Bakersfield Night Sky – June 21, 2014
By Nick Strobel
Today is the official start of the season of summer for us in the northern hemisphere and the season of winter for those in the southern hemisphere. The official start of the seasons are marked by the precise positions of the Sun against the backdrop of the stars. The start of our summer is when the Sun reaches the June solstice point, the farthest north of the celestial equator. Since the precise positioning of the Sun marks the start of the seasons, I can tell you that summer began this morning at 3:51 AM Pacific Daylight Time. For those at a latitude of 23.5 degrees North, the Sun will reach the point straight overhead (the zenith) at about noon (or about 1 PM if they are using daylight savings time). On this day the Sun will takes its longest path above the horizon, rising farthest northeast and setting farthest northwest that it will do all year.
Although the Sun's energy will be hitting our part of the Earth most directly today, the summer solstice is usually not the hottest day of the year because it takes time for the Earth to heat up, much in the same way it takes a dessert or casserole dish time to heat up in a regular oven. July and August are usually our hottest months---though, hopefully the hot days of our early June this year won't mean that we're going to have even hotter summer days!
In a week and a half, on July 1st, the Orbiting Carbon Observatory-2 (OCO-2) spacecraft is scheduled to launch. The goal of OCO-2 is to measure the production and absorption of carbon dioxide all over the globe, the "sources and sinks" of carbon dioxide. Carbon dioxide is released and absorbed by many natural processes in the oceans and the land in what is called the carbon cycle. 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. 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 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. This knowledge will provide much tighter constraints on predictions of what the carbon dioxide levels will be for our descendants 50 years from now.
A side benefit of OCO-2 is that it will be able to measure how well food crop plants are absorbing carbon dioxide---a direct measure of how productive the world's new food baskets are going to be. That's an important thing to know as we consider how to feed the additional two billion people that will be living on the Earth in just 35 years.
This last part of today's column is going to be a bit more philosophical about what the findings of astronomy tell us about our place in the universe. Near the beginning of the 1955 film "Rebel Without a Cause", a high school group is at the Griffith Planetarium for a field trip. The planetarium show ends with the Sun blowing up, leading to the destruction of the Earth and all the while the background star field remains the same. Now the astronomer in me knows that the star field 7 billion years from now will not be the same and that the Sun is not going to blow up but that wasn't the main point of the planetarium show. The presenter wanted to show that we are so insignificant compared to the rest of the universe that it won't even notice when our entire solar system is gone.
There a similar sort of scene in the 1989 film "Jesus of Montreal". The film is about what happens to a group of actors who develop an unconventional update of a Passion play at a religious shrine in Montreal. One of the characters is introduced doing a voiceover for a science documentary abou tthe events leading up to the birth of our solar system and the eventual death of the Sun. The science documentary ends with the elements that made up the solar system being returned to the universe and the narrator says, "When the last soul vanishes from Earth, the universe will bear no trace of man's passing." It's sort of a depressing message that could lead to nihilism.
One student shared his fear of the astronomy class with me after a class period several years ago. His fear wasn't the usual one about not understanding the physics and math but, rather, he feared learning about how small we are compared to the universe and getting lost in grand scheme of things. He asked me how I dealt with the tininess of humans. I told him that for me the belief of Psalm 8 is how I avoid getting lost. Despite how tiny and short-lived we and even our civilization are compared to all that God has made, God considers us special with the responsibility of taking care of this planet and each other.
Although Carl Sagan was not a religious person, I can hear echoes of Psalm 8 in his writing about the preciousness of our planet when it appears as merely a "pale blue dot" as seen from billions of miles away. One of the scenes in the final episode of the Cosmos reboot that aired two weeks ago, is a simulation of the solar system as the outward-bound Voyager 1 spacecraft saw it in 1990 when it turned its camera inward from beyond the orbit of Pluto at about 3.7 billion miles away. Looking back at the Earth from that great distance, the Earth is one tiny blueish-white speck about a tenth of a pixel in size. That image of the Earth is called the Pale Blue Dot. The image of the solar system was made at the request of Carl Sagan, who starred in the original Cosmos series.
Sagan used the image to underscore how tiny the Earth is and how insignificant it seems against the vastness of even our tiny solar system. But yet that's our home. Sagan ended his reflection with why that speck is still important and worth taking care of. He said:
"The Earth is the only world known, so far, to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment, the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another and to preserve and cherish the pale blue dot, the only home we've ever known."
That last sentence is not a scientific statement but a belief statement. Whether this arises from a humanist perspective or from a religious perspective, it is indeed a belief, a base-level assumption from which our better actions and decisions flow. It is that belief that shapes how I interpret the data of what we've discovered from science about our home and its place in the universe and why making the effort to discover how the Earth works in order to protect the future of generations to come is worthwhile. It is why teaching about it is a worthwhile endeavor.
I have taught several thousand students and given planetarium shows to many thousands more school children in my time at Bakersfield College. What is one student in all those thousands? In the coming school year, the Kern Community College District will serve the equivalent of nearly 20,000 full-time students. Many of the faculty and student services staff will serve those students as individuals because of a caring that comes from Psalm 8 or something similar. Despite the fact that one person is just one of many thousands and a student is with us for just a few years, we tend to each individual student's needs because education happens when a student can make a one-to-one connection with a teacher, counselor, librarian, or advisor at a school or college. In a recent meeting about BC's accreditation mid-term report, some even talked about the education of our community as a sacred task. Yes, teaching is worthwhile endeavor. It's why I will continue to try to improve how I present things to my students and answer each of their questions (and I definitely have a lot of room for improvement).
Another reason we seek to understand the universe through science and why I teach about it is because there are a lot of really cool, interesting things out there! Some of those things are planets. Three of the outer planets are easily visible in our evening sky tonight. From West to East, they are Jupiter, Mars, and Saturn. The first star chart below shows the western sky at 9:15 PM when the sky is finally getting dark enough to pick out several of the constellations on this date of the shortest night of the year. Jupiter is very low next to the dimmer stars of Gemini but because Jupiter is so bright, you'll probably still be able to pick it out through the dusty haze of dusk. By the second week in July, Jupiter will make a straight line with the two brightest stars of Gemini, Pollux and Castor. Mars is high in the southwest drifting eastward among the stars of Virgo. By the second week of July, Mars will be next to the brightest star of Virgo, Spica. Saturn is high up in the south among the dim stars of Libra. Farther to the left of Libra will be the bright reddish "rival of Mars" star at the heart of Scorpius, Antares. In the east we're now able to see all of the stars of the Summer Triangle at a decent time in the early evening, Deneb in Cygnus,Vega in Lyra, and Altair in Aquila. Higher up will be the bowtie shape of the central part of Hercules. The second star chart below shows the eastern sky. Don't forget the free public star party on the first Saturday of July!
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