Space & Earth Info

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)

Climate Change

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:  

Retrograde Motion Explained

Retrograde Motion Simulator

Retrograde Motion Simulator II


The motion of the Sun and the Stars


Annalema in motion

Spinning stars with North Star in the Middle


Bad Astronomy:  Misconceptions about Astronomy Answered

Bad Myths of Science

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?

How Do the Tides Work?

Did we go to the moon?

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



All Things about the Moon

What does the moon look like right this very moment?

Moon Illusion:  Why does the Moon look BIGGER on the horizon?

The Smiling Moon photo

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)

How Eclipses Occur

Eclipse over NYC

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

Cassini Mission to Saturn

Galileo Mission to Jupiter

Missions to Mars


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.

Absorption Spectrum

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

Karl Popper

Thomas Kuhn

Richard Feynman