Modern Value of Venus Transits

In 1716, Halley proposed that transits of Venus could be used to measure the Sun's distance, thereby establishing the absolute scale of the Solar System and solving one of the greatest problems in astronomy at that time. The technique required that expeditions travel to the far ends of Earth so that the differing parallax of the observations could be used to derive the distance to Venus. Today the distance to the Sun and planets can be measured extremely accurately using radar, so the 2004 transit will have no scientific value in this regard. Still, it is a remarkably rare event, which was of great importance during the early history of astronomy.

With the recent discovery of the first transit of a planet around another star [Henry, Marcy, Butler, and Vogt, 1999] interest in extra-solar transits is high. The 2004 transit of Venus may be of use in developing and testing new techniques and strategies for the detection and characterization of other extra-solar planets.

However, the greatest value of the 2004 transit lies in public outreach and educational opportunities to share this unique event with non-scientists. The public, amateur astronomers, educators, students and the media are genuinely fascinated with the transit and its rich scientific, cultural, political and intellectual history. A few of the educational websites focusing on the transit include:

sunearth.gsfc.nasa.gov/sunearthday/2004/index_vthome.htm
NASA Goddard's Sun-Earth Connection Education Forum has selected the transit as its theme for 2004. It will organize a series of resources and activities for every classroom and age group.

analyzer.depaul.edu/paperplate/Transit%20of%20Venus/Introduction.htm Chuck Bueter's "Paper Plate Education" website contains transit-related photos, diagrams, and maps.

www.transitofvenus.info
Jay Pasachoff (Williams College) provides links to international transit projects and provides some photographs of past transits.

didaktik.physik.uni-essen.de/~backhaus/VenusProject.htm
Professor Udo Backhaus (University of Essen, Germany) has organized a project for observing, photographing and evaluating the transit of Venus. Its target audience is composed of schools and amateur astronomers with some astronomical equipment.

www.transitofvenus.org
An exhaustive list of links for transits of Venus.

Rarely does an astronomical event occur which can be observed directly by the public using simple equipment. With justifiable concerns about the scientific literacy of today's citizens, the transit is a golden opportunity to stimulate, educate and (dare we say) entertain. It may even serve to ignite the imaginations of a few students who may continue on to become part of the next generation of scientists.

The predictions presented at this NASA 2004 Transit of Venus web site are provided as a resource for the public, educators, media and especially students attempting to measure the scale of the solar system.