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(Click for frequent words.) 64 Lunine 63 Paul Spudis 63 Sasselov 62 Mössbauer 62 RHESSI 61 VIRTIS 61 NASA Cosmic Background 61 Grillmair 61 exoplanetary 61 Kounaves 61 Dikpati 61 Jenniskens 61 DISR 60 Adam Riess 60 Foing 60 Cassini flyby 60 Konacki 60 Vikhlinin 60 Solar TErrestrial RElations Observatory 60 Andrea Ghez 60 Hubble observations 60 planetary Transits 59 Gaensler 59 Tom Krimigis 59 Galileo spacecraft 59 EPOCh 59 NASA WMAP 59 astrometric 59 Ellen Stofan 59 Dalcanton 59 Spudis 59 Peter Jenniskens 59 Stadermann 59 SIRTF 59 Astrophysics Cambridge Mass. 59 A'Hearn 59 Spergel 59 Richard Mushotzky 59 NuSTAR 59 IBEX spacecraft 58 Hakan Svedhem 58 Svedhem 58 Wilkinson Microwave Anisotropy Probe 58 Kepler Mission 58 Thiemens 58 Cassini 58 Tegmark 58 NASA Far Ultraviolet 58 Mercury flyby 58 ESA Integral 58 STScI 58 Galaxy Evolution 58 Voyager spacecraft 58 Franck Marchis 58 ESO VLT 58 Ed Weiler 58 DIXI 58 orbiting gamma ray 58 Composite Infrared Spectrometer 58 Comet Halley 58 Jonathan Lunine 58 Giovanni Cassini 57 ray Space Telescope 57 astrophysical phenomena 57 Churyumov Gerasimenko 57 Buesseler 57 Christopher Chyba 57 Werthimer 57 Cosmic Microwave Background 57 MARSIS 57 RXTE 57 twin STEREO spacecraft 57 Roukes 57 Hörst 57 Jeffrey Kargel 57 Awschalom 57 Cassini ultraviolet 57 extrasolar planetary systems 57 Fermi telescope 57 Douglas Osheroff 57 CoRoT satellite 57 de Pater 57 director Charles Elachi 57 Mars orbiting spacecraft 57 Djorgovski 57 Saturn Cassini 57 Heliophysics 57 Svensmark 57 Astrophysical 57 Climate Experiment GRACE 57 Convection Rotation 57 Cassini imaging 56 SPICAM 56 Sushil Atreya 56 Kashlinsky 56 X ray spectrometer 56 Heterodyne Instrument 56 neutron spectrometer 56 NASA STEREO 56 UA Lunar 56 Gravitational lensing 56 SSRL 56 Kailash Sahu 56 Cassini ion 56 cosmological observations 56 Magnetospheric 56 Eric Becklin 56 millisecond pulsar 56 Orbiter MRO 56 COROT 56 Nasa Jet Propulsion 56 Jamie Elsila 56 Keck Interferometer 56 Neutron Spectrometer 56 ESA Cluster 56 sterile neutrino 56 Carolyn Porco 56 Cassini Huygens 56 Wolszczan 56 NASA Voyager spacecraft 56 THEMIS spacecraft 56 planetary astronomer 56 STEREO spacecraft 56 MARSIS radar 56 NASA Cassini spacecraft 56 geoneutrinos 56 Stéphane Udry 56 Helioseismic 56 Jakosky 56 Hubble Space Telescope HST 56 Lunar Reconnaissance Orbiter LRO 56 Interior Laboratory GRAIL 56 O OREOS 56 NASA Wilkinson Microwave 56 Cancri e 56 Elachi 56 Applied Physics Lab 56 NASA Interstellar Boundary 56 Winglee 56 Explorer IBEX 56 Evolution Explorer 56 X ray observatory 56 Mary Voytek 56 Lunar Prospector 56 Dauphas 56 polarimetry 56 NASA Lunar Prospector 56 Christophe Lovis 56 Anisotropy Probe WMAP 56 SeaWiFS 56 Guhathakurta 56 gamma ray observatory 56 Orbiter LRO 55 optical wavelengths 55 David Wettergreen 55 EPOXI mission 55 Higgs bosons 55 XMM Newton satellite 55 Gerhard Schwehm 55 Comet Hartley 55 Carey Lisse 55 Solar Dynamics Observatory 55 Bindschadler 55 Vourlidas 55 Gravity Probe 55 