What do precision laser metrology and broadband femtosecond lasers have to do with each other? Plenty! This marriage was the reason Ted Haensch and Jan Hall shared the 2005 Nobel Prize in Physics. Part of that experiment has been reproduced at BYU, and it has been used to correct a serious spectroscopy error in atomic ytterbium. This work was published in Phys. Rev. A 94, 052511 (2016).
This image was secured during the installation of the 0.9-m telescope at the BYU West Mountain Observatory. Data for this image is from August 27, 2009. This was the first night that a CCD had been mounted on the telescope so that imaging was possible. This 'First Light' image shows the globular cluster known as M15 in the constellation of Pegasus. The distance to this cluster is more than 33,000 light years and yet individual stars are easily resolved all through the cluster. Globular cluster stars have an extremely low abundance of heavy elements as compared to stars found in the solar neighborhood and represent the oldest population of stars known in the Galaxy. It is interesting to note the many cool red giant stars that are visible in the cluster as well as a large number of evolved horizontal branch stars that are blue in color. Many of the horizontal branch stars are known to be RR Lyrae variable stars that are useful as distance indicators since it is possible to determine their luminosity and compare that value to their apparent magnitude as measured from the observed images. The color image processing for this picture is the work of renowned image processing guru, Dr. Rob Gendler.
This solar eclipse image was secured on October 23, 2014 by Dr. Michael D. Joner. This observation was made at 4:05 PM MDT a couple of miles west of the BYU campus in Provo, Utah. In this near alignment of the Earth, Moon, and Sun only about 50% of the solar photosphere was blocked by the disk of the Moon as viewed from Provo. The result was a partial solar eclipse. The large group of sunspots near the center of the Sun has been cataloged as AR 2192. This is the largest active region seen during the current solar cycle. The dark central spot is significantly larger than the Earth. The entire sunspot complex is more than 100,000 km across.
The small black spot projected on the Sun just above the foreground clouds in Provo is caused by the planet Venus as it transits for the last time this century. The transits of Venus come in pairs separated by eight years that only occur after a period of 105 or 122 years without a transit visible from the Earth. If you missed this event, the next opportunity will be in December of 2117. Finding the transit of an Earth sized planet across a stellar photosphere was the primary mission of the Kepler spacecraft as it searched for extrasolar planets up through August 2013. The difficulty of this mission is apparent when you note the tiny fraction of the Sun's light that is blocked by the transit of a planet the size of Venus.
This image was taken with a DSLR at the West Mountain Observatory about an hour before sunrise on 4 April 2015 by Dr. Michael Joner. Near the center of the constellation of Sagittarius is a bright star that was not seen just a few weeks earlier. This new naked eye star was discovered on March 15, 2015 in survey images taken in Australia. Spectroscopic observations secured the next night confirmed that this is a classical nova, and it was named Nova Sagittarii 2015 No. 2. A classical nova is a binary system where a white-dwarf star collects gas from a close companion star so that the material flows onto the surface of the white dwarf. As the material builds up on the white dwarf, the bottom layers become hot and dense so that they ignite in a runaway hydrogen-fusion reaction which blasts the shell off into space and causes a temporary increase in luminosity by a factor of 50,000 or more. Unlike supernovae that destroy the progenitor star, novae are recurrent events. It is estimated that about 40 novae occur in the Milky Way each year, and about ten of these are visible from Earth. This nova is expected to fade away in a month or two and return to a luminosity close to what it was before this outburst.
25 Feb, Today
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Kent Gee and Traci Neilsen et al. recently published an article titled "Comparison of Acoustic Intensity Vectors with SPL and Phase Distributions of Supersonic Je" in Asian Joint Conference on Propulsion and Power (Kagawa, Japan, March 2016).. Click on the image above to read it.
All Planets Panorama: For 360 degrees, a view along the plane of the ecliptic is captured in this remarkable panorama, with seven planets in a starry sky. The mosaic was constructed using images taken during January 24-26, from Nacpan Beach, El Nido in Palawan, Philippines....
This photograph and Description come from NASA's Astronomy Picture of the Day web site.