Friday, February 27, 2009

Fermi Problem Friday

Fermi Problem Friday

Movies movies movies. Movies are fun. You sit back, relax and entertainment erupts right before your eyes. That reminds me, the new Jonas Brothers movie is coming out soon.
Oh how I digress. Anyhow, you often feel hungry or sleepy during the film. Hunger is your body's way of telling you that the tummy meter is running on empty. And sleepy is the result of insufficient fuel in the tummy tank. Movies theaters know this about your body and that is why they offer a variety of delicious items: everything from popcorn to Swedish Fish. You don't want to be caught snoring by the significant friend/person next to you.

This brings us to our Fermi Problem:
How much energy do you get from digesting one piece of popcorn. Assuming you went for all the buttery yummyness. And how many pieces does it take to give you enough energy for the duration of the film. Assume it's not the Jonas Brothers. That might take more.
Popcorn being as expensive as it is at theaters and with economy the way it is, this is a very important question.

Funfact: Movie theaters make more money on concessions than ticket sales.
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Thursday, February 26, 2009

Bottle Rocket


What you're seeing below isn't the Coca-Cola Company's latest marketing gimmick but may very well be the next generation of spacecraft propulsion. This contraption, made from a glass bottle surrounded by an aluminum can demonstrates how easy a plasma propulsion system could be made.






The rocket engine works when nitrogen is pumped through a quartz tube (a glass coke bottle stands in here) and magnets surrounding a metal antenna (the coke can). Inside the tube the magnets and antenna emit radio frequency energies, charging the gas into plasma and the magnetic fields guide it out the back of the engine for thrust. This is called the VASIMR effect. The kicker is the engine is 10 times more efficient than normal rocket engines, because they generate 10 times as much propulsion per weight of fuel. In addition, the nitrogen used here is much cheaper and easier to handle than normal rocket fuel.

Already some space probes have used similar processes. NASA's Deep Space One used an earlier type of this ion drive. There's still a lot of development and refinement to be done before this type of drive can be outfitted for a manned space craft. Not to mention, it still needs a tremendous amount of safety investigation before a VASIMR engine can be strapped to the back of a space shuttle.



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Wednesday, February 25, 2009

The Best Science Writing

The votes have been tallied and the results are in! Right on the heels of the Oscars, the American Institute for Physics announced the Awards for Best Science Writing this year.

Does the idea of a top secret team of physicists hired by the Defense Department, the Department of Energy and the intelligence services in order to solve the government's biggest problems sounds like science fiction? Believe it or not, it's true and it's the subject of the Journalism category winner this year. Ann Finkbeiner's book "The Jasons" chronicles the secret meetings held every year by the nation's smartest minds on everything from nuclear weapons to climate change.

A revolution in physics was afoot in 1932, just before the dawn of the nuclear age, and the first glimmers of quantum mechanics. In Copenhagen a new younger generation of physicists met and outlined the foundations of the new quantum theory. Gino Segre's book "Faust in Copenhagen," winner of the Scientist award, ruminates on this historic meeting against the backdrop of the coming World War, nuclear weapons, and the ethics of science.

In 2036 an asteroid the size of the Rose Bowl called Apophis will safely pass close to Earth. Probably. There is a tiny chance that it could strike the planet causing mass devastation, but the odds against it are about 100,000 to one. Julia Court's NOVA special "Asteroid," winner of the Broadcast category, looks at the people who scan the skies looking for the next "planet killer" and the likelihood of a meteorite striking Earth.

Everyone sneezes, especially around hay fever season. "SNEEZE!" by Alexandra Siy and Dennis Kunkel is a beautifully illustrated look at nine different causes for sneezing. The colorful electron microscope images of dust particles and pollen fit with the engaging text wonderfully. Winning in the Children's category, "SNEEZE!" is a great way to get kids introduced to the microscopic world.



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Tuesday, February 24, 2009

How'd They Do That Tuesday: Bow and Arrows


It's said that Robin Hood once split an arrow clean in half and William Tell shot an apple from off the top of his son's head. If these feats of marksmanship don't impress you, than check some of these guys out. Archery has been around since the Stone Age, and is chock full of physics.






You may ask: How'd They Do That!?

The short answer is: "Years of practice."

The slightly longer answer is: "Physics, and years of practice."

