And I Keep Hitting Re-peat-peat-peat-peat-peat-peat

We all do it…whether it is driving the same route to work every morning regardless of how much traffic is present, picking up your afternoon coffee/tea/soda even though you know you will need to pee on the drive home, or stopping by McDonalds for a quick bite even though the food is awful. We all have bad habits. Sometimes these habits are much easier to spot from the outside. For instance, who hasn’t questioned Selena Gomez’s habitual boyfriend choice of Justin Bieber? From the outside it seems so obvious…just quit him or it: whatever it is. But it must be more difficult than it sounds, I mean why else am I drinking my afternoon tea as I write this?

That pretty much sums it all up. I keep hittin’ re-peat-peat-peat-peat-peat-peat.

Habits, good or bad, are behaviors that have become automated. They are activities that were once goal-oriented that now occur in response to a stimulus, activities that we do without really thinking about outcomes. For example, I would get thirsty in the middle of the day after eating lunch, which led me to consciously get a drink in the afternoon. Now getting an afternoon drink has become routine – a habit. Regardless of whether I am thirsty or not, I grab a drink in the afternoon. This has become problematic as I am attempting to be healthier and drinking more water in the morning; hence my problem when I drive home.

The exact mechanisms by which a goal-oriented activity becomes a habit are not well understood. Recent studies have demonstrated a shift in brain activity: while goal-oriented, conscious activity stimulates the prefrontal cortex (the place in the brain where decisions are made), habits are traced to the basal ganglia, which plays a role in emotions, voluntary motor movements, and certain types of learning (Graybiel, 2008; Yin and Knowlton, 2006).

Well, maybe I should just grab a smaller tea, one that isn’t larger than my stomach…

So, why do we form habits? Since habits are generally formed from goal-oriented activities, we receive a reward when we perform these behaviors. For example, drinking tea quenches thirst. This reinforces the thought process in our brains leading to habit formation. But then one has to wonder: why do we maintain bad habits that don’t stimulate reward anymore?

Most of these habits, like smoking or eating junk food, once came with a reward – perhaps the idea of looking cool or a quick way to stifle hunger, respectively. Regardless of whether it may be harmful or whether your opinion changes about what is cool, once the habit is formed it is very difficult to break.

Another explanation for persistent bad habits is the concept called “sunk cost fallacy”. Sunk cost fallacy is the idea that once you have invested in something you are compelled to see it through, even if the benefit remains elusive. For example, how many of us have eaten to the point of bursting our jeans at an all-you-can-eat buffet? I know I have (it’s all you can eat, not eat all you can!). We feel we have to get the most bang for our buck, even if it means we’ll be spending more money to buy antacids later. The same concept holds true for some habits - it may be difficult to stop a habit once you have invested in that behavior. I know I will continue drinking this tea because I already bought it. Selena Gomez may feel she has already invested so much in Justin Bieber that it doesn’t seem right to just give him up.

Interestingly, studies have shown that other animals, including pigeons, are also affected by the sunk cost fallacy (White and Magalhaes, 2015). In this study, pigeons were given a reward (food) after pecking a button a few times. The scientists then introduced a second button and varied how many pecks it took to receive food, one requiring only a few pecks and the other requiring up to 30. Pigeons were more likely to stick with whichever button they initially chose, regardless of how many pecks it took to get the food. In other words, after investing in an option that works, pigeons were less likely to change course and expend energy exploring other options. So maybe we can blame our inability to break bad habits on ancient evolutionary echoes of our animal instincts?

 

Scientists have shown pigeons also fall prey to "sunk cost fallacy", providing a fertile ground for bad habits to take root.

 

Habits are routines; they are triggered by a reoccurring stimulus. So how do we break them? It is difficult to break habits because you perform them without thinking. Simply being aware of what triggers your habit will help you break it (Quinn et al., 2010). So next time you find yourself stopping at McDonalds or grabbing that unhealthy snack, think about what just happened. What triggered your desire? Force your brain not to take the short cut or easy way out, but to think objectively about your choice and the ensuing outcomes.

 

Studies have also indicated that the best time to break a habit is when you go on vacation because you are changing up your routine - you won’t have the same stimulus or trigger provoking your habit (Gross, 2012). So I guess to break my afternoon tea habit I should take a week and go to Hawaii…yeah, I like the sound of that.

