Category Archives: Physics

Polymagnets® will Revolutionize the Ways in Which Magnets are Used

The U.S firm Correlated Magnetics Research (CMR), Huntsville, AL, invented and is the sole manufacturer of Polymagnets®, which are precision-tailored magnets that enhance existing and new products with specific behaviors that go far beyond the simple attract-and-repel behavior of common magnets. Polymagnets have been granted over 100 patents, all held by CMR. You can visit their website at the following link:

http://www.polymagnet.com

CMR describes Polymagnets® as follows:

“Essentially programmable magnets, Polymagnets are the first fundamental advance in magnets in 180 years, since the introduction of electromagnets. With Polymagnets, new products can have softer ‘feel’ or snappier or crisper closing or opening behavior, and may be given the sensation of a spring or latch”.

On a conventional magnet, there is a North (N) pole on one surface and a South (S) pole on the opposite surface. Magnetic field lines flow around the magnetic from pole to pole. On a Polymagnet®, many small, polarized (N or S) magnetic pixels (“maxels”) are manufactured by printing in a desired pattern on the same surface. The magnetic field lines are completed between the maxels on that surface, resulting in a very compact, strong magnetic field. This basic concept is shown in the following figure.

Polymagnet field comparison

The mechanical 3-D behavior of a Polymagnet® is determined by the pattern and strength of the maxels embedded on the surface of the magnet. These customizable behaviors include spring, latch, shear, align, snap, torque, hold, twist, soften and release. The very compact magnetic field reduces magnetic interference with other equipment, opening new applications for Polymagnets® where a conventional magnet wouldn’t be suitable.

The above figure is a screenshot from the Smarter Every Day 153 video, which you can view at the following link. Thanks to Mike Spaeth for sending me this is a 10-minute video, which I think you will enjoy.

https://www.youtube.com/watch?v=IANBoybVApQ

More information on Polymagnet® technology, including short videos that demonstrate different mechanical behaviors, and a series of downloadable white papers, is available at the following link.

http://www.polymagnet.com/polymagnets/

This is remarkable new technology in search of novel applications. Many practical applications are identified on the Polymagnet® website. What are your ideas?

If you really want to look into this technology, you can buy a Polymagnet® demonstration kit at the following links:

https://www.magnetics.com/product.asp?ProductID=164

or,

http://www.mechanismsmarket.com/kits/

Polymagnet demo kit   Source: Mechanisms Market

 

The Invisible Man may be Blind!

Metamaterials are a class of material engineered to produce properties that don’t occur naturally.

The first working demonstration of an “invisibility cloak” was achieved in 2006 at the Duke University Pratt School of Engineering using the complex metamaterial-based cloak shown below.

Duke 2006 metamaterial cloakSource: screenshot from YouTube link below.

The cloak deflected an incoming microwave beam around an object and reconstituted the wave fronts on the downstream side of the cloak with little distortion. To a downstream observer, the object inside the cloak would be hidden.

Effect of Duke metamaterial cloakSource: screenshot from YouTube link below.

You can view a video of this Duke invisibility cloak at the following link:

https://www.youtube.com/watch?v=Ja_fuZyHDuk

In a paper published in the 18 September 2015 issue of Science, researchers at UC Berkley reported creating an ultra-thin, metamaterial-based optical cloak that was successful in concealing a small scale, three-dimensional object. The abstract of this paper, “An ultrathin invisibility skin cloak for visible light”, by Ni et al., is reproduced below.

“Metamaterial-based optical cloaks have thus far used volumetric distribution of the material properties to gradually bend light and thereby obscure the cloaked region. Hence, they are bulky and hard to scale up and, more critically, typical carpet cloaks introduce unnecessary phase shifts in the reflected light, making the cloaks detectable. Here, we demonstrate experimentally an ultrathin invisibility skin cloak wrapped over an object. This skin cloak conceals a three-dimensional arbitrarily shaped object by complete restoration of the phase of the reflected light at 730-nanometer wavelength. The skin cloak comprises a metasurface with distributed phase shifts rerouting light and rendering the object invisible. In contrast to bulky cloaks with volumetric index variation, our device is only 80 nanometer (about one-ninth of the wavelength) thick and potentially scalable for hiding macroscopic objects.”