A bow works the same way a spring does. The moment you start pulling back on a bowstring, potential energy is stored in the flexing limbs of the bow. The instant you let go of the string, all of the stored energy is transferred instantly into the arrow, sending it flying down range. This is why it’s very dangerous to pull back and let go of a bow when with no arrow, called a "dry fire." The energy your arm transferred into the bow has no place to escape to, and stays in the bow itself. Arrows fly pretty fast and in the video you can see how much a stiff arrow flexes after its shot, so you can tell there is a lot of energy in them. So much energy in fact if you dry fire a bow, it can shatter.

You may wonder, if your arm is the source for all this energy, how come the results are much less dramatic when you just throw the arrow? The amount of energy needed to move the string at high speeds is much less than the amount of energy needed to move your heavy arm at the same speeds. Your body can't generate the huge amount of energy needed to move the combined mass of your arm and the arrow at speeds over ninety meters a second. But by exerting the energy over more time, storing it in the bow, and then only using the lightweight string to push the arrow, more power is transferred into the arrow.

Gravity is an important factor too, and even though Isaac Newton didn't define it until 1687, archers have been taking it into account throughout history. The force of gravity is constantly accelerating bodies to Earth's surface at 9.8 meters per second squared. There are no other forces acting on the arrows keeping them in the air, so even though they're traveling very fast in a horizontal direction, there's nothing keeping them afloat vertically and would hit at the same time as a dropped penny. Usually they just hit the target before the ground. The trick archers have found to compensate for the force of gravity is simple though, aim higher.




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Monday, February 23, 2009

Unlocking the Secrets of the Superconductor

High temperature superconductors are a "hot item" of study these days, and scientists at the Queen Mary, University of London and the University of Fribourg have recently announced that they are one step closer to understanding how it all works.

When electricity travels through a metal (or "conducts") there is always some resistance in the material that converts a portion of the electricity to unusable heat. The less resistance the less energy lost. However when temperatures get mighty cold, within a couple of degrees above absolute zero, materials tend to lose all of their resistance. Electricity is able to flow through these materials without losing any of their energy, hence the term "superconductor." Certain copper based materials have been found to superconduct at much higher temperatures (though still only as high as a frosty -130 degrees C), but the reasons behind it have baffled scientists for decades.

Last year a whole new breed of high temperature superconductors based on Iron-arsenic compounds was discovered. Scientists comparing the two compounds noticed that their superconductive property seemed to emerge from a specific magnetic state. With further research and exploration, this find could unlock the secrets of superconductors.

This would be huge. Already cold temperature superconductors are used in things like MRIs and power colliders like the LHC, almost anywhere where high powered precision magnets are needed. If we could find out exactly what makes superconductors tick, room temperature superconductors could be around the corner.

The uses for these would be tremendous. Right now it's estimated that between 8 and 10 percent of electricity sent over the grid is converted heat and wasted. Think about it, that's entire power plants worth of energy wasted. Test programs in labs have found none of this electricity would be lost in superconductive wires. These kinds of wires are unfortunately impractical right now because the energy needed to refrigerate them is far greater than the energy saved.


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Friday, February 20, 2009

Physics Across America

Spring break season is fast approaching which means one thing. ROAD TRIP!!! Never fear because physics is everywhere you go. Remember that when you . . .

Try something new in Experiment Georgia

Hurry to Speed Kansas

Recharge in Energy Illinois

Get electrified in Kilowatt California

It may shock you to learn that there's a Volt Montana

I bet you can't resist going to Ohm California

Definitely take a look through Telescope Pennsylvania

Just don't get too steamed in Boiling Point California

Blast off to Mars Pennsylvania, Jupiter North Carolina, Saturn Texas or Pluto West Virginia

Are you feeling pulled to Gravity Pennsylvania

Catch some rays in Gamma Missouri

Don't get caught up too long in Vortex Kentucky

What have you heard about Echo Utah

I've always felt pulled to Magnet Georgia

It can get pretty intense in Bright Star Alabama

Connect the dots in Constellation Arizona

I hope you don't feel too pressured in Gas City Indiana

Families can bond in Atomic City Idaho

Don't be too negative about Electron Washington



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Thursday, February 19, 2009

Hi-Ho, Hi-Ho, It's Off to Jupiter We Go!

