PORT  MACQUARIE  OBSERVATORY 
                         e NEWSLETTER
October 2003  Port Macquarie Astronomical Association Inc.    Number 4
WELCOME!

This month we look at the Moon our nearest neighbour in space. It will be well placed for study during the first half of the month. When the Moon moves out of the evening sky later on in the month you will be able to enjoy our own galaxy, the Milky Way. Our article in "The Universe Made Simple" series tells all. Don't you sometimes feel like giving up? We have a first hand story form someone who became an astronomer in spite of huge difficulties. "Strange Road To Astronomy" is a special story. All our usual features are there as well.

Read on!
 

THE MOON - THE WORLD NEXT DOOR

We are so used to it being there we often don't notice it. Humans have walked on it's surface so it seems ordinary somehow, not nearly as exciting as Mars or some distant star. Yet it is another world with hills and valleys, large flat plains and giant craters. It is a mere 400,000 km away, nothing in astronomical terms, and it is this closeness that makes it so easy to study. Throughout the first half of this month it will be in an ideal position to study. You won't need a powerful telescope, a pair of binoculars or even your naked eyes will show you a lot. 

When you look at the moon one thing is immediately obvious, parts of it are dark in colour, other parts are light. The light areas consist of mountains and craters and are older than the dark areas. The dark areas are called "mare" which is latin for seas. The first people to look at the Moon through a telescope thought that these areas were seas because they were smoother than the rest of the Moon. However these areas are actually ancient lava flows which welled up from the interior billions of years ago and covered the original surface. 

The Moon means craters. They range from a metre in diameter to hundreds of kilometres across. They are the result of impacts by meteors over billions of years. A pair of binoculars will show hundreds of them.

 
For all the Moon facts and animations go to www.solarviews.com/eng/moon.htm
 

A good way to get to know the Moon is to go on a nightly tour. www.inconstantmoon.com/index.htm will introduce you to the part of the Moon that is visible on a particular night. Simply go to the site, scroll to the bottom of the page, click on Lunar Tours and a calendar will be displayed, click on todays (or any) date and then you will be introduced to the Moon.

 
If you're really serious about getting to know the Moon you can access three lunar atlases at www.lpi.usra.edu/research/la_home.html 

There are a number of online books about the Moon available at http://nssdc.gsfc.nasa.gov/planetary/online_books.html#moon  Some are simple, some are quite heavy. You will have to spend time finding the ones that suit you. 

So how about going outside tonight, looking up and getting to know our nearest neighbour in space.

 
OUR WEB SITE
It's just waiting for you. . . . . . . http://users.bigpond.net.au/esther
CONTACT US
You can reach us at . . . . . . . portobs@tsn.cc  (please note change in host name)  
 
STRANGE ROAD TO ASTRONOMY

Once in a while you hear of someone who has reached a seemingly impossible goal by overcoming a host of difficulties and disadvantages. Marianne Doyle is such a person, here is her story:- 

From a very young age I wanted to be an astronomer, but I come from a working class family that did not even consider the possibility of a university education. Every primary school talk I gave during the mid-to-late sixties was about our solar system. I knew about every planet, their moons, their rotation and revolution periods the lot. I left school at the end of 1973 having completed junior school to a very high standard. My future, as far as I could see, lay in working in offices with the dream of becoming an astronomer being just that - a dream.

After many years and many experiences a divorce, working overseas, travel, single parenthood and working with disabled children in preschools - the event which came to determine my fate occurred while I was flying a $2 kite with my son in the back yard on a winter's morning. The kite was heading towards a tree and to save it I jumped over the back fence, landed in a hole, and heard a snap. I had broken my leg. It turned out to be the best thing that had happened in years.

Having to slow down for the first time and spend six weeks with my leg in a cast, I had plenty of time to think about where my future lay. Working with children and being a single parent sounded like a sure way to end up in one of those jackets where you get to hug yourself. Hmm… astronomy! I began to seriously consider it and one day I happened to mention it to a friend. She said, "Go for it! The local high school does adult external education, so why not contact them and see what you can do?"

I looked into it further. It turned out I needed to complete junior science, which I had never done in high school, and senior english, physics, chemistry and maths in order to qualify for university. My son was starting school the following year so it seemed to be the right time to try it.

The plan went something like this: "I want to do a PhD in astronomy but I have lots of hurdles to jump. First junior science and senior english… Wow, I passed with flying colours! Oh well, onto the next challenge: senior physics, maths and chemistry… Wow, a rank well within the required level for university! Okay I will try to get a place at university… Wow, I did it! Hmm… now to complete undergraduate." Within seven weeks of starting university, I was struggling so much that I saw a career counselor for help. He stared at me in disbelief and said, "You are a single parent and doing how many credit points? Many single people still living at home with mum and dad find university study a struggle. Cut down your work load." It was the best advice I was to receive. I completed my undergraduate course in four years instead of three. The plan continued. "Well I did it, but will I get into honours?" To get into honours I needed to achieve a GPA … and blah blah blah. To my amazement, I did. "Now I have to get through honours." It was SO HARD! It took 18 months to complete, and included a broken rib and the untimely and unexpected death of my project supervisor, who was both my friend and mentor on my journey to becoming an astrophysicist. Then - "Wow, how did I manage to get first class honours? Oh, but will I get a PhD scholarship?" Getting a scholarship was crucial as I could not afford to continue my studies without financial assistance and I couldn't bear to see my career come to an end when I was so close. And I did get it. I am now doing a PhD in astrophysics, with a scholarship, which makes me feel like a millionaire in comparison to the last 14 years.