If you have a subscription to Science, you can read the full paper at the following link:

http://science.sciencemag.org/content/349/6254/1310

Eric Grundhauser writes on the Atlas Obscura website about an interesting quandary for users of an optical invisibility cloak.

“Since your vision is based on the light rays that enter your eyes, if all of these rays were diverted around someone under an invisibility cloak, the effect would be like being covered in a thick blanket. Total darkness.”

So, the Invisible Man is likely to be less of a threat than he appeared in the movies. You should be able to locate him as he stumbles around a room, bumping into everything he can’t see at visible light frequencies. However, he may be able to navigate and sense his adversary at other electromagnetic and/or audio frequencies that are less affected by his particular invisibility cloak.

You can read Eric Grundhauser’s complete article, “The Problem With Invisibility is Blindness,” at the following link:

http://www.atlasobscura.com/articles/the-problem-with-invisibility-is-the-blindness?utm_source=howtogeek&utm_medium=email&utm_campaign=newsletter

Recognizing this inconvenient aspect of an invisibility cloak, researchers from Yunnan University, China, have been investigating the concept of a “reciprocal cloak,” which they describe as, “an intriguing metamaterial device, in which a hidden antenna or a sensor can receive electromagnetic radiation from the outside but its presence will not be detected.” One approach is called an “open cloak,” which includes a means to, “open a window on the surface of a cloak, so that exchanging information and matter with the outside can be achieved.”

You can read the complete 2011 paper, “Electromagnetic Reciprocal Cloak with Only Axial Material Parameter Spatially Variant,” by Yang et al., at the following link:

http://www.hindawi.com/journals/ijap/2012/153086/

An all-aspect, broadband (wide range of operational frequencies) invisibility cloak is likely to remain in the realm of fantasy and science fiction. A 10 March 2016 article entitled, “Invisibility cloaks can never hide objects from all observers,” by Lisa Zyga, explains:

“….limitations imposed by special relativity mean that the best invisibility cloaks would only be able to render objects partially transparent because they would suffer from obvious visible distortions due to motion. The result would be less Harry Potter and more like the translucent creatures in the 1987 movie Predator.”

You can read the complete article at the following link:

http://phys.org/news/2016-03-invisibility-cloaks.html

Further complications are encountered when applying an invisibility cloak to a very high-speed vessel. A 28 January 2016 article, also by Lisa Zyga, explains:

“When the cloak is moving at high speeds with respect to an observer, relativistic effects shift the frequency of the light arriving at the cloak so that the light is no longer at the operational frequency. In addition, the light emerging from the cloak undergoes a change in direction that produces a further frequency shift, causing further image distortions for a stationary observer watching the cloak zoom by.”

You can read the complete article, “Fast-moving invisibility cloaks become visible,” at the following link:

http://phys.org/news/2016-01-fast-moving-invisibility-cloaks-visible.html

So, there you have it! The Invisible Man may be blind, the Predator’s cloak seems credible even when he’s moving, and a really fast-moving cloaked Klingon battlecruiser is vulnerable to detection.

 

 

Simulating Extreme Spacetimes

Thanks to Dave Groce for sending me the following link to the Caltech-Cornell Numerical Relativity collaboration; Simulating eXtreme Spacetimes (SXS):

http://www.black-holes.org

Caltech SXSSource: SXS

From the actual website (not the image above), click on the yellow “Admit One” ticket and you’re on your way.

Under the “Movies” tab, you’ll find many video simulations that help visualizes a range of interactions between two black holes and between a black hole and a neutron star. Following is a direct link:

http://www.black-holes.org/explore/movies

A movie visualizing GW150914, the first ever gravitational wave detection on 14 September 2015, is at the following SXS link:

https://www.black-holes.org/gw150914

At the above link, you also can listen to the sound of the GW150914 “in-spiral” event (two black holes spiraling in on each other).  You can read more about the detection of GW150914 in my 11 February 2016 post.

