A search for life on Earth from the Galileo spacecraft

  title={A search for life on Earth from the Galileo spacecraft},
  author={Carl E. Sagan and William R. Thompson and Robert Carlson and Donald A. Gurnett and Charles W. Hord},
In its December 1990 fly-by of Earth, the Galileo spacecraft found evidence of abundant gaseous oxygen, a widely distributed surface pigment with a sharp absorption edge in the red part of the visible spectrum, and atmospheric methane in extreme thermodynamic disequilibrium; together, these are strongly suggestive of life on Earth. Moreover, the presence of narrow-band, pulsed, amplitude-modulated radio transmission seems uniquely attributable to intelligence. These observations constitute a… 

Properties of an Earth-like planet orbiting a Sun-like star: Earth observed by the EPOXI mission.

These observations furnish high-precision and high-cadence empirical photometry and spectroscopy of Earth, suitable as "ground truth" for numerically simulating realistic observational scenarios for an Earth-like exoplanet with finite signal-to-noise ratio.

Earthshine observations of an inhabited planet

Earthshine is sunlight that has been reflected from the dayside Earth onto the dark side of the Moon and back again to Earth. In recent times, there has been a renewed interest in ground-based

Terrestrial glint seen from deep space: Oriented ice crystals detected from the Lagrangian point

The Deep Space Climate Observatory (DSCOVR) spacecraft resides at the first Lagrangian point about one million miles from Earth. A polychromatic imaging camera onboard delivers nearly hourly

An overview of observations by the Cassini radio and plasma wave investigation at Earth

On August 18, 1999, the Cassini spacecraft flew by Earth at an altitude of 1186 km on its way to Saturn. Although the flyby was performed exclusively to provide the spacecraft with sufficient


The Search for Extraterrestrial Intelligence seeks radio and optical signals from other technological civilizations. Underpinning the search is the idea that life on planets around other stars is

Photometric variability in earthshine observations.

The results based on earthshine monitoring indicate that specular reflection should provide a useful tool in determining the presence of liquid water on extrasolar planets via photometric observations.

Planetary Atmospheres and Chemical Markers for Extraterrestrial Life

A decade of exoplanet research has led to surprising discoveries, from giant planets close to their star, to planets orbiting two stars, all the way to the first hot, confirmed rocky worlds with

Characterizing Earth-like planets: from CoRoT to DARWIN/TPF and beyond

The detection of terrestrial exoplanets is at its dawn with the detection of the first very low mass planets by microlensing and radial velocimetry. The transit method from space should help getting

Characterization of extrasolar terrestrial planets from diurnal photometric variability

A model is reported that predicts features that should be discernible in the light curve obtained by low-precision photometry, which suggests that the meteorological variability, composition of the surface, and rotation period of an Earth-like planet could be derived from photometric observations.

A test for the search for life on extrasolar planets - Looking for the terrestrial vegetation signature in the Earthshine spectrum

We report spectroscopic observations (400 to 800nm, R = approx 100) of Earthshine in June, July and October 2001 from which normalised Earth albedo spectra have been derived. The resulting spectra



The Search for Early Forms of Life in Other Planetary Systems: Future Possibilities Afforded by Spectroscopic Techniques

A consideration of the basic chemistry of life as we know it suggests good reasons for expecting carbon compounds and water as fundamental elements in extraterrestrial life. It is then possible to

The Earth as a radio source: Terrestrial kilometric radiation

Radio wave experiments on the Imp 6 and 8 satellites have shown that the earth emits very intense electromagnetic radiation in the frequency range of about 50–500 kHz. At peak intensity the total

The absorption and dissociative or ionizing effect of monochromatic radiation in an atmosphere on a rotating earth part II. Grazing incidence

The absorption of radiation from the sun in an atmosphere varying exponentially with the height is considered, as in a former paper; but here the earth's curvature, and that of the level layers in

Satellite observations of type III solar radio bursts at low frequencies

Type III solar radio bursts have been observed from 10 MHz to 10 kHz by satellite experiments above the terrestrial plasmasphere. Solar radio emission in this frequency range results from excitation

The Galileo Solid-State Imaging experiment

The Solid State Imaging (SSI) experiment on the Galileo Orbiter spacecraft utilizes a high-resolution (1500 mm focal length) television camera with an 800 × 800 pixel virtual-phase, charge-coupled

Near-Infrared Mapping Spectrometer experiment on Galileo

The Galileo Near-Infrared Mapping Spectrometer (NIMS) is a combination of imaging and spectroscopic methods. Simultaneous use of these two methods yields a powerful combination, far greater than when

Natural and man‐made emissions at 1.0–5.6 MHz measured between 10 and 18 RE

A survey has been undertaken of the 1.0- to 5.6-MHz electric field spectrum measured with the Active Magnetosphere Particle Tracer Explorers/Ion Release Module spacecraft at distances of 15–18

Galileo Ultraviolet Spectrometer experiment

The Galileo ultraviolet spectrometer experiment uses data obtained by the Ultraviolet Spectrometer (UVS) mounted on the pointed orbiter scan platform and from the Extreme Ultraviolet Spectrometer

The Galileo Plasma wave investigation

The purpose of the Galileo plasma wave investigation is to study plasma waves and radio emissions in the magnetosphere of Jupiter. The plasma wave instrument uses an electric dipole antenna to detect