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Scientific Commuting: How Much Faster? [Uncertain Principles]

Science Blogs Physcial Sciences - 23 March, 2012 - 16:17

Back in the summer, I did a post mathematically comparing two routes to campus, one with a small number of traffic lights, the other with a larger number of stop signs, and looked at which would be faster. Later on, I did the experiment, too.) Having spent a bunch of time on this, I was thinking about whether I could use this as a problem for the intro physics class. I decided against it last fall, but something else reminded me of this, and I started poking at it again.

So, I played around a bit with some numbers, and came up with the following possible framing for a question. I'll throw this out here, to see what people think, then I'll post some solutions in a few hours.

A car starts from rest at the beginning of a straight 1km course, accelerates up to some speed, cruises at constant speed for a while, then decelerates to a stop at the end of the course. A second, identical car does the same course, but decelerates to a stop at the halfway point. It then immediately accelerates back to its cruising speed, and then decelerates to a stop at the end of the course.

How much faster does the second car have to go in order to complete the course in the same time as the first car?

Obviously, this requires some assumptions about the speed and acceleration of the car, which might make for some useful discussion. You can find the necessary math at the first link above, if you want to work it out. For a class using a clicker-type response system, I'd turn it into a poll question like so:

How much larger must the cruising speed of the second car be to finish in the same time as the first car?

So, we'll leave this up for a while, and then this afternoon, I'll post some analysis. Feel free to share your thoughts about appropriate assumptions, etc. in the comments. Or to suggest ways to re-cast the problem that might be more useful. This is classical physics, though, so you don't get to choose more than one option.

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Categories: Education

How to Teach Relativity to Your Dog On the Radio and in Vestal, NY [Uncertain Principles]

Science Blogs Physcial Sciences - 23 March, 2012 - 15:55

sidebar_relativity_cover.jpgThe quick publicity items for this weekend:

1) I will be on the Science Fantastic radio show either Saturday or Sunday, depending on when your local affiliate runs it (or when you choose to livestream it over the Internet). The interview has already been recorded, which leaves me free for:

2) I will be signing and possibly reading from the new book at the Barnes and Noble store in Vestal, NY at 2pm on Saturday. If you're fortunate enough to live in the Southern Tier, stop by and say hi.

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Categories: Education

How to Have My Dog Teach You Physics [Uncertain Principles]

Science Blogs Physcial Sciences - 22 March, 2012 - 16:52

"Hey, dude," the dog says, looking concerned. "We need to talk."

sm_talking_in_lab.jpg

"Yeah? What's up?"

"Look, it's great that you're transcribing the human puppy's stories into Twitter and all, but I'm feeling left out. I've got my own Twitter account and all, but you hardly ever type any of my tweets any more. I have to do it myself, and it's hard to be witty when you have to type with your nose."

"I'm sorry. Is there something specific you'd like to tweet about?"

"Well, yeah," she says, in a tone like I've said something stupid. "I mean, obviously, we have a new book about relativity. And look at this picture-- we're in a cool physics lab! I want to tweet about physics!"

"OK, we can do that. Anything specific you have in mind?"

"Ummmm... no. But I bet somebody else could come up with physics things for me to talk about, if you asked them..."

------

Which is how we got to here. So, here's the deal: If you're on Twitter, ask a physics question of Emmy using either her Twitter name (@queen_emmy) or the hashtag #dogphysics, and she'll answer. Ever wondered how a dog would explain general relativity? The second law of thermodynamics? Why cats land on their feet, even when you chase them off a high place really fast? Ask your question, and I'll give you her response.

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Categories: Education

This is what your Universe looks like! [Starts With A Bang]

Science Blogs Physcial Sciences - 21 March, 2012 - 22:31

"Deep into that darkness peering,
long I stood there, wondering, fearing,
doubting, dreaming dreams no mortal
ever dared to dream before." -Edgar Allen Poe When you look out into the darkness of a moonless, unpolluted night sky, you'll of course notice that it's full of stars, planets, and the occasional extended object.

MilkyWay_June8_08-1024x682.jpeg

(Image credit: Bob King at AstroBob.)

But you'll also notice that there are plenty of regions that -- other than a few stars -- don't really have very much going on. One such region, visible in the southern skies pretty much year-round, is the constellation of Sextans.

sextans.jpegsextans-t.jpeg

(Images credit: Jim Kaler.)

A region of space where there isn't very much going on -- no bright stars, no planets, no close, extended galaxies or nebulae -- is ideal for looking out, deeply, into the Universe.

You may remember, very famously, that the Hubble Space Telescope has done that a number of times, producing images such as the magnificent Hubble Ultra-Deep Field, an image which contains around 10,000 galaxies!

hudf.jpeg

(Image credit: NASA / ESA / S. Beckwith (STScI) and the HUDF team.)

And that, well, that's a lot. But is that the record?

If it was, it certainly isn't anymore! Because that region of space I showed you, above, in the constellation of Sextans? The European Southern Observatory has -- with their VISTA telescope -- created the deepest wide-field image of all-time, containing over 200,000 galaxies!

eso1213a.jpg

(Image credit: ESO/UltraVISTA team. Acknowledgement: TERAPIX/CNRS/INSU/CASU.)

The ESO has released a couple of videos, where you can see exactly where on the sky this region is, and zoom in a bit on some of these 200,000+ galaxies. In the video below, the full region of the survey -- known as UltraVISTA, of the COSMOS field -- is visible at about 0:31 into the clip.

(Video credit: ESO/A. Fujii/Digitized Sky Survey 2/UltraVISTA teamESO; music by John Dyson.)

