Earth

   

The Sun

The stages of the Sun's evolution, from left to right: nebula, proto-star, main sequence, red giant, expanding helium an nitrogen shells, white dwarf. A white dwarf fades into a black dwarf.

The stages of the Sun's evolution (top row), from a nebula of gas and dust to a planetary system to a white dwarf.

The Sun is a medium-size yellow dwarf star   -   a small main sequence star in middle age. In five billion years it will expand into a red giant.

The stages of the evolution of the solar system (below): 1. (top left) nebula, 2. (lower left) star with disc of gas and dust, 3. (top right) sun with rings, 4. (lower right) star with planets.

Our solar system at its inception   -   a cloud of gas and dust revolving about a star, the Sun.  

The stages in the evolution of a solar system.

 

 

 

 

Our Solar System

The Planets

  

Discussion on weekly BBC radio programme In Our Time hosted by Melvyn Bragg

27 May 2004

 

With guests Paul Murdin, Hugh Jones and Carolin Crawford

 

http://www.bbc.co.uk/programmes/p004y25b

The planets

The night sky

The Moon, Mercury and Venus.

The Moon and Venus

The Moon and Mars

The Asteroid Belt between Mars and Jupiter

Asteroids

 

Episode # 10 from the 2010 History Channel documentary series How the Earth was Made

 

Advertisement

 

https://www.youtube.com/watch?v=iN3AByKfWQg

 

Documentary

 

https://www.youtube.com/watch?v=fGEz5_r8u3A

 

The asteroid belt is the source of many meteorites.

The Moon, Venus and Jupiter

Mercury, Venus, Mars, Jupiter and Saturn in the night sky.

Venus, Mars and Uranus in the evening sky.

Venus, Mars and Neptune in the night sky.

The Kuiper Belt

The Kuiper belt is a disc of asteroids beyond Neptune orbiting the Sun on the same elliptical plane and in the same direction as the planets. It is much bigger and wider than the Asteroid Belt.

Most comets that take less than 200 years to orbit the Sun are thought to come from the Kuiper Belt. They are called short-period comets. They orbit the Sun on the same elliptical plane and direction as the planets.

Halley's Comet

Halley's Comet completes an orbit of the Sun every 75 to 76 years.

The Oort Cloud

It is thought that a spherical cloud of large icy particles surrounds the solar system and the Kuiper Belt. It is called the Oort Cloud.

Comets that take more than 200 years to orbit the Sun are thought to come from the Oort Cloud. These comets orbit the Sun from all directions rather than one elliptical plane.  

A long-period comet in the night sky.

Ring of Fire

Episode # 7 from the 2010 documentary series 

How The Earth Was Made

https://www.youtube.com/watch?v=2MDhYbeBQcU

Continental drift from 200 MYA to the present

How the Continents were formed –

Alfred Wegener and Plate Tectonics 

 

Episode # 55 of the documentary series Great Moments in Science and Technology (2003) 

 

https://www.youtube.com/watch?v=4GmP_hXyPq0

   

Plate Tectonics

 

Discussion on the weekly Thursday BBC radio programme In Our Time hosted by Melvyn Bragg 

 

With guests Richard Corfield, Joe Cann and Lynne Frostick

 

24 January 2008

http://www.bbc.co.uk/programmes/b008q0sp

The Last Ice Age

Quartenary (Pleistocene Glaciation) 2.58 MYA - 11,700 YA

 

Pleistocene 50,000 to 18,000 years ago

Pleistocene 50,000 to 18,000 years ago

The Earth today

---------------------

THE DRIFTING OF THE CONTINENTS

Known as CONTINENTAL DRIFT

British documentary film / 1970

HORIZON / TIME LIFE

50:49

https://www.youtube.com/watch?v=1Bn3G-n4L5s&t=103s

48:44

https://www.youtube.com/watch?v=rY9IL1F9aj8





--------------------------

There are four main theories of the Moon's origin:

The prevailing theory of the Moon's origin is that a collision between two spheres created the Earth and the Moon.

 

 

Source: from Nick Strobel's Astronomy Notes

(http://www.astronomynotes.com/solarsys/moonformation.png)

 

 

There are three older theories:

 

- the Moon was a planet captured by Earth

 

 

- Earth and Moon were formed together as a twin-planet from a cloud of gas and dust

 

 

 

- a large chunk of Earth was forced out of it by centrifugal force

 

 

 

 

 

Like Earth, the Moon has a solid inner core of iron (orange) and a liquid iron outer core (yellow).

The Moon 

Discussion on the weekly Thursday BBC radio programme In Our Time hosted by Melvyn Bragg

 

With guests Paul Murdin, Carolin Crawford and Ian Crawford

 

3 November 2011

 

http://www.bbc.co.uk/programmes/b016lh15

 

 

-----------------

 

The Sun is a single star. Alpha Centauri is a binary-star system. The two stars are Alpha Centauri A (Rigil Kentaurus) and Alapha Centauri B (Toliman).  

To the naked eye and through a telescope A and B often appear as one star.

A and B viewed from the Hubble Space Telescope.

Note that Hubble Space Telescope photos are actually black and white. They are colourised later through guess work.  

A and B are like the Sun. A, the primary star, is slightly bigger and 50% brighter that the Sun.

B, the secondary star, is slightly smaller and half as bright as the Sun.

A and B orbit a common centre of gravity once every 80 years. Their distance from each other varies by about 60%. When closest the distance is about that from the Sun to Saturn. and When farthest apart, the distance is about that from the Sun to the Kuiper Belt. 

Alpha Centauri A and B may be part of a three-star system with Proxima Centauri, a red dwarf. A red dwarf is a small star, much cooler and far dimmer than the Sun. Red dwarfs are the most common stars in the galaxy.     

Proxima Centauri is about 4.24 light years from the Earth and thus closer than Alpha Centauri A and B. Thus, it is actually 

the closest star to the Sun. It is one-seventh the size of the sun and 50% larger than Jupiter, the biggest planet in our solar system.

Proxima Centauri is about 0.20 light years from A and B. It may be orbiting about the same gravitational centre as A and B. If so, it may take more than half a million years to complete one orbit.

The Milky Way visible to the naked eye in the night sky.

the Milky Way seen through time-lapse photography

 

The Andromeda Galaxy is the closest major galaxy, 2.5. million light years the Milky Way.  

Visible to the naked eye in the night sky.

  

 

Journey to the Edge of the Universe

 

6-min. documentary

 

https://www.youtube.com/watch?v=Zr7wNQw12l8

 

 

 

Journey to the Edge of the Universe

 

National Geographic documentary (90 min.)

HD 1080p

 

https://www.youtube.com/watch?v=68tpCpDOsyA

 

or

 

https://www.youtube.com/watch?v=b1Mi6W50rmY

 

or

 

https://www.youtube.com/watch?v=1lIAQL0DrQU

 

or 720p

 

https://www.youtube.com/watch?v=tmWV5ZnKOAg

 

 

 

The Shores of the Cosmic Ocean

 

Episode # 1 of 13 from the series Cosmos with Carl Sagan (1980)

 

https://www.youtube.com/watch?v=6YgBXLUSsmg

 

 

 

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