On the “Sounds” tab on the SXS website, you’ll find that different types of major cosmic events are expected to emit gravitational waves with waveforms that will help characterize the original event. You can listen to the expected sounds from a variety of extreme cosmic events at the following SXS link:

http://www.black-holes.org/explore/sounds

Have fun exploring SXS.

 

NSF and LIGO Team Announce First Detection of Gravitational Waves

Today, 11 February 2016, the National Science Foundation (NSF) and the Laser Interferometer Gravitational-Wave Observatory (LIGO) project team announced that the first detection of gravitational waves occurred on 14 September 2015. You can view a video of this announcement at the following link:

https://www.youtube.com/watch?v=_582rU6neLc

The first paper on this milestone event, “Observation of Gravitational Waves From a Binary Black Hole Merger,” is reported in Physical Review Letters, at the following link:

http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.061102

The recorded signals from the two LIGO sites, Livingston, LA and Hanford, WA, are shown below, with the Hanford data time shifted to account for the slightly later arrival time of the gravitational wave signal at that detector location. The magnitude of the gravitational wave signal was characterized as being just below the detection threshold of LIGO before installation of the new advanced detectors, which improve LIGO sensitivity by a factor of 3 to 10.

LIGO signals

Source: NSF/LIGO

This milestone occurred during the engineering testing phase of the advanced LIGO detectors, before the start of their first official “observing run” on 18 September 2015.

Analysis and simulations conducted on the data indicate that the observed gravitational wave signals were generated when two orbiting black holes coalesced into a single black hole of smaller total mass and ejected about three solar masses of energy as gravitational waves.

In the Physical Review Letters paper, the authors provide the following diagram, which gives a physical interpretation of the observed gravitational wave signals.

Binary black holes merge

Note the very short timescale of this extraordinarily dynamic process. The recorded gravitational wave signals yielded an audible “chirp” when the two black holes merged.

With only two LIGO detectors, the source of the observed gravitational waves could not be localized, but the LIGO team reported that the source was in the southern sky, most likely in the vicinity of the Magellanic Clouds.

Localization of black hole merger Source: NSF/LIGO

The ability to localize gravitational wave signals will improve when additional gravitational wave detectors become operational later in this decade.

For more information on the current status of LIGO and other new-generation gravitational wave detectors, see my 16 December 2015 post: “100th Anniversary of Einstein’s Theory of General Relativity and the Advent of a New Generation of Gravity Wave Detectors.”

Update: 3 October 2017

 Congratulations to Rainer Weiss, Barry C. Barish, and Kip S. Thorne, all members of the LIGO / VIRGO Collaboration, for their award of the 2017 Nobel Prize in Physics for the first direct observation of gravitational waves. You can read the press release from the Royal Swedish Academy of Sciences here:

https://www.nobelprize.org/nobel_prizes/physics/laureates/2017/press.html

You also can read the scientific background on this award on the Royal Swedish Academy of Sciences website at the following link:

https://www.nobelprize.org/nobel_prizes/physics/laureates/2017/advanced-physicsprize2017.pdf

 

Anyone Can Quantum

Nobel Laureate Dr. Richard Feynman is famously quoted as saying, “I think I can safely say that nobody understands quantum mechanics.” University of Southern California (USC) graduate student Chris Cantwell, the inventor of Quantum Chess, is seeking to change that view by demonstrating that, in the right framework, anyone can grapple with some of the basic concepts of quantum mechanics. In particular, Chris Cantwell views Quantum Chess as a means of “demystifying the quantum world through play.” In Quantum Chess, all of the conventional chess moves are allowed as well as certain quantum moves for all pieces except pawns.

Quantum Chess isn’t a game you can purchase right now, but the short video, “Anyone Can Quantum,” provides an entertaining demonstration of what quantum gameplay will be like in the near future. This video was created by Caltech’s Institute for Quantum Information and Matter (IQIM) (‪http://iqim.caltech.edu) in association with Trouper Productions (‪http://trouper.net). In the video, actor Paul Rudd (Ant Man) challenges Stephen Hawking to a game of Quantum Chess for the right to give the keynote address at Caltech’s 26 – 27 January 2016 special event, “One Entangled Evening: A Celebration of Richard Feynman’s Quantum Legacy.”