Zooming even deeper into the field and panning around, the video below showcases some of the highlights of this survey.

(Video credit: ESO/A. Fujii/Digitized Sky Survey 2/UltraVISTA teamESO; music by John Dyson.)

Of course, they've also created an interactive, zoomable version of this survey. I've taken the liberty of creating for you a sample of what it's like to zoom in, by a factor of 4, on a given region of the original, full wide-field survey.

To remind you, here's the original image.

eso1213a.jpg

Now, let's zoom in to the upper-left quarter of this field.

eso1213a_4th.jpg

Now, let's take another quarter (lower right) of that, for 1/16th of the original image.

eso1213a_16th.jpg

And another quarter (lower right) of that, giving us just 1/64th of the original field-of-view...

eso1213a_64th.jpg

And another quarter, bringing us to 1/256th the original...

eso1213a_256th.jpg

And finally, down to the maximum resolution, just 1/1,024th of the original image!

eso1213a_1024th.jpg

Remember, as we did this, that the only remarkable thing about this patch of space is how unremarkable it was! With the exception of two or three faint stars, every dot of light in this image is a galaxy, containing hundreds of billions (or more) of stars! And by doing this to the entire image, we can determine that there are more than 200,000 galaxies in this space.

And that's what your Universe looks like! I'll be away at MidSouthCon until next week; hope you have a great one until then!

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Categories: Education

Shedding Light on Quantum Gravity: "Probing Planck-scale physics with quantum optics" [Uncertain Principles]

Science Blogs Physcial Sciences - 21 March, 2012 - 17:05

ResearchBlogging.orgIt's been a while since I did any ResearchBlogging posts, because it turns out that having an infant and a toddler really cuts into your blogging time. Who knew? I keep meaning to get back to it, though, and there was a flurry of excitement the other day about a Nature Physics paper proposing a way to search for quantum gravity not with a billion-dollar accelerator, but with a tabletop experiment. There's a write-up at Ars Technica, but that comes at it mostly from the quantum gravity side, which leaves room for a little Q&A from the quantum optics side.

Wait a minute, you said this is in Nature Physics? I don't have access to that. You're in fine company, because neither do I. Thanks to the arxiv, though, you can read a preprint for free, and that's what I'll be working from.

OK, so what's the deal with this quantum gravity stuff? Are you telling me they can make a black hole with lasers, now? No, there aren't any black holes involved, even though black holes are the canonical example of a system where you need quantum gravity to understand what's going on. Black holes are rather difficult to work with, though, so people who want to look for a quantum theory of gravity try to find other ways to see its effects.

In this case, they make use of the fact that most theories of quantum gravity involve a minimum length scale. That is, there's a minimum length below which you can't talk about distances in any sensible way.

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Categories: Education

Max Kurzweil Describes the Science Behind the Potato Chips [USA Science and Engineering Festival: The Blog]

Science Blogs Physcial Sciences - 21 March, 2012 - 16:00

By Max Kurzweil

allen kurzweil.jpgWhen we're at a baseball game or on a picnic we call 'em chips. But when we're cooking up experiments at the Chip Science Institute we maintain in our basement, or at the USA Science and Engineering Festival in Washington D.C., we call the world's most beloved munchie "research material."

For the last five years my dad and I have been using potato chips as a portal into the world of biology, chemistry, earth science, and physics. Who knew thin-sliced, deep-fried tubers could teach us about buoyancy, electrostatics, surface tension, acoustics, forensics, Bernoulli's principle, and more. When we tell you that investigating the material properties of the potato chip can be a BLAST, we mean it. (We'll be giving away a few dozen potato propulsion pipes to prove the point!) So for folks who like snacking on science high in saturated facts, you can't go wrong analyzing the material properties of chips, bags, lids, spuds, and tubes. Hope to see in D.C. -Max Kurzweil, co-inventor of Potato Chip Science (the bright blue bag of experimental swag).

You can meet Max Kurzweil and Featured Author Allen Kurzweil at the Festival Sunday, April 29th at 12:45 PM on the Family/Hands On Science Stage.

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Categories: Education

There has been a large earthquake in Mexico [Greg Laden's Blog]

Science Blogs Physcial Sciences - 20 March, 2012 - 20:46

The 7.6 7.4 magnitude earthquake struck 120 miles east of Acapulco. There are no details yet.

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UPDATE: With a bit of time passing, it is starting to look like a lot of stuff got shook-up, but there was not a lot of significant damage anywhere.

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Categories: Education

A Martian Supernova for Skywatchers Everywhere! [Starts With A Bang]

Science Blogs Physcial Sciences - 20 March, 2012 - 19:20

"When I had satisfied myself that no star of that kind had ever shone before, I was led into such perplexity by the unbelievability of the thing that I began to doubt the faith of my own eyes." -Tycho Brahe When stars reach the end of their lives, there are many possible fates that they can have. Among the most spectacular, however, are stars that end their lives by going supernova, where a single star can outshine even an entire galaxy for a brief moment in time.

sn2006gy_3panel.jpeg

(Image credit: SN 2006gy, X-ray by NASA / CXC, Nathan Smith, Weidong Li et al., IR by PAIRITEL / Lick / U.C. Berkeley / J.Bloom, and C.Hansen.)

Last year, we experienced the closest supernova in a generation, when a star died a spectacular death in a relatively nearby galaxy.

Although it isn't nearly as spectacular as what we'd get to see if we experienced another supernova within our own galaxy, a phenomenon not experienced on Earth since 1604!

sn1604wiki.jpeg

(Image credit: Stellarium.)

