According to Evolutionists, what is the age of the Earth and universe?
4.54 billion years
The current age estimate accepted by most Evolutionists for the Earth and our solar system is 4.54 billion years, plus or minus 0.02 billions years. What is this based on?
This estimate was deduced from the ratios of different lead isotopes found in meteorites. By other means, the oldest age estimate, to date, for an Earth rock is 3.96 billion years (Slave Province, Northwest Territories, Canada). The oldest age estimate for a meteorite is 4.6 billion years.
According to a leading expert:
“The best value for the age of the Earth is based on the time required for the isotopic composition of lead in the oldest (2.6-3.5 billion years) terrestrial ores, of which there are currently only four [235U to 207Pb to 238U to 206Pb], to evolve from the primordial composition, recorded in meteoritic troilite, to the composition at the time (measured independently) the ores separated from their parent rocks in Earth's mantle. These calculations result in ages for the Earth of 4.42 to 4.56 billion years with a best value of 4.54 billion years.” 
Evolutionary Age and Composition of the Universe
13.7 billion years
Data from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite was analyzed to estimate the age of the universe at 13.7 billion years since the “Big Bang”.
"The Big Bang is properly envisioned as the expansion of space, with matter carried along, rather than an explosion hurtling matter into empty space." [Sky & Telescope, October 2003 p. 32.]
The expansion rate and size of the universe are estimated by the red-shift of light coming from distant galaxies. Brightness of supernovas in the most distant galaxies are dimmer than predicted. Hence they are considered further distant than predicted. This is thought to indicate that "the universe's expansion is speeding up" [Ibid, p. 34]. A “dark energy” has been proposed to power this acceleration. This energy is thought to be 73% of all energy in the universe.
23% of all energy is calculated to be nonbaryonic “dark matter”. This unseen stuff is needed to keep star clusters and galaxies from dispersing over multi-billions of years. This leaves only 4% left for baryonic (normal) matter that we can see through telescopes.
G. Brent Dalrymple, "So How Old Is the Earth, Anyway?," NCSE Reports, Volume 11, No. 4 (Winter 1991), pp. 17., also see: G. Brent Dalrymple, The Age of the Earth (Stanford: Stanford University Press, 1991).
Author: Paul S. Taylor Films for Christ and Thomas H. Henderson.
Copyright © 1998, 2003, Films for Christ, All Rights Reserved—except as noted on attached “Usage and Copyright” page that grants ChristianAnswers.Net users generous rights for putting this page to work in their homes, personal witnessing, churches and schools.