News and Events

Comet PanSTARRs, C/2017 T2, shared this stunning telescopic field of view with galaxies M81 and M82 on May 22/23. Of course, the galaxies were some 12 million light-years distant and the comet about 14 light-minutes away, seen in planet Earth's sky toward the Big Dipper. A new visitor from the Oort Cloud, this Comet PanSTARRs was discovered in 2017 by the PanSTARRs survey telescope when the comet was over 1 light-hour from the Sun, almost as distant as the orbit of Saturn. With a beautiful coma and dust tail, this comet has been a solid northern hemisphere performer for telescope wielding comet watchers this May, following its closest approach to the Sun on May 4. In this deep image from dark California skies the outbound comet even seems to develop a short anti-tail as it leaves the inner Solar System.
Check current conditions and historical weather data at the ESC.
A new study from researchers at Brigham Young University and Pennsylvania State University provides the most accurate estimate of the number of Earth-like planets in the universe. The team looked at the frequency of planets that are similar to Earth in size and in distance from their host star, stars similar to our Sun. Knowing the rate that these potentially habitable planets occur will be important for designing future astronomical missions to characterize nearby rocky planets around Sun-like stars that could support life.
Students of the Physics 106 afternoon section participated in an extra credit opportunity that took hands-on learning to a new level. Inspired by a classic MIT challenge, Professor Della Corte gave each student a small kit containing two thumb tacks, two paper clips, six feet of copper wire, two neodymium magnets, and a block of wood. He then sent his students on their way with limited instructions: Design your own motors, only using materials from the kits. Any drop of glue or strip of tape would disqualify them.
Liz Finlayson, who is graduating from the Physics Teaching program, was recently highlighted in the APS Spring 2020 newsletter
New telescope installed in the campus dome on February 22, 2020

Selected Publications

BYU Authors: David D. Allred and Matthew R. Linford, published in Proc. SPIE

To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k*log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems.

BYU Authors: Eric J. Lysenko and Tracianne B. Neilsen, published in Proc. Meet. Acoust.

Wave conversion and transmission at the interface between solid earth and fluid atmosphere result in air-ground and ground-air seismic and acoustic (seismo-acoustic) coupling. Seismo-acoustics is particularly relevant in observational geophysics; networks of seismic instrumentation are increasingly collocated with infrasonic pressure sensors and used in the study of a wide array of natural and anthropogenic sources. Two field experiments were carried out to isolate the ground-air converted signal from subaerial explosions. One experiment used 17” balloons filled with a stoichiometric oxy-acetylene mix placed on the ground, and another used Pentex configured at depths of 30 and 60 cm. Ground-radiated signals were isolated with a portable soundproof box constructed of mass-loaded vinyl, soundproofing composite board, liquid nails and wood glue to dampen air-borne sound waves. Random incidence insertion loss of the box was estimated and applied to signals measured outside the box. These filtered signals are compared with the signals observed from a microphone placed inside the box. Preliminary analysis shows evidence of ground radiated signals detected in the Pentex experiment, but not in the balloon experiment. These observations need confirmation with additional seismic and infrasonic signal processing methods. However, preliminary results suggest a viable technique for isolating ground-borne acoustic waves.

BYU Authors: Tracianne B. Neilsen, Kent L. Gee, and Scott D. Sommerfeldt, published in Proc. Meet. Acoust.

Energy-based quantities, such as acoustic vector intensity, kinetic energy density, and specific acoustic impedance, rely on the acoustic particle velocity. The particle velocity is often approximated via Euler’s equation using the gradient of the complex pressure across closely spaced microphones, which is traditionally found using the cross-spectral density. In contrast, the Phase and Amplitude Gradient Estimator (PAGE) method [Thomas et al., J. Acoust. Soc. Am., 137, 3366-3376 (2015)] relies on gradients of pressure magnitude and phase. For a broadband source, the PAGE method allows for the phase to be unwrapped, which extends the usable bandwidth of the particle velocity calculations well above the spatial Nyquist frequency. The benefits of the PAGE method are demonstrated in plane wave tube experiments in which two microphones are spaced 10-360 cm apart. The traditional processing method underestimates active acoustic intensity and kinetic energy density well below the spatial Nyquist frequency. The PAGE method, however, extends the reliable bandwidth of active acoustic intensity, kinetic energy density, and specific acoustic impedance, to the spatial Nyquist frequency, and above when phase unwrapping can be applied. This increased high frequency reliability allows for microphones to be spaced farther apart, which then increases the low frequency reliability as well.