When they occur within our own galaxy, supernovae are so bright that they outshine all the other stars, all the planets, and can often even be seen during the day. They're very rare, though, occurring less than once per century, on average, in our own galaxy.

But there are other galaxies that have better luck than we do.

hs-2007-15-a-xlarge_web.jpeg

(Image credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA).)

Many galaxies, unlike our own, are actively forming large quantities of stars! In many spiral galaxies, like NGC 1672, above, pink regions can line the arms of galaxies, surefire evidence of recent, intense star formation. Recent mergers, including the gobbling up of small, satellite galaxies, as well as simply the density waves of spiral arms can often trigger this type of star formation all on their own.

But when galaxies gravitationally interact with one another -- even when separated by millions of light years -- they can intensify this ongoing star formation.

With this in mind, let me introduce you to one of the nearer galaxies in our night sky: Messier 95 (M95).

M95_281202.jpeg

(Image credit: Paul and Liz Downing.)

Messier 95 is a spiral galaxy, with strong inner arms and faint outer arms, located 38 million light years away. It's also very close to Messier 96, and Messier 105; together, with a few other galaxies, they form a group! The image below, created by me with Stellarium, shows the entire group, all contained within just a single degree in the night sky.

Mars_M95_SN.jpg

You'll also notice, in the upper right of the image, lies the planet Mars.

Shining brightly in the night sky, Mars, in many locations, is the brightest object visible in the sky during much of the night. It doesn't look like it, in the image above, because I've artificially reduced its brightness by a factor of many thousands. Normally, astronomical observers look for the following traits when they go to take their observations:

  • clear, dark skies,
  • far away from any sources of light pollution,
  • a moonless night, and for the most hardcore,
  • high altitudes (to limit atmospheric interference).
But if you want to take a look at Messier 95, you'll want to make sure to leave Mars out of your field of view, otherwise you'll never see the galaxy! Why's that?

M95-wide1-1024x822.jpeg

(Image credit: Jim Misti / Map created with Stellarium, retrieved from Astro Bob.)

Messier 95 is located less than half-a-degree away from Mars in the night sky, but appears to be about 100,000 times less bright than the red planet right now. On the magnitude scale (smaller is brighter), M95 is magnitude 9.7, while Mars is of magnitude negative one.

But you'll want to see Messier 95 now, because in a region of that galaxy that contained absolutely nothing, a very bright object suddenly appeared just four days ago, and is increasing in brightness; it's got to be a supernova! Zooming in on the earlier image of M95, I want to show you exactly where you should look if you want to see it; anyone with an 8" telescope or bigger (and the proper magnification -- 100x for an 8") should be able to find it! (But no smaller than a 6" under the best of circumstances for now; you'll waste your time looking for it.)

m95_paulandliz_add.jpg

(Image credit: Paul and Liz Downing, marked by me.)

At this point, we haven't officially determined whether it's a type Ia supernova (formed by an exploding ancient white dwarf) or a type II supernova (formed from a very massive, young star that's finished burning its nuclear fuel), but look at the location: it's right on one of the outer spiral arms! That's one of the key places where young, massive stars form, and so just by looking at that, I can tell you that it's almost definitely a type II supernova.

Want to know what it looks like through a telescope? Take a look, below.

New_SN_and_Mars.jpg

(Image credit: Nik Szymanek.)

As you can see, marked by the lines, there's a fairly distinct object that looks like a star within our own galaxy. But that's not a Milky Way star, a few hundred or a few thousand light years away, but a supernova in Messier 95, located 38 million light years distant! Over the coming weeks, the supernova will continue to brighten, and will be more clearly visible and more easily seen. But one thing that won't change all that much is that ruinous light pollution, captured by Nik Szymanek, above.

Know what's causing it? That's Mars!

Mars_SN_deepsky.jpg

(Image credit: Nik Szymanek from Deep Sky Videos / Brady Haran.)

If you want to see more, and you can't wait for the information to unfold, there are two things I recommend you check out. First, David Bishop has some early photos on his site, where you can find before-and-after photos of Messier 95.

And if you need more right now, Deep Sky Videos has put together a wonderful presentation -- released just yesterday -- on this supernova so far.

So if you can find Mars, and you have a good enough telescope and good enough skies, you can be among the first to see the latest supernova in our night sky!

Update: The supernova has been confirmed! It's a Type IIp supernova, and its name is SN 2012aw! It will brighten, and continue to be visible probably into June, when Mars will have (finally) moved a considerable distance away. Keep watching!

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Categories: Education

The Quantum Universe by Brian Cox and Jeff Forshaw [Uncertain Principles]

Science Blogs Physcial Sciences - 20 March, 2012 - 15:59

So, this is the new book from the authors of Why Does E=mc2?, covering quantum mechanics in a roughly similar manner. This book, or, rather, Brian Cox talking about some material from this book, created a bit of controversy recently, as previously discussed. But other than that, Mrs. Lincoln, how did you like the play?

The big hook here is that they set out to discuss quantum mechanics for a popular audience using a Feynman-type picture from the very beginning. This is an intriguing idea, and sort of appealing in the same basic way that Sakurai's famous graduate text in quantum mechanics and Townsend's undergraduate version appealing. Those books are interesting because they come at the subject from a different angle, formulating everything first in terms of spin-1/2 particles, rather than wave mechanics. This makes certain types of problems much easier to deal with, and lets students see the subject in a very different light.

