Show notes for episode 195. Monday the 5th of May 2014.
Hosts: Jesse, Lianne, Julie
Title: Chip off the ol’ Sag A*
Tonight we featured live guest Dr. Daryl Haggard, a researcher monitoring a gas cloud that has just whipped around the Milky Way’s super massive black hole. We were lucky enough to have her son’s two cents on the subject as well. Julie was in and out all night due to connectivity issues, but was able to hang on long enough to hear Jesse’s dog, Chip, bark at a very scary sound outside the door. Paul wasn’t on the show tonight, so Australia was only mentioned once, but he was instant messaging the hosts the entire time (listen for laughs). Thanks for tuning in everyone, podcast and show notes below.
This week in space/astronomy history:
1. May 6, 1975 – NASA announces that Canada will build the Shuttle robot arm. NASA invited Canada to participate in the Space Shuttle Program in 1969. What that participation would entail was not formalized until 1975 when NASA and the Canadian National Research Council (NRC) signed a memorandum of agreement for Canada to develop and build the Shuttle Remote Manipulator System, known as the Canadarm.
2. May 9, 2003 – Hayabusa launched. Made by the Japan Aerospace Exploration Agency (JAXA), it’s mission was to rendezvous with the near-Earth asteroid 25143 Itokawa and return samples to Earth for study.
3. May 5, 1961 – Alan Shepard becomes the first American in space. He flew the Freedom 7 on a suborbital flight. Shepard also returned to space travels aboard Apollo 14 as Commander
Live Guest: Dr. Daryl Haggard on the G2 gas cloud near SagA*
Bio: Dr. Haggard completed her Masters at San Franciso State University, where she worked on ‘High-Resolution X-ray & Optical Imaging of Binary Populations in ω Centauri,’ and then completed her Ph.D. at the University of Washington, working on ‘The Fraction of X-ray-active Galaxies in the Field from the Chandra Multiwavelength Project and the Sloan Digital Sky Survey.’ Now Dr. Haggard is a CIERA post-doctoral fellow at Northwestern University in Illinois, where she has focused her attention on the Milky Way’s centre, where there is a super massive black hole called Sagittarius A*. Dr. Haggard is also the editor for the AASWOMEN Newsletter and an elected member of the AAS High Energy Astrophysics Division. Her twitter handle is @DarylHaggard.
Suggested Reading: Dr. Haggard’s Bio, Northwestern University Press Release, G2 discovery Press Release, G2 Simulation[VIDEO observations
1. Daytime Fireball Over Southern Ontario May 4, 2014. At about a 4:15 PM EDT on May 4 a fireball meteor was observed in southern Ontario. The shockwave occurred south-east of Peterborough. Astronomers have determined that the object was probably about ½ meter in diameter with a mass of a few metric tonnes when it entered Earth’s atmosphere. The energy released would have been equivalent to a few tens of tons of TNT. Suggested Reading: CBC article, EarthSky article.
2. 3rd Annual What’s up in Space? recap. Event website.
3. Astronomy Day is May 10th. Astronomy Day Wiki, Ontario Science Centre Event,
4. Mercury’s volcanic past. It appears the planet Mercury was much more volcanically active in the past, and for a much longer time frame than originally thought. Explosive volcanism is only made possible by the presence of volatile chemicals in the crust of the planet. These chemicals would be things like water, carbon dioxide, and others with low boiling points. Without volatiles, there can’t be explosive volcanism. Mercury was thought to have degassed any volatile chemicals very early on in its history (i.e., approximately 4.4 billion years ago when it formed). However, data from the MESSENGER satellite now currently orbiting Mercury (at over 2000 orbits now), indicate the presence of pyroclastic flow sites. The team in a study published in the Journal of Geophysics: Planets, looked at 51 different pyroclastic sites imaged by orbiting satellite MESSENGER. They found two things: 1) The craters didn’t all form at the same time. As the pyroclastic vents have been eroded to different amounts, it appears the volcanism was happening over a large range of time. 2) They happened over a large time frame of Mercury’s history. Some of the volcanic identifiers occurred inside impact craters on the surface of Mercury. There is a standard method for dating craters on Mercury, by using how much of the walls of the crater have eroded. It appears some of the pyroclastic vents occur within craters that date to ages between 3.5 and 1 billion years old, indicating Mercury didn’t degas all of its volatile chemicals early on in its formation. Suggested reading: IFLS, Journal of Geophysical Research: Planets, Brown University Press Release, MESSENGER homepage.
5. Astronomers Determine the Length of an Exoplanet day. Using the Very Large Telescope (VLT), astronomers from the Netherlands have measured the rotation rate of an exoplanet. The exoplanet in question is Beta Pictoris b, which has a day that lasts 8 hours; for reference, the shortest day in our Solar System is Jupiter’s at 9.9 hours to complete a rotation. Coupled with the fact that Beta Pictoris b is a larger planet than Jupiter, this short day indicates the equator of the planet is rotating at 100 000 km/h (much faster than Jupiter’s 47 000 km/h, and Earth’s 1700 km/h). The astronomers were able to measure this using a very high resolution spectrograph to detect absorption features in the atmosphere of the planet. Then using the principles of Doppler shift, were able to measure the rotation speed. Suggested Reading: ESO Press Release, Nature paper, VLT wiki, The Doppler Effect (also this, hehe).
Thanks for listening!
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