- Eric Meyers
- Â Self - Narrator 43 episodes, 2004-2009
- Michael Izquierdo
- Â Narrator / ... 13 episodes, 2007-2011
- Rushmore DeNooyer
- Â Narrator / ... 11 episodes, 2009-2011
- Roger Tilling
- Â Narrator / ... 6 episodes, 2004-2009
- Craig Sechler
- Â Narrator / ... 5 episodes, 2009-2010
- Mark Boslough
- Â Self - Physicist / ... 4 episodes, 2006-2010
- Peter H. Schultz
- Â Self / ... 4 episodes, 2009-2010
- Jay Melosh
- Â Planetary Scientist / ... 4 episodes, 2004-2010
- Lawrence Krauss
- Â Self - CWR University / ... 4 episodes, 2005-2011
- Bill McGuire
- Â Self / ... 3 episodes, 2004-2010
- Chris McKay
- Â Self - NASA / ... 3 episodes, 2005-2009
- Jeff Hester
- Â Self / ... 2 episodes, 2007-2008
- Iain Stewart
- Â Self - Geologist 2 episodes, 2008-2009
- Sten Odenwald
- Â Self / ... 2 episodes, 2008-2009
- Rob Naughton
- Â Narrator 2 episodes, 2010-2011
- Dave Grinspoon
- Â Self - Curator of Astrobiology / ... 2 episodes, 2004-2006
- Mario Acuna
- Â Self - Former NASA Research Scientist / ... 2 episodes, 2005-2008
- Jose Borrero
- Â Self - Professor and Researcher / ... 2 episodes, 2005-2006
- Konrad Steffen
- Â Self / ... 2 episodes, 2007-2010
- Kimberly Weaver
- Â Self 2 episodes, 2008
- Daniel Lathrop
- Â Self - Professor of Physics / ... 2 episodes, 2005-2008
- Lynn Rothschild
- Â Self - NASA / ... 2 episodes, 2008-2009
- Costas Emmanuel Synolakis
- Â Self - Engineering Professor / ... 2 episodes, 2004-2005
- David Deamer
- Â Self - Professor of Biomolecular Engineering / ... 2 episodes, 2008-2010
- Jeremy Bloxham
- Â Self - Mallinckrodt Professor of Geophysics / ... 2 episodes, 2005-2008
- Kevin R. Grazier
- Â Self - Hollywood Science Advisor / ... 2 episodes, 2006-2011
- Heidi Hammel
- Â Self / ... 2 episodes, 2006-2008
- Geoff Marcy
- Â Self - Professor of Astronomy 2 episodes, 2006-2010
- Jack Szostak
- Â Self - Harvard Medical School / ... 2 episodes, 2008-2010
- Seth Shostak
- Â Self - Senior Astronomer / ... 2 episodes, 2004-2010
- Debra Fischer
- Â Self - Planet Hunter / ... 2 episodes, 2004-2010
- Charles Pellegrino
- Â Self - Author / ... 2 episodes, 2004-2009
- Penelope Boston
- Â Self / ... 2 episodes, 2004-2008
- Mike Theiss
- Â Documentarian / ... 2 episodes, 2004-2007
- John Lundberg
- Â Self - Crop Circle Maker / ... 2 episodes, 2004
- Michio Kaku
- Â Self - Author of 'Physics of the Impossible' / ... 2 episodes, 2005-2008
- Todd Disotell
- Â Self - Science Expert 2 episodes, 2007-2008
- Chris Cook
- Â Narrator 2 episodes, 2007
- Michael Carroll
- Â Narrator / ... 2 episodes, 2008-2011
- Chris Broyles
- Â Narrator / ... 2 episodes, 2008-2009
- J.V. Martin
- Â Narrator 2 episodes, 2009
- David Morrison
- Â Self - Senior Astrobiologist / ... 2 episodes, 2009
- Minik Rosing
- Â Self - Geologist / ... 2 episodes, 2010
- Lucy Jones
- Â Self - Chief Scientist, USGS Multi-Hazards Demonstration Project for Southern California 1 episode, 2004
- Helen Fisher
- Â Self - Anthropologist 1 episode, 2006
- Robert Ballard
- Â Self 1 episode, 2007
- Luann Becker
- Â Self 1 episode, 2007
- Phil Plait
- Â Self 1 episode, 2008
- Lance Lewman
- Â Self - Narrator 1 episode, 2008
- Paul Davies
- Â Self - Arizona State University 1 episode, 2008
- Scott Sandford
- Â Self - NASA 1 episode, 2008
- Robert Caldwell
- Â Self - Cosmologist 1 episode, 2008
- Christopher Scotese
- Â Self 1 episode, 2008
- Jim O'Connell
- Â Self - Anthropologist 1 episode, 2008
- Mark H. Seibert
- Â Self 1 episode, 2009
- Rob Burnett
- Â Self - TauTona Mine 1 episode, 2009
- Sean Raymond
- Â Self 1 episode, 2009
- Reg E. Cathey
- Â Self - Narrator 1 episode, 2010
- Alan Peterson
- Â Narrator 1 episode, 2010
- Lars Schmitz
- Â Self - UC Davis 1 episode, 2010
- Dan Russell
- Â Narrator 1 episode, 2011
- Mark Keller
- Â Self - Narrator 1 episode, 2011
- Gloria Day
- Â Self - 1964 Anchorage Earthquake Survivor 1 episode, 2004
- Christian Koeberl
- Â Self - University of Vienna 1 episode, 2006
- Randy Thornhill
- Â Self - University of New Mexico 1 episode, 2006
- Michelle Thaller