You can view the almost 12 minute video at the following link.

https://www.youtube.com/watch?v=Hi0BzqV_b44

Here are a few of screenshots from the video.

Quantum chess match announcement

Quantum chess players

Quantum superposition is demonstrated by “Schrodinger’s king”, which could be in two places at one time.

Without superposition                                                      With superposition

Without superposition             With superposition

Quantum entanglement of the king & bishop enabled a bishop to move through a king.

Without entanglement                                                  With entanglement

Without entanglement           With entangelement

Resolution of the game required a quantum measurement to determine the winner.

For those of you who can’t wait to play a real game of Quantum Chess, Chris Cantwell has launched a Kickstarter funding program. Find out details at the following link:

https://www.kickstarter.com/projects/507726696/quantum-chess

You can find out more about the 26 – 27 January 2016 Caltech event, One Entangled Evening: A Celebration of Richard Feynman’s Quantum Legacy,” at the following link:

https://www.caltech.edu/content/one-entangled-evening-celebration-richard-feynmans-quantum-legacy

 

 

Where in the Periodic Table Will We Put Element 119?

The first periodic table of elements

In 1869, Russian chemist Dimitri Mendeleev proposed the first modern periodic table of elements, in which he arranged the 60 known elements in order of their increasing atomic masses (average mass, considering relative abundance of isotopes in naturally-occurring elements), with elements organized into groups based their similar properties. Mendeleev observed that certain properties recur at regular intervals in the periodic table, thereby defining the groupings of elements.

Mendeleev stamp Source: http://we-are-star-stuff.tumblr.com

This first version of the periodic table is compared to the modern periodic table in the following diagram prepared by SIPSAWIYA.COM. Mendeleev’s periodic table consisted of Groups I to VIII in the modern periodic table.

Mendeleev_sipsawiyagif

The gaps represent undiscovered elements predicted by Mendeleev’s periodic table, for example, Gallium (atomic mass 69.7) and Germanium (atomic mass 72.6) . You can read more about Mendeleev’s periodic table at the following link:

http://www.sipsawiya.com/2015/07/history-of-periodic-table.html

German chemist Lothar Meyer was competing with Mendeleev to publish the first periodic table. The general consensus is that Mendeleev, not Meyer, was the true inventor of the periodic table because of the accuracy and detail of Mendeleev’s work.

Element mendelevium (101) was named in honor of Dimitri Mendeleev.

Evolution of the Modern Periodic Table of Elements

The modern periodic table organizes elements according to their atomic numbers (number of protons in the nucleus) into 7 periods (vertical) and 18 groups (horizontal). The version shown below, in the International Union of Pure and Applied Chemistry (IUPAC) format, accounts for elements up to atomic number 118 and color-codes 10 different chemical series.

PeriodicTableMeltingPoint

Source: http://sciencenotes.org/printable-periodic-table/

Hundreds of versions of the periodic table of elements have existed since Mendeleev’s first version. You can view a great many of these at The Internet Database of Periodic Tables curated by Dr. Mark R. Leach and presented at the following link:

http://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=All

Glenn T. Seaborg (1912 – 1999) is well known for his role in defining the structure of the modern periodic table. His key contributions to periodic table structure include:

  • In 1944, Seaborg formulated the ‘actinide concept’ of heavy element electron structure, which predicted that the actinides, including the first 11 transuranium elements, would form a transition series analogous to the rare earth series of lanthanide elements. The actinide concept showed how the transuranium elements fit into the periodic table.
  • Between 1944 and 1958, Seaborg identified eight transuranium elements: americium (95), curium (96), berkelium (97), californium (98), einsteinium (99), fermium (100), mendelevium (101), and nobelium (102).

