Invisibility physics: Kerker’s “invisible bodies”

(This is a continuation of my “history of invisibility physics” series of posts.  The earlier posts are: Part I, Part II, Part III, Part IV, Part V, Part VI)

The history of invisibility physics truly began with the concept of radiationless motions of charged particles, as described by Ehrenfest in 1910 and Schott in 1933.  There are many more discoveries associated with these and related phenomena, which would eventually be referred to as nonradiating sources.

I would like to jump ahead in the history a little bit, however, and discuss a paper published in the Journal of the Optical Society of America in 1975 by Milton Kerker, entitled, “Invisible bodies”.  The article, relatively unknown today, is the first article to describe an object which is invisible in the true sense of the word — although the object itself is microscopic!

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Posted in Invisibility, Optics | 17 Comments

ResearchBlogging editor’s selections: Soothing troubled waters, zombie stars, risky business with oil, visual recognition, and time and power

  • Pouring oil on ‘troubled waters’. Historically, sailors believed they could calm choppy water by pouring oil on it, and small-scale tests indicate at least a partial truth to this.  Could the Gulf oil spill have a similar effect?  In a fascinating post, Kevin at Deep Sea News describes the history and science of this odd idea.
  • Night of the living dead stars. We know that stars can gobble up smaller objects with their gravitational fields.  At his eponymous blog, Professor Astronomy looks at the evidence that a “dead” white dwarf star has recently gobbled up a dwarf planet!
  • Inevitability and Oil, Pt. 1: the inherent risk for accidents in complex technology. We all know that BP screwed up big time in the Gulf, but are we learning the wrong lessons from the accident by making them the only villain?  Hannah at Culturing Science discusses the disaster in terms of commonly-used theories of risk.
  • Putting visual recognition software to the test. How close are we to having computers that can identify objects visually as well as a person?  Not very close at all, apparently; Greg Fish at Weird Things describes research on the effectiveness of visual recognition software.
  • Standardized time and power relations. Finally, Krystal at Anthropology in Practice takes some time to talk about time, and how forced changes in culture and politics can affect a people’s perception of it.

Check back next week for more “miscellaneous” selections!

Posted in General science, Science news | 4 Comments

Swimming (well, kneeling) with stingrays!

This past week I’ve been rather quiet about blogging and tweeting because I’ve been on vacation with the Wife and some of her family in Myrtle Beach, SC. We just returned yesterday and had a quite nice time, though like many vacations I feel perhaps even more exhausted than before we left!

There were many nice aspects to the trip, but for me the highlight was a stop at Ripley’s Aquarium.  The aquarium itself it relatively small, and most of the exhibits can be passed through within an hour, even at a leisurely pace.  Nevertheless, they have a few really neat opportunities there, including an extra behind-the-scenes tour one can take that culminates with a hands-on encounter with their resident stingrays!  The Wife and I did the Swim With Stingrays Tour, and included with the event was a nice CD of pictures of our experience.

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“On the decline of mathematical studies, and the sciences dependent upon them”

I was browsing the internet a few weeks ago, and came across an opinion piece lamenting the poor state of mathematical education and the detrimental effect it has had on science.  The provocative piece starts as follows:

It is a subject of wonder and regret to many, that this island, after having astonished Europe by the most glorious display of talents in mathematics and the sciences dependent upon them, should suddenly suffer its ardour to cool, and almost entirely to neglect those studies in which it infinitely excelled all other nations.  After having made the most wonderful and unhoped-for discoveries, and pointed out the road to more; suddenly to desist, and leave these to be cultivated, and the road to more to be explored, by other nations, is very remarkable.  It seems as strange as the conduct of a conqueror would be, was he to conquer all the countries around him, and then tamely to suffer his own and the subjugated ones to be possessed, governed, and cultivated, by those whom he had conquered.

