Young's Double-Slit Experiment

Good Evening,

At the University of Colorado Physics Department website, I found a modern example of Young's double-slit experiment useful for showing how light behaves when traveling through either one or two slits. This experiment is well-known for first presenting evidence to suggest light's wave-like nature in a time when many only believed in its presumed particle nature. Originally performed by professor Thomas Young in 1803, the outcome played an important role in the general acceptance of a wave theory of light and the natural wave-particle duality of all kinds of particles. The experiment is thought to be at the heart of all quantum mechanical weirdness.


A projector and background display setup with two slits (Image: CU).

Basically, light fired at a thin plate with single slit cut in it will diffract and propagate onto a background surface appearing as a one-band pattern. Interestingly, light waves in the double-slit version of this experiment radiate from the two slits in or out of phase and interfere with each other, either constructively or destructively (like sound waves), to create a background pattern of bright and dark fringes.

Now, if you were to perform the experiment with individual particles of matter such as electrons, it is surprising that a similar interference pattern of fringes begins to appear in the background. Classical particles would be expected to go through either slit by chance and not interfere with each other at all. According to quantum theory, a fringe pattern could only happen if a single electron in superposition with itself changes into a wave of potentials and then interferes with itself after going through both slits, maintaining its wave-like nature until it arrives at the background surface as a particle. Other proposed solutions include the electron passing through just one slit, the other slit, or even neither slit.

Many thought this explanation deviated too much from the expected Newtonian particle behavior of only going through one slit at a time. However, when scientists place an observing device at the slits in order to see what an approaching electron actually does, its particle nature becomes more apparent causing the background pattern to change into a mere two bands. It acts as if the information gathered about which way a particle goes through prevents any wave-like behavior from taking effect. This suggests that certain observation techniques are enough to influence how objects interact at a quantum level. A successful attempt to determine the path of a particle, while leaving the fringe interference pattern produced by wave-like behavior unaffected, was completed in January of 2012 by using entangled photons and a light source with two intensity maxima. This method also allows particle and wave-like natures to exist simultaneously.

The Copenhagen interpretation of quantum mechanics states that the act of observation instantly measures and reduces a system's set of possible outcomes to randomly assume one probable value. This phenomenon is also known as collapsing the wave function and it links an object or a system's unobserved state to recognizable properties such as momentum or position. In fact, it is currently thought that any physical system might exist in all of its theoretically possible states until one of them is either observed or it evolves with time via physicist Erwin Schrödinger's famous equation. For this case, a quantum entity exists having two potential natures until some attempt to extract either one of them is made. This experiment is significant for showing wave-particle duality and how an observer can have the role of determining the reality of a quantum mechanical situation.

Samuel

Robotic Vehicles on Mars

Happy Holidays!

Interest in exploring the Red Planet started with the first robots designed to investigate it in the 1960s, and continues today with the Mars Science Laboratory Curiosity, where recent efforts have shown to be what looks like evidence of an ancient riverbed and organic molecules on the Martian surface. Organic molecules are those containing carbon and are potential indicators of life.


Mars and Earth riverbeds in comparison (Image: NASA).


A landscape of Mars created by Pathfinder in 1997 (Image: NASA).

Mars is the fourth planet from our Sun and is believed to be about 10.7% the mass of Earth and approximately half of its size. It is currently thought that sustainable life on Mars may be possible and might have existed there a long time ago, if Earth and Mars share similar planetary histories. We know that they both have polar ice caps, an atmosphere, and unique terrain features. With several vehicles set to test for habitability on Mars in the future, humans will be able to properly assess whether a manned mission to Mars prevails as a safe and advantageous exploration plan.

Samuel

Higgs Boson Found

Good Evening,

In around December of 2011, preliminary research efforts began to hint at the presence of a new bosonic particle with Higgs-like properties. It was officially announced on July 4, 2012, by the ATLAS and CMS teams working at CERN, that these findings were definitely signs of something important. Regarded as the key to understanding the origin of mass, even the spark that caused the Big Bang, the new Higgs boson's unique yet brief appearance quickly became the object of joyous celebration worldwide as the excitation ripples of a particle collision revealed a signal, measuring near the 125-126 GeV mass-energy range, that had finally brought into reality the standard model particle predicted to exist since 1964.


Results consistent with the expected signature of the Higgs boson (Image: CMS).