 

This is where I will be until I break my tea habit. I kind of hope it takes awhile.

 

Contributed by: Sarah Deffit

 

Graybiel AM (2008). Habits, rituals, and the evaluative brain. Annual review of neuroscience, 31, 359-87 PMID: 18558860

Quinn JM, Pascoe A, Wood W, & Neal DT (2010). Can't control yourself? Monitor those bad habits. Personality & social psychology bulletin, 36 (4), 499-511 PMID: 20363904

White KG, & Magalhães P (2015). The sunk cost effect in pigeons and people: a case of within-trials contrast? Behavioural processes, 112, 22-8 PMID: 25305066

Yin HH, & Knowlton BJ (2006). The role of the basal ganglia in habit formation. Nature reviews. Neuroscience, 7 (6), 464-76 PMID: 16715055

Gross, T. Habits: How They Form And How To Break Them. NPR (2012). http://www.npr.org/2012/03/05/147192599/habits-how-they-form-and-how-to-break-them

Outbreak! Time To Review The Origins Of Vaccination

The US is currently experiencing an alarming spike in the number of measles cases. Yes, measles! Don’t we have a vaccine for that virus? Yes, we do. It first became available in 1963 and was so effective that by 2000 the US declared it had eliminated measles. But in 2014, a record 644 cases suddenly appeared in 23 distinct outbreaks.

Measles is caused by a very contagious virus that infects the respiratory system, causing high fevers, coughing, and a nasty rash. Complications are common and can lead to life-threatening situations, especially in undeveloped nations. Measles has rarely been seen in the US in recent decades, but has made an alarming resurgence in 2014-15.

Unfortunately, 2015 is shaping up to be a bad year for measles, too, largely due to a multi-state outbreak propagated by so-called anti-vaxxers attending Disneyland in California. A study published last month showed that this single incident has spread measles to seven states and two additional countries and was due to parents who declined to vaccinate their children. Sadly, many of those who were infected were innocent bystanders of this misguided decision - they could not be vaccinated due to age or a legitimate medical condition.

We’ve recently discussed some of the fears the anti-vaccine movement cites to justify their opposition to vaccination, much of which stems from the completely fraudulent studies of the disgraced doctor, Andrew Wakefield. But perhaps it is worthwhile to take a trip back in time to review the origins of vaccination, which begin with the horrifying disease called smallpox.

Referred to as “the Speckled Monster”, smallpox is caused by an extremely contagious virus with a signature “dumb-bell” appearance.

Once infected with the smallpox virus, the victim becomes covered head to toe with burning pustules. The virus can also infect internal organs, which usually meant death in less than a month. Those lucky enough to survive the infection were left badly scarred and disfigured. Humanity has been struggling with this dreadful affliction since at least 1100 BC. We know this because the mummy of Egyptian pharaoh Ramses V contains the signature pockmarks caused by smallpox. Recent genetic studies suggest that the smallpox virus emerged 3000 to 4000 years ago in east Africa.

Smallpox is one of a number of infectious agents that has been a major factor in steering the course of history. Smallpox was instrumental in the conquering of the Aztecs in 1521 by Hernan Cortes and the Incas by Pizarro in 1533. Disturbingly, the early Puritan settlers in North America considered smallpox a “miracle” that purged their “New World” of the Native Americans.

The first advance in treating smallpox, which hinted at a new era of medicine, was made around 950 AD in China. Someone took note that smallpox survivors never got the disease twice and got the idea that maybe by giving someone a tiny bit of the disease on purpose would protect them from the real thing. To do this, they took the scabs from someone who looked like they were beating the infection, ground them into a powder, and blew them up the nose of someone who hadn’t caught smallpox yet. It sounds disgusting, but it worked! The scab-sniffers got very mild cases of smallpox but recovered.

By the late 1600s, the Chinese practice of delivering smallpox scabs into healthy people to prevent the disease had been refined and spread to the Turkish Empire. As shown above, a drop of pus from a person beating smallpox was scratched into the skin to “inoculate” another person and prevent him or her from getting the full-blown disease. The technique spread to England thanks to Lady Mary Wortley Montagu, wife of the ambassador to Turkey in the early 1700s.

