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NASA Flies Plane Into Hurricane Earl
Photo: NASA
NASA, in its ongoing effort to study just about, well, everything, has outdone themselves this time.
They flew a DC-8 into Hurricane Earl in an effort to study how hurricanes and tropical storms form. SWEEEET!
They also got this really cool satellite image of Hurricane Danielle (northern one) and Hurricane Earl (southern one) in the same image.
Photo: NASA Click for Large version
The Physics Of X-Ray Imaging
So here is Part One of my series of the “Physics Of” medical imaging. First up is the most recognizable: X-ray Radiography.
Radiography (which uses x-rays, but the images are generally called “X-Rays”) are the most common form of medical imaging, and are incredibly useful. Thousands of images are performed everyday and medicine was revolutionized when this non-invasive means to study the body was discovered.
But how exactly do we get x-rays and use them for imaging?
Lets start with a bit of history. The first X-ray image was created by a guy named Wilhelm Rontgen in 1895.
Wilhelm Rontgen
Rontgen called them “X” rays because they were an “unknown” type of radiation, and the name kind of stuck.
The first image was of Rontgen’s wife’s hand, and is pretty cool because you can actually make out her wedding ring.
First image using X-rays of Wilhelm Rontgen's wife's hand
I actually find this a bit funny. I just picture a crazy looking physicist saying “Honey! C’mere! Stick your hand in front of this radiation for a second!”
Luckily for Mrs. Rontgen, x-rays, in small doses, are not very dangerous. So what exactly are x-rays?
X-rays are electromagnetic waves just like visible light, radio waves and microwaves. They have a wavelength range of roughly 0.01 to 10 nanometers (1 nanometer = 1 billionth of a meter).
When talking about x-ray imaging, however, its easier to think of x-rays in terms of photons. Photons are like tiny wave “packets” and electromagnetic waves can be described as a big collection of photons.
X-rays are generated in an x-ray tube (unsurprisingly). Basically, a bunch of electrons are shot at a piece of metal (usually tungsten, the same metal used in old school incandescent light bulbs). Now what happens next is a little complicated, but really cool…
So the electron travels at a certain speed toward the piece of tungsten; it has kinetic energy, which is the energy of motion. But as it gets close to the Tungsten it will run into an electric field produced by the metal, and will actually slow down.
X-ray Tube
Now, in physics there is principle called the conservation of energy. Basically this just says that energy can never be created or destroyed, it can only change form. So when the kinetic energy (energy of movement) of the electron drops (when it slows down) that lost energy has to go somewhere. Where it goes, in fact, is in the generation of an x-ray. The electron will actually emit an x-ray when it gets slowed down by the tungsten. Pretty sweet eh?
Schematic of X-ray tube. Electrons come in from the bottom, strike the tungsten target (the anode) and emits x-rays
This is actually a type of radiation called Bremsstrahlung, which is German for “braking radiation”.
Schematic Diagram of Bremsstrahlung
Ok, so now we got x-rays, how do we make an image?
Well, if we fire x-rays at, oh lets say, YOU! the x-rays will interact with your body. How you ask?
Well when an x-ray passes through the body, it may get absorbed or scattered by the body. An x-ray gets absorbed when the x-ray hits an electron in our body, and the electron “jumps” out of the atom. This is called the photoelectric effect.
The Photoelectric Effect
The x-ray may also get scattered. This just means that the x-ray will get close to the nucleus of an atom and get kind of turned in another direction due to the electric field of the nucleus. This is known as Compton Scattering.
Compton Scattering Effect
In spots of our body that very dense like bones, the x-rays have a much higher chance of getting absorbed or scattered than if they pass through muscle or fat, which are less dense. So if we were to stick a piece of film which is sensitive to x-rays behind someone getting a radiograph, you would get lots of x-rays hitting the film when they pass through muscle or fat, but very few pass through bones (or metal, if you’re really unlucky).
