Bakersfield Night Sky – November 2, 2013
By Nick Strobel
A week ago Friday was a great night of celebrating Bakersfield College's 100 years of service to Kern County. Over 400 guests wined and dined in the Gil Bishop Sports Center, nicely decorated for the evening. The following day was another day of celebration at Wesley UMC's Fun Day in their pumpkin patch as I helped monitor the jump house for the children who came to day's festivities in the patch. Reflecting back on both events and looking forward to the upcoming Thanksgiving holiday, I'm thankful that I get to spend most of my time at two places with open doors and that are in the "business" of transforming lives.
In the astronomy research realm a recent story from my JPL news feed made me thankful for all of the abundant liquid water we have on this little planet of ours. Planets like ours with all of the liquid water might be less common than originally thought, even though we know of plenty of exoplanets in the habitable zones of their planet systems. Life as we know it needs liquid water so the habitable zone definition is based on the temperatures needed for liquid water to exist on the surface of the exoplanet---not too close to the star so that the temperature is below the boiling point of water and not too far from the star so the temperature is above the freezing point of water. Life as we know is based on the atom called carbon. Of all the atoms, carbon is the most versatile for making the long, complex molecules needed for biochemistry. Well, it turns out if a planet system is made from a gas cloud with too much carbon, the planet-building chunks will contain very little water.
Our star, the Sun, is a relatively carbon-poor star, so the gas cloud it (and the planets) formed from was relatively low in carbon. That explains why the terrestrial planets are made largely of silicates instead of carbon. Planets forming from gas clouds with more carbon will have plenty of carbon, some of which may even be in the form of layers of diamond in the planet. However, these carbon-rich gas clouds will snag the oxygen away from the hydrogen, so the water molecules cannot be formed in great abundance like we have in our solar system. For most places in our solar system, the water is in the form of ice. The liquid water on our planet makes up less than 0.023% of the mass of the Earth and just 1% of that miniscule fraction is fresh water that we can use to drink and grow our crops and we have to share that tiny amount of water with over 7.1 billion people (climbing to 9 billion by 2045).
The Mars orbiter mission, MAVEN (short for "Mars Atmosphere and Volatile EvolutioN"), is still go for launch on November 18th. MAVEN will study Mars' upper atmosphere to find out how Mars' atmosphere is leaking away now and what all happened in the past to make it have such a thin atmosphere. Liquid water cannot exist on Mars' surface today because its atmosphere is too thin. At low enough pressures, water will boil at even room temperature, so water will exist in either solid or gaseous (vapor) form without any liquid intermediate state. If you mix in chemicals like perchlorate in with the water, it is possible to have that mixture be in a liquid state for a short time on a place like Mars.
On the surface of Mars, the Opportunity rover that landed in 2004 is now climbing a hill called "Solander Point" on the rim of the Endeavour Crater. The ridge material were uplifted and overturned by the great impact that made the crater billions of years ago, so that the older materials will be on top of the younger layers instead of usual reversed sequence. Most of the rocks that Opportunity has studied are sulfate-rich rocks that formed in wet, but very acidic conditions. Earlier this year, Opportunity found some very old rocks that formed in wet more neutral pH conditions, like its larger cousin, the Curiosity rover, found in Gale Crater. The Opportunity science team is hoping to map out the transition from a wet, neutral pH watery time in Mars' early history to the drier, acidic water time in its later history as Opportunity climbs Solander Point. Also, the slope of the hill will keep Opportunity's solar panels at a better angle to catch the Sun's rays as Endeavour Crater heads into the winter season.
A couple of other ice worlds are in the astronomy news. One is Comet ISON that I've talked about in previous columns. A recent image from the Hubble Space Telescope shows that it is still active and in one piece. The nucleus is too small to see even with Hubble, between 0.5 to 1.5 miles across, but there are no multiple bright spots indicating any break up yet. The comet nucleus is the mountain-sized frozen chunk of dirt, dust, and ices of water, carbon dioxide, ammonia, etc. from which all of the material comes. When the nucleus gets to within Saturn's or Jupiter's distance from the Sun, it warms up to form a dirty atmosphere called the "coma" around the nucleus. At about the distance of Mars from the Sun, the Sun's solar wind and photon pressure is strong enough to push the coma material outward to form the tails that can stretch a few million miles. We still don't know how bright ISON will get around Thanksgiving time. ISON is now about a fist-width at arm's length below Mars in the pre-dawn sky, to the right of the back end of Leo (see the first star chart below) and you still need a telescope to see it.
The other ice world in the news is Comet C/2012 X1 (LINEAR) because it recently flared up to become over 250 times brighter (about six magnitudes in the astronomer's brightness scale). It is now possible to see it with binoculars on a dark sky by looking toward the constellation of Coma Berenices just above the eastern horizon shortly before sunrise---see the first star chart below. Before the flare-up, you needed a large telescope to detect Comet C/2012 X1. It is about 3.0 astronomical units from the Earth (one astronomical unit is about 93 million miles). By November 17th it will pass close to the bright star Arcturus. While you're looking at those two comets, see if you can spot Comet Lovejoy (C/2013 R1) and Comet Encke in the eastern pre-dawn sky. The first star chart below shows the location of all four comets. Of these four, only ISON is expected to become visible to the unaided eye.
The Moon is at New Phase tomorrow early morning. In fact, observers on the other side of the world, in Africa, will be able to see a very brief total solar eclipse when the New Moon is exactly lined up with the Sun. For us here in Kern County it means that the Moon is not going to spoil any views of the dark sky. Hopefully, any of my students still needing to do their meteor skywatch project will take advantage of this weekend to observe under a sky without any interference of the Moon. Next Saturday the Moon will be at First Quarter phase for the last of the free public star parties held by the Kern Astronomical Society at Russo's Books in The Marketplace. Hopefully, the weather will cooperate and keep the skies clear for that. Come by any time between 8 and 10 PM to take a look at the sights through the KAS telescopes.
In the early evening, Venus is now alone because Saturn and Mercury are too close to the Sun on our sky for us to see. Mercury passed between us and the Sun ("inferior conjunction") yesterday and Saturn will pass behind the Sun on November 6th. Venus will get even brighter this month as it catches up to us but it is going to remain fairly low in the western sky. It is now among the stars of Sagittarius. The Great Square of Pegasus will already be halfway up in the eastern sky by the time the sky gets dark enough to see other things besides Venus. In the northeastern sky, the Pleiades star cluster becomes visible after 7 PM (or 6 PM after daylight savings time ends on Sunday morning). The cross-shape of Cygnus the Swan will be high up directly overhead at that time. The second star chart below shows early evening western sky. Venus will set shortly after 8 PM tonight (still daylight savings time) and you'll need to wait until about 11 PM to see bright Jupiter rise up with the stars of Gemini.
Want to see more of the stars at night and save energy? Shield your lights so that the light only goes down toward the ground. See www.darksky.org for how.
Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com