Science, Technology, and the Universe: Key Concepts
Science and Technology
Science: Body of knowledge obtained through observation and reasoning from which general principles and laws are deduced.
Technology: A set of skills used to build objects and machines to adapt to the environment and meet our needs.
Applications of Science
The history of science presents examples of applications of science that are tragically harmful to humans. The technology of warfare, biological warfare, nuclear power, pesticides, drugs, human cloning, etc., have been harmful to humanity and living things. This can only be solved by another science that questions the methods, schemes, and values of the science that created them.
The Universe
The universe encompasses everything that has existed, exists, and will exist in any place and on any terms. It consists of powdered material and energy in a cosmic void. There are also interstellar matter, stars, and planets.
Galaxies
Galaxies are organizational units of the universe.
Milky Way
The Milky Way belongs to the cluster of galaxies called the Local Group, which belongs to the Virgo supercluster. Its length is 100,000 light years.
Nebulae
Nebulae are large masses of gas and dust. They are nurseries of stars. Examples include the Horsehead Nebula, the Eagle Nebula, and the Clock Nebula.
Stars
Stars are large masses of gases at very high temperatures, emitting energy as radiation of all kinds. Their fuel is hydrogen, which undergoes thermonuclear fusion reactions. They release energy in the form of many different types of reactions.
Asteroids
Asteroids are rocky bodies smaller than a planet orbiting the Sun in an orbit inside that of Neptune.
Meteorites
A meteorite describes the light that occurs when a fragment of extraterrestrial matter enters the Earth’s atmosphere and disintegrates.
Comets
Comets are celestial bodies made of ice and rock that orbit the Sun in highly elliptical orbits.
The Big Bang Theory
The Big Bang Theory attempts to answer how the universe was formed. It is currently one of the most considered theories. It was proposed by the astronomer Lemaitre in 1927. It states that the universe was created from a huge explosion, the Big Bang.
Origin of the Solar System
Any theory about the origin of the solar system must explain the following facts:
- The Sun and the planets revolve in the same direction.
- The planets travel in nearly circular orbits lying in the same plane.
- The rotation of most planets occurs in the same direction of translation.
- The planets near the Sun are small and dense. The outer planets are large and light.
- All planetary bodies have large impacts.
Planetesimals Theory
The Planetesimals Theory, conceived between 1944 and 1950, proposes that the solar system was formed about 4.5 billion years ago from gas and dust in a nebula located in the Milky Way.
Seismic Waves
P waves: Compress and expand the material in the same direction of propagation. They move at an average speed of 5.5 to 13.5 km/s.
S waves: Deform material particles that cross so that they vary in a direction perpendicular to the propagation. Their speed is about 4 to 8 km/s.
Surface waves: These are the slowest waves. They form when the other seismic waves reach the surface and are transmitted exclusively by it, causing disasters. They do not penetrate the Earth’s interior.
Earth’s Structure
Discontinuities
Abrupt changes indicate that the seismic wave enters a new type of material or a material with a different viscosity state. This is called discontinuities. They indicate that the Earth has a layered structure. The three large Earth layers are the core, mantle, and crust.
Plate Tectonics
The phenomena occurring on Earth were interpreted independently. First, the origin of mountains was considered, then the formation of volcanoes and earthquakes, and then mineral deposits, etc. Around 1960, relationships between these aspects began to be found, the theory of plate tectonics began to develop, and evidence supporting it was found.