I have to say, I'm a little disappointed by NASA's announcement yesterday about its next big space venture. The American space agency and its European counterpart will team up for a joint mission to Jupiter, the largest planet, and its moons. Each agency will each launch their own satellite in 2020 to reach the fifth planet by 2026, where they'll split up the observations of the planet and moons.

I'm thrilled that we're going back to Jupiter. Of all of the planets in the solar system to visit, Jupiter has so many features that are begging for closer study. The diverse moons around the planet make up its own miniature solar system. Starting out, the largest one, Ganymede, is bigger than the planet Mercury, and thought to have a liquid water ocean miles below its surface. Just as tantalizing for life is Europa, which may also have a liquid oceans miles below its cracked surface of ice. Though unlikely for life, Io is the most geologically active body in the solar system, and likely the only moon with its own magnetic field. I could wax on and on all day about the sixteen moons that make up the Jovian system, but I'll spare you.

Here's the thing; why won't any of the spacecrafts land on any of these moons?! We have this great opportunity to get right up close to the most interesting and diverse lunar system in the solar system, and we're stopping short. Don't get me wrong, I'm ecstatic about the return to Jupiter, but it could be so much more. The other mission under consideration was a return to Saturn, complete with a probe to land on Titan. Why not then land on one of Jupiter’s moons?

Take Mars as a marvelous example. The amount of mapping information gathered by various orbiters was tremendous to be sure, but we actually had to land physical robots on its surface before we had conclusive proof of its watery past.

Jupiter being a gas giant has no actual surface to land on, but the moons are just teeming with potential discoveries. Ideally I would love to see some kind of lander able to drill down through the top sheet of ice on Europa to its sea underneath. Of course the engineering needed to put such an ambitious mission together is probably out of reach right now. Even so, some kind of rover would be a tremendous boon for both science and for the public interest. The rovers Spirit and Opportunity have been public favorites since they first started trundling around Mars's surface more than five years ago. Another ambitious mission would be just what the agency needs to keep the public interest.


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Wednesday, February 18, 2009

Gentlemen, Start Your Accelerators!

Yeee-Ha! What we have here is a good old physics challenge on our hands! The problems plaguing Cern's Large Hadron Collider may cost it the coveted prize of discovering the elusive Higgs Boson. Last week at the annual AAAS meeting, Fermilab's Tevatron director Pier Oddone said that there was between a 50 and 96 percent chance of discovering the so called "God particle" before the end of the year.

It's the showdown of the supercolliders!

The Higgs boson is the theorized elementary particle that gives matter its mass. So far no one has directly observed it, because the only way to "see" it is to slam two heavy particles together at nearly the speed of light and carefully comb through the wreckage. So far no particle accelerator has been powerful enough to see it, but they've been getting close. The LHC should have no problem seeing the little bosons when operating at full speed, but it'll be out of commission for quite a while still.

Last fall, the LHC shut down after an electrical short damaged over fifty of the superconductor's magnets. Repairs have dragged on, and the restart date has been pushed back to sometime in November, over a year after the collider was originally supposed to be finished. Full high energy collisions would follow in early 2010.

Now, Fermilab's Tevatron in Batavia Illinois is looking to capitalize on the delay. Though Cern's LHC has eclipsed Fermilab as the biggest and most powerful particle accelerator around, the old Tevatron still has some fight left in it.

Like any good race for the gold, there's been trash talking coming from both sides. At the meeting Lyn Evans, project leader of the LCH said to Dr. Dmitri Denisov of Fermilab, "The race is on,"

"If they do find the Higgs, good luck to them. But I think it's unlikely they will find it before the LHC comes online. They may well be in a position to get a hint of the Higgs but I don't think they'll be in a position to discover it" Evans said, "In one year, we will be competitive. After that, we will swamp them."

Then Denisov said, "It's a race. Whoever is first is first."

And then LCH is all like "No way!" To which Fermilab says "Bring it!" and then LCH is all like "As if!"

Well maybe that last little paragraph didn't really happen, but the race is on! I'll be bringing you updates as they occur!



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Tuesday, February 17, 2009

How'd They Do That Tuesday: Compasses

The old phrase "opposites attract" gets tossed around a lot around Valentines Day, which got me thinking about forces. Electromagnetism is the original inspiration for the term, what with positive charges attracting negative charges, and north poles attracting south poles and the like. I then figured what a good idea for Tuesday!

