“Make Science Fun!!! Try using hand puppets the next time you play Heisenberg Uncertainty Principle with Friends” (via ellev - reposting as image not text, )
Happy Birthday to Niels Bohr (1855-1962), who would have been 126 years old today. Bohr made fundamental contributions to both Quantum Mechanics and general atomic structure. He was also a part of the team for the Manhattan Project. He earned the Nobel Prize in Physics in 1922.
Don’t Tear Your Einstein Posters Down Quite Yet
The Physics world has received quite a bit of attention these past few days after scientists at CERN have apparently detected that neutrinos can travel faster than the speed of light. At the LHC, pictured above, particles called neutrinos are created. Neutrinos can be thought of as very anti-social particles when it comes to matter, and pass directly through them- with trillions of these particles passing through every inch of your body each second. So these scientists detected neutrinos after traveling hundreds of kilometeres to a detector called OPERA - and they found something shocking. It seems, by dividing the particle’s distance traveled and the time it took to get there, that the neutrinos reached the detector before light would have. A similar beam of photons, which compose light, reached the detector in 2.43 milliseconds - but the neutrinos were apparently 60 nanoseconds faster!
But I’m not trashing my Einstein t-shirts yet. This is a fantastic claim, and should be received with a ton of skepticism. Even the scientists themselves are not causing the madness that the media is, they have remained calm and want their results to be peer-reviewed and tried again and again. The likely occurrence is a statistical error; a number of small errors added together in the right conditions caused the scientists to measure such a speed.
The scientists used a GPS to measure the distance traveled, which could be off by even a fraction of a fraction of a meter. Additionally, it is very difficult to determine exactly where and when neutrinos are created; so an error in that could cause a speed under-calculation. Neutrinos are tricky little buggers, and are extremely hard to measure since they hardly interact with matter.
Bad Astronomy made an excellent point concerning the supernova 1987A. That supernova itself occurred when the core of a very massive star collapsed; and the outer layers were destroyed. Although the star was 160,000 light years away, it released an incredibly intense stream of neutrinos that we could easily detect. If we apply a similar speed to the neutrinos in this case as has apparently been found in CERN; we find that we should have detected the stream of neutrinos four years earlier than the light! Since OPERA claims that the neutrinos traveled 730 km in a slightly faster time than 2.43 milliseconds, neutrinos would travel 160,000 lights years four years faster than light would. However, we detected the light and neutrinos at a very similar time; if you account for the time it took for the star to actually collapse the times line up exactly.
Although finds like this can be exciting; don’t run away with your imagination quite yet. While the possibility is fascinating, even the scientists who actually performed the experiment are not quite sure yet. Just wait patiently, more information is being found as quickly as possible.
The Four Fundamental Forces.
In Physics, the fundamental forces describe how particles interact with one another. The four known forces are the Strong Nuclear Force, the Weak Nuclear Force, Electromagnetism and Gravitation. These forces are considered fundamental because they cannot be explained in terms of any other force. The quest to bring together the four forces into a single entity (a TOE - Theory of Everything) is the pursuit of many physicists, but so far has proven to be a challenging task, which even eluded Einstein himself!
Strong Nuclear Force
Strength: 1 (All strenghts to follow are relative to this one.) Range: 10-15 m
The Strong Nuclear Force, aptly named because it is the strongest of the four forces, is responsible for everything that we know today. This force holds together the protons and neutrons together in the atomic nucleus despite the particles’ urge to repel each other. The mediators of the Strong Nuclear Force are particles called Gluons, which also hold quarks together to form particles such as the proton.
Electromagnetism
Strength: 1⁄137 Range: Infinite
The Electromagnetic force is responsible for, as you can probably tell, electricity and magnetism. This force is mediated by Photons, massless particles that are the basic unit of light. You probably know that opposite charges attract, and like charges repel - this is a direct result of the Electromagnetic force. When a particle attract or repels another particle, what actually happens is that photons are exchanged, and the release or absorption of the photon’s energy causes the particle to come closer or dart away. This force is responsible for many everyday, observable occurrences. The Electromagnetic force is why your computer isn’t falling right through your desk right now; because the atoms in your computer and in the desk resist being displaced from the exchange of photons.
Weak Nuclear Force
Strength: 10-6 m Range: 10-18 m
The Weak Nuclear Force is the most unfamiliar to us in our everyday lives. However, it is the force that is responsible for radioactive decay and hydrogen fusion in stars. The mediators of this force are the massive W and Z bosons. This force is also capable of changing the flavor of a quark, i.e. changing one type of quark into another.
Gravity
Strength: 6 * 10-39 m Range: Infinite
Gravity, of course, is the most familiar of all the fundamental forces. However, is it also the least likely to compromise, as it has proven extremely difficult to associate gravity into the other forces into a Theory of Everything. In fact, the modern model of the Universe, the Standard Model, does not even include gravity because of this! In short, Gravity is a force by which physical bodies attract each other. In more precise terms, Gravity is an inverse square law with incorporates the masses of two bodies, the gravitational constant, (6.67300 × 10-11 m3 kg-1 s-2,) and the distance separating the bodies. Gravity is most observable by providing weight to objects and what causes objects to fall to the ground when dropped. Gravity also causes coalesced matter to remain intact, thus accounting for most of the macroscopic objects in the Universe. Every object exerts a gravitational force on every other object, although the force becomes extremely weak at large distances.
To show the weakness of Gravity compared with the other forces, consider this. After running a comb through your hair several times, place it close to a flat piece of paper. If done correctly, the paper should lift up and touch the comb. An entire planet’s gravity was required to keep that piece of paper down, but a simple comb with a few charged particles was able to pick it up!