exobiology 55 neutrino oscillation 55 Charles Elachi 55 Director Charles Elachi 55 Malcolm Fridlund 55 exoplanets planets 55 Bernard Foing 55 Ed Weiler NASA 55 Alycia Weinberger 55 Drake Deming 55 JIMO 55 Nikku Madhusudhan 55 occultations 55 Giovanni Fazio 55 Descent Imager Spectral Radiometer 55 YORP effect 55 Deep Impact eXtended Investigation 55 AB Aurigae 55 Conselice 55 Ketterle 55 Don Gurnett 55 XMM Newton 55 stellar occultation 55 ESA Herschel 55 Mary Cleave 55 Halzen 55 Geminga 55 Zarnecki 55 GALEX 55 KIPAC 55 Bruce Margon 55 Moon Mineralogy Mapper M3 55 Diviner instrument 55 galactic cosmic rays 55 orbited Jupiter 55 Martian meteorites 55 martian meteorites 55 AMSR E 55 WMAP satellite 55 Gravity Probe B 55 NASA ICESat 55 Mars Color Imager 55 NASA THEMIS 55 THEMIS satellites 55 chondrites 55 Huygens mission 55 KamLAND 55 Vassilis Angelopoulos 55 Anthony Colaprete LCROSS 55 Pierre Simon Laplace 55 Anisotropy Probe 55 Mars Climate Sounder 55 Submillimeter Array 55 Fermi LAT 55 Hipparcos 55 photochemistry 54 Tod Strohmayer 54 YES2 54 NASA Stardust spacecraft 54 Mini TES 54 Foton M2 54 Planck spacecraft 54 Chodas 54 KBOs 54 Hegerl 54 Nasa spacecraft 54 Hubble Near Infrared 54 satellite altimetry 54 WISE infrared 54 imaging spectrometer 54 Budker 54 Comet Hartley 2 54 comet Boethin 54 UVOT 54 Jupiter Icy Moons 54 De Pontieu 54 Bonnie Buratti 54 Abdalati 54 Avishay Gal Yam 54 Avi Loeb 54 NASA EPOXI mission 54 ChemCam 54 Jean Luc Margot 54 Maria Zuber 54 neutral mass spectrometer 54 Einstein equations 54 coronal heating 54 distant supernovae 54 moons orbiting Saturn 54 Jupiter moon Io 54 infrared astronomy 54 gamma ray spectrometer 54 Ken Edgett 54 Ohmura 54 Huchra 54 LADEE 54 spectroscopically 54 EPOXI 54 Carnegie Institution Geophysical 54 Cassini Huygens spacecraft 54 extrasolar 54 Otto Bliesner 54 Natalie Batalha 54 interferometers 54 DZero 54 Observatory SDO 54 Kuiper Belt Objects 54 synchrotron X ray 54 supersymmetric particles 54 Fran Bagenal 54 NASA Jet Propulsion Lab 54 Gravitational waves 54 David Southwood ESA 54 Kristin Laidre 54 neutrino oscillations 54 multiwavelength 54 Keck telescope 54 antineutrinos 54 Ralph McNutt 54 Arkani Hamed 54 Schawinski 54 STEREO mission 54 JDEM 54 Molczan 54 FORCAST 54 Johns Hopkins Applied Physics 54 Stephane Udry 54 Jack Lissauer 54 Heliophysics Division 54 X ray telescopes 54 Zolensky 54 RS Ophiuchi 54 Foton M3 54 interplanetary spacecraft 54 Earth Connection Coronal 54 D CIXS 54 infrared telescopes 54 Caltech astronomer 54 ESA Planck 54 spokesman Grey Hautaluoma 54 Pascale Ehrenfreund 54 Kuiper belt objects 54 Heliospheric Observatory SOHO 54 OGLE TR #b 54 Lars Hernquist 53 Sromovsky 53 Mastcam 53 Near Infrared Camera 53 retrograde orbit 53 ESO astronomer 53 Mandushev 53 GLAST 53 Trey Ideker 53 coronal loops 53 Neil Gehrels 53 quantum chromodynamics 53 ESA Rosetta 53 ARPES 53 Kuiper Belt Object 53 SN #A 53 Jon Giorgini 53 Imaging Spectrometer 53 Lagrangian 53 William Happer 53 Ulysses spacecraft 53 cosmological parameters 53 Dan Werthimer 53 Mini