Out of the four fundamental interactions known to exist: gravitation, electromagnetism, the strong nuclear force, and the weak nuclear force, the exchange of a boson acting as a force carrier particle is what allows each kind of field or interaction to work. Just as the photon mediates the electromagnetic force, and the strong force gluon holds together particles inside the nucleus of an atom, the Higgs boson is responsible for converting Higgs field energy into corresponding elementary particles with mass.

Although fermions are the elementary particles that acquire mass to become the basic building blocks of ordinary matter, coupling with the Higgs field, an energy condensate which permeates throughout everything and the vacuum of empty space, is also thought to give the weak nuclear force bosons: W+, W-, and Z, their exceptionally large masses. This process is due to a spontaneous symmetry breaking of the electroweak interaction, which sets apart the electromagnetic and weak forces, described to be unified parts of the same interaction only in an environment like that of the early Universe.

The level of certainty in this finding suggests that there is enough evidence to conclude a reasonably sound discovery. "A 5-sigma result represents a one-in-3.5 million chance of the result being noise. This is undeniable proof that a boson, with very Higgs-like qualities, has been discovered by the two detectors." Along with being its own antiparticle, various other specific properties characterize the standard model Higgs boson, a few of which were accurately detected in the experimental results of this year. The recently found boson's rapid decay into the appropriate lighter particles, for example, serves as some evidence to label it the Higgs boson and to support the concept of the Higgs field. Future research efforts in this area may also clear the way for an new sector of physics entirely. ”Supersymmetry provides both a natural context for the Higgs field and a possible explanation for the small but finite value of dark energy.“ Known for its major innovations in modern science, the Large Hadron Collider's recent landmark achievement will serve as a crowning jewel for everyone who has patiently worked hard in anticipation of the new boson's arrival.

Samuel

Deep Space Satellite Exploration

Good Evening,


Both Voyager 1 and 2 are displayed above (Images: NASA).

The NASA/JPL Voyager Satellite Program actively controls these two satellites. Launched in 1977, they are the farthest known, still working man-made objects to ever travel across our Solar System. Please enjoy the link provided!

Special Note: The first artificial satellite to complete an orbital circuit around our planet was Sputnik 1, on October 4, 1957. This date marks the beginning of what is classically referred to as the Space Age. :-]

Samuel

Matter and Antimatter Tales

The distinct inequality between everyday matter and antimatter in the Universe is one of the most fascinating and extraordinary puzzles known to modern cosmology. Baryon asymmetry shows that there is an inferable amount of antimatter unavailable within our observable Universe. The natural phenomenon is left to generate wonder about whether it is simply missing or located somewhere else.

Daily experience is mostly due to baryonic matter's physical influence on reality as regular matter. Not to be confused with matter from the element Barium, a particle of baryonic matter, or a baryon, is a type of composite particle (hadron) made up of three elementary particle quarks, same as a proton or a neutron. An electron is a different kind of elementary particle that is classified as a lepton but also plays an important role as a fundamental constituent of the atom.

Antimatter is the substance considered to be the counterpart to regular matter composed primarily of oppositely (occasionally equally) charged antiparticles with an opposite quantum spin. Antielectrons (positrons) for example, appear naturally from specific radioactive decay (Beta+), deep within atmospheric thunderstorm activity, and theoretically, traveling along cosmic rays projected by stars and black holes. The first person to ever predict antimatter existed was Nobel laureate Paul Dirac in 1930, including his work for the Dirac sea, his theoretical model of the vacuum. Determinately, I believe dark matter is inherently different from antimatter because Earthly antimatter is more recurrent.

When a particle of matter collides with its antimatter partner, the result is they annihilate one another in an exciting flash of energy producing photons and then they disappear. Given presumed equal initial amounts of matter and antimatter, this process is thought to have taken place repeatedly in the moments early after the Big Bang, while somehow leaving behind a significant portion of baryonic matter that characterizes the universe we live in today.

The massless photon and the hypothetical graviton are both bosonic particles considered to be their own antiparticle. A neutrino is another particle, an electrically neutral lepton, that has an antiparticle mostly due to its different spin. “Neutrinos are fundamental particles that were first formed in the first second of the early universe, before even atoms could form.” It is now known that neutrinos have a non-zero mass and through a special process called neutrino oscillation, they periodically morph into one of three uniquely-termed flavors: electron, muon, and tau. A precise measurement of the long-sought theta13 neutrino mixing angle was successfully obtained in March, 2012, by researchers at the Daya Bay Reactor Neutrino Experiment in China. Neutrinos are variably encountered as a part of the large amount of radiation emitted by our Sun, and are relatively abundant throughout the Cosmic Microwave Background radiation of our Universe. Also found within nuclear reactions, neutrinos were first postulated by Nobel laureate Wolfgang Pauli in 1930.

