The famed Mars meteorite Allan Hills ALH contains 4-billion-year-old native organic molecules, the carbon-containing building blocks of life as we know it, a new study suggests. And that's not all. The organics contain nitrogen, another ingredient that Earth life depends on, and were found within carbonate minerals, which usually form in groundwater. So the discovery adds to an emerging picture of a wet and potentially habitable Mars in the distant past, study team members said. Related: Mars life: Exploration and evidence. This picture has been fleshed out by a range of observations over the years, including recent work by NASA's Mars rover Curiosity.
The Age of the Moon
The Age of the Earth - Lead Isotopes as a Current Scientific Clock: Paul Bechard
Isochron dating is a common technique of radiometric dating and is applied to date certain events, such as crystallization , metamorphism , shock events, and differentiation of precursor melts, in the history of rocks. Isochron dating can be further separated into mineral isochron dating and whole rock isochron dating ; both techniques are applied frequently to date terrestrial and also extraterrestrial rocks meteorites. The advantage of isochron dating as compared to simple radiometric dating techniques is that no assumptions are needed about the initial amount of the daughter nuclide in the radioactive decay sequence. Indeed, the initial amount of the daughter product can be determined using isochron dating. This technique can be applied if the daughter element has at least one stable isotope other than the daughter isotope into which the parent nuclide decays. All forms of isochron dating assume that the source of the rock or rocks contained unknown amounts of both radiogenic and non-radiogenic isotopes of the daughter element, along with some amount of the parent nuclide.
Until the mids, it was impossible to know when each of the flows occurred. However, as this video segment adapted from NOVA describes, scientists are now using tiny artifacts of life encased in hardened lava flows to piece together the mountain's complex geological and biological history. Flowing lava erases nearly everything in its path. An entire forest can be wiped out by streams of molten rock. In some circumstances however, a flow may encase a small amount of plant material before it is entirely incinerated.
Certainly the majority of scientists accept radiometric dating. Most people, even the experts in the field, forget the assumptions on which radiometric dating is based. Radioactive Dating There are basically two different kinds of radioactive dating methods. One is the Carbon system used for dating fragments of once-living organisms. It furnishes some good evidences that creationists often use.