Bakersfield Night Sky – January 3, 2015
By Nick Strobel
Happy New Year and Happy Perihelion Day! Today at 10:37 PM the Earth will be at its closest distance to the Sun, a mere 91.4 million miles. Even though our part of the Earth (Kern County) is closer to the Sun in actual distance than during the spring and summer, the northern hemisphere is tipped away from the Sun during the fall and winter and it is the angle of the Sun that makes all the difference. During the fall and winter the Sun's light is hitting our part of the Earth at a more glancing or shallow angle than during the spring and summer, diluting its heating effect. Also, the Sun is above our horizon for a shorter time. Less cooking power and less cooking time mean the temperature is lower.
Shortly after sunset tonight look low in the southwest to see Venus shining very bright. In the evening twilight glow and typical haze layer at the horizon, Venus may be be the only bright point you see down low in the southwest but you may also see slightly below it another bright point. That's Mercury. Speedy Mercury will be less than a degree away from Venus by next Saturday, January 10th. The first star chart below shows tonight's view and next Saturday's close conjunction of the two inner planets. Mercury will move away from Venus and climb farther away from the Sun over the following nights and reach its greatest separation from the Sun on January 14th. After that it will quickly fall back toward the Sun and be lost from view in the next week and a half and be between us and the Sun (inferior conjunction) on January 30th. Above and to the left of Venus will be the much dimmer orange-red Mars. Shortly after 8 PM on the opposite side of the sky, you'll see bright Jupiter rising in the east. The Waxing Gibbous Moon will be already up in the eastern sky at sunset. The Moon will be at full phase tomorrow. A Waning Gibbous Moon will pass below Jupiter the night of January 7th (see the second chart below).
The year 2015 promises to be an exciting year in astronomy filled with new discoveries, especially as we explore worlds in our solar system for the first time up close. For the first installment of this column in 2015, here are some particularly noteworthy events we look forward to in the coming year.
At the end of January, the Soil Moisture Active Passive (SMAP) spacecraft will launch on a three-year mission to measure soil moisture and the freeze-thaw state of all regions of land on the globe. It turns out that Bakersfield has a special connection to the SMAP mission. The SMAP project manager at JPL, Kent Kellogg, grew up in Bakersfield. He graduated from South High in 1979 and joined JPL in 1983 after getting his degree from Cal Poly San Luis Obispo. The SMAP mission will improve our understanding of all of the intricasies of how water moves about the globe and is taken up in the soil and in the plants we eat or feed the animals we eat. SMAP's measurements will enable us to understand the processes that link the terrestrial water, energy, and carbon cycles; enhance weather and regional climate forcasting skills; and develop improved flood prediction and drought monitoring capabilities.
Although recent storms have brought us some much needed moisture, they have not replenished our water reservoirs enough to end the drought. In fact, it would take about 11 trillion gallons (about 1.5 times the volume of the largest reservoir in the US) to recover from the drought. That result is from a different NASA satellite called GRACE that measures the gravity field of the Earth very precisely to find what places have more mass such as a mountain range or a filled water aquifer or less mass such as an empty water aquifer or shrunken ice sheet. The mission has been operating since 2002, so we've been able to see how different parts of the Earth have changed.
The Dawn spacecraft will reach the largest asteroid, dwarf planet Ceres, in early March. Dawn studied the second-most massive asteroid, Vesta, between July 2011 and September 2012. Then in a first for an interplanetary spacecraft, it left from orbiting one object to travel to another object and orbit it. Its ion propulsion is what made that possible. Ceres is about 590 miles diameter with a surface area equal to about 38% of the 48 contiguous states. That's a lot of surface of interesting geology that has not been seen before. We think Ceres has a water ice mantle sandwiched between a rocky core and a thin, dusty crust. There is the possibility that some of the water is liquid. Almost a year ago, astronomers using the Herschel Space Observatory discovered water vapor surrounding Ceres, so there may be geysers shooting up thin plumes of water vapor when parts of Ceres's surface warm slightly.
Later in March, on March 20, there will be a total solar eclipse. The total solar eclipse will start in the north Atlantic Ocean south of Greenland. The path of totality will loop to just east of Iceland and then to north of Norway and Siberia. Totality will last up to 2 and 3/4 minutes.
Two weeks later on April 4th, there will be a total lunar eclipse. We will be able to see it from Bakersfield after midnight in the early morning hours of April 4th. The Full Moon will enter the Earth's umbra at 2:16 AM and leave the umbra at 5:45 AM. Because the Moon is traveling through the very top part of the Earth's umbra, totality will be very brief: from 3:58 to 4:02 AM. Yes, just 4 minutes of total lunar eclipse.
New Horizons will fly by Pluto on July 14, getting to within 6200 miles as it flies by at 31,300 mph. Pluto will be 3.06 billion miles from Earth at that time, so the radio signals traveling at the speed of light will take 4 hours 25 min to reach us. The "encounter" will begin about 4 weeks before closest approach. The New Horizons spacecraft will begin making daily studies of Pluto and its five moons about 4 weeks before closest approach and continue the daily studies about 4 weeks after closest closest approach. However, most of the data about Pluto will be gathered in the 24 hours around closest approach. It will take about 9 months to download the entire dataset from the encounter.
On September 13th will be a Partial Solar Eclipse but it will be visible only in South Africa, Madagascar, and Antarctica. Two weeks later on September 27th will be a total lunar eclipse with much more convenient viewing time for us than the April eclipse. The eclipse will have already started when the Full Moon rises: the Moon will enter the Earth's umbra at 5:07 PM and the Moon will rise about 5:45 PM. Totality will last from 6:11 PM to 7:23 PM and the Moon will leave the Earth's umbra at 10:27 PM.
Finally, there will be a Full Moon on December 25 to illuminate the rooftops for Santa on his rounds. Enjoy watching the sky!
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