out complex life forms pretty quickly by damaging tissue, DNA and causing lethal radiation sickness. Only very high-energy cosmic rays can reach our atmosphere at latitudes close to the equator, however lower-energy ones can reach polar latitudes.

Those that do penetrate the Earth’s magnetic shield collide with nitrogen, oxygen and other atoms in the air, generating highly energetic and invisible showers of ionised “secondary particles”, which cascade down on us in vast numbers, penetrating everything and everyone. The atmosphere provides good protection for those on the ground because particles hitting them will have undergone more collisions with atoms, but exposure is greater at high altitudes because the air is thinner.

Body shock

What can this do to the body? Cosmic radiation is ionising, which means the particles involved are energetic enough to knock charged particles from atoms – potentially causing chemical changes in body tissue that can increase risks from cancers and genetic abnormalities.

While this might sound scary, it should be made clear that we are regularly exposed to low doses of ionising radiation in other forms with no apparent health consequences in the overwhelming majority of cases – from radon in the air, naturally occurring radioactive substances in the ground such as uranium, building materials and during medical procedures.

The risks of individuals suffering health effects as a result of being exposed to ionising radiation of any kind – whether from cosmic rays, a nuclear power plant, an X-ray machine, or airport full body scanner – are measured in sieverts or rems (1 sievert equals 100rem). “The same potential risks exist,” says Major Alan Hale at the US Air Force School of Aerospace Medicine, based at Wright-Patterson Air Force Base, Ohio. “Health risk assessments are based on frequency, duration, and intensity level.”

The average person on Earth is exposed to around 350 millirems (mrem) per year. The average annual dose for US citizens is 620mrem , according to the US National Council on Radiation Protection and Measurements. About half of this comes from man-made sources such as X-ray, mammography and CT scans, while the other half comes from natural sources, of which only about 9% comes from cosmic radiation.

Cosmic radiation exposure levels during flights vary according to altitude, latitude and the space weather at the time. Typically, passengers flying from London to Chicago could expect to be exposed to around 4.8mrem, and those travelling from Washington DC to Los Angeles would be exposed to close to 2mrem. This compares to an airport body scanner which delivers around 0.1mrem and a chest X-ray that can vary between 2mrem and 10mrem.

As people travel more often and further away, frequent travellers should be aware of their exposure levels, says Mike Lockwood, professor of space environment physics at Reading University in the UK. “No need to panic, but cosmic radiation should not be ignored,” he says.

Your flight route is particularly important to consider, because exposure rises at higher latitudes. Because cosmic radiation particles are charged, they are deflected towards the North and South Poles by the Earth’s magnetic field lines. At these latitudes the magnetic field lines are closer to vertical, making it easier for cosmic ray particles to enter the atmosphere.

Airlines, however, prefer polar routes because they are shorter with lower head winds, meaning shorter journey times and lower fuel costs. A number of flights from the US to northern Europe and Asia pass directly over the North Pole – for example from San Francisco to Paris. The same goes for flights from, say, Santiago in Chile to Sydney in Australia, which cross the South Pole. “Airlines rotate staff around flight routes so nobody does exclusively polar routes,” says Lockwood.

Risky business

In the US, pilots and flight attendants have been officially classed as “radiation workers” by the Federal Aviation Administration since 1994. Staff regularly working on high-latitude flights are exposed to more radiation than workers in nuclear power plants. Despite this, the airlines don’t measure the radiation exposure of their staff, or set safe limits on the doses they can safely receive.

Among flight crews, there has been a lot of research into links between cosmic radiation and health risks, especially cancer. However, attempting to work out whether small additional doses of ionising radiation are linked to actual disease is far from straightforward.

In 2002, Scandinavian researchers analysed data from 10,000 male airline pilots over 17 years, and found they were at greater risk of developing melanoma and prostate cancer. However the charity Cancer Research UK says this may be related to other lifestyle factors such as the pilots spending more time sunbathing than the average person.

Two different groups of scientists from Japan and Italy combined their efforts in 2006 to look at health risks to female flight crew members from cosmic radiation. They found that women working on planes were more likely than average to develop breast cancers and melanomas, but again the authors admitted they could not be sure this was to do with cosmic rays. A meta-analysis published last year in the Journal of Radiological Protection concluded that overall cancer risk was not elevated, but that “malignant melanoma, other skin cancers and breast cancer in female aircrew have shown elevated incidence.”

