You are currently browsing the category archive for the ‘physics’ category.
Early this month, we had our first commissioning run of the Folded Port Infrared Echellette, or FIRE, a near-infrared spectrograph designed for the Magellan Telescopes. After a two-week installation period in late February/early March led by the instrument PI Rob Simcoe, FIRE team members John Bochanski and Matt Smith from MIT and Craig McMurtry from U. Rochester, and Magellan engineers (I missed all the action, teaching 250 students Physics 1), FIRE was ready to view the sky for a week-long commissioning run starting March 28th.
Early results have been spectacular. A few of the image frames from the first week are shown below. The high quantum efficiency and low readnoise of the Teledyne Hawaii 2RG detectors, and the excellent image quality of the Baade Telescope, has resulted in higher sensitivity than originally planned. In the echelle mode, Rob has estimated roughly 20-25% efficiency, including telescope and slit losses, and a nearly-flat zero point of 16-17 AB magnitudes (1 count/sec/pixel) across the 0.85-2.4 micron range. In plain language, this means we can observe very faint sources – such as a the coldest brown dwarfs and highest redshift quasars – with the echelle mode’s moderate resolution (λ/Δλ ≈ 6000). The prism-dispersed mode has also proven very sensitive, and we’ve been able to follow-up several J ≈ 19-20 cold brown dwarf candidates from WISE with relative ease. Look for first science results in the literature soon!
The roughly twice-daily ocean tides ebb and flow on different timescales and to different heights depending on the relative orientations of the Sun and Moon. It is the gravitational pull of these the two bodies that are responsible for our tides, a fact first explained by Isaac Newton. When the Moon is full (and again when it is new), it, the Earth and the Sun are nearly aligned – a situation know as syzygy (one of my favorite words). In this orientation, the tidals forces combine to amplify the tidal surge; we have a spring tide. Throw in some big surf and an unusually close Moon, and you’ve got quite a shorebreak.
I’m trying a (yet another) new thing for teaching, putting together “minilessons” for my Physics 1a class at UCSD covering specific topics that I don’t get to in lecture, or are worth a little focused attention. This was a somewhat intensive project as time is short (the quarter has already started!) and I’ve never made a “video enhanced podcast” before, but I think I’ve got must of the bugs worked out. You’ll nevertheless clearly notice some audio edits.
The audio was recorded on my laptop (built-in mic) into Garage Band; the slides were made in Powerpoint and saved off as individual images, and then individually dragged into the podcast track in Garage Band. The whole thing was saved off as a AAC encoded .m4a file that Youtube seems to be able to handle.
Have a look, let me know what you think and if you learned anything! The lectures themselves are also being audio and video podcast from UCSD.
Some of my 8.012 Physics I (Classical Mechanics) lectures are now avaiable at MIT TechTV in the 8.012 collection (http://techtv.mit.edu/collections/8012). I shot these with a tripod and fixed camera from the back of the room, so the sound and video resolution is not great, and there appear to be some weird pauses in a few of the videos (lame “update” to iMovie), but nonetheless you might get something out of them (I sure hope my students did!).