These primitive vaccination efforts carried a great deal of risk compared to today’s methods. Since the individual was being inoculated with live smallpox virus, there was always a chance of developing full-blown smallpox and dying, along with the risk of transmitting smallpox to others. To offset the latter, England instituted “inoculation stables”, woeful low-cost sheds where peasant children were sent to stay until they either died or recovered from the smallpox inoculation.

Enter Dr. Edward Jenner. Born in 1749, he did time in an “inoculation stable” as a young lad. Smallpox may not have scarred his skin, but his experience in the stable scarred him psychologically. He decided to dedicate his life to finding a better way to beat the “Speckled Monster”. Just like the Chinese in 950 AD, keen observation is what led Jenner to an amazing breakthrough. But Jenner’s eureka moment didn’t occur in the lab or in the hospital. It came to him while observing…milkmaids.

Milkmaids had a reputation for always being pretty, with clear and smooth skin, largely because they never seemed to suffer smallpox and the extensive scarring it left in its wake. There was even a saying at the time, “If you want to marry a woman who will never be scarred by the pox, marry a milkmaid.”

In talking to milkmaids, Jenner learned that they frequently caught cowpox, a very mild disease carried by the cattle they handled every day. The milkmaids who caught cowpox would develop a few pustules on their hands that resolved on their own fairly quickly. But when Jenner proposed that cowpox was protecting the milkmaids from smallpox, most people wrote the idea off as superstitious nonsense.     

Jenner knew he had to conduct an experiment to prove the naysayers wrong. Jenner somehow convinced the parents of a young boy named James Phipps to be the guinea pig in his experiment. Jenner took cowpox pus from a milkmaid’s hand and scratched it into James’s arm. As expected, the boy developed a mild case of cowpox and recovered from it, unscathed. He called the process "vaccination" based on the Latin word for cow, "vacca". 

The next step was to see if the cowpox vaccination protected the boy from real live smallpox. So Jenner, probably with shaking hands, inoculated James with smallpox pus taken fresh from a victim at the height of the illness. Each day they waited for what must have seemed like an eternity, but James never came down with smallpox. Jenner was not only right, but his success also inspired others that we do not have to take infectious disease lying down. We can fight it.

Jenner tried 20 more times to inoculate James Phipps with smallpox, but the boy never showed a single pustule. What did James get for being used as a lab rat? Jenner built him a cottage, which is today the Jenner Museum.

So what is actually happening here? How does vaccination protect someone against an infectious disease? Unbeknownst to Jenner, we now know that microbes cause infectious disease – viruses, bacteria, fungi, and parasites. We also know that we are equipped with an immune system that battles these foreign invaders. A vaccine trains the immune system to recognize an invader before it conquers too much territory. Microbial invaders consist of foreign proteins (called antigens) that are recognized by immune cells as “non-self”. These immune cells take up to two weeks to fully kick into gear and destroy the invaders. In some cases, the invaders grow too fast or produce toxins and the immune system just can’t outpace the infection.

But when the immune system wins, it remembers the invader. If the pathogen dare challenge you again, your immune system reacts much more quickly, usually destroying the invader before you even experience symptoms. Vaccination allows your immune system to preview antigens from a weakened form of the virus (like smallpox from a pustule of a recovering patient) or a related virus that causes little or no disease (like cowpox), so it will be “primed and ready” for the real invader if it should come along.
 

With the first vaccination came the first anti-vaxxers. James Gillray, who drew this infamous cartoon in 1802, misled people into believing that Jenner’s cowpox inoculation would “bovinize” people, causing them to give birth to calves or have them spring out of the body. 

The word “virus” comes from a Latin word meaning “poisonous force”. Humanity has been battling these forces for thousands of years and through persistence and hard work, we finally hit upon a remarkably safe and effective antidote. To refuse the antidote may seem like a personal choice, but as evidenced by the recent measles outbreak, it puts all of us in danger.

Contributed by:  Bill Sullivan

Follow Bill on Twitter. Google+.

Majumder, M., Cohn, E., Mekaru, S., Huston, J., & Brownstein, J. (2015). Substandard Vaccination Compliance and the 2015 Measles Outbreak JAMA Pediatrics DOI: 10.1001/jamapediatrics.2015.0384

Babkin, I., & Babkina, I. (2015). The Origin of the Variola Virus Viruses, 7 (3), 1100-1112 DOI: 10.3390/v7031100

Marrin, Albert. “Dr. Jenner and the Speckled Monster”, Dutton Children’s Books, New York, 2002.