Element seaborgium (106) was named in honor of Glenn T. Seaborg.  Check out details Glenn T. Seaborg’s work on transuranium elements at the following link:

http://www.osti.gov/accomplishments/seaborg.html

Four newly-discovered and verified elements

On 30 December 2015, IUPAC announced the verification of the discoveries of the following four new elements: 113, 115, 117 and 118.

  • Credit for the discovery of element 113  was given to a team of scientists from the Riken institute in Japan.
  • Credit for discovery of elements 115 , 117 and 118 was given to a Russian-American team of scientists at the Joint Institute for Nuclear Research in Dubna and Lawrence Livermore National Laboratory in California.

These four elements complete the 7th period of the periodic table of elements. The current table is now full.

You can read this IUPAC announcement at the following link:

http://www.iupac.org/news/news-detail/article/discovery-and-assignment-of-elements-with-atomic-numbers-113-115-117-and-118.html

On 28 November 2016, the IUPAC approved the names and symbols for these four new elements: nihonium (Nh), moscovium (Mc), tennessine (Ts), and oganesson (Og), respectively for element 113, 115, 117, and 118.  Nihonium was the first element named in Asia.

Dealing with super-heavy elements beyond element 118

The number of physically possible elements is unknown.

In 1969, Glenn T. Seaborg proposed the following extended periodic table to account for undiscovered elements from atomic number 110 to 173, including the  “super-actinide” series of elements (atomic numbers 121 to 155).

Glenn Seaborg 1969 extended periodic table copy R1Source: W. Nebergal, et al., General Chemistry, 4th ed., pp 668 – 670, D.C. heath Co, Massachusetts, 1972

In 2010, Finnish chemist Pekka Pyykkö at the University of Helsinki proposed an extended periodic table with 54 predicted elements. The extension, shown below, is based on a computational model that predicts the order in which the electron orbital shells will fill up, and, therefore, the periodic table positions of elements up to atomic number 172. Pekka Pyykkö says that the value of the work is in showing, “how the rules of quantum mechanics and relativity function in determining chemical properties.”

Pyyko 2010 periodic tableSource: Royal Society of Chemistry

You can read more on Pekka Pyykkö’s extended periodic table at the following link:

http://www.rsc.org/Publishing/ChemScience/Volume/2010/11/Extended_elements.asp

You can read more general information on the extended periodic table on Wikipedia at the following link:

https://en.wikipedia.org/wiki/Extended_periodic_table

So where will we place element 119 in the periodic table of elements?

Based on both the Seaborg and Pyykkö extended periodic tables described above, element 119 will be the start of period 8 and it will be an alkali metal. Element 120 will be an alkaline earth. With element 121, we’ll enter the new chemical series of the “super-actinides”.

These are exciting times for scientists attempting to discover new super-heavy elements.

Where does neutronium fit in the periodic table?

Neutronium is a name coined in 1926 by scientist Andreas von Antropoff for a proposed “element of atomic number zero” (i.e., because it has no protons) that he placed at the head of the periodic table. In modern usage, the extremely dense core of a neutron star is referred to as “degenerate neutronium”.

Neutronium also finds many hypothetical applications in modern science fiction. For example, in the 1967 Star Trek episode, The Doomsday Machine, neutronium formed the hull of a giant, autonomous “planet killer”, and was portrayed as being invulnerable to all manner of scans and weapons. Since free neutrons at standard temperature and pressure undergo β decay with a half-life of 10 minutes, 11 seconds, a very small quantity of neutronium could be quite hazardous to your health.

14 January 2019 Update:  2019 marks the 150th anniversary of Dimitri Mendeleev’s periodic table

You’ll find a very good article, “150 years on, the periodic table has more stories than it has elements,” by Elizabeth Quill on the Science News website.  Here’s the link:

https://www.sciencenews.org/article/periodic-table-elements-chemistry-fun-facts-history

18 January 2019 Update:  Possibly the oldest copy of Mendeleev’s periodic table was found at the University of St. Andrews in Scotland

On 17 January 2019, the University of St. Andrews posted a news article stating that a periodic table of the elements dating from 1885 recently was found at the university and is thought to be the oldest in the world.

