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Fermilab Double-Checking CERN’s (and their own) Math

September 27, 2011 1 comment
Detector used in the MINOS experiment at Fermilab.

Of course the big news of the past week is the OPERA experiment’s measurement of neutrino’s travelling faster than light.

The paper is up on arXiv. I’ve gone through it and nothing jumps out as to what they could have possibly done wrong. Chad Orzel on his blog Uncertain Principles has written a really nice summary of the paper and what the group actually did.

(Aside: I just read How to Teach Physics To Your Dog by Orzel, and I would definitely recommend it to a reader with a budding interest in quantum mechanics.)

Now it looks like the US based Fermilab is going to go over some old data to see if they can support (or contradict) the results of the OPERA experiment.

It was back in 2007 that Fermilab announced the results of their MINOS (Main Injector Neutrino Oscillation Search) experiment. They also found neutrinos travelling faster than the speed of light, however they had a much larger margin of error than the OPERA experiment, so they did not receive much attention.

Now, they are going to go back over their old data, as well as add some new data, to see what they find.

“The MINOS experiment has plans to update their original 2007 measurement with a number of improvements, including 10x more data,” wrote MINOS spokesperson Jenny Thomas, a professor of particle physics at University College London in an email to TPM’s Idea Lab.

“We should have a result in 4-6 months as the data is already taken. We just have to measure some of our delays more carefully,” she added. [TPM]

So in 6 months (I know, science is slow!) we will hopefully add another chapter to this fascinating story.

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Faster Than Light Particles! So, Warp Speed Ahead, Right???

September 22, 2011 3 comments

The OPERA detector at Gran Sasso National Laboratory in Italy

I’ll have more to say about this story once I see the work on arXiv, but I feel I should comment now because this story is exploding.

The interwebs and blogospheres are abuzz with the news that researchers at CERN have measured the velocity of neutrinos which seem to be travelling faster than light.

Neutrinos are nearly massless  subatomic particles which have been known to travel near the speed of light. But, like all other things in the universe, they are not supposed to be able to travel faster than light.

Basically the experiment involves the creation of neutrinos at CERN in Geneva, Switzerland, and the neutrinos travelling 730 km to a laboratory 1,400 meters underground in Italy. There, an experiment called OPERA (Oscillation Project with Emulsion-tRacking Apparatus) detects those neutrinos and measures how quickly it took them to make the trip.

The neutrinos arrived 60 nanoseconds sooner than they should have. This means they were travelling at a speed of about 299 800 km/s, which is slightly higher than the speed of light, which is about 299 792 km/s.

This discovery will rock the very foundation upon which modern physics is built. Seriously, this is like the discovery that the world is round or wave-particle duality; it’s a complete game-changer.

If it’s true.

Like a lot of folks out there, I am quite skeptical of this discovery. Think of it this way: which of these two scenarios is more likely,

  1. Particles can travel faster than light, completely re-writing modern physics and decades of previous research. Or,
  2. These guys made an innocent mistake.

Now, it is certainly possible that this discovery will turn out to be genuine. However, it is much more likely that there was some kind of error or misinterpretation which has led to this result.

I would like to point out that the researchers have revealed their work in the proper way. They are excited, but very skeptical themselves and are asking the academic community to review their work and try to find a flaw. Antonio Ereditato, a physicist at the University of Bern in Switzerland and OPERA’s spokesman said in an interview

Whenever you are in these conditions, then you have to go to the community

THIS is science in action, folks! A group of physicists think they have discovered something awesome. But they haven’t started trumpeting their results like they have been absolutely confirmed, no emails were leaked suggesting the discovery, and they didn’t go to some rogue publication to get their work in print prior to peer-review.

Beautiful, isn’t it?

I am very hopeful this turns out to be a genuine discovery. I can’t wait to read the papers and hear the response from the scientific community.

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Ryan

Build Your Own Cloud Chamber!

September 14, 2011 Leave a comment

Cloud chambers are nifty little tools which physicists used in the 1920s to 1950s to study ionizing radiation. They were responsible for the discovery of the positron in 1932, which garnered Carl David Anderson the Nobel Prize in Physics in 1936.

After the 1950s, the Bubble chamber became the more useful tool to study radiation, but cloud chambers remain the simplest and easiest to build.

In fact, you can even build one yourself! Here’s a cool video demonstrating how they work and how you can build one:

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Ryan

Canada Finds Evidence of Failed 1845 Arctic Expedition

September 2, 2011 Leave a comment
File:John Franklin.jpg

Sir John Franklin

In 1845, the Franklin Expedition, led by John Franklin, set sail from England looking for the Northwest Passage.

Unfortunately, the expedition became stuck in the Arctic ice near King William Island and the entire expedition (128 people) was lost.

Just yesterday, Parks Canada announced that an archeological project in the Canadian arctic had found evidence of Franklin’s two lost ships, the HMS Erebus and HMS Terror (now THAT’S a name for a ship!)

