Jumping Sundogs, Cat's Eye and Ferrofluids
Total Page:16
File Type:pdf, Size:1020Kb
Article Jumping Sundogs, Cat’s Eye and Ferrofluids Alberto Tufaile 1,* , Michael Snyder 2 , Timm A. Vanderelli 3 and Adriana Pedrosa Biscaia Tufaile 1 1 Soft Matter Lab, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo 03828-000, Brazil; [email protected] 2 Technical Space Science Center, 235 Martindale Drive, Morehead State University, Morehead, KY 40531, USA; [email protected] 3 Ferrocell USA, 739 Route 259, Ligonier, PA 15658, USA; [email protected] * Correspondence: [email protected] Received: 20 April 2020; Accepted: 2 July 2020; Published: 8 July 2020 Abstract: We have explored some features of the complex fluids present in Earth’s atmosphere by the observation of some optical phenomena and compared them to the optical phenomena observed in gems and magnetic materials. The main feature of a complex fluid is that it contains polyatomic structures such as polymer molecules or colloidal grains. This paper includes some setups using tabletop experiments, which are intended to show concretely the principles discussed, giving a sense of how well the idealizations treated apply to the atmospheric systems. We have explored sundogs, light pillars, and the halo formation, which involve the existence of a certain structure in the atmospheric medium, resembling the structures observed in some types of gems and ferrofluids. Keywords: sundogs; crown flash; ferrofluids; complex fluids; polarization; cat’s eye effect 1. Introduction The observation of atmospheric optical phenomena has caused a sense of wonder in many people throughout history, such as the sundogs, crown flashes, parhelic circles, light pillars, or the miracle of the sun. All of these phenomena are rare, and we can hardly predict their occurrence. However, the technological development that allows for the availability of cameras and camcorders, associated with the dissemination of the recordings of these phenomena on social networks, allows us to try to give a plausible explanation for these rare events. For example, the crown flash in Figure1 in meteorology is an atmospheric optical phenomenon that consists of a luminous column that moves near dense clouds during the day [1,2]. These images of this atypical event were obtained from a YouTube user’s video (QuadM13) observed at Greenwood, Indiana, USA [3], on the same day that another YouTube user’s video from Shelbyville, Indiana, USA (Chris Mercer) captured another video of this jumping sundog on June 12, 2015 at 6:39 pm CDT [4], with a distance of almost 30 km between the two. Clouds can be an example of a complex fluid [5] that changes constantly due to atmospheric conditions, in which a gas phase contains structures such as tiny ice crystals in motion. The existence of such structure for this kind of system distinguishes a cloud from a simple fluid, with properties which allow self-organization in the presence of an electric field or air flow. In the case of a crown flash or jumping sundogs, one possible explanation for this phenomenon to occur is that sun light is interacting through ice crystals above the clouds in the presence of an oscillating electrical field, while in the case of light pillars, the spatial distribution of particles inside this complex fluid creates the observable light pattern. Condens. Matter 2020, 5, 45; doi:10.3390/condmat5030045 www.mdpi.com/journal/condensedmatter Condens. Matter 2020, 5, 45 2 of 12 Condens. Matter 2020, 5, x FOR PEER REVIEW 3 of 12 Figure 1.1.The The solar solar halo halo is shown is shown in (a) andin (a the) and laser the halo laser obtained halo using obtained ferrofluid using subjected ferroflu toid a subjectedmagnetic field to a is magnetic shown in (fieldb). The is shown jumping in sundog (b). The phenomenon jumping sundog is shown phenomenon in this sequence is ofshown three picturesin this sequence in (c) in states of three 1, 2 and pictures 3, and thein ( dic)ff erentin states values 1, of2 and the magnetic 3, and t fieldhe different can create values a sequence of the of magneticlight patterns, field as can in (d create). For di aff sequenceerent configurations of light patterns of the magnetic, as in (d fields). For 1, different 2 and 3 of configurations these patterns in (ofd), the we canmagnetic emulate field somes 1, patterns 2 and observed 3 of the inse thepatterns crown flash.in (d), we can emulate some patterns observed in the crown flash. Thus, these properties in such a natural environment, which cause so much astonishment in people,Thus, are these the resultproperties of the in emergence such a natural of light environment patterns in, which a complex cause system so much on astonishment a scale of huge in proportions.people, are the This result feeling of ofthe wonder emergence can leadof light to a sensepatterns of transcendence,in a complex system inducing on in a many scale peopleof huge a proportions.deep feeling ofThis connection feeling of withwonder nature, can butlead sometimes to a sense of leads transcendence, to classification inducing of these in many phenomena people as a deepmiracles, feeling omens, of connection conspiracy