Believe it or not, we're all walking on the surface of a gigantic magnet. Compasses work because planet Earth itself is encased by its own magnetic field. A magnetic field is created by a moving electrical charge. Electrons buzzing around an atom's nucleus each create a very small magnetic field, which is usually canceled out by a nearby atom. However in certain metals like iron and nickel, huge numbers of these electrons can line up and create a large scale magnetic field. That's how a typical compass needle is magnetized, but how about planet Earth itself?

The wild thing is scientists are not entirely certain what exactly causes it. The prevailing theory is that the iron core of the Earth is under so much pressure it crystallizes into a solid form. The super hot liquid iron moving and churning all around it creates a gigantic, but relativly weak, magnetic field. This field sticks up out of the Earth's poles and attracts the ends of magnets, but only lightweight ones that are perfectly balanced rotate to point North.

Here’s a question: If the old axiom "opposites attract" is true (which it is when talking about magnets) why is my "North" side of the compass point to the "North Pole."

The reason is simple, the "North Pole" of Earth, is actually the south pole of its magnet. Map makers fudged the name so making sense of directions and compass readings would be easier.

Also the spot where the compass points on Earth is not actually the axis where the Earth rotates. Earth's "Magnetic North," where its field lines emerge and compasses point, lies off the coast of Ellesmere Island in northern Canada. The magnetic pole is always changing intensity and location sometimes even switching direction. Archeologists have been able to track these changes. Tiny magnetic signatures in rocks with iron deposits can tell where and how strong the Earth's magnetic signature was at the time. Using this information, scientists have been able to date ancient human fossils, and even track the drifting continents over millions of years.


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Friday, February 13, 2009

Roses are Infrared, Ultraviolets are Blue . . .

Valentine's Day is nearly upon us and the folks over at Ironic Sans put together a great collection of scientist Valentines cards. Cards are great, but my favorite things about this holiday (aside from the 75% off candy sales the next day) are the "NECCO Sweetheart" candies that make their appearance only once a year. Over the years I must have seen every last phrase on those little wafer candies, which is why I though it would be a good idea to come up with some new ones. ENJOY!


Got some good ones of your own? Post 'em!


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Thursday, February 12, 2009

HEY! I'm Orbiting Here!

UPDATED: Math corrected from yesterday’s typos, see note at the bottom under “comments.” Also the Colorado based Center for Space Standards & Innovation put out a great simulation of the crash, you can see the video here.

UPDATED UPDATE: Well, looks like I wasn't the only one to goof on the collision math at first.


Kablammo! Like something out of a Bruce Willis movie, an American and a Russian satellite collided about 800 km above Siberia. The two blew apart into hundreds of pieces after smacking into each other at over 28,000 km per hour. It must've been one heck of a demolition derby up there.

Even though there are over 17,000 man-made objects over 10 cm in orbit, this is the first time two satellites have accidentally collided. Two years ago China intentionally shot one of theirs out of the sky. NORAD is constantally tracking all satellites in the skies, so they can predict when the big ones are going to hit. We're interested in the odds of a random crash and it's clear that the odds of two satellites accidentally hitting each other is very low. How low you may ask? Lets try to figure it out.

When we're calculating the frequency of hits for a satellite we need to start out with some facts and how they'll interact. We'll start out by borrowing an equation from molecular physics calculating the odds of two molecules colliding.


Here "Z" is the frequency of collisions for a single particle (satellites in this case). "n" represents the density of particles, "d" represents the size of the particles and "C" represents their average speed. The entire equation is divided by 2 to prevent double counting of collisions.

We can find the density of satellites by taking their total number divided by the volume of space they orbit in. Most satellites orbit in spheres between 500 and 1300 km above the surface of Earth. The equation V = 4/3 π r^3 gives us the volume of a sphere. Earth is about 6,300 km in diameter, making its radius (r) 3,150 km. First we find the volume of space the lowest orbiting satellites are in and subtract it from the highest orbiting satellites getting a total volume of space satellites orbit in.


Over 165 billion cubic km is a lot of space. Density here is simply number of satellites per volume. 17,000 / 165,348,213,000 = 1.02813328 × 10^-7 satellites per km^3.