So, the general idea of a book on quantum physics that starts with Feynman's path integral formulation of the theory-- other than, you know, Feynman's own book on QED-- is an interesting idea. The Feynman approach is the starting point for a lot of modern approaches to the theory, and looks very different than the Schrödinger wave mechanics most popular treatments (my own included) take. I got some useful stuff out of their book on relativity, so I was hoping for some useful insights from this one.

Like its predecessor, though, I want to like this book more than I do.

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Categories: Education

How to Teach Relativity to Your Dog Publicity Update [Uncertain Principles]

Science Blogs Physcial Sciences - 20 March, 2012 - 14:51

A couple of cool items in the promotion of How to Teach Relativity to Your Dog:

-- A little while back, I spoke to Alan Boyle, who writes the Cosmic Log blog for MSNBC, who posted a very nice story about the book last night. Mainstream media, baby!

It also uses this very cool picture of Emmy and me in my lab:

emmy_in_lab.jpg

(Many thanks to Matt Milless for taking that and a bunch of others.)

-- This weekend (either Saturday or Sunday, depending on where you are), I'll be on the Science Fantastic radio show, talking about relativity with Michio Kaku. There's a lsit of stations that carry it linked from that page, or you can listen online (this site purports to let you stream it, but I haven't tried yet.

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Categories: Education

Neutrinos and the Search for Extraterrestrial Intelligence [Starts With A Bang]

Science Blogs Physcial Sciences - 20 March, 2012 - 02:35

"To use Newton's words, our efforts up till this moment have but turned over a pebble or shell here and there on the beach, with only a forlorn hope that under one of them was the gem we were seeking. Now we have the sieve, the minds, the hands, the time, and, particularly, the dedication to find those gems--no matter in which favorite hiding place the children of distant worlds have placed them."
-Frank Drake and Dava Sobel Looking up at the canopy of stars in the night sky, and realizing that each point of light is a star system not so unlike our own, one can't help but wonder about those extraterrestrial worlds that we know exist around a tremendous fraction of them.

W3.jpeg

(Image credit: Tom's Eye on the Sky.)

With hundreds of billions of stars and (possibly) upwards of a trillion planets, it's been known for a very long time that there's a definite, real chance that other intelligent life exists right now in our own galaxy.

For decades, we've broadcast radio messages out into space, and built giant arrays of radio telescopes, searching for those same types of signals originating from other sources in the night sky.

vla_soorr.jpeg

(Image credit: VLA in Socorro, New Mexico, retrieved from here.)

Of course, this is a tremendously ambitious task. Even a very intense radio signal will lose its power the farther away from it you are. The problem, of course, is that each time you double the distance away from a radio transmitter, you pick up only one-quarter of the intensity you would have received at a closer distance.

radio%20transmitter.gif

(Image credit: Arthur's Clip Art.)

Even special setups that collimate the beam -- assuming, for example, that an alien species had the idea to point their beam directly at us -- still suffer from this. Even the best setups for beam collimation of light still wind up having the signal spread out over a substantial angle, and still suffers from the problem that the farther away you are, the less intensity you receive squared: a radio transmitter ten times as far away needs to be a hundred times as powerful for you to pick up the signal.

StdFresCollimator.gif

(Image credit: Chris Long.)

It's difficult to imagine that a civilization-generated signal located thousands of light-years away, across the galaxy, would be able to outshine the cosmos by time it reached us.

But we do have one sterling example of a beam we can collimate to an outstanding precision: beams of extremely high-energy particles!

0911188_01-A4-at-144-dpi.jpeg

(Image credit: Maximilien Brice, 2009.)

A pulse of high-energy particles, such as the kinds we create at the Large Hadron Collider, above, achieves speeds around 99.9999% the speed of light, more closely collimated than even the beam from a laser. Now, we sometimes receive high-energy particles -- originating from space -- here on Earth. When we do, how do we identify them?

cosmic_ray_spallation_big.jpeg

(Image credit: Randy Russell using a photo via UCAR / Nicole Gordon.)

They strike the Earth's upper atmosphere, producing a shower of particles. Neutrinos and muons make it to the ground, where -- if we're lucky and prepared -- we can identify them. Launched from Earth, however, the charged particles would certainly hit the atmosphere on the way out. And since muons are unstable, by time they arrived at their destination, the only recognizable signal would be the neutrinos!

In other words, if we wanted to send a signal to an alien world, alerting them to our presence, our best bet would be to send them collimated, patterned pulses of neutrinos!

cs02p06graphic1l.gif

(Image credit: Jerry Ehman, republished from Smithsonian Magazine.)

What's remarkable about this -- even though it wasn't the experiment's intention -- is that we just demonstrated the ability to detect exactly this type of signal!

How's that?

pictures.jpeg

(Image credit: MINERvA team / University of Rochester.)

Last week, scientists announced -- for the first time -- that they sent a neutrino signal through the solid rock of the Earth, in binary morse code, and received it at a neutrino detector over a kilometer away!

completed-TP3-big.jpeg

(Image credit: MINERvA Collaboration.)

Despite the fact that only one out of every ten billion neutrinos can be detected in an apparatus like the MINERvA detector, above, and that the effective transmission rate was only one bit every ten seconds, by repeating the message many times, the detector was able to build up the binary pattern of zeroes and ones, eventually decoding the binary message!

minervadetector.png

(Image credit: D.D. Stancil et al.)

What was the message? Why, the name of the particle itself: N-E-U-T-R-I-N-O.

If someone, thousands of light years away, is sending a repeating neutrino signal towards us, we've just demonstrated the capability of detecting and identifying exactly that type of communication.

