System of Fear: A Dose of Radiation Reality

14 10 2013

In line with last week’s post, please see the below infographic, which paints radiation doses in the visual context of a sort of system of planets according to size (click to enlarge):


As is plainly evident, it’s shocking how much the public perception of radiation doses and negative health effects differs from reality.

(For example, in today’s perceptual climate, who would believe that a person could live within a mile of a nuclear powerplant for a thousand years before receiving the radiation dose from a single medical CT scan?)

If feedback to this is positive, I think I’ll make this the first in a series of similar infographics.  (Perhaps people would find it interesting/useful to next have illustrated the relative magnitudes of nuclear disasters?)


If anyone doubts the numbers in the above diagram, please feel free to investigate the references for yourselves!

International Atomic Energy Agency:

U.S. Environmental Protection Agency:

U.S. Nuclear Regulatory Commission:

U.S. National Council on Radiological Protection (via the Health Physics Society):

U.S. Department of Energy:


The Antimatter Plot Thickens…

30 04 2013

I realize it’s been egregiously silent here at the Astrowright blog for some time.  Apparently, I am not immune to the same disappointing (as a reader) dry spells experienced in/by so many other blogs I’ve followed during the years. 

(With grad school, teaching at CSN, my day-job working for DOE, a side-business or two in flux, moonlighting the occasional and surreal TV project, and with a 1&1/2-year-old at home – let’s just say I’ve come to terms with the reality that I’m not a juggling Jedi yet.)

Excuses aside, however, I wanted to take a moment to relay a devastatingly exciting potential discovery, which itself was prompted by a pleasant surprise…

CERN's ALPHA experiment.  (Credit: CERN)

CERN’s ALPHA experiment – our Anti-Virgil into Dante’s Antimatter Inferno? (Credit: CERN)

Antimatter in Focus

AntimatterSymbolOnlyAs reported on and, which prominently featured the antimatter symbol I created a couple of years back (i.e., the pleasant surprise – thanks, Keith!), we may be one giant leap closer to figuring out antimatter – and with it, peer a little farther into the mysterious underpinnings of the Fundamental Forces of Nature.

In an article titled, “Does Antimatter Fall Up or Down?” Keith Cowing reports that researchers at CERN’s Alpha Experiment recently published in Nature Communications their tantalizing antimatter research progress.  

Specifically, these CERN specialists have identified a process for finally determining whether or not gravity acts upon antimatter the same way it does upon “ordinary” matter, even if they haven’t answered the question quite yet.  (See Keith’s article for more details on their experiment, what it means, and where it’s going.)

Down the Anti-Rabbit Hole

So, why do we or should we care about figuring out what antimatter really is and how the universe treats it?  Well, quite simply, it has the possibility of providing new solutions to many current problems in physics. 

Dark EnergyDark Matter, and questions about early Cosmic Inflation all essentially deal with versions of the same issue: There are apparent problems with the amount of force we see in the universe versus how much we should expect. 

Perhaps a shift in our understanding of fundamental forces, like gravity, will shed new light.

This is to say nothing of the mystery concerning why the universe appears to be all matter and generally no antimatter.  According to physics as we understand it, there’s no reason for the bias.  (Why not areas of high concentrations of antimatter and others of normal matter?)

Why did matter win?

And to make matters yet more interesting, the late, great Dr. Richard Feynman (and others) have described antimatter as being inditinguishable from (or perhaps actually being!) ordinary matter moving backwards through time.  While few physicists believe this is actually the case, it certainly bends neurons considering that it remains a physical possibility*.

(*I should note that this idea of antiparticles moving “backwards” in time, in order to be true, requires a reconstruction of what we mean by “time.”  This is because antiparticles don’t blip out of existence as they move to the “past” with respect to us as we, presumably, continue to move into the “future.”  Instead, we remain with the antiparticles in the same measurable “now” in the universe…)

Antimatter – A Guiding Star

Keep an eye on this one, folks.  It could very well be that the study of antimatter provides us the wedge we need to evolve beyond peering through the keyhole at the universe and instead throw open the door.

Optimistic?  Admittedly. 