Finding their diameter is just a matter of estimating (we'll assume every satellite is spherical here for simplicity's sake). Satellites can run from small bits of space junk only 10 cm in diameter, to the International Space Station which is almost as big as a football field. For the sake of simplicity, ill round and say the average satellite size is 10 meters in diameter, or .01 km so we can keep all of our units straight.

Speeds for satellites vary based on their distance from the Earth. Again for the sake of simplicity, we’ll assume all satellites are orbiting at the same speed of 28,000 km/hr. That's all we should need to find out how often satellites should be running into each other. We start out by plugging our numbers into the original equation:


Giving us the result that an individual satellite will collide with another on average once every: 4.64682715 × 10^14 hours or roughly about once 53 billion years.

That’s the odds for one particular satellite, but all 17,000 would have roughly the same odds. Therefore : 4.64682715 × 10^14 hours / 17,000 = 27,334,277,400 hours or once every …

So, not terribly common at all. This is only the roughest of calculations to figure this collisions conundrum. In fact collisions might be be more likely because these basic equations assume that all space junk is equally distributed, when in fact much if it is concentrated around the equator. The pull of gravity also factors in, as two bodies of junk will attract one another.

On the other hand, the equation I used is for the random Brownian motion of molecules, rather than the ordered orbits of satellites in the sky. Molecules are much freer to move in 3 dimensions, while satellites are mostly trapped at a single altitude. That way, higher satellites are much less likely to interact with lower ones.

But for a back of the envelope, off the top of my head, rule of thumb calculation, that's pretty close without bringing in calculus and probability curves and the like. Let me know what you think. Am I close, or am I just making stuff up as I go?




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Wednesday, February 11, 2009

Capricorn Investments LLC ?

This economic downturn is making people do some pretty crazy things. All across the world, retail sales are slumping, banks are failing and people are losing their houses. However one slim section of the economy that is actually booming amidst this whole mess are the astrologers and psychics of the world. This does not bode well.

No joke; while the economy is falling apart all around us, people are looking the motions of planets and stars for financial advice. A recent CNN story reported that astrologists and psychics have been seeing more business, mostly from people seeking financial advice. Statistics following psychic business are a bit hard to come by, it seems no one bothers to track the industry to carefully. However numerous professional psychics have reported giving out a lot more advice on mergers and acquisitions.

It's not just in the United States either. In Austria an entire insurance company wants to only hire managers and salesmen born under certain astrological signs. In China, which operates on a different astrological calendar, psychics have predicted that 2009, the year of the Ox, will be one of economic hardship and turmoil. I don't think anyone needs anything more mystical than the Wall Street Journal to figure that out.

Is anyone else as worried about this as me? What got us into this mess in the first place were people making bad and unfounded business investments. The last thing the world needs right now are horoscopes guiding the markets. Though it's been around for as long as people have looked up at the night sky, astrology is totally and completely bunk.

Just adding the suffix "-ology" to the end of a word does not make it a science. Simply put astronomy is the science of stars and planets based on measurable facts while astrology is nothing more than a collection of superstitions. Other than how the rotation of the Earth makes day and night and Earth's tilted axis creates seasons, celestial bodies have no impact on business ventures and romances.

Reading your daily horoscope next to the comics section in the morning paper can be a pleasant diversion. Deciding the fate of your business based on stars and planets could easily ruin your company. Remember also, just like everyone else, these psychics are often just out to make money too.


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Tuesday, February 10, 2009

How'd They Do That Tuesday: Lagrange Points

Putting together yesterday's post about planet hunting and intergalactic civilizations got me thinking about some of the ideas for colonizing space right here in our own solar system. One of the more outlandish ideas out there is to fly space stations to colonize the Lagrange Points around Earth.

In other words: Home, Home on Lagrange.

Sorry I couldn't resist. But in all seriousness, what are these points all about?

Lagrange points are wonderful features of orbital mechanics. They're five points around the orbit between the Earth and the Sun where a satellite can park itself and remain the same relative spot. No thrusters needed, no orbital corrections, a spaceship can just relax and let gravity do all the work. These spots (labeled L1-L5) move along with Earth around its orbit, so though they don't say fixed in space, they stay fixed along Earth’s orbit.




