By Ginny Stone
Ah hah! Bet you are wondering why I visited SALT – right? Well, it's not any
old SALT – actually it stands for the Southern African Large Telescope or
sometimes it's even known as “Africa's Giant Eye”. Quite cool, hey?
Photo by Janus Brink
o where is this big eyeball? It's nestled in the
Karoo, near a place called Sutherland. About
235 km from Cape Town, along the N1 (that's the
main road you would take if you were driving
from Cape Town to Joburg). But then you'd turn
north at Matjiesfontein and drive another
130 km or so. Don't worry though, the
roads are all tar, no dirt or gravel.
Hmmm…. why did they build it in such a
far-away place you are probably wondering?
Well, apart from the fact that the South African
Astronomical Observatory (SAAO) has been
situated just outside Sutherland since early in
the 1970s – the main reason is because it's dark.
Photo by Janus Brink
Did you know…
According to good old Wikipedia, the first known practically
functioning telescopes were invented in the Netherlands at the
beginning of the 17th century.
The word “telescope” was coined in 1611 by the Greek
mathematician Giovanni Demisiani. “Tele” means “far” in Greek and
“skopein” means “to look or see”.
When stars burn out, their outer layers form
beautiful planetary nebulae, such as this
Cat's Eye Nebula
Really, really dark. There are no major cities around
to pollute the area with light. On a clear night in
Sutherland the sky is better than any TV show.
You can see thousands of stars, yes, even without a
telescope. Constellations that most of us who live in
cities never ever see, even though they are there.
SALT is way beyond awesome! It's a very big
telescope, big enough to see distant stars and
galaxies a billion times too faint to see with your
naked eye. The astronomers can use SALT to take
colour pictures of starry stuff way, waaaayyyy out
there – stuff that is many millions of light years
away. Mind-boggling… seeing as light can travel
around the world 8 times in one second! That is
about 10 000 000 000 000 (yes, really a trillion)
kilometres in just one year. Wow! Just think of all
the new things they can start learning about the
Universe. How big it is and what exactly it is
made up of. What else is out there?
A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a speed of about 300 000 kilometres
(km) each second. So in one year, it can travel about 10 trillion km.
(More precisely, one light-year is equal to 9 500 000 000 000 kilometres.)
If you could look at the entire universe at once it would look like a
giant spider web, made up of billions of galaxies, and trillions
upon trillions of stars.
Photo by Miles Jarvis
How come stars have
Simple really, their temperatures determine what colour
they are. For instance, Red Dwarf stars can range in size
from a hundred times smaller than the Sun to only a
couple of times smaller. Because they are relatively
small, they burn their fuel very slowly, which allows
them to live a long, long time. Some red dwarf stars will
live trillions of years before they run out of fuel.
ellow stars are like
the Sun. They are
medium sized and
Photo by Janus Brink
they have a medium
temperature. They burn
Of course, whilst South Africans are wildly clever, they did not
their fuel a bit faster, so
build this marvellous piece of technology alone. A lot of the
will only live for about
original design was modelled on the Hobby-Eberly Telescope
10 billion years or so.
in Texas, USA. And how's this for sneaky… the engineer
The Sun is a star.
dudes who built SALT could learn from the “mistakes” made
But… it is only about
the first time around and do an even better job. All in all
five billion years old.
seven countries, South Africa, the United States, Poland,
It still has another five
Germany, New Zealand, India and the United Kingdom
billion years before it will expand, gobble up the Earth and
were all involved in making sure that SALT was built as
eventually shrink again, leaving behind mostly gas, which
perfectly as possible.
will form a beautiful cloud around the star, called a
Of course, because all these scientists and
planetary nebula. (Phew – that's a relief –
astronomers were involved, they get to have
turns using the telescope. But they don't
one less thing for us to worry about!)
actually have to schlep all the way to
Then you get blue stars. They are very
Sutherland, which is good in the
large, compact and are extremely hot.
great scheme of carbon footprints,
They burn up their fuel real fast and
considering air travel is not all that
often run out in only 1 000 000 to
I'm sure you've all watched the bath water
10 000 000 years. (Hahaha – see
getting sucked down the plug hole? (Sometimes
Astronomers from all over the
– it's all relative when it comes to
it even makes those rude slurpy noises?) All the
world can send their “observing
the universe!) Because they are
water, including any dirty bits floating around in it,
requests”, in other words they
so hot they are really bright and
starts to move towards the hole. A black hole is a
stipulate which bit of the galaxy
shine across great distances.
bit like this – sucking up all the stuff left behind in
they want checked out to the
outer space, e.g. burned out stars. Just like a plug Even though blue giant stars are
expert SALT staff who then make
rare, they make up many of the
hole, a black hole uses the power of gravity to
the observations and send the
stars we see at night.
pull things towards it.
data back electronically via the
(And no – it's not a good excuse to say
Visit this cool site if you want to
internet. Beyond awesome!
your homework disappeared into a
find out more about stars and stuff…
You, your family or your school
black hole and that's why you
can also visit SALT. You do have to book
can't hand it in!)
though. There's a fully guided tour of the
visitor centre and a guided tour of selected
Silly rhyme to help
research telescopes during the day. A night tour is also
you remember the order of the planets…
available but then you are not able to look through any of the
The Sun… Mercury, Venus, Earth, Mars, Jupiter, Saturn,
research telescopes. Why? Well duh, the astronomers are busy
using them. You can't visit SALT at night either, so if you badly
My Very Energetic Mother Just Served Us Noodles
want to see “Africa's Giant Eye”, you had better go during
the day. Don't be late for your tour either – that's just rude!
Of course the only drawback is… you do need a
clear sky. If it's all cloudy overcast or misty nobody
can see anything, not even the scientists.
Booking details to visit SALT (during office hours)
Telephone: (023) 571-2436 / Fax: (023) 571-1413
EasyScience is produced by the South African Agency for Science and Technology Advancement (SAASTA),
Email: [email protected]
an operational unit of the National Research Foundation. SAASTA’s mission is to promote the public's
understanding, appreciation and engagement with science and technology among all South Africans.
Or visit www.saao.ac.za for more information.
Visit the website: www.saasta.ac.za for more information.
Sibo in Space - published by Lets Look Publishers.
wondered what a
black hole is?