alactic Observer John J. McCarthy Observatory G Volume 11, No. 4 April 2018 The Ancient Silk Road Reaches to the Sky More on page 20 The John J. McCarthy Observatory Galactic Observvvererer New Milford High School Editorial Committee 388 Danbury Road Managing Editor New Milford, CT 06776 Bill Cloutier Phone/Voice: (860) 210-4117 Production & Design Phone/Fax: (860) 354-1595 www.mccarthyobservatory.org Allan Ostergren Website Development JJMO Staff Marc Polansky Technical Support It is through their efforts that the McCarthy Observatory Bob Lambert has established itself as a significant educational and Dr. Parker Moreland recreational resource within the western Connecticut community. Steve Barone Jim Johnstone Colin Campbell Carly KleinStern Dennis Cartolano Bob Lambert Route Mike Chiarella Roger Moore Jeff Chodak Parker Moreland, PhD Bill Cloutier Allan Ostergren Doug Delisle Marc Polansky Cecilia Detrich Joe Privitera Dirk Feather Monty Robson Randy Fender Don Ross Louise Gagnon Gene Schilling John Gebauer Katie Shusdock Elaine Green Paul Woodell Tina Hartzell Amy Ziffer In This Issue OUT THE WINDOW ON YOUR LEFT .................................... 4 COMMONLY USED TERMS ............................................... 19 CLAVIUS AND TYCHO CRATERS ......................................... 5 REFERENCES ON DISTANCES ............................................ 19 TESS ........................................................................... 5 LAGRANGE POINTS ........................................................ 19 FIRST LIGHT .................................................................. 6 INTERNATIONAL SPACE STATION/IRIDIUM SATELLITES .......... 19 MARTIAN WORKHORSE ................................................... 6 SOLAR ACTIVITY ........................................................... 19 INCREASING RADIATION LEVELS ....................................... 8 CONTACT INFORMATION ................................................. 21 CASSINI RETROSPECTIVE ................................................. 9 SECOND SATURDAY STARS ............................................... 22 EARTH DAY 2018 ........................................................... 9 APRIL GRAPHIC CALENDAR ............................................ 23 EXTREMOPHILES ........................................................... 12 IS LIFE WAITING TO BE DISCOVERED? .............................. 13 APRIL HISTORY ............................................................. 13 APRIL SHOWERS ............................................................ 16 COMET HISTORY ........................................................... 13 JUPITER AND ITS MOONS ................................................. 15 JOVIAN MOON TRANSITS ................................................ 15 TRANSIT OF JUPITER'S RED SPOT ..................................... 15 SUNRISE AND SUNSET ...................................................... 16 ASTRONOMICAL AND HISTORICAL EVENTS ......................... 16 April Astronomy Calendar and Space Exploration Almanac An early evening gathering of the two inner planets and a waxing crescent Moon, as viewed from New Milford, Connecticut. At the time the photo was taken, Mercury was approximately 73.9 million miles (118.9 million km) from Earth and Venus was a distant 150.2 million miles (241.7 million km). The Moon at the time was a mere 235.2 thousand miles or 378.5 thousand km from the Earth. Mercury, on its inside orbit, is quickly closing the distance. Mercury reaches Inferior Solar Conjunction on April 1, 2018 when Mercury is directly between the Earth and Sun and closest to Earth. Venus, which has just emer ged from behind the Sun, doesn't reach Inferior Solar Conjunction until October 26, 2018. Photo: Bill Cloutier Out the Window Moon by the year 2001. In reality , returned from there have been used on Your Left" since 1972, U.S. astronauts have not to date the formative event to 109 left low-Earth orbit (venturing only million years ago (compared to T'S BEEN MORE than 45 as far as 350 miles in altitude to ser- billions of years for most craters in- years since we left the last vice the Hubble Space Telescope), cluding Clavius). I footprint on the dusty lunar and since 2011 have relied upon Tycho is a classic, lar ge com- surface. Sadly, as a nation founded Russian rockets to go to and from plex impact crater with a terraced on exploration and the conquest of the International Space Station. inner wall, relatively flat floor with new frontiers, we appear to have There is renewed interest in re- deposits of impact melt, and a lost our will to lea"d as a space- turning to our celestial neighbor . central peak (comprised of mate- faring nation. But, what if the av- In December, President Trump rial brought to the