So on the radiograph muscles and fat show up dark, and bones show up white. BAM! Radiograph!
Chest Radiograph
See, now that wasn’t so bad was it? Pretty interesting if you ask me.
The next installment of my “Physics Of” medical stuff series will be something that takes x-rays to the next level: Computed Axial Tomography, commonly called “CAT” scans.
Hummingbirds in Slo-Mo and HD! OMG!
I know, I’ve been slacking this weekend. Why?
Well it was Alison’s birthday on Friday. So I did the boyfriend thing and took her out for a nice sushi dinner etc. She has the full details of the evening on her blog, so feel free to read them here.
Also, I just bought StarCraft II.
I been waiting for this for all of the 15 years Blizzard has been keeping us all in suspense (its awesome too, btw). So that ate up most of my weekend.
So I’ll be back in full form this week. But to get you started, here’s a video I came across on the weekend.
Its some pretty remarkable footage of hummingbirds which I read about on Mental_Floss. The footage is from a Nature documentary which aired on PBS.
I’ve always found hummingbirds really interesting; being able to hover in mid-air and then dash away like a UFO is pretty sweet.
(Protip: You can watch the video in HD on YouTube.)
The parts I find really interesting are the “flower-view” of the hummingbird eating, as well as when it catches an insect in mid-air in a fraction of a second. Seeing a hummingbird as a predator is something I never could have imagined.
So I hope you enjoy this, my brief foray into blogging about Ornithology. Birds have never been my main interest, but c’mon, hummingbirds in slow motion? Awesome!
Woo Hoo! Isotopes Rule!
Gotta love the Isotopes!
After a 15 month hiatus, the Chalk River nuclear reactor in Ontario, Canada, is starting to once again produce isotopes used for medical imaging.
The Chalk River reactor produced one third of medical isotopes used for imaging procedures all over the world. Namely, it produced Molybdenum-99, which is created as a fission product in the nuclear reaction.
The Molybdenum-99 isotope is unstable, and will decay into Technetium-99m. The Technetium can then be injected into a patient to perform medical scans.
Molybdenum-99 is kept in specialized containers while it decays into Technetium-99m
Now, I did my Masters thesis on Magnetic Resonance Imaging, so these medical procedures bring back some good memories for me. As such, I am going to start a series of posts describing the “Physics Of…” various medical techniques.
These will include things like X-Rays, PET scans, CAT scans, etc. So look forward to that, its a subject I hold very dear to my heart.
Hurricane Katrina As Seen From Space: 5 Years Later
Its been almost 5 years since the disaster of Hurricane Katrina.
The city of New Orleans has not yet fully recovered from the devasting effect of the hurricane, which made landfall in the United States on August 29, 2005, and the failure of the levees which were supposed to protect the historic city.
As a way of reminding us all of the terrible impact the hurricane had, NASA has released this retrospective video. It contains images and analyses from a wide variety of satellites which imaged the hurricane as it developed, travelled through the Gulf of Mexico, hit the city of New Orleans, and finally it shows the amount of flooding which occured after the hurricane hit.
From a scientific standpoint, it is very interesting to see how the hurricane progressed in its development. Unfortunetly, the images of those trapped on rooftops are still burned into my memory, so the knowledge gained from studying this hurricane is somewhat bittersweet.
Dinosaur Found in Sewer by My House!
Yup, its totally true.
A city worker in Edmonton, Alberta (not far from yours truly) was having a regular, shitty day at work in the sewer. Thats gonna be my only sewer joke, I swear.
So this young man named Aaron Krywiak found what he described as “an interesting shaped rock.” Well that rock turned out to be the tooth of an Edmontosaurus. But thats not all.
Aaron Krywiak
Upon further investigation, Aaron found a “motherlode” of dinosaur bones belonging to Edmontosaurus and Albertosaurus.
Edmontosaurus
Albertosaurus
I love living here. Its pretty cool to be so close to such world class dinosaur research and sites.