Star Trek Shields For Tanks

Last week we talked about shields for protecting

astronauts. This week shields against projectiles.

But they both can use plasma. The Star Trek

shields absorb or deflect energy, but a hunk of rock

would go right through. Read the post to find the

PASS plasma system – it might work better than

a Star Trek graviton shield.

Manny Pacquiao and Floyd Mayweather are going to have the next “fight of the century” on May 2, 2015 in Las Vegas. In "the sweet science" it’s all about hit and don’t get hit. But just as important is to minimize the damage when you do get hit.

We talked last week about how we are developing plasma shields to protect astronauts from space radiation. In a way, that’s the “don’t get hit” part in a nutshell. But space radiation isn’t trying to hit you; it’s just there, and so are you.

In Star Trek, the deflector shields were meant to avoid or minimize the damage of things meaning to destroy them. Like Mayweather’s right cross, photon torpedoes are sent with bad intentions.

Today let’s concentrate on emerging technologies to protect ourselves from things coming at us with bad intentions. In practical terms, using the technology we have right now, this would be most considered armor, but we are quickly moving to deflector shields. And some new armors now have deflecting capabilities.

One of the problems with plasma-based deflector shields is that you are relying on charges to deflect charged things away from you. Projectile weapons are often uncharged, although the metals in them can be charged. You would have to rely on destroying them with energy before they got to you rather than deflecting them away – and engineers are working on that.

Armor is designed to blunt the effect of some projectile, or an explosion + shrapnel. In most cases, the thicker the armor the better – like the traditional methods of shielding spacecraft from cosmic radiation. But newer types of armor are meant to protect in a more pro-active way.

Osmium is the densest naturally occurring

element. This makes it great as a contrast for

transmission electron microscopy. Here we see the

layers of myelin sheath around a neuron in the

brain. The dark lines are the lipid in each layer, as

fats pick up the osmium best.

After the refit of the Enterprise, Mr. Scott described a type of shield to be used that was more like armor. The replicator would produce a wall of very hard metal, I think they used a diburnium-osmium alloy. Then the transporter would project that alloy outside the ship’s hull, like a second layer of the hull. The Defiant had an ablative armor shield as well. Heck, so did Iron Man.

Ablative armor is a physical shield intended to be sacrificed. Its destruction dissipates much of the energy of the incoming projectiles or beam. We use ablative armor on returning vehicles from space. The heat shield tiles on the old Apollo missions were a form of ablative armor. The space shuttles had reusable tiles, but Orion is going back to an ablative system on the underside portion of the vehicle that will be hottest (4000˚ F).

A newer technology, called advanced ablative armor, will anticipate an attack and put additional armor where needed when needed. It's essentially a big catcher’s glove - stick it out where the pitch is coming.  Fullerene would be a good candidate for ablative armor – it is strong and light.

Real science has made more use of reactive armor than ablative armor. Reactive armor is also called active protection. This armor does something to protect the target, it doesn't rely on its material strength alone.

The earliest type of reactive armor was (and is) explosive. Explosive reactive armor (ERA) is meant to repel the killing mechanism of anti-tank missiles and rockets. High explosive armor piercing (HEAT) projectiles do their damage by breaking the outer hull by kinetic force, and then setting off an explosion that injects superheated copper through the hull and into the cab where the electronics and people are.

The army has been touting the effectiveness of ERA

since 2007, but the 2011 paper independently

confirmed it. This is a Bradley tank with the ERA

installed as an additive armor. It needs to be a certain

distance from the hull of the tank in order to protect it

maximally. Each individual box is an explosive unit, so

protection is precise to the area being struck.

ERA counters this by providing it’s own shape charged explosive. When the HEAT projectile pierces a thin metal plate on the outside of the tank, an explosion between it and the main hull of the tank throws a lot of energy out (away) from the hull. This counters the explosion and injection of liquid copper, repelling it away from the hull.

What you have to watch out for is tandem HEAT weapons, where one is fired right after the other at the same target point. The ERA charge which protects against the first won’t be there for the second.

