hubble: Hubble Space Telescope Data

Description

Data on distances and velocities of 24 galaxies containing Cepheid stars, from the Hubble space telescope key project to measure the Hubble constant.

Usage

data(hubble)

Arguments

format

A data frame with 3 columns and 24 rows. The columns are:

Galaxy

{ A (factor) label identifying the galaxy.} y{ The galaxy's relative velocity in kilometres per second.} x{ The galaxy's distance in Mega parsecs. 1 parsec is 3.09e13 km.}

source

Tables 4 and 5 of Freedman et al. 2001. The Astrophysical Journal 553:47-72

Details

Cepheids are variable stars which have a known relationship between brightness and period. Hence the distance to galaxies containing these stars can be estimated from the observed brightness of the Cepheid, relative to its absolute brightness as predicted by its period. The velocity of the galaxy can be estimated from its mean red-shift.

The data can be used to get a reasonably good idea of the age of the universe A data free alternative estimate of 6000 years is given in the reference (not the source!).

References

Freedman et al. (2001) Final results from the Hubble space telescope key project to measure the Hubble constant. The Astrophysical Journal (553), 47-72.

http://www.icr.org/pubs/imp/imp-352.htm

NUCLEAR DECAY: EVIDENCE FOR A YOUNG WORLD - IMPACT No. 352 October 2002 by D. Russell Humphreys, Ph.D.

Wood, S.N. (2006) Generalized Additive Models: An Introduction with R. CRC