with theories nature, or but even sometimes an extraterrestrial leads to classif manifestation,ication of these as we phenomena can see in the as miracles,comments omens, made byconspiracy several users theories on the or videoseven a mentionedn extraterrestrial above. manifestation In this way, it, isas interesting we can see to in carry the commentsout relatively made simple by andseveral accessible users on experiments the videos to mentioned demonstrate above some. In of this the mainway, conceptsit is interesting present to in carrythese phenomena.out relatively simple and accessible experiments to demonstrate some of the main concepts presentThe in use these of analogous phenomena. systems can facilitate the presentation and interpretation of these phenomena. See, forThe example, use of theanalogous formation systems of the solarcan halofacilitate in Figure the 1presentationa and the formation and interpretation of the laser halo of usingthese phenomena.ferrofluids in See Figure, for 1example,b. Even consideringthe formation that of the solar first casehalois in mainly Figure related1a and tothe geometric formation optics, of the whilelaser halo the second using caseferrofluids is associated in Figure with 1b. light Even diffraction, considering both systemsthat the show first howcase lightis mainly can be related projected to geometricaround the op lighttics, sourcewhile the due second to its interactioncase is associated with particles with light suspended diffraction in, both a fluid. systems Another show case how is lightthe oscillating can be projected light flash around in Figure the 1lightc, which source can due beassociated to its interaction with di withfferent particles states of suspend the staticed lightin a patternsfluid. Another in Figure case1d, is ifthe we oscillating consider thatlight a flash characteristic in Figure light 1c, which pattern can can be respond associated to changes with different in the statesstate of of some the static type oflight field patterns that controls in Figure the movement1d, if we consider of particles that that a characteristic are interacting light with pattern light, as can in respondthe case ofto Figurechanges1d, in showing the state some of some of these type possibleof field that field controls states for the the movement same light of sourceparticle placeds that are in interactingdifferent positions, with light, simultaneously. as in the case of An Figure important 1d, showing result that some can of be these obtained possible with field all states of this for is the same light source placed in different positions, simultaneously. An important result that can be obtained with all of this is the existence of conditions that allow the emergence of a self-organization that manifests itself through the observation of an optical phenomenon on an atmospheric scale. Condens. Matter 2020, 5, 45 3 of 12 existenceCondens. Matter of conditions 2020, 5, x FOR that PEER allow REVIEW the emergence of a self-organization that manifests itself through3 of the 12 observation of an optical phenomenon on an atmospheric scale. InIn thisthis way, way, this this work work presents presents some some plausible plausible explanations explanations for some for ofsome these of events these and events connects and themconnect to others them interesting to other interesting systems that systems are based that in are the based same in concepts the same but concepts in different but scales,in different using scales, some principlesusing some of principle physicss and of physics material and science. material In thescience. next In section, the next we section present, we our present method; our after method that,; weafter explore that, we the explore phenomenon the phenomenon of light pillars of light and pillars compared and compared them with them the with light the patterns light patterns in gems. in Ingems. Section In 4S,ection we investigate 4, we investigate the polarization the polarization patterns patterns of ferrofluid of ferrofluid and related and patterns related inpatterns crystals. in Finally,crystals. we Finally, present we our present conclusions our conclusion in Sections in5. Section 5. 2.2. Materials and Methods InIn orderorder toto simulatesimulate somesome opticaloptical phenomena,phenomena, wewe havehave usedused materialsmaterials withwith magneto-opticalmagneto-optical properties.properties. We havehave usedused aa thinthin filmfilm of ferrofluidferrofluid subjected to an external magnetic field field (Ferrolens) (Ferrolens).. WhenWhen lightlight interactsinteracts withwith thisthis thinthin filmfilm ofof ferrofluid,ferrofluid, itit undergoesundergoes didifferentfferent eeffects,ffects, andand wewe cancan observeobserve somesome analogies analogies between between the atmosphericthe atmospheric phenomena phenomena and the and magneto-optical the magneto light-optical patterns, light whichpatterns, intend which to show intend some to principlesshow some involved, principles giving involved, a sense of giving how well a sense the idealizations of how well treated the applyidealizations to the atmospheric treated apply systems to the atmospheric [1,6,7].