The first point, L1, is easy enough to understand. It's the point exactly between the Earth and sun where the pull of gravity is exactly equal. The pull of Earth's gravity and the Sun exactly cancel each other out, and a satellite can hang out in that space indefinitely. L2 is on the far side of the Earth (as seen from the Sun) where the masses of the two massive bodies are exactly in line with each other and form a single gravitational pull. For the L2 point, it would be like orbiting around a single object with the masses of the Earth and Sun combined. The more mass an object has, the stronger the pull of gravity, so the farther from the center of gravity the satellite would have to orbit to stay in sync with the rest of the system. The L3 point combines the two masses the same way, only it's on the line on the far side of the Sun.

L4 and L5 only work if one body is at least 24.96 times more massive than the other. Our sun is thousands of times greater than the Earth, so no problems there. In order to stay balanced between the Earth and the Sun, L4 and L5 are the same distances away from both bodies. To find these points, all one has to do is draw an equilateral triangle out from the Sun and Earth and L4 and L5 are where the triangle's third point intersects Earth's orbit. There, the pull of gravity is equal between the two bodies so the satellite won't fall towards either the Sun or Earth. Also, because it's on the same orbit as Earth, its speed around the sun will be the same, locking it in place around the Earth.

Of course satellites aren't the only things that can take advantage of the Lagrange points. Scientists discovered two big clusters of gas following Earth at its L4 and L5 spots. The Earth and Sun isnt the only system with these points either. Any pair of massive bodies orbiting each other have them. At the L4 and L5 spots between Jupiter and the Sun are entire asteroid fields.

We've already started using the first two Lagrange points for observatories. The Wilkinson Microwave Anisotropy Probe (WMAP), which studies the cosmic microwave background radiation, has been parked at L2 since 2001. The Hubble's replacement, the James Webb Space Telescope, will be moving in next door once it's launched in 2013. Wilder proposals have been suggested for the other points as well. The points have long been a popular spot for science fiction writers to put space colonies and the like. My favorites are all the stories about parallel Earths located at L3 that we might never know were there because they're always eclipsed by the Sun. Spooky right?


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Monday, February 09, 2009

Life, the Universe, and Exoplanets

Planets outside our solar system are a hot item these days. Last year the first photos of "exoplanets" were taken. Just last week scientists announced they discovered the smallest exoplanet yet, coming in at just two times the size of Earth, while the week before scientists were even able to predict the weather on one over 190 light years away. The forecast; Sunny with highs over 2200 degrees, lows around 900 or so.

In late December 2006, the European Space Agency launched their COnvection ROtation and planetary Transits satellite, dubbed COROT. Its primary mission: Find planets outside of our solar system. It's already discovered at numerous planets orbiting far away stars, and its mission has really only begun. NASA's own satellite, called Kepler, is getting ready for launch in early March that will look for small rocky planets like earth.

COROT finds these planets by carefully observing the light emitted from stars. It focuses on a region of the sky for days at a time and look for any stars that dim ever so slightly because of a planet blocking out some of the star's light as it passes between it and the Earth. This kind of careful observation can best be done by satellites outside the Earth's atmosphere. In space stars don't twinkle, so any stellar dimming is likely because of a transitioning planet, eclipsing the star. Pointing the telescope directly at a star is not a very efficient way to look for planets. The star's light will overwhelm any that's reflected off the planet. It would be like looking for a firefly next to a searchlight. It is doable, thats how we were able to take photos of exoplanets, just not very practical.

So where does that leave ET in all of that?

Of course we haven't been able to find life outside our own planet yet. A team in Britain has put together an estimate of how many intelligent civilizations there may be in our galaxy. Extrapolating data from over 300 planets have already discovered, a team from the University of Edinburgh have estimated there are anywhere between 361 and 38,000 intelligent civilizations in our galaxy. These predictions should be taken with a grain of salt the size of Halley's Comet of course. There's no way to tell for sure how widespread life is around the galaxy without leaving our solar system. But the odds look encouraging. Estimates vary but our Milky Way Galaxy is thought to contain roughly a trillion stars. That's rather a lot of stars, and even if small percentage of them have planets, and a small percentage of those planets have life, that's still a lot of life in the galaxy. Probably. Hopefully.