- Â Self - Cal Tech 1 episode, 2007
- Don Walsh
- Â Self 2 episodes, 2006-2007
- Robert Poreda
- Â Self 1 episode, 2007
- Chandra Wickramasinghe
- Â Self - Cardiff University 1 episode, 2008
- Steve Squyres
- Â Self - Principal Investigator 1 episode, 2008
- John M. Grunsfeld
- Â Self 1 episode, 2008
- Andrew J.S. Hamilton
- Â Self - University of Colorado 1 episode, 2008
- Gonzalo Giribet
- Â Self 1 episode, 2008
- Jim Bowler
- Â Self - Geologist 1 episode, 2008
- Mike Drake
- Â Self 1 episode, 2009
- Patrick Morrissey
- Â Self 1 episode, 2009
- Esta van Heerden
- Â Self - Biochemist 1 episode, 2009
- Joe Kunches
- Â Self 1 episode, 2009
- Barry Aithchison
- Â Townhouse Resident 1 episode, 2010
- Ivan Barker
- Â Self 1 episode, 2010
- Nadia Fröbisch
- Â Self - University of Chicago 1 episode, 2010
- Linda Guthrie
- Â Self - 1964 Anchorage Earthquake Survivor 1 episode, 2004
- Fran Bagenal
- Â Self - Professor 1 episode, 2006
- Marc Mani
- Â Self 1 episode, 2006
- Farouk Elbaz
- Â Self 1 episode, 2006
- Robert Vrijenhoek
- Â Self - Senior Scientist 1 episode, 2006
- Eric Rignot
- Â Self - NASA 1 episode, 2007
- Mark Hay
- Â Self 1 episode, 2007
- Stan Woosley
- Â Self - UC Santa Cruz 1 episode, 2007
- Kip Thorne
- Â Self - Cal Tech 1 episode, 2008
- Bert Roberts
- Â Self - Earth Scientist 1 episode, 2008
- Gary Hinshaw
- Â Self 1 episode, 2008
- Scott Maxwell
- Â Self - Rover Driver 1 episode, 2008
- Paul Silver
- Â Self - Geophysicist 1 episode, 2008
- Robin Canup
- Â Self 1 episode, 2009
- Paul Bellan
- Â Self 1 episode, 2009
- Sam Bornstein
- Â Fruit Farmer 1 episode, 2010
- Jörg Fröbisch
- Â Self - Paleontologist 1 episode, 2010
- Wayne Ivers
- Â Self - Senior LA Fire Department Official 1 episode, 2004
- Arthur Aron
- Â Self - Stony Brook 1 episode, 2006
- Ross Anderson
- Â Self - Geology Research Associate 1 episode, 2006
- Ben Benjamin
- Â Self - Trinity Photographer 1 episode, 2006
- Ronald Greeley
- Â Self - Regents' Professor of Geology 1 episode, 2006
- Lee Kump
- Â Self 1 episode, 2007
- Peter Tsou
- Â Self - NASA 1 episode, 2007
- Richard Alley
- Â Self 1 episode, 2007
- Phil Nuytten
- Â Self - Nuytco Research 1 episode, 2007
- Peter Olson
- Â Self - Professor of Geophysics 1 episode, 2008
- Richard Gordon
- Â Self - Geophysicist 1 episode, 2008
- Tiziana Di Matteo
- Â Self 1 episode, 2008
- Matthew Coller
- Â Self - Monash University 1 episode, 2008
- John Chalmers
- Â Self - UC San Diego 1 episode, 2008
- Richard Ellis
- Â Self 1 episode, 2008
- Hap McSween
- Â Self - Rover Science Team 1 episode, 2008
- Toby Owen
- Â Self 1 episode, 2009
- Richard Grieve
- Â Self - Planetary Geologist 1 episode, 2009
- Karel Schrjiver
- Â Self 1 episode, 2009
- Sabrina D'Amour
- Â Astronaut 1 episode, 2010
- Ryosuke Motani
- Â Self - UC Davis 1 episode, 2010
- Rosaly Lopes
- Â Self - Planetary Geologist 1 episode, 2006
- Geoffrey Miller
- Â Self - University of New Mexico 1 episode, 2006
- John Wasson
- Â Self - UCLA 1 episode, 2006
- Charles Fisher
- Â Self - Professor of Biology 1 episode, 2006
- Ralph von Frese
- Â Self 1 episode, 2007
- Breea Govenar
- Â Self 1 episode, 2007
- Jack Lissauer
- Â Self 1 episode, 2007
- Jonathan Overpeck
- Â Self 1 episode, 2007
- Mimi Hill
- Â Self - Geophysics Lecturer 1 episode, 2008
- Sue O'Connor
- Â Self - Archaeologist 1 episode, 2008
- Steven Ritz
- Â Self 1 episode, 2008
- Rob Manning
- Â Self - Rover Engineer 1 episode, 2008
- Johan Richard
- Â Self 1 episode, 2008
- Neal Zapp
- Â Self 1 episode, 2009
- Bruce Marsh
- Â Self - Geologist 1 episode, 2009
- Carey Lisse
- Â Self 1 episode, 2009
- Michael Everhart
- Â Self - Sternberg Museum of Natural History 1 episode, 2010
- Luke Bontius
- Â Astronaut's Assistant 1 episode, 2010
- Vladimir I. Keilis-Borok
- Â Self - Research Group Leader, International Institute for Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Science 1 episode, 2004
- Chris German
- Â Self 1 episode, 2007
- Don Perovich
- Â Self 1 episode, 2007
- Steve Desch
- Â Self - Arizona State University 1 episode, 2007