Most plane passengers, however, needn’t worry too much, unless they fly regularly over the poles, says Lockwood. Even though their exposures might take them over the recommended annual dose, these limits have been set well below the level likely to cause actual health problems, he says. More dangerous would be spending a lot of time in Cornwall, in the UK, where naturally-occurring radon gas seeping from the ground means inhabitants are exposed to 780mrem per year, nearly three times the national average.

And while some fear that unborn babies could be at risk from cosmic radiation during flights, this is unlikely to be the case unless the women are flying several times a week, according to the US Aerospace Medical Association.

Sun trap

There are however times when cosmic radiation becomes more of a concern because of emissions from our Sun. Usually the solar energetic particles (SEPs) that reach us are of low energy, but the Sun is temperamental.

Levels of radiation and brightness from our star vary, with peaks in both occurring approximately every 11 years. The more sunspots appear on the surface, the more active the sun becomes and the more protons it sends our way. But the sun also has much longer phases, and currently, it is at a grand solar maximum – a phase that began in the 1920s. During this phase, the peaks of the solar cycle are larger and huge magnetic storms on the surface of the Sun, called coronal mass ejections (CMEs) or solar flares, are more frequent. These events fill space with streams of high-energy protons and electrons, some of which quickly reach Earth.

Measurements show solar activity has begun to calm recently and past experience indicates that it will continue to fall over coming decades. Once the Sun leaves its grand maximum, there will be fewer solar storms, but theory suggests those that do occur could be more powerful, ejecting more dangerous high energy particle in our direction. In short, passengers should expect higher exposures in the coming decades.

“Solar energetic particles events are difficult to assess, but being aloft at high latitudes during a big solar storm would be a large dose,” says Lockwood. “There are no studies that give the actual risk factor, but you certainly wouldn’t want it to happen twice to one individual.”

People who have been unlucky enough to get caught in such an event should be informed, he adds. “It would not be wise for them to risk a second such exposure, and more regular health checks would be a good idea, as we already do for recognised radiation workers”. According to NASA, a strong solar storm in late October 2003 subjected passengers on polar flights – from Chicago to Beijing, for instance – to radiation well above the limit recommended by the International Commission on Radiological Protection.

Cosmic forecasting

Very few passengers check the space weather when they fly, but airlines do. In some instances they have varied flight paths to lower latitudes because of predicted solar activity, particularly SEP events during solar flares. “The most pressing reason for this is that the SEP cause radio blackouts,” says Lockwood.

So what can passengers concerned about their exposure to cosmic radiation do, short of stopping flying? Could they perhaps choose to sit in parts of planes that are subject to a lower dose of particles, or fly only at night, in order to put the Earth between them and the Sun? Unfortunately all seats on aircraft are equally affected and exposures are just as high at night.

Would it be possible to shield planes? After all, crew quarters onboard the International Space Station, which is located at the outskirts of the Earth’s magnetosphere, are lined with high-density polyethylene several centimetres thick. The hydrogen atoms in it are great at absorbing and dispersing radiation.

The airline industry is increasingly using carbon fibre-based composites to build planes because of their strength and low weight. These are much better protection against cosmic radiation than standard aluminium, and metals in general, says physicist Nasser Barghouty at Nasa’s Marshall Space Flight Center in Huntsville, Alabama.

In the meantime, the US Federal Aviation Administration’s Civil Aerospace Medical Institute has an online tool that allows individuals who are concerned to calculate their cosmic radiation exposure levels on specific routes.

Cosmic radiation comes in a wide variety of forms at varying energy levels, and calculating the health effects of low doses of radiation on specific individuals is complex, and inevitably involves simplification and estimation. The research that has been carried out on those who fly most frequently – airline crew – is far from conclusive.

The available evidence suggests that those who fly occasionally have little to worry about. Likewise most frequent flyers are also probably fine but could protect themselves with more frequent medical check-ups if they are worried.

So next time you fly, consider the galactic radiation from supernovae all around you – but try not to let it spoil your trip.