Chemistry olympiad dating moon rock online dating is it safe
The isotopic method of determining absolute age is the most accurate and desirable way of dating planetary surfaces, but collecting and returning rock samples from distant planets and satellites is a difficult and expensive endeavor.
Furthermore, some surfaces, such as those of the icy satellites of Jupiter and Saturn, may not yield rocks that are datable by current isotopic techniques.
The technique depends on an erosion model that relates the shape of a crater to the integrated flux of meteoroids and secondary debris that have impacted the surface since the crater was fresh.
The method provides a means of estimating absolute surface ages in areas not sampled by the Apollo missions and suggests that some mare regions may be as young as about two billion years.
In practice, this procedure requires an accurate assessment of the initial abundances of the isotopes produced in the radioactive decay.
An assessment of mineral composition can be made from spectrophotometric observations, and plausible densities and masses can then be assigned to well-observed small bodies ().
Cratering rates are estimated from the collision rates and from the masses and impact velocities of the colliding bodies by means of either empirical crater scaling laws or by more elaborate computer calculation of crater formation (Shoemaker, 1977).] Significant uncertainties are associated with each of these steps, particularly with the assignment of masses and with the calculation of crater sizes.
These objects include small bodies of asteroidal appearance and the nuclei of comets.
The population of these objects can be estimated by statistical methods from the rates at which they are discovered by systematic searches of the sky (Shoemaker et al., 1979).