The signals of intelligent life could already be there. We just need to listen in the right way, and neutrinos might be the answer!

(Also, a big thanks to Randall for the elegant new blog banner; hope you like it!)

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Categories: Education

Are Books and Kindles Correlated? [Uncertain Principles]

Science Blogs Physcial Sciences - 19 March, 2012 - 17:37

I'm trying not to obsessively check and re-check the Dog Physics Sales Rank Tracker, with limited success. One thing that jumped out at me from the recent data, though, is the big gap between the book and Kindle rankings over the weekend. The book sales rank dropped (indicating increased sales, probably a result of the podcast interview), while the Kindle rank went up dramatically. This suggests that people who listen to that particular podcast are less likely to buy new books on the Kindle than new books on paper.

This got me wondering, though, whether this was an anomaly, or a general truth. That is, is there any correlation between the sales rank of the paper edition of a book and the sales rank of the Kindle edition of the same book? Happily, the sales rank tracker spits out all the hourly rankings in a nice table that I could copy into SigmaPlot and crank away on, producing the following:

bookvskindle2.PNG

This is a plot showing the Kindle sales rank of How to Teach Relativity to Your Dog (vertical axis) versus the sales rank of the paper edition (horizontal axis). I smoothed the hourly data a bit, averaging together five hours, because it's really noisy, but that makes almost no difference.

What does this say? Well, that there's a pretty weak correlation between them. The data points fall more or less in a wedge extending up and to the right, which tells you that when one is really high, the other tends not to be very low, and when one is low, the other also tends to be low, but the relationship between them is pretty weak. At a book rank of about 25,000, the Kindle rank ranges from about 14,000 to about 96,000.

This is for the recently released book, though. Maybe more data would make a clearer picture? In a word, no. In a thousand words (i.e., one picture):

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Categories: Education

Another Week of GW News, March 18, 2012 [A Few Things Ill Considered]

Science Blogs Physcial Sciences - 19 March, 2012 - 16:22

Logging the Onset of The Bottleneck Years
This weekly posting is brought to you courtesy of H. E. Taylor. Happy reading, I hope you enjoy this week's Global Warming news roundup

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Categories: Education

Chasing Stephen Hawking [Dean's Corner]

Science Blogs Physcial Sciences - 19 March, 2012 - 01:14

x2_b8b96ee.jpeg

Imagine spending a day with the brilliant physicist Stephen Hawking. What would you ask him? Guess who did, on St. Patrick's Day?

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Categories: Education

Dog Physics on the Radio [Uncertain Principles]

Science Blogs Physcial Sciences - 17 March, 2012 - 15:29

sidebar_relativity_cover.jpgI've done a bunch of publicity stuff for How to Teach Relativity to Your Dog, some of which frustratingly continue to not appear yet, but one thing from this week has gone live: a podcast interview on the Matt Lewis Show, where I talk about why and how I explain physics to the dog, and a little bit about why relativity is cool.

I continue to struggle a bit with the fact that relativity is a very visual subject-- most of the best explanations involve pictures, which aren't much help in an audio-only medium. I had trouble with this at Boskone, too-- when I was doing a reading, it was hard to find a section to read that didn't involve a lot of diagrams. And I still tend to go on a little too long in my descriptions. It went all right, though, and Lewis gets points for being the first person I've talked to about this to get my description of the dog voice as "a sort of Andy Kaufman 'Foreign Guy' thing."

So, if you've got 15 minutes to kill, check it out.

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Categories: Education

The Fat Lady Sings for OPERA [Starts With A Bang]

Science Blogs Physcial Sciences - 17 March, 2012 - 02:10

"The saying 'It's not over 'til the fat lady sings' is erroneous, because women who are fat are never listened to." -Margaret Cho Last year, the OPERA collaboration made worldwide headlines when they announced the results of a remarkable experiment.

beamtrajectory-en-71dd9-8be65.png

(Image credit: OPERA / CERN.)

From over 730 kilometers away, in another country, neutrinos were created by one of the most powerful particle accelerators in the world. Protons at over 99.999% the speed of light were smashed into matter, creating a highly collimated beam of neutrinos, which was launched through the Earth at, presumably, speeds indistinguishable from the speed of light.

Underground, beneath the Italian mountain of Gran Sasso, laid the huge OPERA detector, capable of detecting these high-energy neutrinos.

operadetector.jpeg

(Image credit: OPERA / INFN / CERN.)

But what it was also able to do, so they claimed, was to measure the timing of these neutrinos so accurately as to be able to test Einstein's theory of special relativity!

As you well-know, nothing is supposed to be able to move faster than the speed of light in a vacuum. Nothing. Which is why it was absolutely shocking when they released their first results.

opera.jpeg

(Image credit: OPERA Collaboration; T. Adam et al.)

60 nanoseconds early, they said, their neutrinos arrived. This wasn't an error, either, they said, as their uncertainties were only around 10 nanoseconds. And if that was true, over the distances they were talking about, that means these neutrinos would be moving something like 7,500 m/s faster than light, which is huge!

speed_of_light_4.jpeg

(Image credit: United Visual Artists / Tom Oldham.)

As we've said many times, claims like these, that are extraordinary, require evidence that is also extraordinary. So I was very excited to report that, in short order, we were going to either confirm or refute OPERA's claims!

neutrinobeam.jpeg

Because two experiments -- T2K in Japan, above, and MINOS in the USA, below -- were all set up to measure the same exact thing to even better precision.