Modern neutrino oscillation research has led scientists to believe that neutrinos played an important role by inducing the baryonic asymmetry in the developing cosmos. “Reactions involving neutrinos and antineutrinos in the early universe could have skewed the ratio of matter and antimatter production, leading to our matter-dominated universe.” A fourth kind of sterile neutrino depends upon the existence of a particle with some mass that is essentially detectable only through its gravitational influence. "In addition, data from WMAP show the most likely number of neutrino families in the early Universe was four, and the Chandra X-ray Observatory detected faint pulses of X-rays (from a dim dwarf galaxy) suggesting the decay of heavier neutrinos into lighter ones." Sterile neutrino masses are theorized to be their own antiparticle, which enables neutrinoless double beta decay, and they are also granted to be the ideal candidate to explain dark matter. "Not only could this "sterile" neutrino be the stuff of dark matter, thought to make up the bulk of our universe, it might also help to explain how an excess of matter over antimatter arose in our universe."

For the first time, low-temperature antihydrogen was produced and isolated by physicists at CERN using the Antihydrogen Laser Physics Apparatus (ALPHA) in 2010. The next year, more antihydrogen atoms were captured and studied for an outstanding duration of 1000 seconds. The very latest research efforts are geared towards providing useful information on the emission spectrum, potentially equal to that of the element hydrogen, by using microwave radiation on the trapped anti-atoms. Whether or not antimatter is destined to exist here on Earth indefinitely is worth the contemplation.

Studying ephemeral antimatter is done to look for discrepancies in the Charge, Parity, and Time reversal symmetry of the physical laws that operate within our world. A particle moving forward through time in our universe is described to be virtually indistinguishable from an antiparticle moving backwards through time in a mirror universe, according to fundamental CPT symmetry. Understanding the behavior of antimatter might eventually be able to shed light on how this form of matter interacts with the known fundamental forces and what techniques can be employed for its practical use. Discovering the cause for the apparent abundance of matter over antimatter in the universe would help to resolve the baryon asymmetry conundrum while also expanding our knowledge on the natural processes required for a universe to develop into one like ours.

Samuel

Water on the Moon

Good Evening!

With the discovery of evidence confirming the existence of water on the Moon on October 9, 2009, the Moon is no longer thought of as a dry space rock.

"NASA's Lunar Crater Observation and Sensing Satellite, or LCROSS, found what scientists called "a significant amount" of water and other materials on the floor of a lunar crater."


Centaur being launched towards the Moon by LCROSS (Image: NASA).

LCROSS was designed to look for signs of frozen water near the Moon's South Pole. Its probe was successful at detecting natural water in the form of ice particle debris within the impact plumes created by the empty Centaur rocket motor's collision with the Moon.


The satellite's impact locations on the Moon's surface (Images: NASA).

The satellite made a total of two collisions on the Moon's surface, which were studied by it, the Lunar Reconnaissance Orbiter (LRO) partner satellite, and telescopes all over the world. The first LCROSS impact was the Centaur rocket stage, ejected towards Cabeus crater (red) near the Moon's South Pole (green). Once water particles were successfully identified, the second impact was the LCROSS probe itself crashing into the surrounding Cabeus crater area (blue) to complete the mission. The LRO remained in orbit collecting data and did not undergo any collision.

Lunar water can be used by astronauts as a natural resource while in space. It is not practical to transport the amount of Earth water needed for long-term human space exploration into space so this discovery provides astronauts with a longer potential stay on the Moon. The LCROSS and LRO were the first two missions carried out by NASA as a part of the United States' 2004 Vision for Space Exploration program, designed to increase public enthusiasm for space exploration.

NASA has been preparing for a return mission to the Moon in order to research and attempt to live off the land in 2018 or 2019, a date that would mark the 50th Anniversary of NASA's first manned Moon landing (1969), Apollo 11.

Samuel

Particle Accelerator by CERN

Good Evening,

Tonight I write to express my interest in Earth's largest operating machine. The Large Hadron Collider is the most complex scientific instrument in use today. It is run by the European Organization for Nuclear Research (CERN) and it is buried 574 ft (175 m) below ground on the border of France and Switzerland near Geneva, Switzerland.


The LHC can be found buried underground in Europe (Image: CERN).


The central LHC accelerating ring. It spans a 5.3 mile long (8.6 km) diameter (Image: CERN).