I still haven’t made it to the Royal Tyrell Museum though, which is where these fossils are going to be taken. Not to worry, I’ll get there soon and you’ll be sure to hear about it!
Sumo Wrestlers Getting Free iPads Because Hands Too Fat
Yup, its not a joke.
Japan’s governing body of Sumo wrestling is going to distribute iPads to the various “stables”, which is where the wrestlers train (seriously, THATS not a joke either!) so that they can communicate with each other more easily.
Apparently the wrestlers struggle with cell phones because their hands are simply too large to work the keypads.
Well, using an iPad is a bit more high-tech than a dialing wand. I would expect nothing less from the technology geniuses in Japan.
Our Glorious Planet: As Seen From Mercury
I never ceases to amaze me just how massive the universe is.
Take for example, this photo of the Earth and our moon, taken from roughly 114 million miles away.
Image Courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Click on the image to wonderfully aggrandize (thank you Thesaurus.com).
The image was taken from a NASA mission called MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging). MESSENGER was launched in 2004 and has done 3 flybys of Mercury, on its way to be in a permanent orbit to study the planet in 2011.
It is truly humbling to see our planet as a tiny speck in the vastness of space.
As Carl Sagan would say: “One voice in the cosmic fugue.”
Princess Leia’s Gold Bikini: Hotness of an Epically Nerdy Magnitude
So I’m not sure how I read about or ran across this website, but the awesomeness was just too much. I simply HAD to share it with all of you.
Now, recently I named the Star Wars Trilogy as #2 on my top 10 favourite sci-fi movies. And what I didn’t put in my explanation (I assumed it was understood) was that one of the reasons I loved Return of the Jedi was *drumroll* Princess Leia’s gold bikini.
Now I saw Return of the Jedi when I was just a young lad. It is quite possible that seeing this scene was the turning point in my thinking girls have cooties, to thinking they are beautiful.
Thanks Star Wars!
And it seems there is a website entirely dedicated to the gold bikini, and they even sell replicas.
Now, the full costume will run you over $450, but if you have a girlfriend willing to wear it, seems it could be a small price to pay :)
Oh, and in less important news,the Star Wars trilogies will be released on Blu-Ray next year. Sweeeet.
The Science of ‘Beer Goggles’
Oh yes, we’ve all been there.
You knock back a few pints, maybe a few jager bombs and the party really gets started. You think maybe it’s the dimly lit dance floor, or maybe its because you have no idea what time it is, but that girl (or guy) your are dancing with suddenly seems a lot more attractive.
Colloquially, it is known as the Beer Goggle effect. Alcohol is making everyone in the room seem more attractive than if you were sober. It is a well documented effect, and psychologists are trying to nail down what exactly is happening to our brains when this happens.
A study recently published in the journal Alcohol (they have a journal for everything these days, even *guh* homeopathy) may shed some light on whats going on here.
Many studies have shown that when humans rate a person’s face as “attractive”, this is largely due to high levels of symmetry in the person’s face. For example, their nose isn’t crooked (like mine) or their eyes aren’t at different heights, things like that. Any asymmetries will cause attractiveness scores to fall.
So the way this study worked was the experimenters went to a bar after everyone had a chance to down a few drinks. They showed 64 students a series of pictures, some of whom were sober (the control group), and some were intoxicated. The students then rated a series of photos of faces, symmetric and some asymmetric, as attractive or not attractive.
The conclusion was that alcohol worsens our ability to detect symmetry in a peoples faces, consequently making them appear more attractive (not surprising).
What WAS surprising about this study though, was that alcohol affected women’s abililty to detect symmetry more than men. So women actually have a stronger “Beer goggle” affect than men. Crazy.
Of course, guys tend to get much more rambunxios when they are drinking than women, so that’s why this result may be surprising.
But cool stuff. Next time at the bar if you are worried about bringing home an ugo just make sure you look at them in bright light, before turning out the light.
Cheers everyone!
A Quantum of Knowledge 