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Friday, February 06, 2009

Focused on a Fuzzy Galaxy

The European Space Agency just released this spectacular image of the galaxy NGC 4921 in the Coma cluster of galaxies. The detail is really jaw dropping especially considering the galaxy is over 320 million light years away. The image is actually stitched together from about 80 photos of both visible and infrared light taken by the Hubble Space Telescope.

NGC 4921 is a spiral galaxy, but as you can see in the photos, its arms are clouded and indistinct. This is because of its crowded neighborhood. Galactic clusters can be volatile places, jostling and colliding galaxies into each other. Spiral galaxies tend to have a tough time in these active environs and the fact that NGC 4921 was able to hold onto its spiral shape at all is pretty remarkable. Phil Plait at the Bad Astronomy blog has a great write up about this latest addition to Hubble's remarkable portfolio.

My favorite part of the image is the dozens of other galaxies hanging out in the background. The Coma cluster is a surprisingly big and dense cluster of galaxies containing over 1000 galaxies. Located in the Coma Berenices constellation near Leo in the northern Hemisphere, the cluster contains several galaxies bright enough to be seen with an amateur telescope on a clear night. Most of the other galaxies in the cluster are football shaped elliptical galaxies.

It's sometimes hard to fathom exactly how far away 320 million light years away really is. Everyone knows a light year is the distance light travels in a year, but how far is that really? Starting out, light travels at roughly 186,000 miles a second, just about the distance from the Earth to the moon in a single tick of a clock. It took the Apollo astronauts three days to make the same journey.


If the Apollo astronauts left Earth and pointed their space craft at NGC 4921, the trip would take over 82 trillion years, more than six thousand times the current age of the universe. In the galactic scale of things, 320 million light years, really isn't that far away.


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Thursday, February 05, 2009

Beanie Bosons

I found my Higgs boson! He was behind the couch the whole time.

No not the theorized subatomic particle that gives matter its mass, the gray plush toy from Particle Zoo.

This little guy is adorable, and he's got a whole menagerie of brother and sister particles. The whole gang's there, everyone from the regulars like electrons, neutrons and protons, exotics like neutrinos and positrons, and even theoreticals and hypotheticals like gravitons, tachyons and my own little Higgs boson. Every particle (and anti-particle) from the standard model of physics is available and adorable.

Julie Peasley started making her line of plush particles in 2007. After attending a lecture at UCLA, inspiration hit and she started her line of subatomic stuffed toys. She makes all of them by hand in her Las Angeles studio.

Peasley has really put a lot of care in to making each plushie. The best part is how each little guy gives a good idea of what small particles are like. Every plushie comes with a tag that gives a rundown of each. The heavy Higgs boson is filled with gravel for extra heft, while the massless photon weighs next to nothing. At 11 cm long, the little photon is the same size as the wavelength of a microwave. I call mine "Mike."

You can get really creative with these guys. On the one hand they make great visual aides when trying to figure out the strange world of subatomic particles. It's the best way I've found to keep a gluon and a muon straight. And you can have a lot of fun with them too. You can build your own whole plushie elements. Put an electron around a proton and you have an atom of hydrogen. Add a neutron and BAM: Deuterium! Add another 91 protons and electrons and an extra 145 neutrons there’s the worlds largest uranium-238 atom.

These little guys also make for great gifts. Neutrinos are nearly massless particles that travel through matter, but barely ineract with any of it. For this reason, scientists have had a devil of a time trying to pin any down, even though trillions pass through the average person's body every second. Now, scientists can interact with neutrinos as much as they'd like by giving them a hug.



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Wednesday, February 04, 2009

This is What a Bad Idea Sounds Like


The University of Idaho is facing a sever budget shortfall and will likely have to trim down some of its offered majors. The administration drew up a list of 41 different academic programs that could be axed, and among them is the physics major. Should the cut go through, the Dean of the College of Science Scott Wood said that he wanted the physics department to focus more on research than teaching.

What?!

University research is important to be sure, but just as important is training the next generation of physicists. The more people out investigating the fundamentals of the universe, the more likely revolutionary discoveries will be made and utilized. Not to mention, I find it hard to imagine that the university would even be able to keep its place as a cutting edge research facility if it doesn't have a physics major to encourage enrollment.