However, we’re due for our big 21st Century paradigm shift in the sciences.  What with the recent 100 Year Starship Symposium hinting at what the future has to offer us (along with humanity’s expanding view of our galactic neighborhood and our desire to get out there and engage it), it’s high time we get on inventing that superluminal propulsion system to Alpha Centauri, already.

I’m not getting any younger.

Calculating your own natural radiation dose in context

26 06 2012


Traditional Radiation Trefoil Hazard Symbol. (Image credit: ORAU)

A Dose of Radiation Information

How much radiation is normal?

In light of Fukushima, sensationalized media, political fear-stoking, and rampant misinformation regarding radioactivity, consider this post an easy-to-reference tool/resource.  With it, you can be armed to understand and quickly make sense of this over-mystified, natural aspect of reality when it comes up.

For starters, here’s the simple reality about how much radiation you receive in a year just for standing on Planet Earth:

The average natural annual radiation dose for a U.S. resident is about 300 millirem, and when including man-made commercial products and medical procedures (MRI scans, etc.), the average dose jumps up to 600 millirem per year.  This is what we all get every year and bears no known, measured relationship to developing cancer.

  • Note: For the international units, divide all “millirem” numbers by 100, (i.e. 3.6 millisieverts.)  Or, an online converter can be found here.

However, what does that mean?  I’m completely aware that unless you’re a professional in the field of health physics, (as I am,) this number has no context.  So, allow me to explain just what this really means using things we can all identify with.

Hold on to your hats.

So, What’s My Dose?

For context, below is a list of the amount of radioactivity you receive in a year from very familiar items/sources:

  • Cosmic radiation  = 26-96 millirem (higher with altitude)
  • From standing on the Earth itself (geology) = 20-90 millirem (higher nearer igneous mountains)
  • From your own brick/stone/concrete building = 7 millirem
  • From your own body (food/water!) = 40 millirem
  • From breathing (naturally-produced radon) = 200+ millirem
  • For flying 1,000 miles in an airplane = 1 millirem
  • From having a dental/chest/normal x-ray = 50 millirem each
  • From having an annual mammogram = 75 millirem
  • From having a single CT scan = 150 millirem
  • From smoking a pack of cigarettes a week (polonium) = 200 millirem
  • From consumer goods = 10 millirem

Just add these up to produce your own, custom average annual radiation dose.

Wait.  My house/food/body/atmosphere is radioactive?

Yes.  Not to fear.  Just like the small amounts of chemicals that we can reliably tolerate, (e.g., trace arsenic, lead, etc.,) so too are trace amounts of radioactivity completely tolerable.

Fukushima in Context

Now, as you can see in the above plot of the radioactivity measured at the entrance of Fukushima nuclear powerplant as the disaster happened, it looks pretty dramatic.

  • (Note: The numbers are reported in “micro”sieverts per hour, which are admittedly reading a much smaller span of time, (hours versus years,) but are in units 1,000 times smaller than the “milli”sievert international units described above.  This is important.)

However, instead of running for the hills just yet, let’s take a look at what the numbers actually say.

The March 15th hydrogen explosion at the plant, which occured roughly 84 hours after the earthquake, shows the largest spike of activity: for a brief period upwards of nearly 12,000 microsieverts per hour.

But let’s take this apart.  What does that mean?  12,000 microsieverts is the same as 12 millisieverts.  12 millisieverts is the same as 1,200 millirem.

Now, compare this to the above list of natural radiation values, with an eye toward the annual average does of 360 millirem.

Yes, if reading correctly, this implies that simply standing on planet Earth every year nets everyone the same external radiation dose that would have been received if standing at the gates of the Fukushima Daichi powerplant during the worst part of the disaster for a full 15 minutes.

With these, even worst-case numbers, it becomes obvious that one could stand at the entrance to Fukushima during the worst period of the disaster for a full three minutes and have earned only the equivalent radiation dose of… an average chest x-ray.

Granted, this isn’t something one would necessarily want.  This is upwards of 15% of your natural average dose.  -But your biology wouldn’t ever notice the difference.  And one could go many orders of magnitude more than that before there would be any reasonable expectation of an acute health effect.

