Bakersfield Night Sky – January 4, 2014
By Nick Strobel
For this first column of the year 2014, I'm going to give an overview of some of the astronomy and space exploration events that will take place this year. In April the Gaia spacecraft will start its science operations after undergoing full testing and calibration for three months. The Gaia mission was launched a couple of weeks ago by the European Space Agency (ESA) and it will take a month to get to its orbit around the L2 point, a gravitational balance point of the Earth and Sun that is 930,000 miles further from the Sun than is the Earth. Gaia is going to survey one BILLION stars in our Galaxy and local galactic neighborhood over the next five years. With this survey it will create the most precise 3D map of the Milky Way and finally answer questions about its origin and evolution. Finding the distance to an object is the fundamental measurement because once you know the distance to an object, you can then determine its size, mass, luminosity (power output), density, and motion. The motion of the object enables us to map out the gravity field in which the object moves. The one billion star number is over 10,000 times more stars than what was done with the previous mapping mission (called Hipparcos) two decades ago. Gaia will measure the distances 200 times more accurately than Hipparcos measured. In addition, Gaia will get the 3D velocities and measure changes in brightnesses of all those stars. All this will be used to map how the regular and dark matter is distributed in our Galaxy and trace back the motions of all those stars and thereby determine how our Galaxy has changed over the past several billion years.
Along the way of creating this 3D map of the Galaxy and its history, Gaia will also find thousands of new exoplanets from the wobbling motions of the stars, as well as tens of thousands of new asteroids in our solar system, including some of which will be near-Earth objects. Other discoveries will be failed stars called brown dwarfs and many thousands of supernova explosions in distant galaxies. Also, very precise measurements of space warps from the gravity of massive objects will enable us to test key parts of Einstein's General Theory of Relativity. By the end of five years Gaia will have generated over one petabyte of data. A petabyte is a million gigabytes or about 200,000 DVDs worth of data. Another research part of Gaia is figuring out how to process and analyze such a huge amount of data.
Those are the science reasons for the Gaia mission but why is it worth doing? One question I hear often is why do we spend billions of dollars on space exploration when it could be spent helping people here on Earth. Leaving aside the fact that there are many tens of thousands of people directly employed in the U.S. in space exploration (scientists, engineers, machinists, and clerical/information technology support personnel), we do need some perspective on the money spent in space exploration compared to other human endeavors. The data I have are about what the United States spends on space exploration, so I'll talk about NASA and let the Europeans ask about Gaia and the ESA funding. According to figures from the Office of Management and Budget, NASA's budget accounts for about 1.4% of the part of the federal budget that is negotiated between the President and Congress. This negotiated part does not include the over $2.2 trillion spent on mandatory programs like Social Security, Medicare, and Medicaid. The top line items in the negotiated part of the federal budget include about 50% spent on defense, 6% spent on health and human services, 6% spent on education, 3% spent on housing and urban development, and 2% spent on agriculture. About a third of NASA's tiny 1.4% slice is spent on science and the rest is spent on things like aeronautics (airplanes and air traffic control research), commercial spaceflight, rocket propulsion systems, International Space Station, STEM education, etc. Technology invented for space exploration and space travel finds its way into applications in our everyday lives here on Earth in what are called "spin-offs technologies". In the health and medical applications area, the spin-off technologies include things like LEDs in medical therapies, infrared ear thermometers, ventricular assist devices, artificial limbs, invisible braces, scratch-resistant lenses, space blankets, etc. There are numerous others in the areas of transportation, public safety, environmental and agricultural reousrces, computer technology, and industrial productivity. See http://spinoff.nasa.gov for more about the spin-offs or www.nasa.gov/offices/oct/home/feature_economic_impact.html for a state-by-state economic impact. Overall, a variety of estimates of NASA's benefit to the economy range from three to ten dollars generated for every dollar spent in NASA research. Regardless of the measure used, it is a net gain. In the private sector there are tens of billions of dollars spent by consumers on movie and sports ticket sales alone. There is plenty of money available to solve our social health, education, and poverty problems; it is just a matter of how we choose to allocate what we have.
These economic arguments may satisfy the accountant/business part of us but it misses the more fundamental reason why we spend time and money on space exploration. When I visited family over the winter break, I attended the Christmas Eve service at the church where my brother is the pastor. Among the topics of his sermon was Gaia and why we're "chasing after a billion stars". He didn't know the science reasons behind Gaia but he did know the deeper reason for the mission and why we explore. He said that we explore because we're curious. It is that curiosity that drew us out of the caves. It is that curiosity that pulled us up the hill to gaze out at the sea and curiosity that pushed us to find out what lay beyond the sea. It is that same curiosity that draws us beyond our terrestrial bounds. Whether you believe this curiosity of humans is a God-given gift or that it is a trait enhanced through millions of years of evolution, you cannot deny that curiosity is built into us. At a deep mental or spiritual level we get great pleasure in trying to satisfy our curiosity. So in the vernacular of the day, we explore because it's cool!
