ASTRONOMICAL TABLES OF THE SUN, MOON, AND PLANETS by Jean Meeus Willmann-Bell, Inc. P.O. Box 3125, Richmond, Virginia 23235 QB12.M44 1983 528 83-5762 ISBN 0-943396-02-6 ASTRONOMICAL TABLES OF THE SUN, MOON, AND PLANETS will interest all who thirst for knowledge about past, present, and future celestial events. In compiling these listings of thousands of separate astronomical phenomena. Jean Meeus has created a valuable reference for all who love the sky. Meeus' clear style of explanation liberally sprinkled with examples quickly becomes apparent in his introductory note on time reckoning and the two different time scales used throughout this work. In the first chapter Meeus lists planetary phenomena, concentrating on the 30-year interval 1976-2005. Instead of merely listing, in almanac fashion, all events in simple chronological order, the author provides, in one chapter, over 60 separate tables and columns of events, conveniently arranged into categories. The listing of mutual planetary conjunctions alone, for example, includes 21 separate tables. In the section on planetary phenomena, we can find such data as the ranges in angular distance from the sun for Mercury and Venus at their greatest elongations; the maximum angular distance Venus can appear to wander from the ecliptic (the furthest possible for any naked-eye planet); a list of transits of Earth across the solar disk as seen from other planets (observers on Mars, Jupiter, and Uranus all witnessed such an event in 1984); and the closest approach to Earth of all the planets Venus through Pluto during the 20th Century. Meeus points out several periodicities between planetary events, and many more can be discovered by examining his tables. Long-time skywatchers gradually become aware of celestial rhythms as events unfold year by year; but now, with such data conveniently arranged before us, our consciousness of cycles is quickened. Mercury's elongations, for example, occur about three days later every thirteen years. Venus-sun alignments repeat about two and a half days earlier every eight years. Scanning the tables for Mars, the reader will note that oppositions recur at 25- to 27-month intervals, and that very close ones recur at intervals of 15 to 17 years. Sanning the columns for magnitude, distance, and apparent size of Mars, the reader will note the ebb and flow connecting the distant oppositions (in 1963, 1980,1995) with the close ones (1971, 1988, 2003). Elsewhere in the book, a longer listing of Mars oppositions shows that the approach in the year 2003 will be the closest so far in the Christian era, and that there won't be a closer approach of Mars until the year 2287. In each trip around the sun, Saturn displays two maxima and two minima in its brilliance at opposition. The maxima results from the "open" aspect of the rings as the planet nears the aphelion and perihelion points of its 30-year orbit; the minima correspond to times of edge-on views of the rings. A separate table lists passages of sun and Earth through Saturn's ring plane; telescopic viewers can expect the next edgewise presentation of the rings in 1995-1996. Dates of northernmost and southernmost journeys in our sky are given for most of the planets, as well as dates of celestial equator crossings for the five outer ones. Most of the 1980's were a poor time for northern observers to study the four gas giants: Meeus' tables show Jupiter reached a southernmost point in 1984, Neptune reached one in 1986, and Saturn and Uranus riding low in 1989. Even Mars passed further south in 1986 (nearly 29 degrees south of the equator) than at any time since 1907. But recovery follows quickly. At its very close opposition in 1988 Mars was well placed near the equator Jupiter crossed that boundary in 1987 and reached its northernmost position in 1990. Providing separate lists for each planetary pair-up, while giving the angular distance from the sun for each event, Meeus tells us when to expect the next similar conjunction, and whether it will be seen in the morning or evening sky. Multiple conjunctions between single pairs of planets are bracketed for emphasis; five triple conjunctions between gas giants are slated for 1981-1993, beginning with the much-publicized "Great Conjunction: of Jupiter-Saturn in 1981 and concluding with a Uranus-Neptune thrice pairing in 1993. "quasi-conjuctions" (close approaches between bright planets without a conjunction in right ascension) are omitted in conventional almanacs, but you'll find them here! Of interest to historical investigators (such as Dave Oesper) are tables which help reconstruct the appearance of the sky at times in the distant past. Given are such data as: Dates and times of equinoxes and solstices; oppositions of Mars, Jupiter and Saturn; inferior and superior conjunctions of Venus; illuminated fraction of the moon; celestial coordinates of 48 bright zodiacal stars; and solar conjunctions with 12 bright stars. Continuing at least four centuries into the future, these tables are also useful to those who wish to predict future sky happenings. Students of the moon will find tables of the four principal lunar phases and of the sun's selenographic colongitude. The latter enable the user to fix the location of the moon's terminator (day-night boundary) and the angle of solar illumination on any lunar feature for any hour of observation since the invention of the telescope through the year 2399. Tables giving the dates of equinoxes and solstices of Mars will aid in interpreting observations as far back as the telescopic drawings by Huygens and Cassini. through the recent Viking orbiter and lander missions, all the way to the middle of the 21st century. Sky events for the next several decades are especially well covered. A listing of all occultations of planets and bright stars through the year 2000 is supplied, with data and calculator programs for computation of local circumstances and graze limits. Mathematical procedures are clearly outlined, so PC users can write their own