SAR 53 Higgs singlet 53 robotic landers 53 comet McNaught 53 lunar meteorites 53 Mars CRISM 53 Observatoire de Paris 53 Mars landers 53 Anthony Remijan 53 NASA Fermi Gamma 53 Gell Mann 53 Rosetta orbiter 53 submillimeter wavelengths 53 Compton Gamma Ray 53 Corot 7b 53 geochemists 53 Wilkinson Microwave Probe 53 particle acceleration 53 Mojzsis 53 Deep Impact Principal Investigator 53 sub millimeter wavelengths 53 Kazantzidis 53 Relations Observatory STEREO 53 Nima Arkani Hamed 53 Spectrograph 53 Compact Reconnaissance Imaging Spectrometer 53 spectroscopic measurements 53 ESA XMM Newton 53 polarimetric 53 helium atom 53 P/# A2 53 VLBI 53 Credits ESA 53 Collider Detector 53 Antenna LISA 53 Space Infrared Telescope 53 magnetospheric imaging instrument 53 Jean Pierre Bibring 53 ESA ASI 53 Venusian atmosphere 53 LORRI 53 INMS 53 MINOS 53 Planetary Fourier Spectrometer PFS 53 Hyakutake 53 Sara Seager 53 Paul Alivisatos 53 Karl Menten 53 Dean Pesnell 53 Louis Stodieck 53 spectrographic 53 Maunder minimum 53 X ray emission 53 ultrashort pulses 53 telescopic observations 53 Dimitar Sasselov 53 Peyghambarian 53 Smithsonian astronomer 53 CloudSat 53 spectroscopic analysis 53 Emily Lakdawalla 53 SMOS mission 53 ESO telescopes 53 Richard Vondrak 53 SECCHI 53 BepiColombo 53 radial velocity technique 53 Apollo missions 53 NASA Cassini 53 Professor Pillinger 53 MiniBooNE 53 ESA Mars 53 Saturn Enceladus 53 reionization 53 Klekociuk 53 boson 53 VIRTIS instrument 53 Heliospheric Investigation 53 SwRI Space 53 Pasachoff 53 superheated gases surrounding 53 Reinhard Genzel 53 Gal Yam 53 Scheeres 53 Marchis 53 WFC3 53 Mini Thermal Emission 53 planet Gliese #g 53 Caltech Jet Propulsion 53 HD#b 53 Stanford Synchrotron Radiation 53 Vunjak Novakovic 53 Delta Cephei 53 Gregory Asner 53 GLAST Burst Monitor 53 NOAO 53 orbiting Chandra 53 Jonathan Lunine Cassini 53 Margon 53 Saul Perlmutter 53 Colaprete 53 muon neutrino 53 gaseous planet 53 ROSAT 53 Ruvkun 53 WMAP 53 NASAs 53 Jay Zwally 53 Nasa Ames 53 Ajay Royyuru 53 Fomalhaut b 53 Neutral Mass Spectrometer 53 Dana Yoerger 53 Friis Christensen 53 Kuchner 53 Nasa Kepler 53 Kepler #b 53 astrophysicists 53 Japan NAOJ 52 Michael Zolensky 52 Gmachl 52 spectroscopic observations 52 Robert Jedicke 52 perihelion 52 Joel Primack 52 Hinode 52 ESA ERS 52 Tarduno 52 spiral nebulae 52 Rainer Klement 52 cometary material 52 Matthias Mehl 52 microlensing events 52 Mosier Boss 52 Nobel laureate physicist 52 NASA Goddard 52 ESA SMART 52 Huygens descent 52 AERONET 52 Makiko Sato 52 Sejnowski 52 Harlow Shapley 52 scientist Anthony Colaprete 52 Casani 52 Madhulika Guhathakurta 52 journal Meteoritics 52 Mario Livio 52 diffraction patterns 52 Grammier 52 asteroid orbit 52 Nicolelis 52 Titan flyby 52 Melosh 52 auroral emissions 52 Rayleigh scattering 52 Lika Guhathakurta 52 Meteoritics 52 Faint Object 52 IceCube 52 Alfven waves 52 Markram 52 UA Steward Observatory 52 DEIMOS 52 Bug Nebula 52 Muons 52 Multi Object Spectrometer 52 Fred Hoyle 52 AAVSO 52 Schlom 52 GOCE 52 weak gravitational lensing 