Bakersfield Night Sky – July 16, 2016
By Nick Strobel
On July 4, the Juno spacecraft went into orbit around Jupiter right on schedule. The main engine fired for just one second longer than expected and now Juno is in the first of three 53.5-day capture orbits. During these first very huge orbits, the Juno team will make sure all of the electronics on Juno and data process pipeline are working properly. On October 19, the main engine will fire again to change the orbit into a shorter 14-day one for the science observations. See www.nasa.gov/juno for updates about Juno and what it will learn about Jupiter. (Also, check out my previous columns about Juno!)
In the following few days after Juno went into orbit around Jupiter, Apple iTunes had a very nice “Destination: Jupiter — Visions of Harmony” video on its start screen. The video shows the parallels between the creativity required to design and construct a science spacecraft like Juno and that required to make great music. One of the musicians (Corinne Bailey Rae) even talks about the beauty of the mathematics of music theory and connects it to the mathematics used by scientists to understand the patterns in nature. Our brains are made to find patterns and our souls revel in the patterns of nature, whether we discover the patterns or make new patterns. It is also posted to YouTube for everyone to enjoy. Do a search for “NASA: Visions of Harmony”.
In tonight’s sky, you’ll see a nice line of bright points from the south to the west plus a gibbous moon to the left of line. Jupiter will be the bright point in the west. It is below the back end of Leo as shown in the attached star chart. Next in the line to the left of Jupiter is the brightest star in Virgo, the blue-white hot Spica, which is actually a binary system of blue class B type stars orbiting each other about three times closer than Mercury orbits the sun. Both of the stars are so hot that they radiate most of their energy in the ultraviolet.
Further left is orange-red Mars in the dim constellation Libra. Although Mars is now dimming as we pull ahead of it in our faster inside orbit, Mars is still brighter than any of the true stars in this evening’s sky. A few weeks ago, the Curiosity rover found strong evidence that Mars had significantly more oxygen in its atmosphere long ago at the time when there were also water lakes. That means ancient Mars was a lot more Earth-like than it is today. However, the oxygen was probably not the result of photosynthesis such as what happened on Earth but, instead, is the result of solar wind breaking apart the water molecules and the hydrogen atoms escaping away to space. Mars’s smaller size meant that it lost its protective magnetic field long ago as its core hardened. The loss of the magnetic force field left Mars’s atmosphere prey to the solar wind. The oxygen of the broken-apart water molecules went into the rocks to make the rusty red (iron oxide) dust and minerals such as manganese oxides. Manganese oxides require a significant amount of oxygen to form. Thousands of miles from Curiosity’s location, the Opportunity rover also recently found manganese oxides, so an oxygen-rich environment was clearly a global phenomenon. Check out mars.nasa.gov for more details.
Almost due south at 9:30 p.m. is the last of the bright points in the line, the brilliantly-ringed planet Saturn. Saturn is just above the bright red heart of Scorpius, the supergiant Antares. The Cassini spacecraft orbiting Saturn is now changing its orbit to carry it high above Saturn’s poles. The polar orbits will pass just outside Saturn’s main rings. Another set of adjustments next year in April 2017 will make Cassini pass between the innermost rings and Saturn’s cloud tops for Cassini’s closest view of the planet yet. In mid-September 2017, Cassini will plunge into Saturn’s atmosphere after 13 years of exploring Saturn and its many moons.
Beginning next week you might be able to see some meteors in meteor showers. Meteor showers come from debris left behind by comets. The Delta Aquariid meteor shower produces a modest display that peaks on July 28. The Alpha Capricornid meteors can also be seen in last part of July and usually produce some unusually slow-moving, bright meteors. Because each meteor shower occurs over several days, we may even be able to see a few Perseid meteors even though they peak in the second week of August.
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