April
- Apr 20-23 - American Association of Petroleum Geologists (AAPG) Annual Convention, San Antonio, Texas
- Apr 21 - Comet C/2007 K3 (Siding Spring) Perihelion (2.051 AU)
- Apr 21 - Asteroid 5841 Stone Closest Approach To Earth (1.187 AU)
- Apr 21 - Asteroid 1198 Atlantis Closest Approach To Earth (1.709 AU)
- Apr 21-23 - Workshop: Ground Truth from Mars - Science Payoff from a Sample Return Mission, Albuquerque, New Mexico
- Apr 21-23 - Mars Water Cycle Worhshop, Paris, France
- Apr 21-24 - Conference: The Local Bubble & Beyond II, Philadelphia, Pennsylvania
- Apr 21-25 - Workshop: The Universe Under the Microscope - Astrophysics at High Angular Resolution, Bad Honnef, Germany
- Apr 22 - Lyrids Meteor Shower Peak
- Apr 22 - Asteroid 1941 Wild Closest Approach To Earth (3.929 AU)
- Apr 22-24 - International Workshop on Very Large Volume Neutrino Telescope for the Mediterranean Sea, Toulon, Var, France
- Apr 22-25 - Conference on Blazar Variability across the Electromagnetic Spectrum, Paris, France
- Apr 23 - Asteroid 3192 A'Hearn Closest Approach To Earth (1.182 AU)
- Apr 23 - Asteroid 84225 Verish Closest Approach To Earth (1.415 AU)
- Apr 23 - Asteroid 10001 Palermo Closest Approach To Earth (1.689 AU)
- Apr 23-25 - 3rd International Symposium on Formation Flying, Missions and Technologies, Noordwijk, The Netherlands
- Apr 24 - STS-124 Launch, Space Shuttle Discovery, JEM-PM Kibo (International Space Station 1J)
- Apr 24 - Asteroid 9134 Encke Closest Approach To Earth (1.938 AU)
- Apr 24 - Asteroid 3693 Barringer Closest Approach To Earth (2.690 AU)
- Apr 24 - Lecture: The Importance of Sample Return, Pasadena, California
- Apr 25 - Cassini, Orbital Trim Maneuver #153 (OTM-153)
- Apr 25 - Asteroid 5535 Annefrank Closest Approach To Earth (1.196 AU)
- Apr 25 - Asteroid 5703 Hevelius Closest Approach To Earth (2.013 AU)
- Apr 25 - Asteroid 8734 Warner Closest Approach To Earth (2.016 AU)
- Apr 25 - Asteroid 1578 Kirkwood Closest Approach To Earth (3.531 AU)
- Apr 25 - Lecture: The Importance of Sample Return, Pasadena, California
- Apr 26 - Cassini, Distant Flyby of Titan
- Apr 26 - Asteroid 6373 Stern Closest Approach To Earth (1.493 AU)
- Apr 26 - 10th Anniversary (1998), Cassini, Venus Flyby
- Apr 26 - 160th Anniversary (1848), Andrew Graham's Discovery of Asteroid 9 Metis
- Apr 27 - Comet Mrkos Perihelion (1.469 AU)
- Apr 27 - Asteroid 6456 Golombek Closest Approach To Earth (1.004 AU)
- Apr 28 - Asteroid 2005 LV30 Near-Pallas Flyby (0.050 AU)
- Apr 28 - Eugene Shoemaker's 80th Birthday (1928)
- Apr 28-30 - 2008 Phenomenology Symposium, Madison, Wisconsin
- Apr 28-May 01 - Meeting: AAS Division on Dynamical Astronomy, Boulder, Colorado
- Apr 28-May 01 - 2008 AIAA Responsive Space Conference, Los Angeles, California
- Apr 28-May 01 - 15th AIAA International Space Planes and Hypersonic Systems and Technologies Conference, Dayton, Ohio
- Apr 29-May 02 - Planetary Dunes Workshop: A Record of Climate Change, Alamogordo, New Mexico
- Apr 29 - Asteroid 7934 Sinatra Closest Approach To Earth (1.504 AU)
- Apr 30 - Cassini, Distant Flyby of Telesto & Pallene
- Apr 30 - Comet C/2007 M3 (LINEAR) Closest Approach To Earth (3.094 AU)
- Apr 30-May 02 - Symposium on Geophysics and Remote Sensing in Determination of Near-Surface Structures (GARS2008), Izmir, Turkey
May
- May 01 - Asteroid 23990 Springsteen Closest Approach To Earth (1.313 AU)
- May 01 - 10th Anniversary (1998), Discovery of Dar al Gani 476 (Mars Meteorite)
- May 02 - Space Day
- May 03 - Asteroid 2865 Laurel Closest Approach To Earth (1.452 AU)
- May 03-04 - Jet Propulsion Laboratory Open House, Pasadena, California
- May 04 - Comet 187P/LINEAR Closest Approach To Earth (2.765 AU)
- May 04 - Asteroid 6469 Armstrong Closest Approach To Earth (1.159 AU)
- May 04 - Asteroid 243 Ida Closest Approach To Earth (1.967 AU)
- May 05 - Eta Aquarids Meteor Shower Peak
- May 05-07 - 6th International Conference in Computer Simulation Risk Analysis and Hazard Mitigation, Cephalonia, Greece
- May 05-08 - The Science of Solar System Ices (ScSSI): A Cross-Disciplinary Workshop, Oxnard, California
- May 05-09 - 8th Pacific Rim Conference on Stellar Astrophysics (PRCSA2008), Phuket, Thailand
- May 05-11 - Astronomy Week
- May 06-07 - Microwave Technology and Techniques Workshop 2008: Innovation and Challenges, Noordwijk, the Netherlands
- May 07 - Asteroid 3255 Tholen Closest Approach To Earth (2.305 AU)
- May 07-09 - 5th Astronomical Data Analysis Conference (ADA V), Heraklion, Crete, Greece
- May 07-09 - Workshop: The Warm & Hot Universe, New York, New York
- May 08 - Cassini, Orbital Trim Maneuver #154 (OTM-154)
- May 09 - Cassini, Distant Flyby of Methone & Janus
- May 09 - Comet 2003 KV2 (LINEAR) Near-Earth Flyby (0.297 AU)