Cosmology: Formation of the Solar System
How the Solar System Formed – Simple Explanation
How the Solar System Formed – More detailed Explanation
What do galaxies look like when they collide? - Great photo from the Hubble Space Telescope
Age of the Solar System
Here we are happily talking about the solar system being 4.5 billion years old, but how do we KNOW that the solar system is this old? What is the scientific evidence? The main evidence comes from radioactivity. A few elements are unstable and are likely to “decay” – that is, emit a particle and become a different element. For example, an isotope of potassium (potassium-40) decays to an isotope of argon (argon-40) with a half-life of 1.3 billion years. This means that 1 kilogram of pure potassium-40 would, over 1.3 billion years, turn into 1/2 a kilogram of argon-40 and 1/2 kilogram of remaining potassium-40. Then, another 1.3 billion years later, the 1/2 kilogram of potassium-40 reduces to 1/4 kilogram and another 1/4 kilogram of argon-40. Therefore, we can find out the age of a lump of rock by measuring the ratio of potassium-40 to argon-40
The oldest rocks on Earth are about 3.9 billions years old. There are not very many of such old rocks around since the surface of the Earth has been thoroughly resurfaced. The oldest lunar rocks are about 4.4 billion years old. The oldest rocks ever encountered are meteorites, some of which are as old as 4.6 billion years. These meteorite rocks are thought to have formed during the early condensation of the solar nebula. The planets formed about 0.1 billion (100 million) years later. So, the age of the Earth is probably close to about 4.5 billion years.
Earth: Measuring it, proving Heliocentrism, proving it rotates on axis…etc
How the ancients tried to measure things like the size of Earth, distance to Sun…etc
How Eratosthenes Measured the Earth
Galileo proves Heliocentrism by seeing the phases of Venus with Telescope
How to determine the distance between Sun and Earth
How John Harrison, Clockmaker, Solved the longitude problem
How Cavendish determined “Big G”
How to prove the Earth Spins on its axis (Focault’s Pendulum)
Largest Hurricanes since 1900. Are there more hurricanes today than ever before?
Los Angeles Rainfall for the past 150 years. Is there less rain today than ever? What’s the trend?
Retrograde Motion Simulator II
The motion of the Sun and the Stars
Spinning stars with North Star in the Middle
Bad Astronomy: Misconceptions about Astronomy Answered
Coriolis effect and the direction of your Toilet water
Why does the Moon appear to be large when it rises, and then it shrinks as it is overhead?
Bad Astronomy Index Page (more questions answered)
How Thick is the Earth’s “Skin” (atmosphere)
Thinness 1 Thinness 2 (Ed White Space walk) Thinness 3 (Gemini Rendezvous) Thinness 4 (W/moon)
Felix Jumping to Earth in a Parachute
What does the moon look like right this very moment?
Moon Illusion: Why does the Moon look BIGGER on the horizon?
Sketch of moon going around earth as earth goes around sun. Shows Synodic Period (29.5 days) and Sidereal Period – true orbital period (27.3 days)
Graphical representation of moon phases
Sidreal (27.3 days) vs. Synodic (29.5 days) Moon Month
Earth and Moon
Earth-Moon System seen from Space
Shadow of moon upon the earth during a solar eclipse
Sunset pictures at Doheny State Beach showing seasons
Land of the midnight sun animation
World Sunlight map (illustrates which part of our Earth currently has light, and which has night)
World sunlight map taken at Summer Solstice (June 21)
World sunlight map taken at Spring Equinox (March 21)
What does Astronomy have to do with the Calendar?
Daylight Savings Time Explained -Why do we change our clocks?
Calendar Explained – How it started. Why time zones are necessary….etc.
How many hours do we have in a day and how does it change over the course of a year
Eclipses – Solar and Lunar
World Map which shows where and when solar and annular eclipses will occur (and have occured)
Solar Eclipse of June 20, 2002
Annular Eclipse of May 20, 2012 (5:30 – 7:30 PM local time) – Quicktime movie of eclipse occuring
Comet Hale Bopp – March 22nd was Closest to Earth. April 1st closest to sun
Jupiter hit by Comet Shoemaker-Levy July 16-22 1994
JPL Unmanned Missions
International Space Station Page
How a Rocket Ship Blasts off from earth
How do you put a satellite in orbit: A visual explanation of Newton’s Universal Gravity Idea
How fast does a satellite have to go to reach escape velocity: Mathematical Formula
How a Rocket Ship Orbits the earth and then leaves it’s gravity
Geosynchronous Satellites -Artists conception of what they’d look like
Geosynchronous Satellites – an actual photograph taken from the surface of the earth
Definition of a Geosynchronous orbit
Definition of a Geosynchronous orbit
How do you measure the speed of light?
E = mc^2 Explained as a right triangle
How many minutes would it take you to fall through a whole in the Earth?
Article about the Vomit Comet – How to simulate Zero Gravity here on Earth.
Color of Empty SCHS Swimming Pool
Important People in Astronomy and Physics:
Eratosthenes (276BC-194BC) First to measure the circumference of the Earth
Ptolemy (85-165) Greek Astronomer who first proposes Geocentrism. It isn’t until Copernicus in the mid 1500’s do we question Geocentrism.
Copernicus (1473-1543) First proposes Heliocentrism
Galileo (1564-1642) Proves Heliocentrism by moons around Jupiter, Phases of Venus. Creates the concept of a pendulum clock.
Johannes Kepler (1571-1630) – Realizes that orbits are elliptical and determines a relationship between the period of rotation and distance from the sun.
Christiaan Huygens (1629-1695) Makes first pendulum clocks based on Galileo’s research
Newton (1642-1727) Father of Classical physics, and of calculus
John Harrison (1693-1776) Clock maker who basically invents the pocket watch. His watch can be used on ships to tell the time accurately so they can find their longitude.
Henry Cavendish (1731-1810) Solves the “Big G” constant problem posed by Newton in his Universal Gravitation equation. By solving “Big G”, the mass of the earth can be determined
Jean Bernard Leon Foucault (1819-1868) – Uses a pendulum to illustrate that the earth turns on its own axis
Albert Einstein (1879-1955) – Demonstrates that there are no forces holding the planets in orbit around the sun, rather the sun (and planets) cause a warping of space.
Philosophy of Science:
Hypothesis Non-Fingo – Newton’s claim that he doesn’t understand a reason for Gravity. MS-Word
Text of Copernicus’ De Revolutionibus Wikipedia on De Revolutionibus MS-Word Etymology of Revolution
Owen Gingrich – Harvard Astronomer and researcher of Galileo and Copernicus MS-Word
Teleological Argument – Design of nature leads one to believe there is an intelligent designer