A Radar Determination of the Rotation of the Planet Mercury

  title={A Radar Determination of the Rotation of the Planet Mercury},
  author={G. Pettengill and R. Dyce},
DURING the recent inferior conjunction of the planet Mercury in April, 1965, radar observations were obtained by the Arecibo Ionospheric Observatory in Puerto Rico (operated by Cornell University with the support of the Advanced Research Projects Agency under a Research Contract with the Air Force Office of Scientific Research). The system operated at a frequency of 430 Mc/s, with an antenna gain of 56 dB and a transmitted power of 2 MW. The resulting sensitivity was sufficient to obtain… Expand
When radio waves are transmitted by an antenna system, they will be reflected by objects lying along their path. Radar makes use of this principle to determine the presence of and distance toExpand
Radar surveys of the solar system.
This paper provides a brief account of one aspect of the radar investigations, namely, the study of planetary motions, and shows that the two methods (old and new) complement one another well. Expand
Rotational Period of the Planet Mercury
IN a recent communication by S. J. Peale and T. Gold1 the rotational period of Mercury, determined from radar Doppler-spread measurements to be 59 ± 5 days2, has been explained in terms of a solarExpand
Radar Imaging of Mercury
Abstract Earth-based radar has been one of the few, and one of the most important, sources of new information about Mercury during the three decades since the Mariner 10 encounters. The emphasisExpand
Rotation Period of the Planet Mercury
THE recent radar measurements of Mercury indicate that the period of rotation of the planet is 59 ± 5 days1. This result is in complete disagreement with the previously quoted value of 88 days basedExpand
Thermophysics of the planet Mercury
Recent observations of the thermal emission of Mercury at microwave and infrared frequencies now permit a determination of the thermal and electrical properties of the subsurface of the planet. RadarExpand
The Study of Mercury
Abstract When the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft enters orbit about Mercury in March 2011 it will begin a new phase in an age-old scientificExpand
Earth-Based Radar Studies of Planetary Surfaces And Atmospheres
  • R. Jurgens
  • Geology
  • IEEE Transactions on Geoscience and Remote Sensing
  • 1982
Radar has been used as a remote sensing tool since 1946 when the first echoes from the moon were detected by ground-based radar systems. Since then the sensitivity of our most powerful radar systemsExpand
Mercury's rotation axis and period
Abstract Recent measurements made from high-resolution Mariner 10 photography of the planet Mercury yield a rotation period of 58.6461 ± 0.005 days, in excellent agreement with the period requiredExpand
Genesis of the 1000-Foot Arecibo Dish
The giant radar/radio astronomy dish near Arecibo, Puerto Rico, was conceived by William E. Gordon in early 1958 as a back-scattering radar system to measure the density and temperature of theExpand