Permineralization occurs when an organism is buried, and then elements in groundwater completely impregnate all spaces within the body, even cells. Soft body structures can be preserved in great detail, but stronger materials like bone and teeth are the most likely to be preserved. Petrified wood is an example of detailed cellulose structures in the wood being preserved.

Fossils are any evidence of past life preserved in rocks. They may be actual remains of body parts (rare), impressions of soft body parts, casts and molds of body parts (more common), body parts replaced by mineral (common) or evidence of animal behavior such as footprints and burrows.

Many elements have both stable and unstable isotopes. For the hydrogen example, 1H and 2H are stable, but 3H is unstable. Unstable isotopes, called radioactive isotopes, spontaneously decay over time releasing subatomic particles or energy in a process called radioactive decay.

This is a type of unconformity called a disconformity, where either non-deposition or erosion took place. In other words, layers of rock that could have been present, are absent. The time that could have been represented by such layers is instead represented by the disconformity. Disconformities are unconformities that occur between parallel layers of strata indicating either a period of no deposition or erosion.

The photo shows layers of rock on top of one another in order, from the oldest at the bottom to the youngest at the top, based on the principle of superposition. The predominant white layer just below the canyon rim is the Coconino Sandstone. This layer is laterally continuous, even though the intervening canyon separates its outcrops. The rock layers exhibit the principle of lateral continuity, as they are found on both sides of the Grand Canyon which has been carved by the Colorado River.

The Proterozoic Eon, meaning “earlier life,” is the eon of time after the Archean eon and ranges from 2.5 billion years old to 541 million years old. During this time, most of the central parts of the continents had formed and the plate tectonic process had started.

In order for plate tectonics to work as it does currently, it necessarily must have continents. However, the easiest way to create continental material is via assimilation and differentiation of existing continents (see Chapter 4).

Jupiter’s gravity accelerated the movement of nearby materials, generating destructive collisions rather than constructively gluing material together [14]. These collisions created the asteroid belt, an unfinished planet, located between Mars and Jupiter. This asteroid belt is the source of most meteorites that currently impact the Earth.

The nebular hypothesis is the idea that a spinning cloud of dust made of mostly light elements, called a nebula, flattened into a protoplanetary disk, and became a solar system consisting of a star with orbiting planets [12]. The spinning nebula collected the vast majority of material in its center, which is why the sun Accounts for over 99% of the mass in our solar system.

If the star has enough mass and reaches a point at which the primary fusion element, such as helium, is exhausted, fusion continues using new, heavier elements.

By 1918, women had helped Britain to victory by making drugs, explosives, insecticides, alloys, electrical instruments and other essential laboratory products, and by carrying out research, running hospitals and teaching students.

Modern science is based on the scientific method, a procedure that follows these steps: Formulate a question or observe a problem Apply objective experimentation and observation Analyze collected data and Interpret results Devise an evidence-based theory Submit findings to peer review and/or publication

Originating from the work of Charles Darwin in the mid-19th century, the theory of evolution has withstood generations of scientific testing for falsifiability.

Science denial generally uses three false arguments. The first argument tries to undermine the credibility of the scientific conclusion by claiming the research methods are flawed or the theory is not universally accepted—the science is unsettled. The notion that scientific ideas are not absolute creates doubt for non-scientists; however, a lack of universal truths should not be confused with scientific uncertainty. Because science is based on falsifiability, scientists avoid claiming universal truths and use language that conveys uncertainty. This allows scientific ideas to change and evolve as more evidence is uncovered. The second argument claims the researchers are not objective and motivated by ideology or economic agenda. This is an ad hominem argument in which a person’s character is attacked instead of the merit of their argument. They claim results have been manipulated so researchers can justify asking for more funding. They claim that because the researchers are funded by a federal grant, they are using their results to lobby for expanded government regulation. The third argument is to demand a balanced view, equal time in media coverage and educational curricula, to engender the false illusion of two equally valid arguments. Science deniers frequently demand equal coverage of their proposals, even when there is little scientific evidence supporting their ideology. For example, science deniers might demand religious explanations to be taught as an alternative to the well-established theory of evolution [39; 40]. Or that all possible causes of climate change be discussed as equally probable, regardless of the body of evidence. Conclusions derived using the scientific method should not be confused with those based on ideologies.

the laws of nature are uniform across space and time. Geologists often state that “the present is the key to the past,” meaning they can understand ancient rocks by studying modern geologic processes.

Both types of reasoning are important in science because they emphasize the two most important aspects of science: observation and inference.