programs. Lunar distances are given for each perigee and apogee until the year 2005. Eclipse buffs will appreciate the listing of solar eclipses through the year 2050. Additional data for the same period enable the reader to obtain the times of principal stages of all eclipses of the moon. Data on past and future transits of Mercury and Venus enable the calculation of the four contact times of the planetary and solar disks. By comparing your local sunrise and sunset times, you can determine which lunar eclipses and which planet transits (including those of Venus coming up in 2004 and 2012) can be seen from your area! Jean Meeus' books and articles on celestial phenomena have been enthusiastically received world-wide. His writings are standard references in the field. Serving interests ranging from serious research to simple sky gazing, ASTRONOMICAL TABLES OF THE SUN, MOON, AND PLANETS offers a wide and fascinating selection of data on past, present, and future sky events. --- S. Wormley COBE DETECTS STRUCTURE OF EARLY UNIVERSE APRIL 22, 1992 RELEASE 92-51 Scientists announced today, at the American Physical Society's meeting held in Washington, D.C., that they have detected the long-sought variations within the glow from the Big Bang -- the primeval explosion that began the Universe 15 billion years ago -- using NASA's Cosmic Background Explorer (COBE). This detection is a major milestone in a 25-year search and supports theories explaining how the initial expansion happened. These variations show up as temperature fluctuations in the sky, revealed by statistical analysis of maps made by the Differential Microwave Radiometers (DMR) on the COBE satellite. The fluctuations are extremely faint, only about thirty millionths of a degree warmer or cooler than the rest of the sky, which is itself very cold -- only 2.73 degrees above absolute zero. The DMR is still gathering data and the measurements are expected to become even more precise. The Big Bang theory was initially suggested because it explains why distant galaxies are receding from us at enormous speeds, as though all galaxies started moving away from the same location a long time ago. The theory also predicts the existence of cosmic background radiation -- the glow left over from the explosion itself. The Big Bang theory received its strongest confirmation when this radiation was discovered in 1964 by Arno Penzias and Robert Wilson, who later won the Nobel Prize for this discovery. Although the Big Bang theory is widely accepted, there have been several unresolved mysteries. How could all of the matter and energy in the Universe become so evenly mixed in the instant following the Big Bang? How could this evenly distributed matter then break up spontaneously into objects of all sizes, such as galaxies and clusters of galaxies? The temperature variations seen by COBE help to resolve these mysteries. "The COBE receivers mapped the sky as it would appear if our eyes could see microwaves at the wavelengths 3.3, 5.7 and 9.6 mm, which is about 10,000 times longer than the wavelength of ordinary light," explained Dr. George Smoot, University of California, Berkeley, the leader of the team that made this discovery. "Most of the energy received from the sky at these wavelengths is from the cosmic background radiation of the Big Bang, but it is extremely faint by human standards. "Hundreds of millions of measurements were made by the DMR over the course of a year, and then combined to make pictures of the sky. Making sure all the measurements were combined correctly required exquisitely careful computer analysis," Smoot explained. Another COBE scientist, Dr. Charles Bennett of the Goddard Space Flight Center, Greenbelt, Md., explained that a major challenge for the team was to distinguish the Big Bang signals from those coming from our own Milky Way Galaxy. "The Milky Way emits microwaves that appear mostly concentrated in a narrow zone around the sky. We compared the signals at different positions and at different wavelengths to separate the radiation of the Big Bang from that of the Milky Way Galaxy," said Dr. Bennett. The temperatures and sizes of the fluctuations in the background radiation COBE detected agree with the predictions of "inflationary cosmology," a theory that says the structure and behavior of the Universe were determined by minute fluctuations occurring when the Universe was much younger than one-trillionth of a second. The COBE results provide new evidence in support of the "inflationary" scenario. The amount of gravity provided by these visible fluctuations was inadequate to draw together the galaxies and clusters of galaxies. Instead, astronomers conclude that the galaxies formed only because most of the material in the Universe is invisible and totally unlike ordinary matter. This "dark matter" provides the necessary gravitational attraction for forming galaxies. The fluctuations seen by COBE are too small to explain how the visible matter in the young Universe could condense into the galaxies that now exist. According to COBE scientist Dr. Edward Wright from the University of California, Los Angeles, the COBE measurements support theories postulating large amounts of dark matter. "These theories say that most of the matter in the Universe is invisible to us and must be a new kind of matter, not yet detected in our laboratories," he explained. "Nevertheless, we need such invisible matter to explain how galaxies formed in the early Universe and gathered themselves together into huge clusters. Ordinary matter would be attracted into regions of concentrated dark matter, and the Universe as we know it today could develop, eventually leading to the formation of galaxies, stars and planets," Wright said. COBE was launched in November, 1989, from Vandenberg Air Force Base, Calif., aboard a Goddard-managed Delta launch vehicle. The Goddard Space Flight Center, Greenbelt, Md., manages COBE for NASA's Office of Space Science and Applications, Astrophysics Division, Washington, D.C.