Isotope best dating very old rocks
Here we examine the principal way in which astronomers have learned so much about the stars. Pass sunlight through a triangular prism or bounce it off the finely grooved surface of a compact audio disk and see it break merrily into a band of pure sparkling color, its "spectrum," familiar in the colors of a rainbow, in light glittering from newly fallen snow, in the rings and haloes around a partly- clouded Sun and Moon, in the flash of a cut diamond, and in so many other facets of nature."Spectra" is embedded with links that will take you back to the appropriate parts of the above two sites. The classic colors red, orange, yellow, green, blue, and violet connect in a seemingly infinite number of shades, one blending smoothly into the next.They led to the discovery that certain very heavy elements could decay into lighter elements – such as uranium decaying into lead.
But Earth’s layers of rock did not give up the secret of Earth’s age easily. However, from working with layer upon layer of rock laid down on Earth over long time spans, early 20th century scientists came to believe Earth not of atoms of one chemical element into another.
Most of the energy of the Universe is transported in this way, by radiation.
The visual spectrum of light, however, is but a tiny portion of the whole picture, of a huge spectrum of radiation that extends in both directions from the edges of the rainbow.
Geologists have found annual layers in ice that are easily counted to multiple tens of thousands of years, and when combined with radio isotope dating, we find hundreds of thousands of years of ice layers.
Using the known rate of change in radio-active elements (radiometric dating), some Earth rocks have been shown to be billions of years old, while the oldest solar system rocks are dated at 4.6 billion years.