The 1885 periodic table.  Source: University of St. Andrews

You can read the University of St. Andrews news posting here:

https://news.st-andrews.ac.uk/archive/worlds-oldest-periodic-table-chart-found-in-st-andrews/

Just What are Those U.S. Scientists Doing in the Antarctic and the Southern Ocean?

The National Academies Press (NAP) recently published the report, “A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research”, which you can download for free at the following link if you have established a MyNAP account:

http://www.nap.edu/catalog/21741/a-strategic-vision-for-nsf-investments-in-antarctic-and-southern-ocean-research

Print Source: NAP

NSF states that research on the Southern Ocean and the Antarctic ice sheets is becoming increasingly urgent not only for understanding the future of the region but also its interconnections with and impacts on many other parts of the globe. The research priorities for the next decade, as recommended by the Committee on the Development of a Strategic Vision for the U.S. Antarctic Program; Polar Research Board; Division on Earth and Life Studies; National Academies of Sciences, Engineering, and Medicine, are summarized below:

  • Core Program: Investigator-driven basic research across a broad range of disciplines
    • NSF gives the following rationale: “…it is impossible to predict where the next major breakthroughs or advances will happen. Thus to ensure that the nation is well positioned to take advantage of such breakthroughs, it is important to be engaged in all core areas of scientific research.”
      • NSF notes, “…discoveries are often made by single or small groups of PIs thinking outside the box, or with a crazy new idea, or even just making the first observations from a new place.”
    • Examples of basic research that have led to important findings include:
      • Ross Sea food chain is affected by a high abundance of predator species (whales, penguins and toothfish) all competing for the same limited resource: krill. Decline or recovery of one predator population can be seen in an inverse effect on the other predator populations.  This food chain response is not seen in other areas of the Antarctic ice shelf where predator populations are lower, allowing a larger krill population that adequately supports all predators.
      • Basic research into “curious” very-low frequency (VLF) radio emissions produced by lightning discharges led to a larger program (with a 21.2-km-long VLF antenna) and ultimately to a better understanding of the behavior of plasma in the magnetosphere.
  • Strategic, Large Research Initiatives –  selection criteria:
    • Primary filter: compelling science – research that has the potential for important, transformative steps forward in understanding and discovery
    • Subsequent filters: potential for societal impact; time-sensitive in nature; readiness / feasibility; and key area for U.S. and NSF leadership.
    • Additional factors: partnership potential; impact on program balance; potential to help bridge existing disciplinary divides
  • Strategic, Large Research Initiative – recommendations::
    • Priority I: The Changing Antarctic Ice Sheets Initiative to determine how fast and by how much will sea level rise?
      • A multidisciplinary initiative to understand why the Antarctic ice sheets is changing now and how they will change in the future.
      • Will use multiple records of past ice sheet change to understand rates and processes.
    • Priority II: How do Antarctic biota evolve and adapt to the changing environment?
      • Decoding the genomic (DNA) and transcriptomic (messenger RNA molecules) bases of biological adaptation and response across Antarctic organisms and ecosystems.
    • Priority III: How did the universe begin and what are the underlying physical laws that govern its evolution and ultimate fate?
      • A next-generation cosmic microwave background (CBM) program that builds on the current successful CMB program using telescopes at the South Pole and the high Atacama Plateau in Chile and possibly will add a new site in the Northern Hemisphere to allow observations of the full sky

You will find detailed descriptions of the Priority I to III strategic programs in the Strategic Vision report.

 

100th Anniversary of Einstein’s General Theory of Relativity and the Advent of a New Generation of Gravity Wave Detectors

One hundred years ago, Albert Einstein presented his General Theory of Relativity in November 1915, at the Prussian Academy of Science. Happy Anniversary, Dr. Einstein!

Today, general relativity is being tested with unprecedented accuracy with a new generation of gravity-wave “telescopes” in the U.S., Italy, Germany, and Japan. All are attempting to directly detect gravity waves, which are the long-predicted quakes in space-time arising from cataclysmic cosmic sources.

The status of four gravity-wave telescopes is summarized below.

