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What is the SKA?

Currently under development, the SKA or Square Kilometre Array, will be the world's largest radio-interferometry based telescope, with its antennas having an effective collecting area of approximately one square kilometer (1 000 000 m²). For comparison, LOFAR, a radio interferometer currently under construction in Norway and spanning many European countries, will have a coverage of 300 000 m².

SKA Animation:

Location! Location!

Only two countries of the original four, South Africa and Australia, are still being considered as the central location for this telescope. I say central location as this telescope is huge! Observing stations shall span the continents from either South Africa to Madagascar or from Western Australia extending across the Tasman Sea to New Zealand. Being Australian I am of course barracking for Western Australia to win the bid. Regardless of the winner, the data from this revolutionary telescope will be made public for anyone to access and work with!

One of the major requirements for the location is the presence of a radio quiet zone which not only exists currently but shall remain into the future. The final decision for its location shall be made in 8 days (February 7^th) and announced later in the month. So an exciting and suspenseful month lies ahead!!

Put it on my tab!

At a budgeted cost of 1.5 Billion € (~ $2 Billion USD) this telescope represents a huge investment into astronomical research. It is a truly international endeavor funded by partners from 20 nations from the UK and Australia to Portugal, Poland and Russia.

Facts about the SKA.

• When completed, the SKA shall have the highest sensitivity and angular resolution (< 0.1”) of any radio-interferometer. Consisting of high frequency dishes and medium and low frequency aperture arrays, the antenna will mostly be focused at a central locale with the remainder forming 5 spiral arms up to 3000 km long!

• It shall be 50 times more powerful and have a surveying capability 10000 times greater than any telescope currently in use.

• It will generate 160 Gigabits of data every second from each dish! With 3000 dishes that’s 10 times the rate at which data is uploaded and downloaded from the internet World-Wide! If we include the low and medium frequency arrays this data rate rises to 100 times.

So what do we do with this much data?

How can we store it?

And most importantly, how can we find the useful data in this cosmic expanse of 0’s and 1’s?

The data produced will require supercomputers 50 times more powerful than those used in 2010.

FUN FACT: The fiber optics used to connect the individual arrays, placed end to end, would wrap around the Earth’s circumference twice!

The technology for the SKA is still under design and development with precursor and pathfinder telescopes such as ASKAP and MeerKAT currently under construction to aid in the development and testing of both the components and data reduction and analysis software.

What astronomers wish to do with it?

1.  Study galaxy evolution by mapping hydrogen distribution and investigate the role of dark energy in the expansion of the universe.

2.  Test Einstein's Theory of General Relativity by; (a) looking for gravitational waves using pulsars, and (b) observing the theory's robustness in extreme conditions such as black holes!

3.  Understand the origins of magnetic fields on a cosmic scale and their effects on matter, especially on galaxies.

4.  Study the cosmic "Dark Ages", a period of about 500 million years, when the first luminous celestial objects formed.

5.  Search for radio transmissions (suggesting possible Extra-Terrestrial Civilisations!!) and observe thermal emissions of possible exoplanet formation.

These are just some of the projects for which answers are sought. With all this data though... 

What UNEXPECTED treasures will be found?

What new DISCOVERIES will be made?

What new QUESTIONS will be raised?


Acknowledgements :
http://www.atnf.csiro.au
http://en.wikipedia.org/wiki/Square_Kilometre_Array
http://www.skatelescope.org/

Who are Astronomers?

Who are these people who call themselves astronomers?

Since time immemorial the heavens have fascinated and intrigued. Evidence of lunar cycle recordings have been found from 25,000 years ago, the Chinese first recorded the observation of a supernova in 185AD and again in 1054AD, and in the 900's  the first known descriptions of the Andromeda Galaxy were recorded by a Persian astronomer. Since these times, observations of the celestial sky have evolved from eye-sight observations to space-based telescopes and radio-interferometry observatories such as the Very Long Baseline Array.

Astronomers are those who study the nature of the universe and phemonena which occur throughout it. They include professional researchers at universities and other research institutions, and amateur astronomers who observe heavenly bodies as a hobby. Astronomical investigations involve both theoretical and observational research, ranging from modeling the approximate behaviour of stellar nuclei, to observations of celestial bodies, radiation and the interstellar medium. Such investigations utilise a range of tools including computer simulators, data reduction software and telescopes designed for observing specific wavelengths of the electromagnetic spectrum.

Astronomers are not only involved in research of celestial objects but are also involved in teaching, and collaborative work to design and create new instrumentation, to improve resolution and sensitivity or to investigate physical principles. 

For instance, Einstein’s theory of general relativity predicts the existence of gravitational waves produced by the acceleration of massive bodies. Despite numerous experiments conducted towards such an outcome, gravitational waves are one of few effects predicted by this theorem remaining to be experimentally verified. By observing the frequencies of millisecond pulsars (rapidly rotating neutron stars which emit radiation beams) over a period of time, and inspecting for slight changes in these frequencies, some astronomers are hopeful of discovering these waves. By using a range of pulsars throughout the galaxy, the probability of detecting gravitational waves, if they exist, increases. In essence, this experimental method utilizes pulsars as Galactic-scale detectors! (Click image to view an article on pulsars and laser-based interferometers for gravitational-wave detection)

Pulsars produce signals with such precise signals that some rival atomic clocks for time-keeping accuracy. These signals can even be recorded and the magnitude over time plotted to produce a sound plot of their frequency:

So what else could we learn from these universal time-keepers? This is just one specialised topic within the field of astronomy. Imagine a galaxy filled with celestial objects and phenomena to be studied, understood and, like pulsars, even used as tools themselves. Now try to imagine 100 billion galaxies like this... Mind-boggling isn't it?