While they have not yet found the ships themselves, they did find evidence of the expedition,

“We found bottle glass — possibly from wine or spirit bottles — copper nails, tent canvas, twine, rope … we found some pieces of clay tobacco smoking pipes,” said Jonathan Moore of Parks Canada.

Finding the actual ships of the Franklin Expedition will be quite challenging, as detailed in the Parks Canada news release,

The search for HMS Erebus and HMS Terror is made more challenging by the vastness of the Canadian Arctic and the harsh conditions that are frequently encountered in northern waters. It is also complicated by differing accounts of the fate of Franklin’s ships as preserved in Inuit traditional knowledge, and the many interpretations given to these accounts on the possible resting place of the wrecks.

The survey team uses a particularly cool technique called LiDaR (Light Detection and Ranging) to map the seabed to try to find the wrecks of these two ships.

LIDAR is often used in meteorological surveys to detect temperature and pressure changes in the atmosphere. It can also be applied to mapping the underwater landscape of an area, drastically increasing the efficiency of a search such as this one.

File:LIDAR-scanned-SICK-LMS-animation.gif

This animation shows a LIDAR (appearance based on SICK LMS 219) with a single beam scanned in one axis. The top image shows the scanning mechanism; the middle image shows the laser's path through a basic scene; the bottom image shows the sensor's output, after conversion from polar to Cartesian coordinates.

 

Just another example of sweet tools that physicists use that can be applied in other fields of science, like archaeology.

Realistic Simulation of the Formation of a Milky Way-Like Galaxy

August 31, 2011 1 comment

The first realistic simulation of a spiral galaxy similar to our own Milky Way has been generated by researchers at the University of California, Santa Cruz, and the Institute for Theoretical Physics in Zurich.

The simulation, called ERIS, took 1.4 million processor hours to complete. And that was on the 7th most powerful supercomputer in the world, NASA’s Pleiades supercomputer, which runs at 1.09 petaflops per second.

The simulation follows the formation of a galaxy equivalent to 7.9 × 1011 solar masses (1 solar mass is equal to the mass of our Sun) and has a total of 18.6 million particles.

The resulting galaxy has a radius of 2.5 kilo-parsecs (about 7.7 × 1016 kilometers). Previous attempts at simulating a realistic galaxy have failed, resulting in simulated galaxies which have too large of a central bulge. The finding of this study, which has been accepted for publication in Astrophysical Journal, found that,

A high star formation threshold appears therefore key in obtaining realistic late-type galaxies, as it enables the development of an inhomogeneous interstellar medium where star formation and heating by supernovae occur in a clustered fashion. The resulting outflows at high redshifts reduce the baryonic content of galaxies and preferentially remove low angular momentum gas, decreasing the mass of the bulge component.

Another important result of this work is that it supports the idea that cold dark matter constitutes a large portion of the mass in the universe.

Best Leave Some Things to the Professionals…

August 3, 2011 3 comments

A man in Sweden with a penchant for science and chemistry was arrested for attempting to split atoms in his basement.

Einstein would be so proud.

Apparently Richard Handl even kept a blog about his efforts to build a nuclear reactor in his home. Unfortunately, it is illegal for civilians to own this kind of radioactive material, which included uranium, americium and radium.

With good reason. This stuff can be quite a health hazard, which makes me wonder how he got the stuff in the first place…

In any case, Mr. Handl eventually thought it might be a good idea to ask the Sweden’s Radiation Authority if it was alright if he went ahead and kept some fissionable around his place and, y’know, fission it. (Yes, I used “fission” as a verb. Deal with it.)

Although it is a bit amusing, Mr. Handl faces up to 2 years in jail for his experiment.

Said Handl,

From now on, I will stick to the theory

Physicists Discover New Particle!

July 21, 2011 Leave a comment

Researchers at the soon-to-be-closed-but-won’t-go-quietly Fermilab, have confirmed the existence of the neutral Xi-sub-b baryon.

Baryons are particles composed of three quarks; quarks being elementary of particles. Other baryons include protons and neutrons. The newly discovered Xi-sub-b baryon is about six times more massive than the proton.

The Baryon Family. The Xi-sub-b baryon is the one highlighted in yellow. Image courtesy of Fermilab

The Fermilab press release states:

Combing through almost 500 trillion proton-antiproton collisions produced by Fermilab’s Tevatron particle collider, the CDF collaboration isolated 25 examples in which the particles emerging from a collision revealed the distinctive signature of the neutral Xi-sub-b. The analysis established the discovery at a level of 7 sigma. Scientists consider 5 sigma the threshold for discoveries.

Wow, 7-sigma! That’s a pretty high level of certainty.

Unfortunately, due to a lack of funding, the Tevatron particle accelerator at Fermilab will close operations in October of 2011. Way to go out with a bang guys!