Earth, Moon & Sun

End of Topic Review

During the first term we have managed to cover the first of four topics in the GCSE Astronomy course.

Next term we will study 'Planetary Systems'. In this unit we will cover our Solar Sytem, Comets, Meteors and how we search for planets outsuide of our Solar System.
This is a good time to fill in any gaps in your knowledge.

Click here to see the full breakdown of everything you need to know from the Earth, Moon & Sun topic. Read pages 11 to 14.

Would you be able to write about the following?
This should give you a good idea on how you are following the course so far.

• The most important features of the Earth?
• The electomagnetic spectrum and the issues with observing each part of the spectrum with relation to the atmosphere.
• Why is the sky blue?
• What is light pollution?
• Eratostene's calculation of the Earth's circumference.
• What is the difference betweeen a Solar day and a Sidereal day?
• Refracting and Reflecting Telescopes.
• The Van Allen Belts
• The Moon's main features
• What are the Maria and Highlands and what caused the Maria.
• The far side and near side of the Moon and the differences between them.
• Rilles and Wrinkle Ridges.
• ALSEPS.
• Giant Impact Hypothesis.
• How to observe the Sun safely.
• What are Sunspots, including a labelled diagram and what causes them.
• Different rotational periods of the Sun.
• Using Sunspots to calculate the Sun's rotational period.
• The Solar cycle and butterfly diagrams.
• Nuclear Fusion as the source of the Sun's energy.
• Solar Prominences, Solar Flares, Solar wind and the Aurora.
• Solar and Lunar eclipses.
• Lunar phases.
• Shadow sticks and sundials.
• The equation of time.

Don't worry about memorising all the big numbers yet. We'll get those sorted closer to the exam.

For help you could;

• Read your text book.
• Read your notes.
• Ask for help from Mr.Williams during break, lunch or after school.
• Visit this excellent GCSE Astronomy revision website.

Sir Patrick Moore

1923 - 2012

Patrick Moore had presented 'The Sky at Night' since 1957 up until last month.
He has inspired a generation of Astronomers.
Below are some clips from the show and some pictures from Patrick's career.



 

How Eratosthenes measured the circumference of the Earth

Eratosthenes was an interesting character

He was a mathematician who lived in the 3^rd century BC who did some very important work.

He gets a mention on this course for his brilliant measurement of the Earth’s circumference.

Despite all his great work in many fields his nickname was ‘Beta’ as he tended to be second best in a number of disciplines.

Eratosthenes lived in Alexandria in Egypt but was born in Syene (now Aswan) and it was these two places that he used in his calculation.

 

Syene lies on the Tropic of Cancer.

On June 21^st (midsummer’s day) on the Tropic of Cancer, the sun is directly overhead (at our Zenith) at noon.

Any vertical object would have no shadow.

He was in Alexandria though, which is about 800 km North.

He measured the angle of the Sun here by looking at the shadow of a vertical object and calculated that this angle must be the same angle between Syene and Alexandria from the centre of the Earth.
 

See diagram below.

 

This showed that there is 7 degrees between Syene and Alexandria.

You need about 50 lots of 7 degrees to make a full circle so you must need about 50 lots of the distance from Syene to Alexandria to get around the world.

He calculated the Earth’s circumference to be about 40,000 km, which was pretty much spot on!

If you are able to understand this, you should do very well on the course.

A* and A grade students will be able to explain how Eratosthenes did his calculation with the use of a diagram.

Using the National School's Observatory (NSO)

It is now easy to get your own images of the Universe using a professional telescope
You won't need to buy any equipment and you can do it from the comfort of your computer.

You just need to get a log in for the National School's Observatory (NSO) off Mr Williams.

It's free and it allows you to request the Liverpool John Moores University telescope, located in sunny Tenerife high up on a mountain, to take an image of a point of interest of your choosing in the night sky.

The special thing about this is that they are YOUR images.
The University got funding for the project by giving up time on their telescope to schools like ours so your image will be unique.

You can use it to get images of the Planets, Craters on the Moon, Nebulae, Galaxies or even search for asteroids.
Below are some examples of 3 colour images produced by our Astronomy class of 2012 as part of their coursework.

                

M57 (The Ring Nebula) by Lottie Aitken                                                                 NGC 6946 by Emma Irving

                     

M27 (Dumbell Nebula) by Mark Hogan                                                 M76 (Little dumbell nebula) by Oriana Gibson

Just get logged in, click on 'Go Observing' and follow the instructions.
You may have to wait a few days for the telescope to get round to taking your image.
Once you have your obesrvations you will need to download and use LT image to view them.
This page explains it all.

Enjoy!