- Peter Steinberg
- Â Self - Brookhaven National Laboratory 1 episode, 2008
- Robert Hazen
- Â Self 1 episode, 2008
- Matt Wallace
- Â Self - Rover Engineer 1 episode, 2008
- Wendy Freeman
- Â Self 1 episode, 2008
- Tim Crow
- Â Self - Psychiatrist 1 episode, 2008
- Richard Norris
- Â Self 1 episode, 2008
- Stephen Mojzsis
- Â Self 1 episode, 2009
- Mark Zoback
- Â Self - Geophysicist 1 episode, 2009
- Nicola Fox
- Â Self - NASA 1 episode, 2009
- Jonathan Steen
- Â Astronaut's Assistant 1 episode, 2010
- Pat Embree
- Â Self - Geologist 1 episode, 2010
- Gary Lofgren
- Â Self - NASA 1 episode, 2007
- Nicholas K. Coch
- Â Self 1 episode, 2007
- Benjamin Weiss
- Â Self - Assistant Professor of Planetary Sciences 1 episode, 2008
- Huw Barton
- Â Self - Archaeolgotist 1 episode, 2008
- Chris Leger
- Â Self - Rover Driver 1 episode, 2008
- Michael John Russell
- Â Self - NASA 1 episode, 2008
- Paul Valdes
- Â Self 1 episode, 2008
- Diane Moore
- Â Self - Mineralogist 1 episode, 2009
- Eric Feigelson
- Â Self 1 episode, 2009
- Alessandro Morbidelli
- Â Self 1 episode, 2009
- Samantha Farrow
- Â Apartment Resident 1 episode, 2010
- Akiko Shinya
- Â Self - Fossil Preparator 1 episode, 2010
- John Spencer
- Â Self - Staff Scientist 1 episode, 2006
- Deborah Kelley
- Â Self - Marine NOAA Ocean Explorer 1 episode, 2006
- Hal Levison
- Â Self - Southwest Research Institute 1 episode, 2007
- Neil Armstrong
- Â Self - NASA Apollo XI Astronaut 2 episodes, 2004-2008
- George Bryan
- Â Self 1 episode, 2008
- Robert Bednarik
- Â Self - Archaeologist 1 episode, 2008
- Julie Townsend
- Â Self - Rover Driver 1 episode, 2008
- Tom Knight
- Â Self - MIT 1 episode, 2008
- Gibor Basri
- Â Self 1 episode, 2009
- Jerry Bellian
- Â Self - Geologist 1 episode, 2009
- Gary Huss
- Â Self 1 episode, 2009
- Steven Clarke
- Â Bus Shelter Man 1 episode, 2010
- Susan Humphris
- Â Self - Senior Scientist 1 episode, 2006
- David Kring
- Â Self - University of Arizona 1 episode, 2007
- Buzz Aldrin
- Â Self - NASA Apollo XI Astronaut 1 episode, 2008
- Bruce H. Tiffney
- Â Self 1 episode, 2008
- John Callas
- Â Self - Rover Project Manager 1 episode, 2008
- Steve Webb
- Â Self - Austrialian Studies Expert 1 episode, 2008
- Steve Ruppell
- Â Self - Geologist 1 episode, 2009
- Sophie Jaremko
- Â Bus Shelter Elderly Woman 1 episode, 2010
- Paul Wignall
- Â Self 1 episode, 2008
- Jonathan Bogais
- Â Self - Navigation Expert 1 episode, 2008
- Frank Hartman
- Â Self - Rover Driver 1 episode, 2008
- Jim Head
- Â Self - Planetary Geologist 1 episode, 2009
- Daniel Cargnello
- Â City Worker 1 episode, 2010
- Gary Glatzmaier
- Â Self - Professor of Earth and Planetary Sciences 1 episode, 2008
- Jake Matijevic
- Â Self - Rover Engineer 1 episode, 2008
- Ken Caldeira
- Â Self 1 episode, 2008
- Qaisal Al-Awqait
- Â Self - Columbia University 1 episode, 2008
- Ashley Stroupe
- Â Self - Rover Driver 1 episode, 2008
- Emilio Herrera-Bervera
- Â Self - Geophysicist 1 episode, 2008
- John Moore
- Â Self - Anthropologist 1 episode, 2008
- Bramley Murton
- Â Self - Marine Geochemist 1 episode, 2009
- Richard Holland
- Â Self - Biologist 1 episode, 2008
- Nils Olsen
- Â Self - Adjunct Professor 1 episode, 2008
- Stephen Hawking
- Â Self - Cosmologist 1 episode, 2004
- Peter Elliott
- Â Self - Primate Behavioral Actor 1 episode, 2004
- John Hutchison
- Â Self - Inventor 1 episode, 2004
- Robert Schoch
- Â Boston Universty / ... 1 episode, 2004
- Joshua Wurman
- Â Self - Meteorologist 1 episode, 2004
- Bruce Gernon
- Â Self - Flight Instructor & Property Developer 1 episode, 2004
- Dan Durda
- Â Senior Research Scientist, Southwest Research Institute 1 episode, 2004
- Gary England
- Â Oklahoma City / ... 1 episode, 2004
- Stan Goldenberg
- Â Self - Meteorologist 1 episode, 2004
- Russell Schweickart
- Â Self - Apollo 9 Astronaut 1 episode, 2004
- Bryan Norcross
- Â CBS Weather Control / ... 1 episode, 2004
- Spencer Wells
- Â Self - Geneticist and Anthropologist 1 episode, 2004
- Nik Williams