More realistically, even standing at the Fukushima gates during the unprecedented event of external venting from the internal containment of reactor number 2, (with an exposure rate of 0.5 millisievert per hour), it’s a full hour of loitering there before one would rack up the external exposure of simple set of dental x-rays.

Funny how the perception and the reality differ, eh?

Unwanted radioactive material is serious, just as a leak from underground gasoline storage tanks that could contaminate drinking water is serious.  But that seriousness must be given honest context.


Hopefully this has provided a window into the reality of radiation protection, and it is my sincere wish that this was and will continue to be a useful go-to when radiation numbers come up in the media.

Feedback is welcome, and if desired, I would be happy to put other radiation values in context… (Chernobyl, Three Mile Island, going to the Moon, etc.)

Go forth and combat radiation misinformation!

[Sources for the above information: American Nuclear Society, the National Council on Radiation Protection and Measurement, the U.S. Department of Energy.]

Summer Hits: Martian Water, Asteroid Nukes, Orbital Antimatter!

1 10 2011

Here’s a recap of some of this summer’s greatest hits in space news that you might have missed:

Water on Mars

Dark streaks as summer flow features in Newton Crater, Mars. (Credit: NASA)

In an utterly tantalizing development, scientists analyzing imagery from the Mars Reconnaissance Orbiter (MRO) have announced what appears for all the world to be direct evidence of water on Mars!

Because the MRO has been orbiting the Red Planet since 2006, it has been able to view the same portions of the world at different times of year with an eye toward spotting any potential seasonal changes.  This past August, the MRO team reviewing this growing dataset hit paydirt.

Specifically, the team identified dark streaks on the slopes of steep terrain in the southern hemisphere that are found during Martian spring and summer; these features disappear during Martian winter only to return once again the following spring.

While there are multiple possible explanations, the most likely amongst them appears to be the flow of briny (salty) groundwater that warms in the hotter months, breaches the surface, and evaporates/sublimates as it flows downhill.

Time will tell on this one, but all eyes should be on the possibility of subsurface briny Martian aquifers!

Russian “Armageddon”

Asteroid impact as depicted in the film "Deep Impact." (Credit: Paramount/Dreamworks)

This past August, Russian scientists took a note from Hollywood and seriously proposed the use of nuclear weapons as a means of asteroid mitigation.

Under the scenario, a dual-spacecraft architecture would be employed, with one spacecraft, called “Trap,” ferrying a nuclear warhead to the target while a second spacecraft, “Kaissa,” (apparently and intriguingly named after the mythical goddess of chess,) analyzes the target asteroid’s composition to determine the appropriate warhead use scenario (deflection vs. break-up).

The spacecraft would be lofted by a Soyuz-2 rocket and/or Russia’s upcoming Rus-M rocket.

While much contemporary research casts doubt on the ultimate effectiveness of a nuclear detonation in such a context, the proposers stressed that the technique would only be used on approaching objects up to 600 yards in diameter.

Orbital Antimatter Belt

Antiprotons trapped in the Earth's magnetic field (in pink). (Credit: Aaron Kaase/NASA/Goddard)

Also this past August, researchers published a stunning (but in retrospect, sensible) discovery in Astrophysical Journal Letters: Earth possess a natural orbiting belt of concentrated antiprotons.

Succinctly, the interactions of high-energy cosmic radiation with the Earth’s atmosphere can produce infinitesimal and ordinarily short-lived bursts of antimatter.  These antiparticles normally react with standard matter present around the Earth and annihilate.

However, in the near-vacuum of space beyond the bulk of the Earth’s atmosphere, some of these antimatter particles are spared immediate destruction.  Many of these antiprotons are then herded by the Earth’s magnetic field into bands or belts, which were recently discovered by the antimatter-hunting satellite PAMELA.

Aside from the “gee-whiz” factor, there are certain technical and economic reasons to get excited about the finding.  For starters, the energy density of antiprotons is on the order of a billion times greater than conventional chemical batteries.  However, at a current production cost on Earth of nearly $63 trillion per gram, antiprotons are a bit hard to come by and even less practical to use for anything other than research; Identifying a natural reservoir such as, say, a naturally-produced orbiting belt could open up additional avenues of use for antimatter as well as be immensely lucrative… if only one could solve the lightning-in-a-bottle problem of antimatter storage.