52 spectrographs 52 Upsilon Andromedae 52 Ohmoto 52 cosmic strings 52 Steward Observatory 52 Giovanni Picardi 52 Laser Interferometer Gravitational Wave 52 millimeter wavelengths 52 Magnetic Imager HMI 52 Space Physics 52 detect gravitational waves 52 Rainer Blatt 52 NICMOS 52 Planetary Transits 52 filamentary structure 52 solar corona 52 Planetary Institute 52 SN#A 52 Observatory LDEO 52 magnetic reconnection 52 Gehrels 52 radio occultation 52 Joe Veverka 52 lunar orbits 52 Boethin 52 Filippenko 52 Libra constellation Vogt 52 Frank Bertoldi 52 Pakrasi 52 Bojowald 52 hydroxyl molecules 52 JQI 52 MPIfR 52 Jay Melosh 52 Pan STARRS 52 Bottke 52 CoRoT 9b 52 planetary nebulas 52 highly elliptical orbits 52 Geophysical Fluid Dynamics 52 rocky extrasolar planet 52 Methone 52 astronomical observations 52 Keck telescopes 52 Jean Pierre Lebreton ESA 52 RRATs 52 Gnedin 52 heliospheric 52 Planck satellite 52 Samuel Ting 52 Dmitri Denisov 52 Michael A'Hearn 52 Alfred McEwen 52 Butterfly Nebula 52 Decadal Survey 52 ultracold gases 52 IKAROS 52 visit http:/saturn.jpl.nasa.gov 52 Infrared Pathfinder Satellite 52 Wolfgang Brandner 52 Suzaku X ray 52 CALIPSO 52 journal Acta Astronautica 52 Hamish Pritchard 52 composite infrared spectrometer 52 EVLA 52 N. Rathnasree 52 Gerard Kuiper 52 Crab Pulsar 52 CDMS II 52 Observatory STEREO 52 ESO PR 52 Sigurd Hofmann 52 Infrared Array Camera 52 powder diffraction 52 Earth magnetosphere 52 Stephan Quintet 52 Spectroscopic 52 meteoroid 52 Cees Dekker 52 Infrared Astronomy SOFIA 52 David Sibeck 52 Michael Studinger 52 High Altitude Observatory 52 Saturn magnetosphere 52 superstrings 52 scatterometer 52 CHIPSat 52 Virtual Planetary Laboratory 52 XMM Newton X ray 52 Viking Lander 52 THEMIS mission 52 Neutron Detector 52 extragalactic 52 journal Icarus 52 Martin Tomasko 52 frequency comb 52 Josefino Comiso 51 UKIRT 51 Gondolo 51 interferometer 51 cometary dust 51 Bruce Jakosky 51 HETE 51 Michael Flasar 51 proton decay 51 supercomputer simulations 51 NanoSail D 51 Gogotsi 51 cryo EM 51 High Resolution Imaging 51 BLG #Lb 51 laser altimeter 51 Thermal Emission Spectrometer 51 Earthlike planets 51 clumpiness 51 PSR J# 51 Keck Observatory 51 Rokhsar 51 Neil DeGrasse Tyson 51 moonlet 51 ion propulsion 51 ESA Envisat satellite 51 Solar Optical Telescope 51 Behrenfeld 51 Saturn rings 51 Carnegie Observatories 51 Anyamba 51 APXS 51 LCROSS 51 Bohdan Paczynski 51 Alexey Vikhlinin 51 Federico Capasso 51 COBE 51 multiband imaging photometer 51 cosmic ray flux 51 gamma ray astronomy 51 particle colliders 51 Leslie Orgel 51 absorption spectra 51 ALH# 51 NASA Stratospheric Observatory 51 infrared spectrograph 51 Martian meteorite 51 STIS 51 x ray scattering 51 Adaptive Optics 51 elemental abundances 51 Igor Mitrofanov 51 SIM PlanetQuest 51 astronomers 51 thermodynamic calculations 51 NASA LCROSS 51 noctilucent clouds 51 Halton Arp 51 outer planets 51 stellar occultations 51 CIRS 51 Dante Lauretta 51 Gael Chauvin 51 beamline #.#.