NOVA-Looking-North-large.jpeg

But another experiment, one that had come out earlier and challenged OPERA's results, had other plans. You see, OPERA had recently announced that they had uncovered two potential problems with their experiment -- the loose cable and a possible timing miscalibration -- which threw their results into doubt.

What it really meant, if you look up at the image of their claimed results, is that their claimed errors, which were tiny, should have actually been much larger due to those issues.

operasynopclarified1.png

(Image credit: Matt Strassler.)

This is a problem that plagues a great many experimental and observational sciences: fully accounting for your systematic errors. After all, it is difficult to account for uncertainties and / or errors due to something you were simply expecting would work properly! You account for systematics based on all the errors you can reasonably anticipate, but once those are over and done with, you stop counting. But when an unexpected error does happen, and you weren't expecting it, it can lead you to have an undue amount of false confidence in what are actually insignificant results.

And it was the ICARUS team -- another neutrino detector underneath Gran Sasso -- that set out to show that OPERA had done exactly that. Intending to refute the OPERA team's results, ICARUS has gone out to set the record straight about Einstein's relativity.

icarus.png

(Image credit: the ICARUS-T600 detector installed in LNGS - HallB, retrieved here.)

Evoking shades of Ethel Merman, ICARUS basically said to OPERA, "Anything you can do, I can do better." And, over practically the same baseline, using the same energy neutrinos created from the same proton beam, ICARUS set out to re-test the OPERA experiment.

Icarus_fig_1.jpg

(Image credit: the latest ICARUS paper; M. Antonello et al.)

Except, you know, without the errors. And what they found should put the whole issue to rest. The OPERA neutrinos, you'll remember, arrived around 60 nanoseconds early, with an originally claimed uncertainty of 10 ns. The ICARUS results, making the same measurements with different equipment?

Icarus_fig_3.jpg

(Image credit: the latest ICARUS paper; M. Antonello et al.)

As others have noted, this time, there can be no doubt that ICARUS has directly refuted OPERA.

It means that, combined with ICARUS' earlier results, we can constrain that not only are neutrinos of this energy not moving at the speed OPERA concluded, but they must be moving much closer to the speed of light than OPERA's original results would have indicated.

newnuvelocitygraph.jpeg

(Image credit: Matt Strassler, edited by me.)

And that's pretty much the end of the line for these faster-than-light neutrino claims. It will be interesting to see what OPERA's next results are, as well as what MINOS and T2K have to say, but with the ICARUS results in and the OPERA uncertainties known to be much larger than originally claimed, there's suddenly no reason to believe that neutrinos move faster-than-light at all.

And if you were skeptical the whole time, good for you. The extraordinary evidence you were waiting for just came in, and it's the sound of the fat lady singing!

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Categories: Education

Neutrinos in the News [Uncertain Principles]

Science Blogs Physcial Sciences - 16 March, 2012 - 22:10

A little more tab clearance, here, this time a few recent stories dealing with those elusive little buggers, neutrinos. In roughly chronological order:< /p>

  • The Daya Bay experiment in China has measured a key parameter for neutrino oscillation (arxiv paper), the phenomenon where neutrinos of one of the three observed types slowly evolve into one of the others. Mathematically, this is described as each of the three types we observe being an admixture of three more fundamental types. This mixing is described in terms of the sine of some "mixing angle," because physicists love geometry, and two of the three mixing angles had already been measured. The Daya Bay experiment measured the third-- or, more precisely, they found that the square of the sine of the third mixing angle is 0.092 +/- 0.016 +/- 0.005, where the two uncertainty values are for statistical and systematic uncertainties. This is somewhat larger than expected, which is probably a good thing, because it may imply more of a difference between matter and antimatter than you get from the simplest models, which in turn would help explain why everything we see in the universe is matter and not antimatter.
  • A group at Fermilab has sent a message via neutrinos (press release), encoding a simple signal in on-off pulses of neutrinos generated at Fermilab and detected by a giant underground detector a kilometer away. This is not particularly useful for anything, because they need a big particle accelerator to make the pulses and a detector with a mass on the order of tons to detect them, but it's kind of cute.
  • Finally, a second group at the Gran Sasso laboratory in Italy has used the same neutrino beam used by the OPERA collaboration to check the time of flight of the neutrinos passing from CERN to Italy, and find that it agrees perfectly with what you expect for neutrinos moving at light speed, not the tiny bit faster that OPERA saw. As usual with particle physics stuff, Matt Strassler has a good and balanced round-up. These results from the ICARUS experiment (I'm not even going to try to figure out what linguistic crimes they committed to get that acronym) are fairly conclusive evidence that OPERA's result was in error, though given the complexity of both measurements, it's still worth repeating the experiment as planned in May.

And that's the news regarding the elusive neutrino.

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Categories: Education

One Year After Fukushima, a Startup Named Kurion Continues to Shed Light on What it Means to Live in the Nuclear Age [USA Science and Engineering Festival: The Blog]

Science Blogs Physcial Sciences - 15 March, 2012 - 16:00

photo-LarryBock.jpg
By Larry Bock
Founder and organizer, USA Science & Engineering Festival
When searching for a prime, real-life example of how science and technology are making a difference in the world right now, my thoughts lately turn to a small but feisty greentech startup that you may never have heard of: Kurion, Inc.

Based in Irvine, CA with 15 employees, this profitable three-year-old company which specializes in nuclear waste cleanup has quietly and effectively been using its technology at the front lines of Fukushima, the site of what is being called one of the largest nuclear disasters in history. Weeks after the unforgettable earthquake and ensuing tsunami struck Japan last year which caused emissions of nuclear contaminants to be released into the air from reactors at the Fukushima Daiichi Nuclear Power Station, Kurion was selected to join a group of multi-billion dollar companies to help clean seawater that was being pumped into the reactors to cool them down.