Technology is already central to modern society, and is only going to be more integrated into every day life as time goes on. Some of the greatest problems facing the modern world such as energy concerns and the environment need new and cutting edge technology to fix them. This technology needs research and development by the country's best and brightest if we want to stay in the game. The competition around the world for newest technology is fiercer than ever, and if the United States wants to continue to compete, we're going to need all the help we can get. Simply put: The easier it is for people to get degrees in physics, the more physicists there'll be, and the more discoveries can be made.

Budgets are tight in universities across the country, and sometime tough choices have to be made. But cutting out the physics program is defiantly a bad idea.



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Tuesday, February 03, 2009

How'd They Do That Tuesday: Rockets

The small family of space faring nations just got a little larger. Iran for the first time launched a small communications satellite into orbit, joining the ranks of the United States, Russia, China, France, the United Kingdom, Israel and India. But how does a rocket really work you might ask. Well that's what Tuesdays are all about.

Newton's first law of motion tells us that in order to get an object moving, we need to exert a force on it. As you can probably tell, thousands of tons of space craft takes a whole lot of force to get moving. That's why when you look at the diagram of a rocket; the vast majority of it is actually fuel tanks. When the fuel is ignited in the rockets engine, its stored up chemical energy is converted into a lot of mechanical energy that pushes the rocket forward.

It's not difficult at all to figure out how much of a push is needed to move a rocket forward. Newton’s second law tells us that Force equals Mass times Acceleration (F=MA). In order to find out what kind of force we need to move the rocket, all we have to do is plug in some known facts. According to Boeing's website the mass of the Saturn V moon rocket with all of its fuel weighs nearly five million pounds, or roughly 2,250,000 kg. Gravity is always accelerating objects down at a constant 9.8 meters per second squared. Multiply the two together and you'll find it takes 22,050,000 newtons of thrust to send the astronauts on their way.

When a rocket enters orbit and everything starts floating around the cabin, people often call this feeling of weightlessness "zero gravity," but that's not quite right. Earth's gravity is still pulling on the rocket, but everything feels weightless because you're actually freefalling. It's the same sensation you get when you're going down a big plunge on a roller coaster. The rocket is actually falling the entire time its in orbit, but the difference is, it's moving forward so fast, the ground falls away at the same rate. In the time it takes the rocket to fall ten feet out of the sky, the Earth has curved away ten feet. This continues all around the globe, until a complete orbit is made, and the process repeats itself.




In order to totally escape the pull of Earth's gravity a spacecraft has to travel at least 11 km per second. That takes a lot of force to get going, which is why the moon rockets were taller than a football field and mostly fuel. Using Newton's second law, see if you can find out exactly how much force it would take to send the 45,000 kg Apollo spacecraft from Earth's orbit to the moon.
Always wondered how something worked? Suggest it in the comments section and we can do a How'd They Do That Tuesday based on your question!


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Monday, February 02, 2009

Pigskin Physics

Give me an "F!"
Give me an "=!"
Give me an "M!"
Give me an "A!"
What’s that spell!?
Newton's Second Law!!
Force! Inertia! Momentum! Rah Rah Rah!

Alright, so chances of that particular cheer erupting at your Super Bowl party last night were probably pretty slim. But physics is everywhere and the big game is absolutely chock full of it. This article in Saturday's New York Times speculates what Isaac Newton might have to say if he were in the announcer's booth for the Super Bowl. A body in motion will remain in motion unless acted on by an outside force, like a defensive tackle. Believe it or not, a really hard football tackle, like the one by Fitzgerald and Breaston trying to stop Harrison in the second quarter, packs more of a punch than a space shuttle launch.

"The best hitters accelerate at the last instant. That final jolt of speed allows them to apply a bigger force to their victim," Professor Timothy Gay of the University of Nebraska in Saturday's article. Gay knows the physics of the gridiron well, having written The Physics of Football in 2004. The book is extensive, explaining everything from forces and trajectories of punts, to the effect of a soggy field on the ball. It even has an entire chapter devoted to "The Wave."

Last year we here at Physics Central hosted our own in-depth look at football physics. We held the first ever "Nano-Bowl," an online video contest where participants explained the physics of the game. You can see the winners, or take a look at all of the 27 entries we received. If you like what you see, we've got another contest looking for the best videos on the physics of toys.


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