# 51 Stellacci 51 Enceladus flybys 51 Fermi Telescope 51 Planetary Science Institute 51 David Spergel 51 Paytan 51 MMT Observatory 51 Planetary Lab 51 Henize #-# 51 linear collider 51 lunar perigee 51 Nasser Peyghambarian 51 spectroscopic technique 51 Prof. Hawking 51 SMOS 51 Roddam Narasimha 51 SDSS II 51 Adaptive optics 51 innermost planet 51 scanning tunneling microscopy STM 51 Accelerator Mass Spectrometry 51 astronomer Seth Shostak 51 Schwehm 51 prebiotic chemistry 51 GRB# 51 NASA Infrared Telescope 51 Larry Soderblom 51 MiniBooNE experiment 51 Shallow Radar instrument 51 Ravishankara 51 Solar Orbiter 51 Mercury magnetosphere 51 Ari Melnick 51 Neils Bohr 51 Comet Holmes 51 Red Rectangle 51 MBARI 51 electron neutrinos 51 Shallow Radar 51 http:/saturn.jpl.nasa.gov 51 Michal Lipson 51 Cepheid variables 51 ultraviolet wavelengths 51 comet nuclei 51 George Djorgovski 51 Ultraviolet Imaging Spectrograph UVIS 51 William Bottke 51 Voorwerp 51 GJ #b [001] 51 Neukum 51 DZero experiment 51 Io Europa 51 photometry 51 inelastic scattering 51 planetary missions 51 New Horizons spacecraft 51 Spectrometer 51 HUDF 51 Uranus Neptune 51 Reconnaissance Orbiter 51 Magellanic Stream 51 Kulcinski 51 SOHO spacecraft 51 Planetary Laboratory 51 Beichman 51 Richard Binzel 51 Philae lander 51 SPIRE instrument 51 Terrestrial Magnetism 51 Cassini radar 51 cosmological theories 51 NASA MESSENGER 51 Dan Durda 51 spacecraft 51 Haumea 51 cosmic microwave radiation 51 Epsilon Eridani 51 Riesselmann 51 radioisotope thermoelectric generators 51 Mossbauer 51 Pierre Drossart 51 Rusty Schweickart 51 X ray wavelengths 51 Terrestrial Planet Finder 51 optical interferometry 51 Uwe Bergmann 51 earthshine 51 Reneke 51 Spaceweather.com 51 Mewaldt 51 Explorer WISE 51 Comet 9P/Tempel 1 51 planetary geology 51 LAGEOS 51 quantum chromodynamics QCD 51 anomalous cosmic rays 51 Drew Shindell 51 Linda Spilker 51 THEMIS 51 Meg Urry 51 radial velocity 51 journal Monthly Notices 51 Context Camera 51 neutrino experiment 51 Veizer 51 accelerator mass spectrometry 51 Itokawa 51 Fritz Zwicky 51 Comet Churyumov Gerasimenko 51 Woese 51 detecting gravitational waves 51 Oganessian 51 gravitational lensing 51 icy moons 51 X ray Spectrometer 51 LCLS 51 Magnetic Imager 51 Einstein theory 51 Multi Object Spectrograph 51 Vakoch 51 VASIMR 51 AKARI 51 intrinsic brightness 51 planetary surfaces 51 positron 51 ASPERA 51 BN Suresh 50 RPWS 50 Great Observatories 50 Yoel Fink 50 orbiting Hubble Space Telescope 50 airglow 50 eclipsing binary 50 orbit insertion 50 orbiting observatories 50 Tropical Rainfall Measuring 50 Comet Machholz 50 Moderate Resolution Imaging 50 microshutters 50 SEGUE 50 ESA GOCE 50 exo planets 50 HiRISE camera aboard 50 neutrino detectors 50 submillimeter wavelength 50 Jayant Narlikar 50 Cepheids 50 Microscopy Electrochemistry 50 Admiral Gehman 50 Higgs particle 50 inhabitable planets 50 BaBar 50 Shoemaker Levy 50 gamma ray emission 50 AMASE 50 geoid 50 quantum teleportation 50 Super Kamiokande 50 WASP #b 50 Omenn 50 MESSENGER 50 lunar module pilot 50 spatially resolved 50 Selvamanickam 50 Robotic