Within three weeks of first contact, TEPCO authorized Kurion's proposed solution to the challenge. Eight weeks later, Kurion's system had been designed, built, air freighted by three Russian Antonov transports, installed and was fully operational removing more than 99.9% of the seawater radioactivity of greatest concern. Other companies which were awarded contracts by the Japan utility TEPCO to aid in this challenging duty were France's AREVA, Japan's Hitachi-GE Nuclear Energy and Toshiba. Of these, only Kurion and AREVA were able to deliver systems in time to prevent the highly contaminated seawater from overflowing the limited available tankage into the ocean and of these only Kurion continues to operate today.

Kurion stands out as the only startup selected -- and for good reason: the firm for a while has been developing a material called "ion specific media" that greatly improves the way cleanup technology is deployed to soak up nuclear particles and as a result shrink the radioactive material down to a small manageable size. The resulting waste stream, an inorganic powder, can further be turned into glass (a standard industry process known as vitrification). Kurion's innovation brings a more modular approach to the vitrification process, so the clean-up technology can be quickly adapted and installed in the contaminated spill site. Add to that Kurion's team composed of nuclear waste industry veterans, and you'll understand why the company was able to enter a direct contractual arrangement with TEPCO.

Since last June, says Kurion's CEO John Raymont, the company's technology has been used as part of what he calls "an unprecedented external reactor water cooling system," designed to replace Fukushima's in-plant reactor water cooling mechanism until the reactor's original nuclear cores can be removed. Bottom line: Kurion's presence at Fukushima is helping to mitigate radiation contamination to humans and the environment, dramatically turning a disastrous situation around.

As the first anniversary of the Fukushima disaster past on March 11th, Kurion and the cleanup are perfect examples of how science and technology are making a difference where it matters around the world. In my opinion, it illustrates in realistic terms what it means to be human in the nuclear age -- with all the benefits and risks nuclear power brings.

To help get this message across, we are proud to include Kurion and its representatives as key participants in the upcoming USA Science & Engineering Festival hosted by Lockheed Martin, the nation's largest celebration of science and engineering. The Festival is on a mission to inspire the next generation of innovators by reinvigorating the interest of our nation's youth in science, technology, engineering and math via hands-on presentations with experts that motivate, compel, excite, entertain as well as educate.

Kurion's participation is especially exciting for me for a couple of reasons. As a startup entrepreneur myself before establishing the Festival several years ago, I co-founded or financed the early stage growth of 40 companies in the life and physical sciences from inception, so I know well of the rigors and challenges that Kurion has and continues to experience to further establish itself in the competitive field of technology. Second, at Lux Capital (one of two venture capital firms backing Kurion), I serve as Chairman of Lux's Advisory Board of industry experts where we are all extremely proud of Kurion's success.

Join visitors at the Festival Expo on April 28-29, 2012, in Washington, DC when we take you inside the power of nuclear energy (along with other exciting areas of science and engineering) with such experts as Kurion, the U.S. Department of Energy, the University of Massachusetts Lowell Physics Department, and the ATLAS Experiment at the Large Hadron Collider who are all helping to make our co-habitation with nuclear power safer and more beneficial. Here is just a sampling of what you'll discover:

How Kurion is Cleaning Up Fukushima -- From Kurion, learn how they perform remediation on contaminated water and stop the spread of radioactive isotopes at Fukushima and other sites. Kurion experts will also demonstrate how an ion-exchange column works and how they trap dangerous particles using their 3-D vitrification simulator.

Future Implications of the Fukushima Disaster -- Meet and hear Fred Bortz, Ph.D., who is among our Featured Authors at the Expo's Book Fair. A physicist-turned-writer, Bortz (whose science training includes three years in nuclear core design), is the author --among other works -- of the recent book, Meltdown: The Nuclear Disaster in Japan and Our Energy Future, which sheds light on the future of nuclear and what the next generation will face in dealing with its development.

Real-Life Applications: From National Defense to Biomedical Photonics -- Learn from these experts: how the U.S. Department of Defense is developing solutions that protect first responders from potential nuclear, radiological, chemical and biological threats; how renowned physicists from the University of Massachusetts Lowell are making life-saving advances in areas ranging from nuclear physics and radiation science to biomedical photonics, and from the American Nuclear Society how to compute your own annual radiation dose.

The Wonders of the Large Hadron Collider (LHC) -- Scientists from the ATLAS Experiment at the LHC take you inside the wonders of the world's largest and highest-energy particle accelerator which was developed over a 10-year period to probe new frontiers in high energy physics including the origins of the universe.

How the DoE is Impacting Climate and Energy Solutions -- Department of Energy scientists from its Atmospheric Radiation Measurement (ARM) facility will demonstrate how its measurements are bringing science solutions to the world, including improving climate models, and researchers from the Department's Berkeley National Laboratory will shed light on how they are developing new approaches to energy by studying infinitesimal particles at the sub-atomic level.

Radiation Physics in 3-D -- Enter a 3D virtual treatment room with experts from the American Association of Physicists in Medicine and learn how a radiation treatment accelerator works. See how medical physics and science are used in the radiation treatment of cancer. Participants will get a 3D view of the technological advances used in this cancer treatment.