surface by the erage citizen had the means to visit signed the Space Policy Directive rebound of rock initially our only natural satellite; what 1, an unfunded mandate that di- compressed by the impact). Its rays would they see out the window of rects NASA to refocus their efforts are not symmetrical, indicating that their spacecraft as they entered or- on establishing a more permanent the crater was formed by an bit around the Moon? This column presence on our Moon. Unfortu- oblique impact (with the incoming may provide some thoughts to pon- nately, as with past presidential projectile impacting the surface at der when planning your visit (if directives, rockets don't get off the an angle less than 45°). only in your imagination). pad without funding. Tycho's diverse topographies, On April 2, 1968, Metro- This month's lunar photo (page including ponds and frozen rivers Goldwyn-Mayer (MGM) released 5) shows the location of two of the of impact melt, have been exten- the now classic science fiction film more prominent craters in the south- sively mapped by the Lunar Recon- "2001: A Space Odyssey." The ern hemisphere and the fictional naissance Orbiter's (LRO) cam- film, premiering shortly before the movie locations; Tycho and Clavius eras. In these images, details as first manned missions to the Moon, craters. Tycho at 52.8 miles (85 km) small as boulders can be seen rest- was based on a screenplay co-de- veloped by producer S tanley Kubrick and author Arthur C. Clarke. It was inspired by a short story that Clarke had written in 1948 called "The Sentinel." The storyboard assumed that mankind would establish a permanent colony and research base on the in diameter is much smaller than Credit: NASA/GSFC/ Clavius at 142 miles (228.5 km) in Arizona State University diameter. However, when the Moon is full, Tycho is much more con- spicuous with its gray halo and bright system of rays (comprised of impact ejecta) that extend for hundreds of miles across the face of the Moon. Rays darken and fade with time, so Tycho's bright rays suggest that the impact was relatively recent. One of the crater's rays traversed theApollo 17 landing site and samples 4 • April 2018 JJMO http://www.mccarthyobservatory.org ing on the crater's 1.4 mile (2.25 km) high central peak. Clavius and The view of the crater's interior Tycho Craters was captured from an altitude of 36.7 miles (59 km), with the (locations of the moon spacecraft rolled over for an ob- base and monolith in the lique perspective. science fiction movie 2001: A Space Odyssey) LRO was launched on June 18, 2009 and, despite what appeared to be an impact by a micromete- oroid in 2014, its wide and narrow angle cameras have returned more than 2.2 billion images (in the form of engineering data records), totaling more than 929.6 TBytes of accumulated data. Much of this information can be accessed through the ACT-REACT- QuickMap interface at http:// quickmap.lroc.asu.edu. Clavius and Tycho Craters (locations of the moon base and monolith in the science fiction movie 2001: A Space Odyssey) TESS As of March 2018, more than 3,700 exoplanets have been found orbiting distant stars by various techniques. The vast majority (ap- proximately 79%) were detected by measuring small, temporary variations (dips) in the light as a planet crosses or transits across the stellar disk. Approximately 71% of the confirmed planets were dis- covered by the Kepler spacecraft. (Kepler has identified an addi- tional 2,700 candidates that have yet to be confirmed as exoplanets). Tentatively scheduled for April 16th, NASA will launch its next generation planet finder, the Tran- siting Exoplanet Survey Satellite (TESS). The spacecraft's four wide field CCD cameras will monitor more than 200,000 stars over an area 400 times lar ger than sur- veyed by Kepler. While not as sensitive as Kepler (Kepler's search Artist Conception of TESS area was a relatively small field of Credits: NASA, GSFC view in the constellations Cygnus http://www.mccarthyobservatory.org JJMO April 2018 • 5 and Lyra, 3,000 light years distant), number of stars discovered to date follow-up observations. Astrono- TESS is designed to monitor with Earth-size planets and the per- mers expect that by observing can- brighter, nearby stars in an all-sky centage of those planets located in didate exoplanets with several dif- search for planets, in particular plan- the habitable zone around their stars). ferent instruments, they can tease ets less than two Earth radii in size In searching the local neighbor- out the size, mass, density and (Super Earths or smaller). In a mis- hood (bright, close stars) for plan- composition of the planets, and sion designed to last two years, as- ets, ground-based telescopes (as possibly atmospheric constituents. tronomers