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"Gregersen, Erik"
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EB editor Erik Gregersen discusses the future of space travel via private companies like Space X
Britannica Insights: What is next for space travel? Matt Sinnott interviews EB editor Erik Gregersen on the launch of the NASA launch and Space X.
Streaming Video
The Britannica guide to heat, force, and motion
Explores the foundations and laws of both thermodynamics and mechanics as well as the lives of those individuals who helped advance these fundamental areas of physics.
Book
Erik Gregersen of Britannica and Dr. Michelle Thaller of NASA discuss of the Apollo space program
Britannica Insights: anniversary of Apollo 11 moon landing on July 20th, 1969. Matt Sinnott interviews Erik Gregersen to talk about the landing and the future of moon landings.
Streaming Video
Eb Editor Erik Gregersen reviews the successes and failures of the U.S. Space Shuttle Program
Erik Gregersen, Associate Editor of Astronomy and Space Exploration for Encyclopaedia Britannica discusses the end of the space shuttle program and if the program accomplished its original mission set in the 1970's.
Streaming Video
Britannica editor Erik Gregersen explains the process necessary to become an astronaut
Erik Gregersen, Associate Editor of Astronomy and Space Exploration for Encyclopaedia Britannica tracks down how one becomes an astronaut and what training is involved to make it into space.
Streaming Video
Collapse and beyond: An investigation of the star formation process
This dissertation presents various studies designed to answer basic questions about young stellar objects in the early protostellar collapse stages. Five dense cores were mapped in $\\rm C\\sp{18}O$ $J = 1-0$ to find what separates the star-forming clump from the static cloud. Several theories predict a separation radius and how the density changes at that radius. We did not see distinct cores with sharply defined radii but low peaks in a pervasive medium. Forty-two star-forming cores were observed in various lines of H$\\sb2$CO, a molecule with an energy level structure such that certain line ratios depend only on the temperature. Temperatures were determined for 17 sources and densities were determined for 11 sources. Sixty-two objects ranging from starless cores to Class I sources were observed in HCO$\\sp{+}\\ J = 3-2$, a line that easily shows the double-peaked signature of protostellar collapse, in order to find more protostellar collapse candidates and the beginning and end of the collapse stage. Eighteen new candidates for protostellar collapse were discovered. Collapse candidates were seen in equal proportions among pre-protostellar cores, Class 0 and Class I sources.
Dissertation