USA: Laser Interferometer Gravitational-Wave Observatory (LIGO)

LIGO is a multi-kilometer-scale gravitational wave detector that uses laser interferometry to, hopefully, measure the minute ripples in space-time caused by passing gravitational waves. LIGO consists of two widely separated interferometers within the United States; one in Hanford, WA and the other in Livingston, LA. These facilities are operated in unison to detect gravitational waves. The Livingston and Hanford LIGO sites are shown in the following photos (Hanford above, Livingston below):

ligo-hanford-aerial-02Source LIGO Caltechligo-livingston-aerial-03Source: LIGO Caltech

LIGO is operated by Caltech and MIT and is supported by the National Academy of Sciences. For more information, visit the LIGO website at the following link:

https://ligo.caltech.edu/page/about

Basically, LIGO is similar to the traditional interferometer used in 1887 in the famous Michelson-Morley experiment (https://en.wikipedia.org/wiki/Michelson–Morley_experiment). However, the LIGO interferometer incorporates novel features to greatly increase its sensitivity. The basic arrangement of the interferometer is shown in the following diagram.

LIGO experiment setupSource: LIGO Caltech

Each leg of the interferometer has a physical length of 4 km and is a resonant Fabry-Perot cavity that uses a complex set of mirrors to extend the effective arm length by a factor of 400 to 1,600 km.

On 18 September 2015, the first official “observing run” using LIGO’s advanced detectors began. This “observing run” is planned to last three months. LIGO’s advanced detectors are already three times more sensitive than Initial LIGO was by the end of its observational lifetime in 2007. You can read about this milestone event at the following link:

https://ligo.caltech.edu/news/ligo20150918

You also can find much more information on the LIGO Scientific Collaboration (LSC) at the following link:

http://www.ligo.org

Italy: VIRGO

VIRGO is installed near Pisa, Italy, at the site of the European Gravitational Observatory (http://www.ego-gw.it/public/virgo/virgo.aspx). VIRGO is intended to directly observe gravitational waves using a Michelson interferometer with arms that are 3 km long, with resonant Fabry-Perot cavities that increase the effective arm length by a factor of 50 to 150 km. The initial version of VIRGO operated from 2007 to 2011 and the facility currently is being upgraded with a new, more sensitive detector. VIRGO is expected to return to operation in 2018.

You can find much more information on VIRGO at the following link:

http://www.virgo-gw.eu

Germany: GEO600

GEO600 is installed near Hanover, Germany. It, too, uses a Michelson interferometer with arms that are 600 meters long, with resonant Fabry-Perot cavities that double the effective arm length to 1,200 meters.

You can find much more information on the GEO600 portal at the following link:

http://www.geo600.org

Japan: KAGRA Large-scale Cryogenic Gravitational Wave Telescope

The KAGRA telescope is installed deep underground, in tunnels of Kamioka mine, as shown in the following diagram.

img_abt_lcgtSource: KAGARA

Like the other facilities described previously, KAGRA is a Michelson interferometer with resonant Fabry-Perot cavities. The physical length of each arm is of 3 km (1.9 mi). KAGRA is expected to be in operation in 2018.

You can find much more information on KAGARA at the following links:

http://www.astro.umd.edu/~miller/Compact/lcgt.pdf

and,

http://gwcenter.icrr.u-tokyo.ac.jp/en/

 

 

The Magnus Effect and its Broad Applications: From Sports to Ballistics to Dam Busting in WW II

The Magnus effect occurs when a moving spherical or cylindrical body has a spin. The observed effect is that the moving, spinning body moves away from the intended direction of travel. The spin alters the airflow around the moving body and, by conservation of momentum, generates the Magnus force. In the case of a flying (thrown) backspinnning round body shown below, the Magnus force is a lift.

Sketch_of_Magnus_effectSource: Wikipedia

The Magnus force is named for German physicist Heinrich Gustav Magnus, who described the effect in 1852. Other scientists had described the effect long before Magnus, notably Isaac Newton (in 1672) and British mathematician and ballistic researcher Benjamin Robins (in 1742), but it was Magnus who got the honor.