It is a very great disgrace for a nation like this, which can proudly boast of a superiority over all others in arts, arms and commerce, to suffer the sublimest sciences, which once were its greatest pride and glory, to be neglected.  Surely a much more solid fame accrues to a people from their superiority in talents than in arms.  Athens is as celebrated for its learning as its commerce or its victories.  It cannot be owing to any want of importance in the sciences themselves that they are neglected; the discoveries made in them are of the most astonishing nature, and such as seemed absolutely beyond the reach of human intellect.  By the marvellous assistance of the mathematics from the simple law of gravity are deduced the orbits of the planets and satellites, their distances, the times of their revolutions, their densities, quantities of matter, and many other remarkable properties too well known to be enumerated.  Were it not for them, mechanics, optics, hydrostatics, geography, and other branches of natural philosophy, would hardly have been known as science.  It is possible that discoveries more wonderful and of greater utility than those already made by the help of mathematics, may some time or other be effected, should some great genius once point out the way.  It is the opinion of many philosophers, that the various forms and diversified properties of bodies are owing to the various laws of attraction and repulsion which their constituent particles exercise upon each other.  Should these laws ever be discovered, we shall become as well acquainted with the structure, affinities, and mutual operations of boides, as we are with the revolutions and actions of the planets upon each other.

As you probably have noted already from the style of writing, this is not a particularly recent article.  In fact, this call-to-arms in favor of mathematics education was written in 1804!

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Posted in ... the Hell?, History of science | 5 Comments

ResearchBlogging editor’s selections: Grandpa vs. the oil, inadvertent cloud-seeding, faith and science, and hip-hop evolution

Check back next Monday for more “miscellaneous” selections!

Posted in General science, Science news | 1 Comment

A mini milestone…

In the midst of all the work I’ve been doing lately, I almost completely overlooked the fact that I’ve passed the 400,000 page view milestone!  It was less than a year ago that I hit the 300k mark, so I’m apparently doing something reasonably well.  Thanks to all who stop by and read!

Posted in Personal | 8 Comments

A visit to the Cleveland Metroparks Zoo

Over the weekend, the Wife and I visited some of her relatives in Cleveland.  Though it was a very short trip, we managed to take a trip to the Cleveland Metroparks Zoo, which has a nice collection of exhibits.  We didn’t have that much time at the zoo — we got a late start and had to head right to the airport afterward — but I nevertheless managed to get some nice pictures of the animals!  Let’s take a look…

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The Giant’s Shoulders #24 is up!

The Giant’s Shoulders #24 is up over at Jost a Mon, and to celebrate the 24th edition it includes a timeline of discoveries made in the 24th year of each century !  Many thanks to Fëanor for assembling such an entertaining interactive carnival!

The deadline for the next edition is July 15th, and it will be held at The Dispersal of Darwin.  It will also be a special event, as it will mark the 2nd anniversary of this carnival’s existence!  Entries can be submitted through blogcarnival.com or directly to the host blog, as usual!

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Joe Hill’s Horns

Joe Hill is a good horror author, but not an incredibly prolific one; his first book was 20th Century Ghosts (2005), a collection of ghost stories, and his second was Heart-Shaped Box (2007), which I reviewed on this blog a couple of years ago.  I really adored Heart-Shaped Box, and when I saw that Hill had a new book out, Horns (2010), I didn’t hesitate to snap it up:

Was it worth the wait?  Definitely!  Joe Hill has produced another fast-paced, well-written novel with a bizarre engaging plot and sympathetic characters.

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Posted in Horror | 3 Comments

ResearchBlogging editor’s selections: primate risk-assessment, not-quite-life on Titan, and 65-year-old precursor to the Web

  • A Bonobo in the Hand or Two Chimps in the Bush? Do different species of primates have the same perception of risk, or does it depend on their feeding habits and environment?  With some clever imagery, Jason at The Thoughtful Animal describes some research that shows how different species make very different choices, and suggests why.
  • The media finds life on titan.  Sort of… OMG we’ve found life on Saturn’s moon Titan??!!  Well, not exactly.  Greg at Weird Things discusses the research on Titan and explains that, while the measurements made suggest the possibility of life, there are lots of other possibilities and the jury is still out on this one.
  • ‘As We May Think’ at 65. In 1945, Vannevar Bush published a visionary article in The Atlantic Magazine that discussed the efficient recording of information and the use of mechanical mathematics machines, an article that is credited as being an inspiration for the creation of the World Wide Web.  Simon at Thinking Out Loud discusses the influence this article had on a generation of computer scientists.

Posted this a little later in the day than usual, but still on Monday!  Check back next Monday for more miscellaneous suggestions!

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