- Â Self - Prosthetics Make-Up Artist 1 episode, 2004
- Raymond R. Anderson
- Â Self - Project Geologist, Iowa Geological Survey 1 episode, 2004
- Leslie Aiello
- Â Self - Professor 1 episode, 2004
- Rick Smith
- Â Self - National Weather Service, Norman, Oaklahoma 1 episode, 2004
- Paulina Zelitsky
- Â Self - Marine Engineer 1 episode, 2004
- James Ward
- Â Self - Radio Operator 1 episode, 2004
- Francis Thackeray
- Â Self - Director: Transvaal Museum of Natural History 1 episode, 2004
- Jim Edds
- Â Self - Storm Photographer 1 episode, 2004
- Steven Fender
- Â Self - Brother of Lewis Fender 1 episode, 2004
- Lee Rogers Berger
- Â Self - Paleoanthropologist 1 episode, 2004
- Chad Morris
- Â Self - Assoc. Director / ... 1 episode, 2004
- Christopher Landsea
- Â Self - Meteorologist, NOAA 1 episode, 2004
- Dave White
- Â Self - Flight 19 Search Pilot 1 episode, 2004
- Hugh E. Willoughby
- Â Self - Florida International Universty 1 episode, 2004
- David Levy
- Â Self - Comet Discoverer 1 episode, 2004
- John Guthrie
- Â Self - Chief Petty Officer, US Coast Guard 1 episode, 2004
- David Lea
- Â Self - Living Letters Productions 1 episode, 2004
- Joel Hagen
- Â Self - Imagery Specialist 1 episode, 2004
- Andrew Fitzpatrick
- Â Self - Wessex Archaeology Expert on Boscombe Bowmen 1 episode, 2004
- Charles O'Brien
- Â Self - Commander 1 episode, 2004
- Chris Carey
- Â Self - Surgeon Who Treated Julie Rakestraw 1 episode, 2004
- Damian Goodburn
- Â Self - Ancient Woodwork Expert 1 episode, 2004
- Jake Lowenstern
- Â Self - Geologist, U.S. Geological Survey, Yellowstone Volcano Observatory 1 episode, 2004
- James Cole
- Â Pilot 1 episode, 2004
- Josh Warman
- Â Self - Meteorologist, Head of the Center for Severe Weather Research 1 episode, 2004
- Adriana Cacciottolo
- Â Self - Maltese Tourist Authority Employee 1 episode, 2004
- Ronald W. Smith
- Â Self - University of Nevada, Las Vegas, Architecture-Societal Relationship Expert 1 episode, 2004
- Richard Smailes
- Â Self - Hardin Construction Engineer 1 episode, 2004
- Dave Ease
- Â Self - Diving Instructor 1 episode, 2004
- Peter Stauning
- Â Self - Danish Meteorological Institute 1 episode, 2004
- Robert B. Smith
- Â Self - Professor of Geophysics, University of Utah 1 episode, 2004
- Dan Werthimer
- Â Self - Astronomer 1 episode, 2004
- Daniel Dzurisin
- Â Self - Geologist, U.S. Geological Survey 1 episode, 2004
- Erik Asphaug
- Â Self - Planetary Scientist, Univ. of California, Santa Cruz 1 episode, 2004
- Howard Brooks
- Â Self - Meteorologist, National Weather Service, Norman OK 1 episode, 2004
- Michael Rampino
- Â Self - Associate Professor, New York University 1 episode, 2004
- Carol Collins
- Â Self - Flying Instructor 1 episode, 2004
- Jim Lushine
- Â Self - Meteorologist, NOAA 1 episode, 2004
- Monte Henderson
- Â Self - Deputy Program Manager 'Deep Impact Mission' 1 episode, 2004
- Lewis Fender
- Â Self - Brother of Steven Fender 1 episode, 2004
- Ken Feder
- Â Self - Professor of Archaeology at Central Connecticut State University 1 episode, 2004
- Gian Quasar
- Â Self - Bermuda Triangle Author & Expert 1 episode, 2004
- Chris Austin
- Â Self - Wildfire Controler 1 episode, 2004
- Paul Weinzweig
- Â Self - Paulina Zelitsky's Husband and Associate 1 episode, 2004
- Lou Beck
- Â Self - Wind Tunnel Test Subject 1 episode, 2004
- Julie Rakestraw
- Â Self - May 3, 1999 Oklahoma CityTornado Head-Injury Victim 1 episode, 2004
- Lora Little
- Â Self - Amateur Sleuth and Follower of Edgar Cayce 1 episode, 2004
- Robin Heath
- Â Self - Author and Researcher 1 episode, 2004
- Brian J. Witzke
- Â Self - Geologist, Iowa Geological Survey 1 episode, 2004
- Nicholas Toth
- Â Self - Experimental Archaeologist 1 episode, 2004
- Jenifer Evans
- Â Self - Research Engineer, Lincoln 1 episode, 2004
- Mike Pitts
- Â Editor for British Archaeology / ... 1 episode, 2004
- John Buxton
- Â Pilot 1 episode, 2004
- Ben Buckley
- Â Pilot 1 episode, 2004
- Brian Jones
- Â Self - Manager: Moholoholo Wildlife Rehabilitation Centre 1 episode, 2004
