Figure 1.1.21.1.2\PageIndex{2}: Canyons like this, carved in the deposit left by the May 18th, 1980 eruption of Mt. St. Helens, are sometimes used by purveyors of pseudoscience as evidence for the Earth being very young. In reality, the non-lithified volcanic deposit is carved much more easily than other canyons like the Grand Canyon.

The big-bang theory proposes the universe was formed from an infinitely dense and hot core of the material.

The universe appears to have an infinite number of galaxies and solar systems and our solar system occupies a small section of this vast entirety. The origins of the universe and solar system set the context for conceptualizing the Earth’s origin and early history.

s: When one rock formation contains pieces or inclusions of another rock, the included rock is older than the host rock.

The Grand Canyon of Arizona illustrates the stratigraphic principles. 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.

In the 1950s, Clair Patterson (1922–1995) thought he could determine the age of the Earth using radioactive isotopes from meteorites, which he considered to be early solar system remnants that were present at the time Earth was forming. Patterson analyzed meteorite samples for uranium and lead using a mass spectrometer. He used the uranium/lead dating technique in determining the age of the Earth to be 4.55 billion years, give or take about 70 million (± 1.5%) [15]. The current estimate for the age of the Earth is 4.54 billion years, give or take 50 million (± 1.1%) [13]. It is remarkable that Patterson, who was still a graduate student at the University of Chicago, came up with a result that has been little altered in over 60 years, even as technology has improved dating methods.

Because science advances as technology advances, the discovery of radioactivity in the late 1800s provided scientists with a new scientific tool called radioisotopic dating. Using this new technology, they could assign specific time units, in this case years, to mineral grains within a rock.

Jupiter’s massive gravity further shaped the solar system and growth of the inner rocky planets. As the nebula started to coalesce into planets, 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.

The planetary composition of the gas giants is clearly different from the rocky planets. Their size is also dramatically different for two reasons: First, the original planetary nebula contained more gases and ices than metals and rocks. There was abundant hydrogen, carbon, oxygen, nitrogen, and less silicon and iron, giving the outer planets more building material. Second, the stronger gravitational pull of these giant planets allowed them to collect large quantities of hydrogen and helium, which could not be collected by the weaker gravity of the smaller planets.

e Doppler effect is the same process that changes the pitch of the sound of an approaching car or ambulance from hi

No place on Earth is completely free of natural hazards, so one of the best ways people can protect themselves is by understanding the geology.

processes. Science is more than just a body of knowledge, science provides a means to evaluate and create new knowledge without bias [1]. Scientists use ob

An objective observation is without personal bias and the same by all individuals. Humans are biased by nature, so they cannot be completely objective; the goal is to be as unbiased as possible. A subjective observation is based on a person’s feelings and beliefs and is unique to that individual.