In any case, this is definitely something to keep an eye on.  For the less techno-jargon-inclined, news reports on the find may be found from the BBC as well as Science Magazine.

Radiation, Japan, and irresponsible reporting: Part II

22 03 2011

Example of a uranium ore mine, a very natural source of radiation and radioactive material… and contamination if you track uranium dust home with you. (Uncredited)

So, after my last post, you’ve got the subtle (and not-so-subtle) differences between radioactivity (overweight atoms), radioactive material (the material containing or composed of the overweight atoms), radiation (invisible light and particles emitted by the overweight atoms), and contamination (having radioactive material someplace you don’t want it).

Hopefully, you can also see why mixing these up prevents people from making any sense of either the situation at hand or what scientists tell them (when they’re actually interviewed) on the news.

For instance, if a newscaster says something akin to, “A plume of radiation was released,” well, that doesn’t really make sense.  That’s like saying, “A plume of blue has been released.”  You can release a plume of blue something, be it smoke, confetti, etc., but you can’t release blue.

Similarly, radiation is produced by something else – so, you could say, “A plume of radioactive steam has been released,” and that means that the plume of radioactive steam would be producing radiation as it moved and dissipated, which is perfectly reasonable.  However, just saying the radiation part is nonsensical, and further, adds to the terrifying mystique around the word “radiation” …

Radioactivity is just chemistry and physics, nothing more, nothing less.

Let me provide a second example.  If a scientist reports that there is “radiation” detected somewhere, you now are prepared to understand what he’s not saying, which can actually be more valuable than what he said.  In saying that radiation has been detected, the scientist has not said that they’ve actually found the radioactive material responsible for producing the radiation, or further, any radioactive contamination.  He’s simply saying that instruments have detected either the invisible, high-energy light (gamma rays/x-rays) or atomic particles being shed by radioactive material.  The radiation in this case could be from the sun, plants, humans (yes! – we’ll get to that), granite, radon from igneous rocks, or something more sinister – the scientist hasn’t specified.  He’s reporting facts.  -At such and such a location, radiation of a given intensity has been found.

So, what can such a statement tell you?  It can tell you from a health perspective how long it’s safe to be in the area where the radiation was detected, but it says nothing about the nature, presence, or movement of the material responsible for producing the radiation.  I cannot stress how important it is that this be made clear in the media.

So, for retention’s sake, I’ll pause here to keep these posts divided into brief segments.  Stay tuned for Part 3, where we discuss how radiation is truly crippled by the laws of physics, how that can be best (and simply!) used to your advantage, and just exactly why it’s bonkers for everyone to be snapping up iodine pills.

Until then, cheers.

Radiation, Japan, and irresponsible reporting: Part I

17 03 2011

Intensity diagram of the Japan quake. The epicenter of the quake is represented by the black star. (Credit: United States Geological Survey)

While the media continues to sensationalize what is already a “gee-whiz” bewildering topic for most ordinary people on planet Earth – nuclear reactors and radioactivity – the recent run on Potassium-Iodide tablets in the United States and on the Internet betrays just how badly the outlets are throwing gasoline on the raging inferno of ignorance out there when it comes to radiation.

I can only presume this is to attract viewers.

Consider this  the first in a small series of posts that seek to contribute a clarifying voice out into the chaos.  To what end?  Hopefully, by the end of these posts, intrepid reader, you’ll understand why the nuclear reactor disasters are serious, but you’ll also see why they pale in comparison to the biochemical environmental apocalypse taking place in Japan due to everything else the earthquake and tsunami destroyed.

So, first, let’s start at the beginning.   What is radiation?

Let me emphasize – there is nothing magical or supernatural about what we call “radiation” and/or “radioactivity.”  A radioactive atom is an overweight version of a “normal” atom, and it naturally tries to get rid of energy to slim down to normal size.  To do this, it “radiates” energy in the form of intense invisible light (gamma rays) and physical bits of itself (atomic particles) away from itself.  That’s it.