- Michael R. Voorhies
- Â Self - Professor of Vertebrate Paleontology, University of Nebraska 1 episode, 2004
- Jeff Piotrowski
- Â Self - Storm Chaser 1 episode, 2004
- Paul Vance
- Â Self - UFO Witness 1 episode, 2004
- Greg Little
- Â Self - Amateur Sleuth and Follower of Edgar Cayce 1 episode, 2004
- Robert Christiansen
- Â Self - Scientist Emeritus, U.S. Geological Survey 1 episode, 2004
- Troy Morgan
- Â Pilot 1 episode, 2004
- Robert Rogers
- Â Self - Meteorologist, NOAA 1 episode, 2004
- Bethany Hamilton
- Â Self - Tiger Shark Attack Victim 1 episode, 2005
- Lynne Kitei
- Â Self - Phoenix Lights Eyewitness 1 episode, 2005
- Dan Severn
- Â Self - Supervisor, College Station SWAT Team, Texas 1 episode, 2005
- Barry Hirshhorn
- Â Self - Geophysicist 1 episode, 2005
- John E. McCosker
- Â Self - Ichthyologist of California Academy of Sciences 1 episode, 2005
- Ryan Johnson
- Â Self - Marine Biologist at University of Pretoria South Africa 1 episode, 2005
- Michael Persinger
- Â Self - Laurentian University, Canada 1 episode, 2005
- Michael Shermer
- Â Self - Skeptic Magazine 1 episode, 2005
- Yannis P. Papastamatiou
- Â Self - Marine Biologist of Hawaii Institute of Marine Biology 1 episode, 2005
- Charles I. Halt
- Â Self - Ex Deputy Base Commander 1 episode, 2005
- Charles McCreary
- Â Self - Director: Pacific Tsunami Warning Center 1 episode, 2005
- Lynn Smith
- Â Self - Communications Manager 1 episode, 2005
- Tom Duckett
- Â Self - Baptist Minister 1 episode, 2005
- Rachelle Strauss
- Â Self - Caught in Flood 1 episode, 2005
- Kenneth M. Kamler
- Â Self - Author 1 episode, 2005
- J. Marvin Herndon
- Â Self - Maverick Geophysicist 1 episode, 2005
- Walter Birkby
- Â Self - Forensic Anthropologist 1 episode, 2005
- Ronald Barrett
- Â Self - Aerospace Engineer 1 episode, 2005
- James Cullen Grissom
- Â Self - Gun Ballistics Expert 1 episode, 2005
- Richard Strauss
- Â Self - Caught in Flood 1 episode, 2005
- Nicco Garnero
- Â Self - Son of Edward J. Garnero 1 episode, 2005
- Blase Kraeer
- Â Self - Detective, City of Pittsburgh Police 1 episode, 2005
- Laurance Doyle
- Â Self - Astrophysicist and Principal Investigator, SETI Institute 1 episode, 2005
- Kim Holland
- Â Self - Hawaii Institute of Marine Biology 1 episode, 2005
- Val Castor
- Â Self - Storm Chaser 1 episode, 2005
- Charles Maxwell
- Â Self - Underwater Cameraman 1 episode, 2005
- Simon M. Clark
- Â Self - Researcher, Lawrence Berkeley National Laboratory 1 episode, 2005
- Andre Hartman
- Â Self - Fisherman and Diver of Ganzenbaai in South Africa 1 episode, 2005
- Ed Garnero
- Â Self - Professor of Geophysics, Arizona State University 1 episode, 2005
- Brenda Archer
- Â Self - Homeowner 1 episode, 2005
- Kerry Sieh
- Â Self - Professor of Geology 1 episode, 2005
- Justin Norris
- Â Self - Lightning Strike Victim 1 episode, 2005
- Simon Boxall
- Â Self - Senior Oceanographer 1 episode, 2005
- Kenneth D. Murphy
- Â Self - Director: Oregon Emergency Management 1 episode, 2005
- Ronald L. Holle
- Â Self - Lightning Safety Expert 1 episode, 2005
- Matt Crawford
- Â Self - Shark Attack Victim in Florida 1 episode, 2005
- Chuck Anderson
- Â Self - Bullshark Attack Victim in Alabama 1 episode, 2005
- Stuart Weinstein
- Â Self - Geophysicist 1 episode, 2005
- Tony Bullimore
- Â Self - International Yachtsman 1 episode, 2005
- Roger White
- Â Self - Researcher 1 episode, 2005
- Louise Brady
- Â Self - Test Subject and Sports Show Host 1 episode, 2005
- Dennis S.Y. Wang
- Â Self - Trauma Surgeon 1 episode, 2005
- Wayne L. Nicholson
- Â Self - Professor of Microbiology 1 episode, 2005
- David Rovinsky
- Â Self - Wilcox Memorial Hospital in Kauai 1 episode, 2005
- Martin L. Fackler
- Â Self - Wound and Terminal Ballistics Expert 1 episode, 2005
- Dana Larson
- Â Self - Oceanographer 1 episode, 2005
- Holt Blanchard
- Â Self - Bethany's Rescuer in Kauai 1 episode, 2005
- Debbi Burns
- Â Forensic Scientist 1 episode, 2006
- Peta Johnson
- Â Female 1 episode, 2006
- Stephen Rashbrook