We can see the Magnus effect at work in sports and in other applications discussed below.

Baseball

The pitcher can impart a spin in a selected direction to throw a curveball, slider or other pitch. Major League Baseball (MLB) uses a system called PITCHf/x, which is installed in every MLB stadium, to track the speed and trajectory of pitched baseballs. The system calculates two values, BRK and PFX, related to the Magnus effect:

  • BRK is a measure of the amount of bend in the trajectory at its greatest distance from a straight line
  • PFX is a measure of the deflection of the baseball due to the spin and drag forces from the path it would have taken under the influence of gravity alone

You can find more information of PITCHf/x at the following links:

https://en.wikipedia.org/wiki/PITCHf/x

and,

http://www.fangraphs.com/library/misc/pitch-fx/

Golf

A backspin on a golf ball creates a lift, as shown in the diagram above, helping to extend the range of the shot. A topspin has the opposite effect, shortening the ball’s trajectory. A spin about a vertical or diagonal axis results in a slice or hook to the right or left, invariably putting the ball into deep grass or some other course hazard. I have trouble visualizing how a golfer imparts a spin about the ball’s vertical or diagonal axis, but apparently it is a lot easier that you might think.

Extreme basketball

Thanks to Dave Groce, who forwarded the following link to a video that demonstrates how the Magnus effect helped a group in Tasmania sink a basketball from the top of a dam.  I have a feeling that there were a lot more basketballs at the bottom of the dam than are shown in the video.

https://www.youtube.com/watch?v=2OSrvzNW9FE

Ballistics

A spinning bullet will encounter a Magnus force if it yaws slightly in flight (i.e., direction of the central axis of the bullet is slightly different than its direction of flight, or velocity vector) or is shot into a crosswind. The direction of the Magnus force will depend on the direction of yaw or crosswind. A sniper shooting at long range needs to consider the Magnus effect.

WW II Dambusters

As reported on the Bomber Command website (http://www.bombercommandmuseum.ca/damsraid1.html):

 “The Dams Raid was conceived in the brilliant mind of Barnes Wallis, an experienced aircraft designer. Wallis had designed the very successful Wellington bomber that had been operational since the beginning of the war and, in his spare time, he searched for weaknesses in the enemy’s industrial infrastructure. The hydroelectric dams of the highly Ruhr Valley became his focus.

He devised a cylindrical, 9,500 pound weapon that could be dropped at low level while rotating backwards at 500 rpm. Released from a height of 60 feet, about 450 yards from the dam, and at a speed of 230 miles per hour, the weapon would then skip along the water (and over any torpedo nets) until it struck the dam wall, the spinning maintaining the weapon’s stability and slowing it down.

The backward rotation would then cause the cylinder to roll down the dam wall where it would explode at a predetermined depth. The wall would be weakened and the great weight of water would cause the dam to collapse.”

Experiments performed by Wallis demonstrated that the Magnus effect gave aerodynamic lift to the bomb and thereby increased the number of bounces before the bomb either struck the dam or stopped bouncing and sank.

p_damsraid1bSource: Bomber Command Museum

There is much more information on Sir Barnes Wallis and the Dams Raid on the Bomber Command website.

For more information, I also recommend the book, “Dam Busters.” By James Holland, published in 2012 by Grove Press, New York.

 

 

Kurzgesagt Explains the Fermi Paradox: Where are all the aliens?

Kurzgesagt (German for “in a nutshell“) is a Munich-based design studio with a distinctive perspective on design and animation in the fields of education, science and commerce. For more background information on Kurzgesagt, visit their website at:

http://kurzgesagt.org/profile/

Then, select “Projects” or “YouTube” on the menu on the left side of the screen to access their library of animated video briefings. The icons for some of your choices in the “Projects” menu are shown below. All project videos also are available on YouTube. I hope you enjoy these briefings.

Kurzgesagt1  The Fermi Paradox

Kurzgesagt2 Who Invented the Internet?

Kurzgesagt3  Time Explained

Kurzgesagt4 Is Nuclear Energy Good or Bad?