Age of the Earth

The age of the Earth is 4.54 ± 0.05 billion years (4.54 × 10⁹ years ± 1%). This dating is based on evidence from radiometric age dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.

Following the development of radiometric age dating in the early 20th century, measurements of lead in uranium-rich minerals showed that some were in excess of a billion years old. The oldest such minerals analyzed to date—small crystals of zircon from the Jack Hills of Western Australia—are at least 4.404 billion years old. Comparing the mass and luminosity of the Sun to those of other stars, it appears that the Solar System cannot be much older than those rocks. Calcium-aluminium-rich inclusions  – the oldest known solid constituents within meteorites that are formed within the Solar System – are 4.567 billion years old, giving an age for the solar system and an upper limit for the age of Earth.

It is hypothesised that the accretion of Earth began soon after the formation of the calcium-aluminium-rich inclusions and the meteorites. Because the exact amount of time this accretion process took is not yet known, and the predictions from different accretion models range from a few millions up to about 100 million years, the exact age of Earth is difficult to determine. It is also difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of possibly different ages.

Kent Hovind

Kent E. Hovind (born January 15, 1953) is an American Christian fundamentalist evangelist and tax protester. He is a controversial figure in the Young Earth creationist movement and his ministry focuses on attempting to convince listeners to deny scientific theories including evolution, geophysics, and cosmology in favor of a literalist interpretation of the Genesis creation narrative found in the Bible. Hovind's views, which combine elements of creation science and conspiracy theory, are dismissed by the scientific community as fringe theory and pseudo-scholarship. He has been criticized by Young Earth Creationist organizations like Answers in Genesis for his continued use of discredited arguments that have been abandoned by others in the movement.

Hovind established Creation Science Evangelism (CSE) in 1989 and Dinosaur Adventure Land in 2001 in Pensacola, Florida. He frequently spoke on Young Earth creationism in schools, churches, debates, and on radio and television broadcasts. His son Eric Hovind took over operation of CSE after Kent began serving a ten-year prison sentence in January 2007 for federal court convictions for failing to pay taxes, obstructing federal agents, and structuring cash transactions. In a separate federal court case in early 2015, a federal court jury found Hovind guilty of contempt of court in connection with a charge of disobeying a prior court order. The trial court, however, threw out the verdict and rendered a judgment of acquittal, concluding that Hovind could not have disobeyed that order.

Earth

Earth /ˈɜːrθ/ (also the world, in Greek: Γαῖα Gaia, or in Latin: Terra) is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.

According to evidence from radiometric dating and other sources, Earth was formed about 4.54 billion years ago. Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis 366.26 times, creating 365.26 solar days or one sidereal year. Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only permanent natural satellite. Its gravitational interaction with Earth causes ocean tides, stabilizes the orientation of Earth's rotational axis, and gradually slows Earth's rotational rate.

The Age

The Age is a daily newspaper which has been published in Melbourne, Australia, since 1854. Owned and published by Fairfax Media, The Age primarily serves Victoria but is also available for purchase in Tasmania, the Australian Capital Territory and border regions of South Australia and southern New South Wales. It is delivered in both hardcopy and online formats. The newspaper shares many articles with other Fairfax Media metropolitan daily newspapers, such as The Sydney Morning Herald.

As at December 2013, The Age had an average weekday circulation of 131,000, increasing to 196,000 on Saturdays (in a city of 4.2 million).The Sunday Age had a circulation of 164,000. These represented year-on-year declines of 14% to 17%. The Age's website, according to third-party web analytics providers Alexa and SimilarWeb, is the 44th and 58nd most visited website in Australia respectively, as of July 2015. SimilarWeb rates the site as the seventh most visited news website in Australia, attracting more than 7 million visitors per month.

Nuclear physics

Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions. The most commonly known application of nuclear physics is nuclear power generation, but the research has led to applications in many fields, including nuclear medicine and magnetic resonance imaging, nuclear weapons, ion implantation in materials engineering, and radiocarbon dating in geology and archaeology.

The field of particle physics evolved out of nuclear physics and is typically taught in close association with nuclear physics.

History

The history of nuclear physics as a discipline distinct from atomic physics starts with the discovery of radioactivity by Henri Becquerel in 1896, while investigating phosphorescence in uranium salts. The discovery of the electron by J. J. Thomson a year later was an indication that the atom had internal structure. At the beginning of the 20th century the accepted model of the atom was J. J. Thomson's "plum pudding" model in which the atom was a positively charged ball with smaller negatively charged electrons embedded inside it.