A Standard Candle in the Dark

Show notes for Episode 192, April 7, 2014
Hosts: Paul, Rob C., Jesse
Title: A Standard Candle in the Dark
This week, we traversed the Solar System discussing a new way to age our own Moon, checking in on the “swimming pool” suspected by Cassini gravity measurements to exist beneath the south pole of Enceladus (satellite of Saturn) and finally meandering out to the realm of the Trans Neptunian Objects.  We then set sail for the gamma ray signatures in our own galaxy (dark matter anyone) before charging off to the distant shores of AGNs and the possible (and exciting) new standard candle method involving accretion disks and dust disks around massive central black holes.

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Comets and Asteroids and TNOs: Oh My!

Show notes for Episode 191, March 31, 2014
Hosts: Paul, Julie, Jen
Title: Comets and asteroids and TNOs: Oh My!

Tonight’s show featured a wealth of observational projects from Messier Marathons through to lunar eclipses and lunar occultations.  The outer solar system was featured with Centaur’s with rings not to mention far flung Kuiper Belt objects spanning the gap between the Kuiper Belt and the Oort Cloud.  A new segment debuted: Observatory Astro Log, featuring brief appearances by a member of the York Observatory Team.

This week in space/astronomy history:
1. March 25, 1655: Christiaan Huygens discovers Titan, moon of Saturn. Titan is the largest moon of Saturn and is the second-largest moon in the solar system. It has a dense atmosphere where lots of interesting chemistry happens. There is evidence for it having stable bodies of liquid on its surface (liquid methane).
2. March 25 1996: Comet Hyakutake closest approach to Earth.  Bright and fast moving, this was a spectacular object easily visible without any optical aid.
3. April 1 1997: Comet Hale-Bopp’s closest approach to Sun

The Observatory Log Book, hosted by Jen Zomederis
– AstroCATS – Astronomy Telescope Show May 3rd and 4th. (Tickets)
– Observatory Calendars available for a $10 donation.  Send a request to observe@yorku.ca and we will drop one in the mail!
– PV & OPV hours change as of April.  Check out yorkobservatory.com for all the details.

News:
1. Lunar Eclipse on April 15th, the first of a tetrad of eclipses, 4 total lunar eclipses in a row all visible from North America!  For This month’s eclipse,  1:58 AM is when the partial phase of the eclipse begins with totality starting at 3:06 AM EDT.  The next 3 total eclipses are October 8 2014, April 4 2015 and September 28 2015. http://science.nasa.gov/science-news/science-at-nasa/2014/27mar_tetrad/
2. Ringed asteroid: The asteroid Chariklo has two dense, narrow rings. It’s the smallest body in our solar system by far to be found with rings (the others being the gas giant planets). Chariklo is the largest of the asteroids known as Centaurs, which orbit the Sun between Jupiter and Neptune. Chariklo’s orbit is between Saturn and Uranus. The rings were discovered when the asteroid occulted a star (UCAC4 248-108672). Observations were made from 7 different observatories in South America. The rings were likely the result of an earlier collision and their configuration indicates they are either very young or that they are affected by yet-to-be-discovered small moons of the asteroid. Suggested reading ESO media release,
3. Sedna-like body discovered: 2012VP113 (nick-named Biden) is only the second object of its kind to be discovered. The first was Sedna, discovered in 2003. Both pretty far from the Sun and have highly elliptical orbits (perihelion of 76 AU for Sedna and 80 AU for 2012VP113). The solar system can be divided into 3 regions: the inner, rocky planets and asteroids (0.39 – 4.2 AU from the Sun), the gas giants (5 – 30 AU) and the Kuiper belt objects (30 – 50 AU). Sedna and “Biden” would be a part of the inner Oort cloud, the outermost grouping of objects in our solar system and the place comets come from. These objects could be the link between the Kuiper belt and the hypothesized outer Oort cloud about 10 000 AU from the Sun. There are two main models for the formation of the inner Oort cloud, as we discover more objects like Sedna and Biden, we will be able to determine which is the more likely to have happened. Suggested reading Discovery article
4. Global Astronomy Month (April is starting off with an online Messier Marathon  Check out astrowebtv.org starting from 1800 hours UT April 1 to catch all of the action, both telescopic and commentary!  Messier marathons are an exciting opportunity to see wealth of diverse non-stellar objects first found by Charles Messier over 200 years ago.  Not for the faint of heart, these marathons can result in all 110 objects being observed in one night.  It is a lot of work but a lot of fun!
5. Lunar occultations this Thursday April 3 with the Moon traversing through the Hyades star cluster.  The advancing dark limb of the Moon will occult a series of 4th and 5th magnitude stars in teh late evening (EDT).  As with all occultation measurements, accurate timing of such events can yield useful positional data on the star or the Moon and can potentially detect heretofore unknown companions.  skyandtelescope.com
6. Planet roundup for the night sky.  From the gas giants Jupiter and Saturn adorning the evening sky to the terrestrial worlds Mars (evening) and Venus (morning) there is no shortage of planets (shining with steady untwinkling light) visible to the naked eye.
7. Cosmos wrap up from last night.  Delighted to see more astronomers from history making their way into the narrative of the show.  John and William Herschel for example.  We enjoyed the discussion and description of the relationship between distance and time.  We also appreciated the tribute to Carl Sagan towards teh end and the role he played in influencing Tyson when he was just embarking onto his astronomy career.

Thanks for listening!

-YorkUniverse Team

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