- Â Self - Narrator 1 episode, 2006
- Jim Green
- Â Self - NASA 1 episode, 2006
- Van Romero
- Â New Mexico Tech / ... 1 episode, 2006
- Ralph Jackson
- Â Self - Curator 1 episode, 2006
- Alex F.M. Kisters
- Â Self - Professor 1 episode, 2006
- Richard Thompson
- Â Self - Director of Studies, Imperial College Physics Department 1 episode, 2006
- Páll Einarsson
- Â Self - Geophysics Professor 1 episode, 2006
- Kate M. Gilliver
- Â Self - Lecturer in Ancient History 1 episode, 2006
- Anthony Iafolla
- Â Male 1 episode, 2006
- Gérard M. Stampfli
- Â Self - Professor 1 episode, 2006
- Mary Ann Cooper
- Â Self - Physician and Head, Lightning Research Program, University of Illinois, Chicago 1 episode, 2006
- Jerry Little
- Â Self - New Mexico Tech Explosives Instructor and Former Bomb Squad Tech 1 episode, 2006
- Samuel A. Bowring
- Â Self - Professor 1 episode, 2006
- Glen Gonzaga
- Â Self - UCLA 1 episode, 2006
- John Rhoades
- Â Los Alamos / ... 1 episode, 2006
- Ben Jeal
- Â Self - Weapons Reconstruction Expert 1 episode, 2006
- Steven A. Cummer
- Â Self - Professor, Duke University 1 episode, 2006
- Mark A.S. McMenamin
- Â Self - Professor 1 episode, 2006
- Randall L. Simpson
- Â Self - Scientist, Lawrence Livermore National Laboratory, High Explosives Applications Facility 1 episode, 2006
- Janet DeLaine
- Â Self - Lecturer in Roman Archaeology 1 episode, 2006
- Joe Dwyer
- Â Self - Professor, Florida Institute of Technology 1 episode, 2006
- Richard David Rosin
- Â Self - Consultant Surgeon 1 episode, 2006
- Ronald C. Blakey
- Â Self - Professor of Geology 1 episode, 2006
- Peter Aicher
- Â Self - Professor of Classical Studies 1 episode, 2006
- Dominic Frisby
- Â Self (narrator) 1 episode, 2007
- Lance Newman
- Â Self - Narrator 1 episode, 2007
- Lance Newman
- Â Self (narrator) 1 episode, 2007
- Charles Klausmeyer
- Â Narrator / ... 1 episode, 2008
- Aarón I. Campos
- Â Minero 1 episode, 2008
- Erik Kaufmann
- Â Self 1 episode, 2008
- David Leckrone
- Â Self 1 episode, 2008
- David Spergel
- Â Self - Princeton University 1 episode, 2008
- Tara Shears
- Â Self - University of Liverpool 1 episode, 2008
- Giovanni Badino
- Â Self 1 episode, 2008
- Tullio Bernabei
- Â Self - Naica Project 1 episode, 2008
- David Giles
-  Self - Industrias Peñoles 1 episode, 2008
- Steve Maran
- Â Self 1 episode, 2008
- Eric Chaisson
- Â Self 1 episode, 2008
- Tod R. Lauer
- Â Self 1 episode, 2008
- Richard Massey
- Â Self 1 episode, 2008
- Stein-Erik Lauritzen
- Â Self 1 episode, 2008
- Howard E. Bond
- Â Self 1 episode, 2008
- Sandra Faber
- Â Self 1 episode, 2008
- Javier Delgado
- Â Self - Miner 1 episode, 2008
- Eloy Delgado
- Â Self - Miner 1 episode, 2008
- Adam Russ
- Â Self 1 episode, 2008
- David Heyman
- Â Self - Asst. Secretary, Office of Policy, Homeland Security 1 episode, 2009
- Dave Hoffman
- Â Narrator 1 episode, 2009
- Mark Bedell
- Â Terrorist 1 episode, 2009
- Sean Carroll
- Â Self 1 episode, 2009
- Andrew Wallace-Hadrill
- Â Self - Historian, Herculaneum Conservation Project 1 episode, 2009
- Roy Livermore
- Â Self - University of Cambridge, England 1 episode, 2009
- Jean Clottes
- Â Self - Prehistoric Art Expert 1 episode, 2009
- Clark Chapman
- Â Self - Senior Scientist 1 episode, 2009
- James F. Kasting
- Â Self - Professor of Geosciences 1 episode, 2009
- Giuseppe Mastrolorenzo
- Â Self - Volcanologist, Vesuvius Observatory 1 episode, 2009
- William F. Bottke
- Â Self - Assistant Director: Department for Space Studies 1 episode, 2009
- Gerard Jasniewicz
- Â Self - Astronomer, University of Montpellier II 1 episode, 2009
- Lee Anne Willson
- Â Self 1 episode, 2009
- Donald Brownlee
- Â Self - Professor of Astronomy 1 episode, 2009
- Peter de Menocal
- Â Self - Professor of Earth and Environmental Sciences 1 episode, 2009
- Don Brown Lee
- Â Self 1 episode, 2009
- Janice L. Bishop
- Â Self - Principal Investigator: SETI Institute 1 episode, 2009
- Charles R. Gallaway
- Â Self - Acting Director: Department of Homeland Security 1 episode, 2009
- Robert C. Whitcomb Jr.