Nuclear power, the byproduct of our existence in the modern age, is here to stay. Join us at the Festival as we explore how to coexist with it responsibly and safely for the benefit of all. For more on the Festival, visit: http://www.usasciencefestival.org/

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Categories: Education

Pi Day Fun Facts! [Starts With A Bang]

Science Blogs Physcial Sciences - 15 March, 2012 - 02:28

"Now go on, boy, and pay attention. Because if you do, someday, you may achieve something that we Simpsons have dreamed about for generations: you may outsmart someone!" -Homer Simpson Today, March 14th, is known tongue-in-cheek as Pi Day here in the United States, as 3.14 (we write the month first) are the first three well-known digits to the famed number, π. As you know, it's the ratio of a perfect circle's circumference to its diameter.

pie.jpeg

(Image credit: LeJyBy at Flickr Creative Commons, retrieved here.)

It's also very, very, very hard to calculate exactly, because it's impossible to represent π as a fraction. (You may remember that's part of the definition of an irrational number.) But that doesn't mean we haven't tried!

The easiest way to try is to either inscribe or circumscribe a regular polygon around a circle of radius 1, and calculate the polygon's area. The more sides you make, the closer you'll get.

Archimedes_pi.png

(Image credit: Archimedes' Pi approximation, by Leszek Krupinski.)

Archimedes, who discovered the fraction 22/7 (which is why Pi Day is July 22 in Europe), took the equivalent of a 96-sided polygon to do this, and found that π was between 220/70 and 224/71, which is not bad for two thousand years ago!

But it's hardly the most impressive approximation for π from back then. That honor goes to the Chinese mathematician, Zu Chongzhi.

%E6%98%86%E5%B1%B1%E4%BA%AD%E6%9E%97%E5%85%AC%E5%9B%AD%E7%A5%96%E5%86%B2%E4%B9%8B%E5%83%8F.jpeg

(Image credit: Statue of Zu Chongzi in Tinglin Park in Kunshan, by Gisling.)

He discovered -- in the 5th Century -- the approximation Milü, which is 355/113. Which is equal to, for those of you at home, 3.1415929... meaning you have to go to the eighth digit to see the difference between this number and π. In fact, if we look at the best fractional approximations of π...

Diaorifa.gif

(Image credit: Gisling.)

we wouldn't find a better one until 52163/16604! (Exclamation point, not factorial!) That was the world's best approximation for π for something like 900 years, until this guy came along. Pretty impressive!

But what if you wanted to calculate π, but wanted to do as little math as possible? No geometry, just basic counting and four-function mathematics? Well, if you can play darts, you can do it!

1000px-Circle_Area.png

It will only get you to π very slowly, but throwing darts (randomly) at a circle with a square of area equal to the circle's radius will allow you to calculate π! How so? Count the darts that land in the circle, divide by the number of darts that land in the square, and that's how you calculate π. (For those of you who write a computer program that can do this, congratulations, you've just written your first monte carlo simulation!)

But let's say you wanted to be more efficient, but you wanted to get to π with arbitrary accuracy, given enough time. Have I got a fun method for you: you can represent it as a continued fraction, and the farther you continue it, the more accurate you'll get!

62971363e3321d4371bd3c8fbed1ae6a.png

For example, here's the results from the first few terms; not bad!

Pi Day is also a special day for anyone interested in astronomy and space! Four famous astronomy and space heroes have their birthday on Pi Day; can you name them all from their pictures?

piday_bdays.jpg

(Okay, okay, one of them is easy!)

As far as the pies go, I'm still no good at making pie crust, but I do have a special treat that I can make, with a circumference and a diameter and everything.

leche_flan.jpeg

(Image credit: Jemma.)

Yes, it's a Leche Flan! Hope your day is as sweet as they come, hope that you enjoyed all the fun facts about pi, and if you're up late over the next couple of nights, enjoy the Pi Day miracle of the Jupiter-Venus conjunction in the night sky!

night-sky-conjunction-jupiter-venus-france_50031_600x450.jpeg

(Image credit: Laurent Lavedar, TWAN, retrieved from National Geographic.)

Happy Pi Day!

(And your birthday boys are, from L-R, Albert Einstein, Apollo 8 Commander Frank Borman, Astronomer Giovanni Schiaparelli, and last-man-on-the-Moon Gene Cernan.) Read the comments on this post...


Categories: Education

Entanglement Is Not That Magic [Uncertain Principles]

Science Blogs Physcial Sciences - 14 March, 2012 - 16:37

One of the things that made me very leery of the whole Brian Cox electron business was the way that he seemed to be justifying dramatic claims through dramatic handwaving: "Moving an electron here changes the state of a very distant electron instantaneously because LOOK! THE WINGED VICTORY OF SAMOTHRACE EINSTEIN-PODOLSKY-ROSEN PAPER!" On closer inspection, it's not quite that bad, though it takes very close inspection to work out just what they are claiming.

That said, though, it's fairly common to hear claims of the form "when two particles are entangled, anything you do to one of them changes the state of the other." This is not strictly true, though, and it's worth going through in detail, if only so I have something to point to the next time somebody starts using that line. This will necessarily involve some math, but I'll try to keep it as simple as I can.

So: the problematic claim is that doing things to one particle of an entangled pair of particles affects the state of the other particle in the pair. This is true only for a very small subset of "doing things" and "affects the state"-- that is, it is absolutely and unequivocally true that measuring the state of one entangled particle in some basis determines the possible outcomes of measurements on the other particle in the pair. However, the vast majority of things you might do to one of the two particles do not produce corresponding changes in the state of the other. In fact, most of the things you might do will appear to destroy the entanglement altogether.

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Categories: Education

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