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Discusses the paradox in explaining the formation of centrifugal icicles. Explanation on how an ice storm in February 2003 produced formation of icicles radiating outward form the center of a rapidly rotating windmill; Reason that the explanation is confusing; Explanation from the inertial perspective.

Highlights the use of video spectroscopy in teaching students about the spectral properties of light. Hydrogen emission and solar fraunthofer lines of the solar spectrums; Quantitative measurements conducted on the solar spectrum; Results of the use of video camcorder in recording the flash spectrum of the chromosphere.

We present optical photometry of six intermediate polars that exhibit transitions to a low-flux state. For four of these systems, DW Cnc, V515 And, V1223 Sgr, and RX J2133.7+5107, we are able to perform timing analysis in and out of the low states. We find that, for DW Cnc and V515 And, the dominant periodicities in the light curves change as the flux decreases, indicating a change in the sources’ accretion properties as they transition to the low state. For V1223 Sgr, we find that the variability is almost completely quenched at the lowest flux, but we do not find evidence for a changing accretion geometry. For RX J2133.7+5107, the temporal properties do not change in the low state, but we do see a period of enhanced accretion that is coincident with increased variability on the beat frequency, which we do not associate with a change in the accretion mechanisms in the system. [ABSTRACT FROM AUTHOR]

We report unfiltered CCD photometry of the first confirmed superoutburst in 2010 April of the recently discovered dwarf nova SDSS J083931.35+282824.0. From a quiescence magnitude of ∼19.8 it rose to 14.0, an outburst amplitude of at least 5.8 magnitudes. Only the plateau phase of the outburst was observed, during which superhumps with peak-to-peak amplitude of up to 0.28 magnitudes were present, confirming this to be an SU UMa-type dwarf nova. The mean superhump period was Psh= 0.07836(2) during the first 3 days and this subsequently decreased to 0.07800(3)d. Analysis of the data revealed tentative evidence for an orbital period Porb= 0.07531(25)d. The fractional superhump period excess was ϵ= 0.039(6), which is consistent with other dwarf novae of similar orbital period. [ABSTRACT FROM AUTHOR]

We present photometry of the first reported superoutburst, during 2008 January and February, of the dwarf nova VSX J074727.6+065050. At its brightest the star reached magnitude 11.4 and this was followed by a slow decline at 0.09 mag/d for 19 days, corresponding to the plateau phase. There was then a rapid decline at 1.66 mag/d to a temporary minimum at magnitude 16.6 where it stayed for two to three days, after which there were six remarkable echo outbursts before the star gradually faded back towards quiescence at ∼magnitude 19.5. The overall outburst amplitude was at least 8 magnitudes and it lasted more than 80 days. During the plateau phase we observed common superhumps with Psh = 0.06070(6)d, but the period increased to Psh = 0.06151(5)d coinciding with the end of the plateau phase and the onset of the rapid decline. This corresponds to a continuous period change with P = +4.4(10) × 10-5. During the echo outbursts there was a superhump regime with Psh = 0.06088(49)d. Evidence is presented which is consistent with the star being a member of the WZ Sge family of dwarf novae. [ABSTRACT FROM AUTHOR]