The First Three Rungs of the Cosmological Distance Ladder

Details The First Three Rungs of the Cosmological Distance Ladder The First Three Rungs of the Cosmological Distance Ladder

2011-09-22

arxiv.org/abs/1109.4957v2

Astronomy and Astrophysics

Astrophysics

Instrumentation and Methods for Astrophysics

34 pages, 11 figures, accepted for publication in American Journal of Physics

Scientific paper

It is straightforward to determine the size of the Earth and the distance to the Moon without making use of a telescope. The methods have been known since the 3rd century BC. However, few amateur or professional astronomers have worked this out from data they themselves have taken. Here we use a gnomon to determine the latitude and longitude of South Bend, Indiana, and College Station, Texas, and determine a value of the radius of the Earth of 6290 km, only 1.4 percent smaller than the true value. We use the method of Aristarchus and the size of the Earth's shadow during the lunar eclipse of 2011 June 15 to derive an estimate of the distance to the Moon (62.3 R_Earth), some 3.3 percent greater than the true mean value. We use measurements of the angular motion of the Moon against the background stars over the course of two nights, using a simple cross staff device, to estimate the Moon's distance at perigee and apogee. Finally, we use simultaneous CCD observations of asteroid 1996 HW1 obtained with small telescopes in Socorro, New Mexico, and Ojai, California, to derive a value of the Astronomical Unit of (1.59 +/- 0.19) X 10^8 km, about 6 percent too large. The data and methods presented here can easily become part of a beginning astronomy lab class.

Affiliated with

Also associated with

No associations

Rating

The First Three Rungs of the Cosmological Distance Ladder does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The First Three Rungs of the Cosmological Distance Ladder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The First Three Rungs of the Cosmological Distance Ladder will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-723784