ERA has been around since the late 1970’s, but there are new versions that actually sense the incoming round and set off the explosive armor BEFORE the rocket gets to the tank or the personnel carrier. Advanced ERA's been further improved by making the inside of the charge non-explosive, merely a rubber that turns to gas and expands the outer plate before the HEAT weapon hits. This is called bulge armor and is helpful against that second shot from a HEAT weapon, not just the first.

Electric reactive armors are being developed as well. One type uses two charged plates separated by an insulator. When a projectile penetrates the outer hull, the first plate touches the second. This completes an electrical circuit that releases a large electric charge and destroys the projectile.

A second type of electrical armor, developed by the British Defence Science and Technology Laboratory, uses a thin layer of a supercapacitor (a material that can store a large electrical charge over time) just internal to the outer armor. When a projectile is sensed by the radar/video/ESP of the armored target, it releases the charge from the capacitor onto the outer metal armor at the precise spot that is being targeted. This creates a huge EM field with flux lines spreading out from the target and acts as a temporary force field to repel/deflect/destroy the incoming projectile. Sounds a lot like a Star Trek deflector shield to me.

The American Defense labs have a version of reactive armor as well, called the American Iron Curtain. It's termed an Active Protection System (APS – because the military is the best in the world at creating initialisms). In this system, highly sophisticated radar and optical systems detect incoming projectiles and even classifies them as to their type and danger.

Projectiles are then fired down from the top of the targeted vehicle to intercept the incoming round and render it a dud. It doesn’t make them blow up early, it deactivates them with a projectile so they can’t blow up. They then just bounce of the hull. Iron Curtain was integrated into several different vehicle defense system in 2012 and 2013.

The left image is the vehicle based PASS system

ready to be deployed by the US Army as a nonlethal

crowd control device. On the right is the plasma

clouds produced by the primary laser. In the near

future, there will be hundreds of plasma cloud spots

and they will be able to form three dimensional shapes.

There is even a plasma-based shield weapon on the way. The United States Army Armament Research, Development and Engineering Center has developed a system called PASS (plasma acoustic shield system). Originally designed in 2007 to be a deterrent by creating a disorienting flash bang, the technology has come far in the past couple of years.

PASS uses a couple of high power lasers. The first creates an intense energy beam that strips the air molecules of their electrons, creating a plasma cloud. The plasma creation (very hot at the point of plasma, but dissipating rapidly as you move away, creates a small explosion, more like a loud bang.

A second laser then hits the plasma cloud just milliseconds later. The plasma absorbs the energy, expands rapidly which creates a shockwave and an even bigger bang. You can set this system up to fire repeatedly in a pattern, creating a wall of light and sound. Depending on the energy levels of the lasers, the wall will appear at various distances from the source.

Increase the energy of the wall (or whatever shape you want to project) and PASS can go from purely disorienting to lethal. Or it could disrupt incoming fire. This was the aim of the US Navy Plasma Point Defense System that was abandoned on the 2000’s, but advances present in PASS have made it feasible again. The PASS wall can’t be seen through and is impenetrable to infrared waves, but it carries some of the same drawbacks as Star Trek shields; you can’t see out either, and you couldn’t fire through it.

Finally, metamaterials may act as a defense shield some day. Structure in three dimensions gives metamaterials their characteristics instead of just the molecules of the material that makes them up. To give an example, cotton T-shirts have certain characteristics based on being made of cotton (soft, stretchy, can be dyed, shows off my guns, etc.). But a metamaterial T-shirt made from cotton might be able to deflect sound waves or do some other amazing things with EM waves, based on the shape that the cotton fibers are given in the shirt.

A soundproof room is a pretty good model for a absorbing metamaterial. 
The quietest room in the world is in Minneapolis. The cones at high 
angles bounce the sound into the other cones at 90˚ from the

first. Sound checks in but doesn’t check out. Metamaterials that absorb 
EM radiation do the same thing, they are just a billion times smaller, 
smaller than the wavelength of the light they absorb.

Recent papers have shown that certain metamaterials can act as energy absorbers. A group from Poland published a study in 2014 that used S-shaped metamaterials cells can absorb low frequency energy. The energy waves enter the S-shaped cells and bounce around until there energy is dissipated. Right now the potential use is for shielding electronics from EM pulses, but they could expand.