Sometimes when I am working, I stop and sit back and drink it all in; I realise that I have finally gotten to exactly where I always wanted to be. My project looks at star formation efficiency in galaxies in the local universe. My supervisor, Dr Michael Drinkwater, is a renowned scientist and a great inspiration. My scholarship provides me with the income I need to live well and give my wonderful, though typical (read strong-willed, determined and argumentative), 14 year old son the kind of life he deserves. There are times I would have just given up without his encouragement and support, and that of my wonderful partner. I even have the chance to use the Narrabri array in August, and will attend the two-week International Astronomical Union conference in Sydney in July. My life is becoming full and wonderful!

The road to astronomy has been long and twisting, but it's been well worth every tear, scream, smile, tantrum and stressed moment! Where to from here? Well, I have to get through my PhD first!

Reproduced with permission from CSIRO.

OCTOBER STAR MAP

Now you can check out all those things you hear about in the newsletter. Each month you can download and print one star map for your personal non-commercial use. For our northern hemisphere readers maps of the northern sky are also available. Included are items of interest for each month.
Visit this link and go to the downloads page.

 

FUN ASTRO QUIZ
How is your knowledge of astronomy? See if you can answer these questions 
1) What is the most common element in the universe?
2) What is the most common gas in the atmosphere of Mars?
3) What is the nearest sun-like single star and how far away is it?
4) What is the nearest planet to the Sun?
 
If you want something a bit more challenging try our HEADACHE!
In December and January three rovers will land on Mars and begin exploration of the surface. During that time Mars will be moving away from us, it's distance ranging from 170 - 320 million km. Contact with the rovers will be by way of radio. How long will it take for a radio signal to get from Earth to Mars?
HINT : Radio waves travel at the speed of light. 
ANSWERS

1) What is the most common element in the universe?
The most common element in the universe is the simplest - Hydrogen. It consists of 
one proton with a single electron orbiting around it.
2) What is the most common gas in the atmosphere of Mars?
Carbon Dioxide is the most common gas in the atmosphere of Mars, making up 95% 
of the total.
3) What is the nearest sun-like single star and how far away is it?
Epsilon Eridani is the closest sun-like single star at 10.5 light years from Earth. The next 
closest is Tau Ceti at 11.9 light years. There are other sun-like stars closer but they are 
members of systems of two or more stars. Alpha Centauri at 4.3 light years consists of 
two sun-like stars orbiting each other.
4) What is the nearest planet to the Sun?
Mercury is the nearest planet to the Sun moving in an elliptical orbit with it's distance from 
the Sun varying between 45 million km and 68 million km. It completes one orbit of the 
Sun in 88 days.
 
HEADACHE ANSWER
 
Q) How long will it take for a radio signal to get from Earth to Mars?
in December and January three rovers will land on Mars and begin exploration of the 
surface. During that time Mars will be moving away from us, it's distance ranging 
from 170 - 320 million km. Contact with the rovers will be by way of radio. 
HINT : Radio waves travel at the speed of light.

A) Light travels at 300,000 km per second (not a bad idea to memorise) so will travel
170 million km in 170,000,000/300,000 seconds which is 567 seconds (rounded to
nearest second).
Divide by 60 to find the number of minutes which is 9.4 minutes.
It will take 9.4 minutes for a signal from Earth to reach the Rovers on Mars. 
Using the same method see if you can work out the travel time for the signal when
Mars is 320 million km away.
 
THE UNIVERSE MADE SIMPLE
OUR GALAXY
The Sun is part of a huge collection of stars called a galaxy. Our galaxy is called the Milky Way and looks much like the galaxy in the photo. The Milky Way contains over 100 billion stars, it is so large that a beam of light that could go around the equator seven times in one second would take 100,000 years to travel across it.
 
In the centre is an area called the nucleus containing many stars and probably a large black hole. It is the bright area in the middle of the galaxy in the photo. The nucleus forms the central bulge of the of the galaxy, around the nucleus is the disk which contains the Sun and billions of other stars. The Sun and all the other disk stars orbit around the nucleus, the Sun taking about 250 million years to complete one orbit at a distance from the nucleus of about 25,000 light years. An obvious feature of the galaxy is the spiral arms. These are pressure waves moving out from the nucleus.
 
 If you can get to a location away from street lights you will be able to  see our galaxy as a band of light across the sky. As we look along  the disk of our galaxy all the billions of stars blend together to form
 this band. If you look at the Milky Way with a telescope the band of  light is resolved into countless stars - it's quite a sight! Because the disk is relatively thin, if you look at another part of the sky you are looking across the disk - rather than along it - so you see fewer stars. Unfortunately due to light pollution you will not see much of the Milky Way in population centres, you will need to get into the countryside where the sky is darker.
 
As you look at the band of light you will see that it is not even, some parts seem to have no stars at all. This is caused by large dark clouds of gas and dust called nebulae blotting out the stars behind them. The Coal Sack nebula near the Southern Cross is an example. Other nebulae glow because they have stars embedded in them, like the Orion nebula.
 
Orbiting around the nucleus are large round clusters of millions of stars called globular clusters. They are magnificent sights through a telescope, Omega Centauri and 47 Tucanae are the best examples.
 
More about our galaxy at www.seds.org/messier/more/mw.html
 
You will need to seek these objects out by making use of star maps. To get the best views you will need dark skies. It really is worth the trouble to get away from town for a few hours one night and see the full glory of our galaxy.
"The Universe Made Simple" "The Moon" "Fun Astro Quiz and Headache" (c) 2003 Matthew Wallace, "Strange Road To Astronomy" courtesy CSIRO, Photos courtesy NASA.
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