Really, radiation science is a form of chemistry.  It’s equally amazing that chemicals can combust to drive cars, that acids burn, etc.  So, let’s get over the “mysterious” hump right here: Radiation is just the chemistry and phsyics of overweight atoms, and it obeys the same laws of physics as everything else.

Second, and most importantly before we go any farther, is to start to understand the terminology used (and misused) everywhere.  So, there is really only one thing you need to understand to understand how radiation works and how to deal with it, and it is this: There is a difference between “radiation” and “contamination.”  A huge difference.  -And to confuse the two is to commit a gargantuan error.

Radiation refers to the invisible light and particles that the overweight (i.e., radioactive) atoms are sluffing off.  Experiencing radiation is like basking in the glow of a heat lamp.  You can get burned/damaged by it, but it won’t come off on you.

Radioactive Material is (unsurprisingly and simply) the name given to material that emits radiation.

Contamination, on the other hand, is when radioactive material is actually moved, blown, spilled, etc., someplace that you don’t want it.  If you get covered with dust that is radioactive material (see above), then you have been contaminated.  This is what you need to wash off, make sure you don’t inhale, etc.

So, what’s the take-home?

  • You can stand next to radiation without fear of getting contaminated.  There’s nothing mysterious in the air – it’s no different than how you can walk away from an x-ray machine without fear of tracking some of the x-rays home with you.
  • Radioactive material emits radiation, but it won’t result in contamination if the material is tidy, safely contained, and solid.

You can see now how if you say, “There’s radioactive material over there!” it means something very different than, “There’s radiation over there!” and very different still than, “There’s radioactive contamination over there!”

The first sentence could simply refer to completely safe-to-handle medical sources or other, completely expected sources of radiation.

The second sentence is very ambiguous and refers to the presence of the invisible light (gamma/x-rays) or particles, meaning that radioactive material must be nearby – but it may still be completely expected.

The third sentence is the only one of the three that implies anything is wrong.  Contamination means radioactive material has been deposited somewhere you don’t want it.  So – by mixing these up, which often happens in the news, the conversation can’t even sensibly go any farther.

To be continued…

Space radiation has Astronauts seeing stars

2 01 2011

View of Earth at night from the International Space Station. The thin atmosphere layer visible acts as a natural radiation shield. (Credit: NASA)

There are many astronauts experiences that are well understood.

Everyone knows about “weightlessness,” or floating in a microgravity environment, (which is actually perpetual free-fall around the Earth, but that’s a technicality for another post.)

Everyone has heard about the problem of space sickness that hits some astronauts and not others.   Disruptions in our sense of orientation (i.e., up and down,) are likely to blame.

However, what many do not know about are the strange “flashes” of light astronauts see while in space and what it might mean for their future heath.  With commercial space travel on the horizon and space tourists and commercial astronauts lining up to take part, the realities of space travel must be explored and disclosed.

The Earth’s atmosphere normally acts as a shielding layer, protecting the surface from cosmic and solar radiation.  However, when we travel beyond the atmosphere, (i.e., space,) we increase our exposure to such radiation.  In truth, these “flashes” reported by astronauts are actually electrochemical reactions occurring in astronauts’ eyes as a result of high-energy radiation striking their retinas.  A radiated particle passes through the lens of the eye, strikes the retina, and fakes out the optic nerve, which in turn interprets the signal as light.

So, aside from being strange, what are the potential effects of these flashes?

There appears to be a relationship between this radiation exposure and later development of cataracts, a disease characterized by a clouding of the lens of the eye.  According to a 2001 study, a total of 39 astronauts have developed cataracts later in life, and 36 of them flew on high-radiation missions, such as those to the Moon.

Scientists are currently working on nailing down the genetic link between radiation exposure and cataracts, but until then, it simply appears that exposure to space radiation increases your risk of cataracts later in life.  Advances in and the regularity of surgically-implanted interocular lenses make cataracts less of a concern, but effects like these are something for the aspiring casual spaceflight participant as well as for future planetary and deep space explorers to be aware of.

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