For an invisibility cloak, you would want the metamaterial to bounce the light around like a prism and then let it go after it passes around the object. But a cloaked object using an absorbing metamaterial would look black; the absorber doesn’t reflect the light so none returns to your eye. This would make for a bad cloak but a great shield - if you can find a way to keep the absorbed energy from destroying the shield.

Right now, the absorbers work in the low gigahertz range, so they absorb radio and microwaves, but a new study shows that some are being developed that absorb in the terahertz range. This is within infrared and visible light frequencies, the types of light used in high-energy laser weapons. Go a bit higher and perhaps we could absorb ultraviolet waves. But wouldn’t that just be sunscreen?

Next week – Mr. Data was an android, but at his most basic he was a robot with artificial intelligence. We’ve got rudimentary robots, but that AI thing is tougher.

Contributed by Mark E. Lasbury, MS, MSEd, PhD

As Many Exceptions As Rules

Mayseless, M. (2011). Effectiveness of Explosive Reactive Armor Journal of Applied Mechanics, 78 (5) DOI: 10.1115/1.4004398

Yoo, Y., Zheng, H., Kim, Y., Rhee, J., Kang, J., Kim, K., Cheong, H., Kim, Y., & Lee, Y. (2014). Flexible and elastic metamaterial absorber for low frequency, based on small-size unit cell Applied Physics Letters, 105 (4) DOI: 10.1063/1.4885095

Grześkiewicz, B., Sierakowski, A., Marczewski, J., Pałka, N., & Wolarz, E. (2014). Polarization-insensitive metamaterial absorber of selective response in terahertz frequency range Journal of Optics, 16 (10) DOI: 10.1088/2040-8978/16/10/105104

Shields Up! Lay In A Course For Mars

No one can deny that Gene Roddenberry was a futurist, even if that 

wasn’t his profession. Futurists like Michio Kaku emulate

 the ideas that Roddenberry put forth in an entertainment venue but 
gave people so much to think about and shoot for.

Gene Roddenberry wasn’t a scientist. He took only a few college courses, and most of those were writing classes. He was an accomplished pilot, so he knew about lift and some basic physics, but his only civilian job outside of writing was as a Los Angeles police officer.

His first TV scripts in LA reflected this line of work; he wrote for TV shows called The Lieutenant, Have Gun - Will Travel, and Highway Patrol. So where did all that sciencey technology come from?

Roddenberry was definitely a futurist. This series of posts has shown, if nothing else, just how savvy he was in creating fictional technologies that had an uncanny ability to become science realities. But, for the life of me, where did he come up with gravitons – subatomic particles that assign gravity to matter? He was walking a beat in LA in the 1960's. That sounds like a lot more than just a convenient story-telling convention.

Gravitons played a role in several of the Star Trek technologies, including today’s topic - deflector shields, or just “shields.” There are a couple of different explanations as to how the shields on the USS Enterprise worked, but the earlier and more accepted explanation in the Star Trek cannon is that the ship had emitters that sent out graviton fields.

Star Trek proposed two kinds of shields, one was large and ellipsoid. It 
protected a large area besides just the ship. The second was contoured 
and was held just meters outside the hull. The shields also had

problems – you could fire through them unless you matched their 
frequency and you couldn’t transport through them.

The gravity field generated around the ship by the emitters protected the it by warping space-time and deflecting matter/energy away from the hull. The force field wasn’t based solely on electromagnetic energy, but it must have played a role, since Geordi, Mr. Scott, and Spock were constantly suggesting to alter the shield frequencies.

The idea of an electromagnetic shield is much closer to our reality at present, since we haven’t yet identified a graviton particle. Electromagnetism was a great choice for Roddenberry, since we all have experience with magnetic fields (two similar poles on magnets will repel each other). Electrical fields likewise repel similar charges. This sounds like a force field we could believe in for the defense of a ship.

Humans on Earth in 2015 don’t have a real need for shields geared to interstellar battle – we haven’t blundered into space wars yet. But we do have a very pressing need for deflector shields in space. And we’re coming close to achieving them.

NASA, the ESA, and many other space programs are taking aim at Mars. We have sent probes, rovers, and satellites; now it’s time for humans to make the trip. But this brings big problems along with the big promise. Space is full of cosmic rays, high-energy electrons, high-speed protons and even heavier atoms. They can all kill you over time or fry your equipment.

