StarWatch: Moravian College Astronomy

StarWatch for the greater Lehigh Valley

FEBRUARY 2018

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1120 FEBRUARY 4, 2018: Sizing Up the Universe: For my first lesson which focuses upon developing a simple, but meaningful definition for astronomy and discussing the subject in its broadest sense, I have my students write a list of all the words that each believes are related to the subject. It is a timed exercise, five minutes in length, and currently, Joe Hall, a former Moravian astronomy student, holds the record for having written 70 entries in that space of time. I’m not even sure I could ever be that quick. In fact, after Joe’s record setting accomplishment, I had to redesign the page to accommodate additional spaces because originally there were only 60. The winner this semester was Beth Thomas who had 66 words. The definition that I developed for astronomy 46 years ago, and that my students discover during the lesson, goes something like this. Astronomy is the science that investigates all matter and energy in the universe. When I met my first astronomy class in 1972, we didn’t know exactly how old the universe was; the estimates ranged from eight to 20 billion years. Now we know that it is 13.82 billion years in the making, and because of that fact, we know from “end to end” it measures over 50 billion light years. A light year is the distance that light travels in one year, about 5.8 trillion miles. In 1972 we fully understood that the universe was expanding, but the fact that we didn’t have the most accurate rate of expansion produced the improbability of its size and age. Then there was the problem of how the universe began. We are still puzzling the answer to that one, but because it was expanding, we anticipated that it had a beginning. Astronomers envisioned an explosive event, something today that we call the “Big Bang.” Currently, it appears to be more of a very gentle pop, although the term “Big Bang” is here to stay. An explosion would have triggered humongous amounts of turbulence which would have created large thermal differences in our observation of the early universe. What we find are differences in temperature across the early universe of a miniscule 1/100,000 K or about 1/180,000-degree Fahrenheit. This is exactly what we should expect if the universe evolved based upon what we observe its structure to be today—like a sponge with huge voids and the spongy material being vast superclusters of galaxies. Another question was the ultimate fate of our universe? The current answer is not philosophically pleasing. We thought (hoped) at one time that the gravity of all of the structures in the cosmos would pull the universe back together to be reborn in perhaps another Big Bang, the Oscillating Universe, but today we know that won’t happen. In the mid-1990s Hubble telescope observations of distant supernovae (exploding stars) revealed that the universe was accelerating, and that what we see in the cosmos around us is only about five percent of the real picture. Twenty-seven percent of the universe represents something called dark matter, which we have hypothesized since the 1930s, and the rest of the universe, about 68 percent, is composed of dark energy. As the universe expands, the amount of matter (dark and what we see) continues to thin, but the amount of dark energy remains constant per unit volume, thus causing the acceleration. Although no matter can touch the speed of light, space may expand beyond that limit. One day into the distant future sentient creatures will wake up to a universe where all of the stars of our Milky Way and the other galaxies that have combined with it have died. The few other galaxies that might still be shining will be so distant that no light from any of them will reach us. The heavens will be black. It makes me happy to realize that we are at least living in the springtime of our universe, an epoch when it is awash with the glow and brilliance of billions of new stars and vibrant galaxies wherever we look. That fragile blush of youth will not last forever.

1121 FEBRUARY 11, 2018: Science and Art: Girl with a Pearl Earring: During my nine years teaching astronomy at Moravian College, I have had many groups of students filter through my classes. In the beginning it was music majors, then I went through a more eclectic period, and now the Saudis have discovered that astronomy can be fun. The majority of my pupils, particularly those majoring in the visual arts, believe that they are disconnected from the sciences and mathematics; so my first responsibility is to ease their angst about a discipline in which they believe that success is a myth. Two books have proven supportive of my philosophy in helping students understand that they can all “do” science: Bulent Atalay’s Math and the Mona Lisa: The Art and Science of Leonardo da Vinci, Smithsonian Books, 2014, and Laura J. Snyder’s, Eye of the Beholder: Johannes Vermeer, Antoni van Leeuwenhoek, and the Reinvention of Seeing, W.W. Norton & Company, 2015. Atalay’s theme in my mind is simply this. Inherent within the ability of any good artist to conceive enduring works is a mathematical sense of proportions, the golden triangle, and the golden rectangle, etc., which gives the artist the ability to place objects in their proper place, perspective, and proportions to one another to be pleasing to the viewer, who also possesses these instinctual concepts, but to a lesser degree. Most artists give no thought about how mathematical their minds must be in order to create good art—they simply create, but da Vinci (1452-1519) was different, understanding the process and experimenting with it laboriously as he slowly created his masterpieces over the duration of years of work. And yet, I never really cared for da Vinci’s art. Yes, it was pleasing and beautiful to behold, but I was never moved by it. I never understood why until I read Snyder’s Eye of the Beholder. I am a horrible artist, but I do appreciate the arts as all of my students discover during my course. I never could draw or paint, but put a camera into my hands, and suddenly I wasn’t so bad. I had a sense of proportion and balance which produced agreeable images to my friends and me. For a while, I even entertained becoming a photographer and sought out critiques from other artists and photojournalists, including National Geographic. Like da Vinci, Johannes Vermeer (1632-1675) was also an experimenter, using the camera obscura, a precursor to modern photographic perspective, to create many of the scenes and subjects which he painted. The device projected an inverted image onto a screen or canvas through a pinhole or lens, creating the perspective of a photograph and a greater ability for Vermeer to manipulate light, something with which I could easily identify. Camera obscuras were being “reinvented” by 17th century Dutch artists. Given the opportunity to own da Vinci’s Mona Lisa or Vermeer’s Girl with a Pearl Earring, it would be Vermeer hands down. The Mona Lisa leaves me flat, but the photographic likeness of Vermeer’s young woman stares deep into my soul, in a similar fashion as National Geographic photographer Steve McCurry’s image of Sharbat Gula taken in late 1984 in a refugee camp in Pakistan. “Stupid astronomer,” you might say if you are into the arts, but not so stupid as you may think. It was aesthetics and photography that nurtured my interest in astronomy, which I personally have labeled the beautiful science. If you have never gazed across a velvety rural nightscape painted with the glimmer of a thousand stars, then your artistic pallet is sorely incomplete. Compare Vermeer’s Girl with a Pearl Earring and McCurry’s Sharbat Gula online at astronomy.org. Click on “this week’s StarWatch.”

