Evolution of Astronomical Theories: From Antiquity to Einstein
Evolution of Astronomical Theories
This document outlines the evolution of astronomical theories from ancient philosophers to modern scientists.
Anaxagoras
Anaxagoras proposed that the sun is a fiery metallic sphere. He also explained eclipses and the phases of the moon.
Thales of Miletus
Thales of Miletus is credited with predicting a solar eclipse.
Aristotle
Aristotle believed that the Earth was at the center of a sphere, with the stars fixed in place. He stated that the Earth is fixed and immobile.
Read MoreMotion, Forces, Energy, Waves, and Optics Concepts
Motion: Change in Position
Motion is the change in position of an object relative to a reference point.
Frame of Reference
A frame of reference is a system for specifying the precise location of objects in space and time.
Displacement
Displacement is the change in position of an object. It always includes direction.
Speed
Speed is the distance traveled divided by the time interval during which the motion occurred.
Velocity
Velocity is the speed of an object in a particular direction.
Acceleration
Acceleration
Read MoreElectricity, Atoms, Communication, and Ecology
Electricity and Atoms
Kilowatt-hour (kWh): Energy supplied to a circuit consuming 1 kilowatt of power for 1 hour.
Batteries: All batteries have a specific place, weight, and occupy space.
Molecule: The smallest particle of a substance that retains the chemical properties of that substance.
Simple Body or Element: Those whose molecules are made up of atoms of the same class (e.g., copper, nickel).
Compound Bodies: Formed by atoms that combine in different proportions (e.g., water, common salt).
Components
Read MoreRelativity, Quantum Theory, and Uncertainty
Relativity: Concepts and Postulates
The study of relativity establishes that time and space are relative. This means that they cannot be handled with an absolute reference system because the measurement of space and time will depend on the observer.
In 1905, Albert Einstein published the Special Theory of Relativity, based on two postulates:
Postulate 1
The laws of physics are the same for all referential frames that move at a constant speed compared to others.
Example: If you are sitting still on a
Read MoreNefertiti Bust and Menkaure Trio: Art of Ancient Egypt
Bust of Nefertiti
The Bust of Nefertiti is one of the best-known works from the New Kingdom, currently located in Berlin.
During the New Kingdom, the pharaoh’s image underwent a change in its idealization. This glorious moment occurred during the reign of Akhenaten in Dynasty XVIII. He moved the capital to Tell el-Amarna and introduced monotheism, the belief in the God Aten.
This deity is symbolized by the solar disk from which rays emerge, ending in hands that touch the royal family. The human body
Read MoreUnderstanding Coulomb’s Law and Electric Fields
Coulomb’s Law
Coulomb’s Law states that the force of attraction or repulsion between two point electric charges is directly proportional to the product of the charges and inversely proportional to the square of the distance (r) between them. It is expressed as: F = kQ1Q2 / r2
Electric forces have the following characteristics:
- The force is directed along the line of junction of the charges.
- The force is repulsive if the charges have the same sign.
- If the two charges are of opposite signs, the force