When powered up, the LHC releases beams made up of protons or ions through a series of interconnected ring-shaped tunnels. Accelerated by giant superconducting magnets, the particles reach speeds approximating 99.9% the speed of light. As they approach the largest ring (highlighted in yellow) which is about 17 mi (27 km) in circumference, engineers collide the particles in testing rooms the size of warehouses. Results are then recorded by sensors placed in these rooms and studied in order to provide useful information for determining the nature of the particles belonging to the standard model of particle physics. Scientists and engineers examine the results of current research efforts to try to either prove the existence of the Higgs boson, the key to the origin of mass in the universe, or to add to the existing knowledge about the dynamics of subatomic particles.


Engineers working inside the LHC (Image: CERN).

Engineers have been maintaining and upgrading the LHC ever since achieving the first successful particle beam circulation in September of 2008. This year, on March 30, 2010, the LHC broke the record for the highest-energy man-made collision event ever planned between two 3.5 teraelectronvolt beams. It has also helped to confirm the existence of the electroweak interaction in the past, allowing a unification of the electromagnetic force with the weak interaction at very high temperatures. With a maximum operating energy of 14 TeV, the LHC is set to advance a new era in physics over the next few years.

Samuel

Innumerable Galaxies

From September 2003 to January 2004, the NASA Hubble Space Telescope was pointed at a region of space with a low brightness and only a few stars in the near field. The region was about the size of a grain of sand at a distance of one meter away from the human eye. With all of the data accumulated during that time, the telescope captured an image that exemplifies just how immense the universe really is.


This photo has been referred to as "humankind's deepest portrait of the visible universe ever" (Image: NASA).

The Hubble Ultra Deep Field image is considered to be one of the most humbling and profound images of all time. The countless number of individual galaxies revealed is not only surprising but also very informative. An image like this makes the universe look like it is truly abundant with other galaxies and stars. It is also interesting to note that the light from the farthest galaxies in this picture has been traveling towards us since early after the Big Bang and represents what those galaxies looked like about 13 billion years ago. This information has enabled a base measurement of early galaxies' distribution and their evolution.

Hubble's successor, the James Webb Space Telescope, is scheduled to be up and running in 2018.

Samuel

Universes and Black Holes

Good Morning!

When I read articles about physics and astronomy, I can't help but get excited when a brand new theory catches my attention and completely changes the way I look at the world around me. A while ago, I stumbled upon such a theory by Nikodem Poplawski at Indiana University, which instills me with great admiration towards modern cosmology research.


An artist's rendition of a universe containing a black hole (Image: Unknown).

A black hole is a region of space from which light and matter cannot escape. It is twice as wide as its Schwarzschild Radius and contains a singularity of infinite density and zero volume at its center. Here is an article from the NationalGeographic.com website that describes just how every black hole may contain another universe.

So, after reading this article, I was interested to know if anyone else was silently questioning their Earthly existence and what they thought about this. I wasn't about to get too excited before DiscoverMagazine.com was amusingly there to remind me just how our universe is not a black hole by clearing up the confusion.

"If anything, our universe also bears a passing resemblance to a white hole" with a singularity in the past and no singularity in the future.

In this article, I learned that the solution to Albert Einstein's space-expansion equation that describes the Big Bang and that of a time-reversed black hole are actually very similar. The author Sean Carroll is also careful to compare the extent of our observable universe (characterized as the Hubble length) with the Schwarzschild Radius of a black hole in order to validate how the universe is actually spatially flat.

Samuel

The Blagburn Surname

Good Evening!

It's a bit late to be blogging right now but I felt like I needed to do a bit of research. I do like my last name and I am intrigued to know of its origin and significance. It is a compound surname and a variation of the English name "Blackburn." Just for kicks, let's examine it more in depth. Here are a few definitions:

Blag - A phonetic derivative of the word "Black," as in the color of coal, ravens, night, or outer space. To blag may also mean to gain access into a private club or party. Lord knows I've tried that!

Burn - Burn refers to an Old-English word for a river. To burn may also mean to combust or to light on fire. I tend to not light things on fire though. :-)

Ideally, a "blagburn" refers to a peaceful river reflecting dim light on a typical British afternoon.

It is also interesting to note that, according to the Online Etymology Dictionary, the same root relative for black produced the word bleach as well... This may be "perhaps because both black and white are colorless, or because both are associated with burning. The noun meaning "a bleaching agent" is recorded from 1898."

The Blagburn surname has been around since the late-1600s and I hope it continues to do so.

Samuel