1122 FEBRUARY 18, 2018: Where have all the Planets Gone?: There is a yin and a yang regarding the location of the planets in the sky. Positions are affected by their own individual orbital speeds which vary for each planet and the Earth’s motion through space. Then there is the sun. If the planets are located to the west of Sol (to the sun’s right), they rise before the sun and are visible only in the morning sky when most of us are asleep. If they are to the sun’s east (left of the sun), we get to see them after sundown when we are normally awake, and the day’s chores are concluded. The sky has been devoid of planets for several months because all of the “wanderers” have been to the west of Sol and visible before sunrise. Things are changing, and as we head towards the vernal equinox, the traditional planets that can be seen with the unaided eye will begin to “spring” into view as their positions move east of the sun. The first wanderers to debut will be Mercury and Venus which will appear to rocket up from the sun in early March. By the 3rd they will sit literally side-by-side separated by only one degree. They will shine with greater luminance through any pair of binoculars, but because of their low altitude, you’ll need an extremely good western horizon. Start viewing the skyline about 25 minutes after sundown just a little to the south of west or to the left of where the sun’s twilight glow is the most intense. Brighter Venus will appear to the left of Mercury. Ten days later, the Messenger God is now four degrees above Venus. Both planets have moved much higher into the western sky and will be visible to the unaided eye about 40 minutes after sundown in deeper twilight, but now due west. I would be at my observing site about 30 minutes after sundown and with binoculars if you own a pair. Both Venus and Mercury will be visible in the same field of view. Brighter Venus will be below Mercury and to the Messenger God’s left. Mercury continues to ride high for the next week while Venus creeps slowly upward into the evening sky. Look for a razor thin 2.5 percent waxing crescent moon on Sunday, March 18 just below Venus. The view will be stunning. If conditions are clear enough, you will also notice the dusky outline of the entire moon against the darkening sky. This phenomenon is called earthshine, light reflected from the unilluminated portions of the moon created by the luminance of a nearly full Earth reflecting off the moon. Earthshine should also be noticeable as the moon climbs higher into the evening sky over the next several evenings. Binoculars will make the earthshine pop. As the week continues, Mercury begins to nosedive towards the sun becoming too close to Sol by the week’s end, March 24, but it’s not over! Mercury makes an encore appearance into the evening sky in late June, this time in the WNW. Venus, however, just keeps on climbing, dominating the western sky right through mid-September when the heavens will also be aglow with Jupiter, Saturn, and Mars. One last note… If you have ever wanted to see Uranus with binoculars, March 28 is the night to give it a try because Venus and Uranus will only be separated by 1/10th degree in the western evening sky. More about the planets next week. Much success!

1123 FEBRUARY 25, 2018: Evening and Morning Planets: The evening sky is currently devoid of planets, but that is about to change this week as Mercury and Venus rapidly ascend into the western sky after sundown. The observations in early March will require an excellent western horizon and probably binoculars because both objects will still be seen with a substantial amount of twilight in the sky. By mid-March both planets will be observable in deeper twilight. On the 18th a thin waxing crescent moon joins the duo to form a upward tilted pointing line in the twilight sky—the moon, Venus, and Mercury; and on March 28 Venus and Uranus are only 1/10th of a degree apart in the deep twilight of early evening. Use binoculars to spot Uranus which will be just above and to Venus’ right! The starlike object closest to Venus will be Uranus, but what about the superior planets that are visible to the unaided eye, the ones that are farther away from the sun than Earth—Mars, Jupiter, and Saturn? They also will be making appearances into the vernal and summer sky. Early October sees a virtual smorgasbord of all the naked eye planets visible after the sun retreats in the west. Jupiter reaches opposition on May 9 and is opposite to the sun with the Earth between the two, meaning that Jove is visible all night. You will need to give Jupiter a couple of hours to gain altitude after sundown before it becomes easily visible in the southeast around 10 p.m. But let’s say that you wanted to view Jupiter this week. It can be done, but you’ll need to wait until the Earth’s rotation has taken it into a high enough position so that buildings and trees will not interfere. Consider 2 a.m. to be a good target time to see Jove low in the SE. That shifts to midnight by early April and 10 p.m. by early May. Saturn is a little sneakier, first rising at sundown on June 27, only 1.5 degrees away from the nearly full moon. If you want to see Saturn now, and get Mars thrown in as an extra treat, I would wait for the morning alarm; 5:30 a.m. to 6 a.m. is a good time. From left to right straddling the south, it will be Saturn, Mars, and Jupiter. After March 1 the moon enters the picture. On March 7 it is above Jupiter; March 9 the moon is approaching Mars; March 10, Luna lurks between Mars and Saturn, and on March 11 it is just to the left of Saturn. On the 12th, the waning crescent moon is close to the dwarf planet Pluto, although trying to see Pluto even with a large telescope can be a challenge. Still you will know in what part of the sky Pluto is located. All the best for a few clear evenings and mornings. Ad astra!

[February Star Map]

[February Moon Phase Calendar]