Bakersfield Night Sky – October 3, 2015
By Nick Strobel
Bakersfield is in a drought. So it was a bit disappointing that the one night that the weather decided to have cloudy skies was the night of the total lunar eclipse. We did manage to catch glimpses of it with the appropriate oo's and ah's. Quite a crowd of people came out to the KAS public star party that night and dodged sprinklers as the KAS members shielded and moved telescopes about to avoid getting soaked. Now we know that Sunday nights are not good nights for public star parties at Panorama Bluff Park. Good thing the rest of them have been on Saturdays. The next one will be on October 24th. That one will be the last one of the star party season.
The New Horizons spacecraft continues to send back images and other data taken from its flyby of Pluto last July. One particularly beautiful image is from a vantage point that has the Sun at a low angle and mountains at Pluto's limb jutting above the otherwise flat horizon line. The low Sun angle produces noticeable shadows from the other mountains in the image to create a really nice 3D effect. I don't think the regular news media picked up this gorgeous image but you can see it and so many more images at the New Horizons website at http://pluto.jhuapl.edu .
Last Monday, a team of scientists announced that they were finally able to confirm that the dark streaks they see forming in the martian spring and summer and then disappearing in the fall and winter are due to liquid water mixing with salts. The spectrometers aboard the Mars Reconnaissance Orbiter have confirmed that water in the dark streaks has combined with chlorine and perchlorate salts. We've known for a while now that water did flow on Mars long ago. However, water present TODAY is a major finding. First of all, life as we know it needs liquid water and everyplace we have found liquid water on Earth, we have found life, including life in some very harsh places. Second, this has major implications for human exploration and living on Mars because it means we can live off the land.
Water is the best liquid material to use for biological activity for a variety of reasons. Liquid water dissolves other compounds better than liquid methane/ethane and biochemical sort of reactions work better in liquid water than liquid methane/ethane. Water is liquid at a wide temperature range. Because of the very low air pressure on the surface Mars (equal to what you would feel about 100,000 feet above sea level on Earth), pure water would be a stable liquid for temperatures of just 0 to 10 deg C. Mixing in with perchlorate salts like we find on Mars increases the range of liquidity from -70 deg C to +24 deg C under Mars' very low air pressure.
What else is good about liquid water? Biochemical reactions will not happen in solids and they would be very inefficient in a gas. Water is liquid at a higher temperature than methane, ethane, and ammonia so chemical reactions will happen more quickly in the liquid water than in the other liquids. Also, frozen water floats! The hydrogen bonds of water make water less dense when it freezes. The frozen water ice could form a protective layer insulating the liquid water below it. The other types of liquids sink when they freeze and could lead to a runaway freezing process where all of the liquid freezes. Finally, water in some form (mostly either gas or solid) is actually quite abundant in the Galaxy so we are not limiting ourselves too much with the water bias.
Liquid water on Mars means human explorers and settlers would not need to bring as much water with them. The water molecules can be broken apart to make oxygen to breathe and hydrogen for rocket propellant or energy generation. Although, we now know that the dark streaks are formed in the presence of liquid water, we don't know for sure where that water comes from, so that's the next step in our investigation.
Earlier in September a team of scientists using data from three Mars orbiters ruled out one popular theory for how Mars's atmosphere became so thin which means I need to update the Mars section of my Astronomy Notes online textbook. (Not the first time and not the last time that I'll be updating that section of Astronomy Notes.) One theory for Mars's thin atmosphere is called the "runaway refrigerator" in which atmospheric carbon dioxide is locked up in the rocks. That reduces the greenhouse effect which causes even more removal of the atmospheric carbon dioxide as it falls to the ground dissolved in rain water on a cooling planet.
Here on Earth there are ways to prevent such a collapse. It's called the carbon cycle. There is a rough balance of natural inputs of carbon dioxide into the atmosphere and removal of carbon dioxide from the atmosphere with the dissolving of carbon dioxide in water being the quickest way and the combining with rocks occuring over much longer timescales. Of course, there is the recent man-made contribution that is an extra input to the carbon cycle, throwing off the natural climate cycle.
The planets Venus on the hot side and Mars on the cool side show what can happen if things get too out of whack on a planet.
Now for what's happening in the Bakersfield sky. Saturn continues its lonely vigil in the evening sky next to the head of Scorpius. It is low in the southwestern sky at sunset and will set about 2.5 hours after the Sun does. Later in October it will set within just 1.5 hours of the Sun.
The really interesting things this month are happening in the early pre-dawn morning sky with close conjunctions of Venus, Jupiter and Mars among the stars of Leo in the east (see the attached star chart). In tomorrow's pre-dawn morning, Venus, Regulus, Mars, and Jupiter, in that order from top to bottom, are equally-spaced along a slight curve in the east about an hour before sunrise.
On the early morning of October 8th, a thin Waning Crescent Moon will form a beautiful triangle with Regulus and Venus that will easily fit within the field of view of regular binoculars. The next morning, an even thinner crescent Moon will form another triangle with Mars and Jupiter.
On October 17 and 18th, dimmer orange-red Mars will be less than half a degree away from the much brighter and whiter Jupiter. That angular distance is about the width of your pinky held at arm's length. On those mornings you might be able to see Mercury very low in the east shortly before sunrise.
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