- Â Self - Certified Health Physicist 1 episode, 2009
- John Rennie
- Â Self - Editor-in-Chief 1 episode, 2009
- D. Christopher Martin
- Â Self 1 episode, 2009
- Irwin Redlener
- Â Self - Director of the National Center for Disaster Preparedness 1 episode, 2009
- Guido Bertolaso
- Â Self - Director of the Civil Protection Department of the Prime Ministers of Italy 1 episode, 2009
- Jonathan Adams
- Â Narrator 1 episode, 2009
- Petrus Matheus Marie Jenniskens
- Â Self - Astronomer 1 episode, 2009
- Benedetto De Vivo
- Â Self - Volcanologist, University of Naples, Federico II 1 episode, 2009
- Don Korycansky
- Â Self 1 episode, 2009
- Stephen Smith
- Â Self - Deputy Fire Chief 1 episode, 2009
- R. Michael Rich
- Â Self 1 episode, 2009
- Andrew Steele
- Â Self - Phd., Astrobiologist 1 episode, 2009
- Karl Foster
- Â Self 1 episode, 2009
- David S. Dearborn
- Â Self - Research Physicist 1 episode, 2009
- Brooke R. Buddemeier
- Â Self - Certified Health Physicist 1 episode, 2009
- Robert C. Smith
- Â Self - Reader Emeritus Physics and Astronomy, University of Sussex, England 1 episode, 2009
- Douglas S. Robertson
- Â Self - Adjunct Professor 1 episode, 2009
- Chantal Jegues-Wolkiewiez
- Â Self - Archaeoastronomer 1 episode, 2009
- J. Matthew Sholl
- Â Self - Medical Doctor 1 episode, 2009
- Pier Paolo Petrone
- Â Self - Anthropologist 1 episode, 2009
- Eric Welling
- Â Self - FBI WMD Operations Unit Chief 1 episode, 2009
- Marcello Martini
- Â Self - Seismologist, Director of Vesuvius Observatory 1 episode, 2009
- Timothy B. Spahr
- Â Self - Near Earth Object Technical Specialist 1 episode, 2009
- Abbey Greslick
- Â Bystander 1 episode, 2009
- Federica Raia
- Â Self - Volcanologist, City College of New York 1 episode, 2009
- Muawia Hamid Shaddad
- Â Self - Astronomer 1 episode, 2009
- Alexander Marshac
- Â Self - Honorary Research Fellow, Peabody Museum of Harvard University 1 episode, 2009
- William H. Menke
- Â Self - Professor of Seismology, Columbia University 1 episode, 2009
- Etha Ali Hussan
- Â Self - Sudanese Camel Herder 1 episode, 2009
- Ron de Poorter
- Â Self - Pilot 1 episode, 2009
- Gayle A. Sugiyama
- Â Self - National Atmospheric Release Advisory Center 1 episode, 2009
- Jean-Michel Geneste
- Â Self - Curator of Lascaux 1 episode, 2009
- Richard A. Kowalski
- Â Self - Astromomer 1 episode, 2009
- James Don Neill
- Â Self 1 episode, 2009
- Lucia Pappalardo
- Â Self - Volcanologist, Vesuvius Observatory 1 episode, 2009
- Dean A. Wilkening
- Â Self - Senior Research Scientist 1 episode, 2009
- James P. Barry
- Â Self - Senior Scientist. at Monterey Bay Aquarium Research Institute 1 episode, 2009
- Page O. Stoutland
- Â Self - Global Security Strategy Director 1 episode, 2009
- Douglas J. Nichols
- Â Self - Research Associate 1 episode, 2009
- Steven R. Chesley
- Â Self - NASA 1 episode, 2009
- Robert Connor Smith
- Â Self 1 episode, 2009
- Coen van Uden
- Â Self - Co-Pilot 1 episode, 2009
- Hinrik Ãlafsson
- Â Self - Filmmaker 1 episode, 2010
- Jake Eberle
- Â Narrator 1 episode, 2010
- Howard Nightingall
- Â Narrator / ... 1 episode, 2010
- Jeffrey B. Halverson
- Â Self - Hurricane Researcher, UMBC 1 episode, 2010
- Jennifer Heldmann
- Â Self - Planetary Scientist 1 episode, 2010
- Jeffrey L. Bada
- Â Self - Professor of Marine Chemistry 1 episode, 2010
- Joseph Golden
- Â Self - Senior Meteorologist 1 episode, 2010
- Richard Greenberg
- Â Self - Professor of Planetary Sciences 1 episode, 2010
- Johann Sigfússon
- Â Self - Film Director 1 episode, 2010
- Geoffrey A. Landis
- Â Self - Physicist at NASA Glenn Research Center 1 episode, 2010
- Russet J. McMillan
- Â Self - Lead Observing Scientist 1 episode, 2010
- George Alexie
- Â Self - Member of Lake Clark Staff 1 episode, 2010
- Haraldur Sigurdsson
- Â Self - Volanologist 1 episode, 2010
- Tim Raub
- Â Self - Geologist 1 episode, 2010
- Nick Jarman
- Â Self - Archaeologist 1 episode, 2010
- Chris Houlette
- Â Self - Archaeologst 1 episode, 2010
- Stan Love
- Â Self - Astronaut 1 episode, 2010
- Alexander Zaitsev
- Â Self - Chief Scientist 1 episode, 2010
- Jacques Laskar
- Â Self - Astronomer 1 episode, 2010
- Walter H. Haas
- Â Self 1 episode, 2010
- E. James Dixon
- Â Self - Director: Maxwell Museum of Anthropology 1 episode, 2010
- Ting F. Zhu
- Â Self - Graduate Student Researcher 1 episode, 2010
- Marco Cocchi
- Â Self - University of Bologna Professor 1 episode, 2010
- Marjorie A. Chan
- Â Self - Professor of Geology 1 episode, 2010
- Tom Murphy
- Â Self - Associate Professor of Physics 1 episode, 2010
- Luca Gasperini
- Â Self - Marine Scientist 1 episode, 2010