Radiation in space will make you sick at the least, and don’t underestimate the problem of being sick in space – think about vomiting in a space suit. But it can also damage DNA and most certainly lead to infertility, given enough time and exposure.

All this damage could occur inside the space ship on a long journey to Mars or beyond, not just on space walks. Most high-energy radiation will pass through the hull of a spacecraft and do damage to the occupants. We need protective shields to keep out the bad particles and waves.

Six months on ISS doesn’t give an astronaut anywhere near the 
radiation exposure that six months on Mars, or going to and from

Mars, would. The reason is that the ISS is still within the Earth’s 
magnetosphere, so it’s protected from most of the dangerous

radiation. To go to Mars, we’ll have to take

our own shield along.

Star Trek: Insurrection showed us an example of using a force field to protect the crew. When Picard and mates were observing Ba’ku from a cloaked duckblind, they used a “chromodynamic shield” to deflect or block the metaphasic radiation that inundated the planet. A force field protected the crew, although it was protecting them from rays that would stop their aging and did in fact restore Geordi’s eyesight for a while.

We don’t have a chromodynamic shield, so we've been looking to more conventional mechanisms of shielding. We could always make the walls of a long distance spacecraft thicker. Concrete would work pretty well, if it was dense and about 2 ft thick. A foot or so of aluminum might do just as well. But these are very heavy. Heavy things don’t make for good space gear.

Interestingly, water is a great absorber of radiation. We could put it between the walls of a spacecraft and it could do a pretty good job of protecting the crew and the electronics.  Hydrogen gas might work as well; notice how water is just hydrogen and oxygen. The sleeping quarters on the ISS are lined with impregnated polyethylene as an additional radiation shield.

But what might work best? – human waste. A privately funded mission to Mars led by Dennis Tito plans to use the astronaut's own excrement as a radiation shield by packing it between the walls of the spacecraft. Organic molecules and water block radiation very nicely, and they’ll be producing more shielding every day. It’s a strange thought that a Mars mission might be jeopardized by constipation.

Dennis Tito is a billionaire investment manager, but first he 

was an engineer. He was the first person to purchase a ride 

into space (Russian rocket) and now he wants to fly 

people around Mars – not to Mars - just a flyby in 2018 

or so. The planets will be aligned to give a 501 day round 

trip then. He wants to use their waste as radiation shielding.

Thank goodness science has kept looking for radiation shields. It's quite the boon that we have natural examples to learn from. The ionosphere of Earth is a great deflector. It’s the reason short wave radio operators can send weak signals very, very far. They bounce off the bottom layers of the ionosphere and back down to Earth, called skywave or skipping. The lower the angle on the way up, the far they will be over the horizon when they bounce back down.

The ionsophere (80-1000 km altitude) is part of the atmosphere of Earth that protects us from cosmic radiation. It consists of ionized air molecules; the ionization comes from the Sun’s energy. What's an ionized gas called?  – plasma.

So we have a plasma shield around Earth – remember this as it will come up again. The magnetosphere (a 40,000 nanoTesla field goes out hundreds of thousands of km) is produced by the spinning of the Earth’s metallic outer core. It participates in the protection because the ions of plasma in the ionsophere are charged, and electrical charges in a magnetic field produce an electric field.

The magnetosphere, in coordination with the

plasmasphere, shunts most of the electrons of

the solar wind and the high energy protons

around the Earth. Where the magnetic lines

come out of the Earth at the poles, you have the

polar cusps. Some radiation can get in there –

we see them as the auroras.

A new study shows that the plasma interacts with the magnetic field and it becomes more important when there are solar storms that greatly increase the energy of the radiation coming at earth. The plasmasphere, a portion outside the ionosphere, reacts to greater energies coming from the Sun and will plume out to be more protective. 

All this protection comes from the fact that ions in plasma are charged, and the magnetic field is charged – and like charges repel. So the high speed electrons of the solar wind and the protons and heavy ions of cosmic radiation that come close to Earth are repelled by the magnetosphere, the plasma sphere, and most importantly by the electric field produced by the interaction between the plasma and the magnetic field. The vast majority of charged particles and waves are swept around Earth and merge again safely behind us. Now that’s a force field.

Several research groups have begun to think about how this could be mimicked on a small scale to protect astronauts in space. A 2005 project from NASA contemplated using vectran balloons covered in gold that could be charged to positive or negative values. Placed above a moon base and electrified, the balloons might create a magnetic bubble that would shunt radiation away and produce a protected cavity underneath.