Exploration 50 Lovis 50 Hubble Space telescope 50 HRSC 50 neutrino mass 50 Peidong Yang 50 cosmic ray particles 50 Lunokhod 50 Sibeck 50 Niels Bohr Institute 50 Hubble orbits 50 moons Phobos 50 Agol 50 Persis Drell 50 Heliospheric 50 relativity theory 50 UCO Lick 50 photoelectron spectroscopy 50 V. Ramanathan 50 Yun Qian 50 LIGO 50 infrared wavelengths 50 protoplanet 50 comet Wild 50 neutron scattering experiments 50 Explorer GALEX 50 Pluto Charon 50 NASA 50 Eagle lunar lander 50 C1XS 50 particle astrophysics 50 Cosmic Background Explorer 50 HM Cancri 50 NASA MESSENGER spacecraft 50 Jeffrey Bada 50 Kavandi 50 Charon Pluto 50 Gliese #c 50 CoML 50 Calibrant 50 X ray afterglow 50 Baross 50 Volker Liebig 50 Spacewatch 50 Ele Ferrannini 50 NASA twin STEREO 50 Abdussamatov 50 Hubble 50 CoRoT 50 Ray Jayawardhana 50 Mars Squyres 50 strange quark 50 Resolution Stereo Camera 50 Wide Angle Search 50 Planetary Camera 2 50 cosmic phenomena 50 La Silla observatory 50 JAXA 50 Fuk Li Mars 50 Submillimeter 50 optical spectra 50 SINFONI 50 carbonate globules 50 Lunar Reconnaissance 50 Villigen Switzerland 50 substorms 50 LRO spacecraft 50 planets comets 50 Aristeidis Karalis 50 primitive meteorites 50 Lawrence Krauss 50 dosimetrists 50 planetary scientist 50 moon Mab 50 X ray observatories 50 Comet Hale Bopp 50 Haymet 50 HiRISE 50 spectral measurements 50 Ring Nebula 50 sodium atoms 50 subsurface ocean 50 NSLS 50 interstellar particles 50 Arik Posner 50 Kurt Retherford 50 Huygens 50 Gas Chromatograph Mass Spectrometer 50 Gravity Recovery 50 supersymmetric 50 isotopic ratios 50 Cosmic Origins Spectrograph COS 50 Ranging MESSENGER spacecraft 50 exo planet 50 Samuel Wickline 50 Conductivity Analyzer MECA 50 Papovich 50 astrophysical sciences 50 Saturn aurora 50 fluorescence spectroscopy 50 Arecibo Observatory 50 Conductivity Analyzer 50 Lunar Module Pilot 50 detect gamma rays 50 Pulickel Ajayan 50 orbiting Saturn 50 proton proton 50 Earthlike 50 Rosaly Lopes 50 COROT 7b 50 Tony Wyss Coray 50 Hawking radiation 50 type Ia supernova 50 planetary orbits 50 Stassun 50 Cloud Aerosol Lidar 50 Optical Spectroscopic 50 mesosphere 50 gamma ray detectors 50 Ray Villard 50 Subaru Telescope 50 polar mesospheric clouds 50 Anthony Colaprete principal 50 Mars Pathfinder lander 50 solar nebula 50 Naomi Halas 50 JWST 50 astrometry 50 Mars Phobos 50 Iapetus 50 spectroscopic 50 Carl Marchetto 50 Fairen 50 Pääbo 50 Beratan 50 Yarkovsky effect 50 Richard Gilbrech 50 Jeffrey Hangst 50 Extrasolar Planet Observation 50 EGRET 50 Triangulum Galaxy 50 MESSENGER spacecraft 50 Galilean satellites 50 antineutrino 50 Ryschkewitsch 50 Landsea 50 distant supernovas 50 Werner Dahm 50 Glikson 50 Scripps Oceanography 50 Radioastronomy 50 NIRCam 50 Inez Fung 50 blackbody radiation 50 Fermi Gamma ray 50 Laurie Leshin 50 Rasio 50 GRBs 50 STEREO 50 HD #b [002] 50 elliptical orbits 50 Titan smoggy 50 polarimeter 50 Flyby spacecraft 50 theoretical calculations 50 spaceborne 50 planets circling 50 homochirality 50 Bahcall 50 Hale Bopp 50 planets atmospheres