No matter how hard we try, and despite the many other online sections and resources here, there will always be more information available in the world than can be contained on one server.
Here are our favorites for this chapter. Go ahead and check them out, but be sure to return back to do more exploring when you're done!
For a good selection of general sites of broad interest and utility that are related to many chapters of the book, see our collection of General Web Destinations For All Chapters.
How Planetary Systems and Life Originate
Describes the state of present understanding regarding the conditions in which our solar system and many other planetary systems were formed, the unique role played by the most primitive bodies in the solar system (comets and asteroids) in allowing us to interpret the record of events in the early solar system, and the many complex processes that subsequently shaped the planets. The discussion proceeds to the possibilities for life elsewhere.
The Discovery of a Planetary
Orbit Around the Nearby Star 51Pegasi
Planetary motions around their host stars, in principle, cause small variations in the radial velocity of the star as viewed from the Earth. The amplitude of these variations depends upon the gravitational influence of the planetary system about the host star. This in turn depends upon the mass and distance from the star of the individual planets. Get the scoop on how the detection of these
variations was used to discover the first confirmed planet found (by us, i.e., humans!) orbiting a different star than our own Sun.
Planetary Searches
Home page for the planetary search program at San Francisco State University. See also our Chapter 4 Image Archive for more information.
The Exploration of Neighboring Planetary Systems (ExNPS)
Are there other worlds in the Universe capable of supporting life? This site documents NASA's plan for a program designed to try to help answer this question, at least for the candidate stars nearest to us in the galaxy. This plan consists of a long term program of study and technological development leading ultimately to the ability to detect and characterize Earth-like planets around nearby stars. See also the Chapter 4 Image Archive.
Detecting Extrasolar Planets With Millimeter-Wave Observatories
Detecting planets circling other stars is a particularly difficult task, and only a few such planets have been discovered so far. In order to answer fundamental questions about planetary systems and their origin, scientists need to find and study many more extrasolar planets. According to this press release put together by National Radio Astronomy Observatory scientists, millimeter-wavelength observatories could provide valuable information about extrasolar planetary systems at all stages of their development.
History
of Discovery and Observations of Near-Earth Objects
Photometric, spectrophotometric, infrared observations all made with optical telescopes, and radar observations are the entire
basis for our understanding of the sizes, shapes, rotation states and mineral composition of the near-Earth asteroids. Understanding the history and composition of these objects may give us insight into the mechanisms for the origin of our Solar system, and planetary systems in general. To date, physical observations of one type or another have been obtained for more than 80 near-Earth asteroids. Find out more at this site. See also The Near-Earth Objects Population.
Circumstellar Disks and Possible
Planetary Systems
What is the nature of the particle disks that were discovered around Beta Pictoris? Mapping the disks might reveal gaps caused by the presence of planets. At wavelengths of 10 microns and beyond, it will be possible for new ground-based telescopes to achieve a resolution as good as 0.3 arcsec, which corresponds to 1-2 AU (1 AU = mean Earth-Sun
distance), comparable to the scale of the Earth's orbit, for the nearest candidate systems. This site explains the program of the new 8-meter Gemini telescopes, one of which is based at Mauna Kea in Hawaii and the other at Cerro Pachon, Chile.
