Brown Dwarfs Are Not Really Brown

Show notes for Episode 184, 2014 February 3
Hosts: Rob C., Paul
Title: Brown dwarfs are not really brown!

McMaster’s McCallion Planetarium:

This week in space/astronomy history:
1. Gerald A. Soffen (February 7, 1926 – November 22, 2000)  Viking (Mars) mission manager, he moved from a successful NASA project scientists to NASA educator.  He now has a crater on Mars named after him.
2. Luna 9 (3 February 1966) made the first soft landing on the Moon (or first soft landing on any other object in the Solar System). 12th attempt.  Operations lasted for about 3 days.  Part of the Soviet Union’s Luna programme, it was another first for the Russians… so would they get the “ultimate” first and put the first human on the Moon?  Interesting side story: the Russians initially delayed releasing images from the surface – but apparently used the internationally-agreed system for transmitting newspaper images.  Jodrell Bank picked up on these signals, and so British newspapers picked up the images and distributed them worldwide! Motivations? Russians wanted higher quality pictures from Jodrell Bank but wouldn’t admit to asking for them… or Russian scientists didn’t want Russian politicians to politicize the event???
3. STS 41B, Space Shuttle Challenger, launched February 3 1984, saw the debut of the Manned Maneuvering Unit (MMU).  Astronaut Bruce McCandless flew the MMU.  The MMU flew only 3 flights before being retired.

1. ESA’s Planet-Hunter Plato. Plato stands for Planetary Transits and Oscillations, and this science mission has moved a step closer to realization for the European Space Agency.  Final approval from all member states won’t come until 2015 but its unlikely that the mission will be stopped at this late stage; the projected launch date is 2024.  Its goal will be to look for Earth-like rocky planets in stable habitable zones around dwarf stars and subgiants that may be able to support liquid water.  It will have a much larger field of view compared to Kepler, and will concentrate on brighter stars (magnitude 8-11) which will make it easier for follow-up measurements from ground-based telescopes.  Plato, if it goes ahead, will follow in the footsteps of ESA’s Solar Orbiter (launch 2017), Euclid (launch 2020), and will differ from NASA’s TESS (Transiting Exoplanet Survey Satellite; launch 2017) as TESS will be looking at closer-in orbits around cooler stars.  (Suggested reading: BBC article, wiki article)
2. Sagan’s Popular Cosmos to Make a Comeback.  “Cosmos: A Personal Voyage”, a documentary series about the Universe, co-written and presented by Carl Sagan in 1980 is to return to our screens. “Cosmos: A Space-Time Odyssey” will be presented by Neil deGrasse Tyson starting 9 March 2014.  Visual effects have been updated, and the music will be composed by Alan Silvestri.  Watch the trailer, and see what you think.  Interesting side-note: Tyson and Sagan did meet but never actually worked as colleagues, but apparently Sagan read Tyson’s application to Cornell – although Tyson eventually chose to go to Harvard (Suggest reading: Personal Voyage wiki, Space-Time Odyssey wiki)
Related: Sagan’s papers available in online exhibit.  Carl Sagan was not only a science popularizer through TV, but also in print. Pale Blue Dot, Contact, Cosmos, and The Demon-Haunted World are titles familiar to many.  Now the Library of Congress has acquired 800 boxes of notes, letters and journals from Sagan’s widow Ann Druyen, and made them 300 items available online for free.  The online collection includes Tyson’s application to Cornell, noted above.   (Suggested reading: Library of Congress press release, Cornell Chronicle article)
3. Mapping weather on a brown dwarf.  Whether you view brown dwarfs as failed stars or over-sized planets, being able to map the weather on the atmospheres of these objects is an  impressive feat – and also paves the way to being able to discern weather patterns on exoplanets too.  Earlier this year, NASA’s Spitzer and Hubble space telescopes teamed up to view different layers within a particular brown dwarf’s atmosphere and viewed its varying brightness.  More recently, ground-based telescopes have studied another brown dwarf about 6.5 light-years distance using a combination of the light’s varying brightness and also its Doppler shift – to indicate whether the light is moving towards or away from us.  Another team used different wavelength filters to probe the different atmospheric layers.  Watch this space as these newly-developed techniques are refined!  (Suggested reading: JPL NASA press release, Sky and Telescope article)
4. Grey holes not black holes… and rethinking event horizons.  Trying to combine the fundamental forces of nature – including gravity, a force that acts on very large scales – with quantum theory, the laws that govern on the smallest scales, has been problematic for decades.  But we need to be able to do that if we are to correctly describe black holes, as noted by famous astronomer Stephen Hawking who recently made a u-turn on some of his previous theories about these exotic objects.  Rather than having event horizons, an imaginary surface surrounding a black hole beyond which nothing (not even light) can escape, we may now have to consider “apparent horizons”.  These apparent horizons would allow information to escape from the black hole, but in a highly disordered and chaotic form.  (Suggested reading: BBC article, Nature article)
5. International Space Station gets new eyes.  New British-built Canadian-operated “Urthecast” cameras attached to the ISS will allow streaming of high-resolution video of Earth.  The hope is to build a business around providing footage of the Earth from space – for example, for news media outlets or social media.  “Skybox Imaging” and “Planet Labs” are similar companies set up for a similar purpose.  NASA is also launching satellites later this year to study winds, storm and other atmospheric- and climate-related patterns on Earth. (Suggested reading: BBC article)

Major Topics Discussed:
Comets of the 20th Century.  While Comet ISON did not dazzle the public during December skies, it did raise awareness of comets to new heights.  But many comets have had their moments of fame, some being referred to, positively or negatively, as the “Comet of the Century”.  Halley’s comet of 1910 caused widespread unease and dazzled the public with great sights.  Yet its return is 1986 was poor at best.  Did you know that their was another comet that almost upstaged Halley in 1910 and is simply referred to as “The Great Comet of 1910”?
Comet Kohoutek in 1974 is remembered for the show it never produced!  It is notoriously difficult to predict a comet’s brightness.  It depends in large measure on the volatile content which is rarely known.  The show is obviously dependent upon the perihelion distance not to mention its relative distance from Earth.
The 20th century finished with a flurry of comet activity.  Remember Comet Shoemaker Levy 9 and the pummeling it gave to the planet Jupiter, not to mention Comets Hyakatake in 1996 and Hale-Bopp in 1997.

Thanks for listening!
-YorkUniverse Team
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