Holmes began his career at a most interesting time, as Lewis describes.
Researchers examined about 50 different melted rock samples collected by astronauts during the Apollo missions in the late 1960s and 1970s.
Using radiometric dating techniques, they found that all but a few of the rocks were between 3.8 and 4 billion years old. Furthermore, many of the samples displayed different chemical "fingerprints," which suggests that they were formed from different meteorites and lunar rocks.
Several attempts to scientifically date the planet have occurred over the past 400 years.
Scientists attempted to predict the age based on changing sea levels, the time it took for Earth or the sun to cool to present temperatures, and the salinity of the ocean.
Any meteorite activity that affected the Moon probably affected Earth as well, scientists say. "Unfortunately, we haven't found many very old rocks on Earth because our planet's surface is constantly renewed by plate tectonics, coupled with erosion," Duncan said.
In 2002, however researchers discovered in sedimentary rocks a version of the element tungsten in amounts not normally found on Earth.
We see this acutely demonstrated in the events she describes..
Lewis described how Arthur and his friend ‘were on the edge of their seats with the excitement of it all, for not only did they become familiar with all the arguments, they also got to know all the big names in science at that time—William Ramsay, Ernest Rutherford, Frederick Soddy and Robert Strutt’ (p. Watching exchange influenced Holmes to take up the sport.
"The evidence is clear that there was repeated bombardment by meteorites," said study team member Robert Duncan from Oregon State University.
The NASA-funded study will be published in , the journal of the international Meteoritical Society.
In a game, the score is determined, not by impersonal scientific measurement, but by the strength, skill and creativity of the players.