- Jóhanna Sigurðardóttir
- Â Self - Iceland Prime Minister 1 episode, 2010
- Pétur Péturss
- Â Self - Farmer 1 episode, 2010
- Peter Smith
- Â Self - Scientist 1 episode, 2010
- Jack Wisdom
- Â Self - Professor of Planetary Sciences 1 episode, 2010
- Jason Phipps-Morgan
- Â Self - Geophysicist and Geologist 1 episode, 2010
- Julian Spragg
- Â Self - Researcher 1 episode, 2010
- Navashni Govender
- Â Self - Fire Ecologist, Kruger National Park 1 episode, 2010
- Bounois Cantnare
- Â Self - French Tourist 1 episode, 2010
- Charles E. Holmes
- Â Self - Research Archaeologist 1 episode, 2010
- Laura Schuster
- Â Self - Park Ranger 1 episode, 2010
- Jeanne Schaaf
- Â Self - Archaeologist 1 episode, 2010
- Jeremy Karchut
- Â Self - Archaeologist 1 episode, 2010
- John P. Lockwood
- Â Self - Volcanologist 1 episode, 2010
- Alan Blumberg
- Â Self - Oceanologist 1 episode, 2010
- Simon Conway Morris
- Â Self - Professor of Evolutionary Palaeobiology, University of Cambridge 1 episode, 2010
- Craig M. Lee
- Â Self - INSTAAR Archaeologist 1 episode, 2010
- Tom Malone
- Â Narrator / ... 1 episode, 2010
- Alfredo R. Huete
- Â Self - Ecologist, Univ of Arizona 1 episode, 2010
- Steen Rasmussen
- Â Self - Research Director 1 episode, 2010
- Bernard H. Foing
- Â Self - Chief Scientist 1 episode, 2010
- Magnus Tumi Gudmunðsson
- Â Self - Geophysicist 1 episode, 2010
- Romano Serra
- Â Self - Astrophysicist 1 episode, 2010
- Ben A. Potter
- Â Self - Assistant Professor of Anthropology 1 episode, 2010
- Bergur Sigfússon
- Â Self - Geologist 1 episode, 2010
- David Mencin
- Â Self - Senior Engineer 1 episode, 2010
- Sigurður G. Ottossón
- Â Self - Farmer 1 episode, 2010
- Dimitar D. Sasselov
- Â Self - Professor of Astronomy 1 episode, 2010
- Vitaly Romeiko
- Â Himeself - Astrophysicist 1 episode, 2010
- Scott B. Luthcke
- Â Self - Geophysicist, NASA 1 episode, 2010
- Carlo Stanghellini
- Â Self - Astronomer 1 episode, 2010
- Maurizio Serrazanetti
- Â Self - University of Bologna Professor 1 episode, 2010
- Hein F. Vosloo
- Â Self - Transmission Division, ESKOM 1 episode, 2010
- Joseph Kirschvink
- Â Self 1 episode, 2010
- Paul Hoffman
- Â Self 1 episode, 2010
- KatrÃn Birna Viðarsdóttir
- Â Self - Farmer 1 episode, 2010
- Paul Spielman
- Â Self - Engineer, Puna Geothermal Venture 1 episode, 2010
- Philip Frost
- Â Self - Remote Sensing Specialist, CSIR-Meraka Institute 1 episode, 2010
- Jim Gehling
- Â Self 1 episode, 2010
- Rögnvaldur Ãlafsson
- Â Self - Iceland Civil Protection 1 episode, 2010
- Paola Vanucchi
- Â Self - Geologist and Geophysicist Researcher, University of Florence, Italy 1 episode, 2010
- H. Jay Zwally
- Â Self - ICESat Project Scientist, NASA 1 episode, 2010
- Gene Carl Feldman
- Â Self - NASA Oceanographer 1 episode, 2010
- Galen Halverson
- Â Self 1 episode, 2010
- Richard Dreyfuss
- Â Narrator 1 episode, 2011
- Jason Alan Carvell
- Â Narrator 1 episode, 2011
- Max Tegmark
- Â Self - Professor, MIT 1 episode, 2011
- Robert Bigelow
- Â Self - Aerospace Entrepreneur 1 episode, 2011
- Philip Currie
- Â Self 1 episode, 2011
- Jeff Jay
- Â Self 1 episode, 2011
- Bryan Grieg Fry
- Â Self - Host 1 episode, 2011
- Franklin Chang-Diaz
- Â Self - Aerospace Engineer 1 episode, 2011
- Anousheh Ansari
- Â Self - Civilian Astronaut 1 episode, 2011
- Zhe-Xi Luo
- Â Self 1 episode, 2011
- Burt Rutan
- Â Self - Aerospace Engineer 1 episode, 2011
- Christopher Cotten
- Â Parallel Universe Traveler 1 episode, 2011
- Richard SantaColoma
- Â Self - Researcher 1 episode, 2011
- Michael Archer
- Â Self - The University of New South Wales 1 episode, 2011
- Christian Meyer
- Â Self - Natural History Museum of Basel 1 episode, 2011
- Stephan Schaal
- Â Self 1 episode, 2011
- Anthony Aguirre
- Â Self - Professor - University of California 1 episode, 2011
- Alan Guth
- Â Self - Professor, MIT 1 episode, 2011
- Laura Mersini-Houghton
- Â Self - Professor - University of North Carolina-Chapel Hill 1 episode, 2011
- Xavier Claramunt
- Â Self - Space Architect 1 episode, 2011
- Yuanqing Wang
- Â Self 1 episode, 2011
- Maris Ensing
- Â Self 1 episode, 2011
- Lawrence Witmer
- Â (Self) 1 episode, 2011
- Gene Giacomelli
- Â Self - Bio-Systems Engineer 1 episode, 2011
- Jo Marchant
- Â Self 1 episode, 2011
- Josephine Clark
- Â Producer 1 episode
- Walter Dudley
- Â Self - Professor of Oceanograpy, Chair of the Scientific Advisory Council for the Pacific Tsunami Museum; Director of the Kalakaua Marine Education Center at the University of Hawaii at Hilo (uncredited) 1 episode, 2005
- Tim Krueger
- Â Fire Inspector (uncredited) 1 episode, 2006