In other space science research, the Orbiting Carbon Observatory-2 (OCO-2) spacecraft is scheduled to launch in July 2014 with the goal of measuring the carbon dioxide in the atmosphere all over the globe. Although we have a very good idea of how much carbon dioxide is released into the atmosphere by fossil fuel burning, we have only a vague idea of how the carbon dioxide is absorbed by the environment, especially at the regional scale. Carbon dioxide is released and absorbed by many natural processes in the oceans and the land in what is called the carbon cycle. We need to learn more about those processes and how they will change as the planet warms up because of the human factor. You need a dense, global, uniform set of measurements to start looking at carbon on the regional scale and OCO-2 will finally give us the data we need to figure it out. Since we can only manage what we can measure, we need OCO-2 to find out what and where are the "sources and sinks" of (what produces and what absorbs) the atmospheric carbon dioxide and thereby get a much better handle on how these sources and sinks contribute to the rise of carbon dioxide in the atmosphere.
In August 2014, the Rosetta mission of ESA will finally rendezvous with Comet 67P/Churyumov-Gerasinmenko after more than a decade's journey. Rosetta was launched in March 2004. Along the way to Comet 67P/CG, Rosetta flew by Asteroid Steins in September 2008 and Asteroid Lutetia in July 2010. Rosetta will be the first spacecraft to orbit a comet and land on its surface. Rosetta will start orbiting the comet in August while the comet is about 3.5 AU from the Sun, between the orbits of Mars and Jupiter. Rosetta will orbit the comet for at least one year. The lander craft will touch down on the surface in November. Comet 67P/CG gets closest to the Sun in August 2015 and the mission is scheduled to end in December 2015, so Rosetta will explore various stages of a comet's activity up close.
On September 22, 2014, the MAVEN spacecraft will arrive at Mars to explore the planet's upper atmosphere, ionosphere, and interactions with the Sun and solar wind. This study of Mars' upper atmosphere will enable us 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 today. Mars' thin atmosphere makes it extremely challenging for any form of life.
In October 2014, 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. The 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.
In the early morning of October 8, 2014, there will be a total lunar eclipse visible from Bakersfield. The Full Moon will go through the northern half of the Earth's umbra shadow. The umbra shadow is the region in which the light source would be totally blocked, so it is the darkest part of a shadow. The umbral part of the eclipse begins at 12:15 AM our time and totality goes from 3:25 AM to 4:24 AM. The Moon will leave the umbra at 5:34 AM. Two weeks later on October 23rd, we will experience a partial solar eclipse. As seen from Bakersfield, the New Moon will partially cover the Sun from 1:03 PM to 3:38 PM our time. At maximum eclipse at 2:25 PM, the Moon will cover up 35.7% of the Sun's surface area. Cities further north will see a bit more covered up but no place will see a total solar eclipse. You can find out the details for other places at http://eclipse.gsfc.nasa.gov/JSEX/JSEX-USA.html .
In our immediate future, Venus is still up an hour after sunset but it is plunging quickly toward the Sun over the next few evenings. It is an extremely thin crescent. On January 11th it will pass between us and the Sun in what is called "inferior conjunction". After that it will begin climbing up away from the Sun and become visible in the pre-dawn morning. Tomorrow on the 5th, Jupiter will be at opposition or directly opposite the Sun on our sky, so it will be rising as the Sun is setting. Jupiter continues moving retrograde in the constellation of Gemini. Mars rises shortly after midnight among the stars of Virgo. The attached star chart shows the midnight sky. By then, Jupiter will be up high in the sky due south. We're catching up to Mars in our faster orbit, so over the next several months Mars will get large enough to see some surface features in large amateur telescopes under excellent sky conditions. Tonight the Moon is visible in the southwest as a Waxing Crescent phase. It will set at about 9 PM. First Quarter phase will be on January 7th and a nearly Full Moon will pass under Jupiter on the night of the 14th/15th.
One last astronomy event to wrap up this column happened this morning. The Earth reached perihelion, the closest distance to the Sun, today at about 4 AM our time. At perihelion the Earth is only 91.65 million miles (147.5 million km) from the Sun but we're still in winter because of the shallow angle of sunlight hitting our part of the Earth and the short amount of time the Sun is above our horizon.
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