No one has thought more about producing a plasma shield than Dr. Ruth Bamford of the Rutherford Appleton Laboratory in England. Since 2008 she has been working on producing mini-magnetospheres that would buffer the small amount of plasma in space; using a magnetic field to hold it in place and build up its density. Together, they would produce an electric field just like the Earth does, and this would shunt radiation and particles away from the protected object.

On the left is the Reiner Gamma lunar swirl. On the right is the 

Reiner crater – no, not for Carl Reiner. We used to think 

the swirls (three on the moon) were dead areas, no magnetic 

field, no water, no nothing. Now we see they are the protected 

areas and are the most interesting places on the Moon.

NASA has also thought about this, using a plasma cloud (probably made from hydrogen gas) on the Sun side of a spacecraft, held in place by a superconducting wire mesh. Unfortunately, superconductors only work to produce a magnetic or electric field if below their transition temperature. And even for the best of materials (YBCO and BSCCO) this is somewhere in the range of -265˚F. If the mesh was exposed to the Sun in space, it would be several hundred degrees at least. Better keep thinking.

A discovery in 2013-2014 brought the thinkers back to Dr. Bamford's mini-magnetospheres. It was discovered that small parts of the moon’s surface are protected from radiation. It turns out that these areas produce weak magnetic fields (few hundred nanaoTesla), and those fields are holding the thin plasma of space in place above them. The field concentrates the plasma, and together they produce a protective electric field to deflect particles and keep the surface of the moon at those spots from being irradiated. Irradiation turns the surface dark, while these “lunar swirls” remain light colored.

This is not a cartoon. The pinkish gas is plasma

and on top of the middle cylinder is a magnet. The

magnetic field deflects the plasma and some builds

up in density on the leading edge. This leading edge

and the magnetic field form an electric field that

would shunt more particles. The dark area around

the magnet is a protected cavity, no cosmic radiation

gets to that point. It’s a real-life deflector shield.

Bamford’s discovery of the mechanisms behind the swirls made her idea of a mini-magnetosphere plasma shield more attractive, since the protective magnetic forces on the moon are much weaker than previously estimates had thought necessary. Therefore, a smaller (lighter, less energy consuming) superconducting coil could be used to create a magnetic field and hold a thin layer of plasma in a bubble around a spacecraft. Bamford’s group has built such a force field in their lab and predicts that a 1.5 ton apparatus could do the job in space!

But wait, there’s more. A plasma shield could also protect a ship from high energy weapons. Plasma has the capability to absorb photons of energy like from lasers or phasers!!! And since plasma has to be at a very high temperature to keep the electrons from re-associating with the nuclei, being in space would help since there would be no air to carry the heat away from the plasma. It would stay hot and maintain itself. In fact, incoming weapons fire would reinforce the plasma state by adding energy.

Next week – we need to talk more about shields. We’re building some pretty cool ones on Earth right now. And some using plasma are already here.

Contributed by Mark E. Lasbury, MS, MSEd, PhD

As Many Exceptions As Rules

Bamford, R., Kellett, B., Bradford, J., Todd, T., Benton, M., Stafford-Allen, R., Alves, E., Silva, L., Collingwood, C., Crawford, I., & Bingham, R. (2014). An exploration of the effectiveness of artificial mini-magnetospheres as a potential solar storm shelter for long term human space missions Acta Astronautica, 105 (2), 385-394 DOI: 10.1016/j.actaastro.2014.10.012

Bamford, R., Gibson, K., Thornton, A., Bradford, J., Bingham, R., Gargate, L., Silva, L., Fonseca, R., Hapgood, M., Norberg, C., Todd, T., & Stamper, R. (2008). The interaction of a flowing plasma with a dipole magnetic field: measurements and modelling of a diamagnetic cavity relevant to spacecraft protection Plasma Physics and Controlled Fusion, 50 (12) DOI: 10.1088/0741-3335/50/12/124025

Walsh, B., Foster, J., Erickson, P., & Sibeck, D. (2014). Simultaneous Ground- and Space-Based Observations of the Plasmaspheric Plume and Reconnection Science, 343 (6175), 1122-1125 DOI: 10.1126/science.1247212