29/04/2007

PRECOCIOUS TEEN EYES UP EARTH

TOMORROW'S WORLD, HERALD ON SUNDAY
by Peter Griffin

A very precocious and observant teenager celebrated a birthday last Tuesday, a day before my own.

At least I'm lucky enough to have my mine fall on Anzac day, giving me a holiday as a present each year. The 17-year-old Hubble Telescope enjoys no days off, as it floats out in space, a sharp-eyed lookout for humanity.

(graphic: Phil Welch, Herald on Sunday)

Since it was launched in 1990, the Hubble has made 800,000 observations and taken 500,000 photographs of some 25,000 celestial objects.

Its photographic handiwork, especially the epic Pillars of Creation photographs, which show the birth of stars in the Eagle Nebula in the constellation Serpens, has delivered scientists a mother lode of information about space.

In the fantastic sci-fi thriller Sunshine, our own Cliff Curtis stares transfixed at the sun as the spaceship he is on hurtles towards the centre of the universe. You feel the same sense of enchantment when you look at the Hubble's panorama of the Carina Nebula that has been released to celebrate the birthday of the telescope, named after renowned astronomer Edwin P Hubble.

The scale of the mosaic, pieced together from 48 pictures taken by the Hubble's cameras, is mind-boggling. It shows an explosive inferno of burning stars 7500 light years away. The image itself is 50 light years wide. A dozen of the stars are estimated to be 50 to 100 times the mass of our own sun. One of the stars, Eta Carinae is about to die a fiery supernova death, while others are newly born.

You can download the image at http://www.spacetelescope.org/images/html/heic0707a.html

If you have a fast internet connection and a large data download cap, go for the 500 megabyte version which gives amazing detail. You'll easily pass an afternoon zooming around this landscape.

The picture isn't exactly what the Hubble has seen. Colours have been added to the picture to represent the gases present - red for sulphur, green for hydrogen and blue for oxygen.

It isn't just a pretty picture. By studying the nebula, which is effectively a massive cloud of dust, hydrogen and plasma, astronomers can learn how our own solar system was formed around 4.6 billion years ago.

The Hubble is possibly the most productive research tool scientists have ever had at their disposal. Daily it generates 10GB of data, while the Hubble Archives share 66GB of information to scientists who have written 7000 papers based on the data.

That would seem to justify the billions spent on launching and maintaining the Hubble. But what of its future?

The orbiting observatory is due for an upgrade next year that will extend its life to 2013. At that stage, the Hubble will be retired in favour of the James Webb Space Telescope, which is smaller than the Hubble but has a much larger mirror than its predecessor.

That means it can see further into the past, watching the light patterns emitted by interstellar activity long since completed. The Webb will be an expensive beast - US$3.5 billion ($4.7 billion) - and at 1600km from Earth, it won't be serviceable by astronauts. Instead, it will be controlled by remote signals sent from a control centre on the ground. Some of the Webb's cameras will be fine-tuned for infrared wavelengths.

That means it will see much more detail. Thanks to the Hubble and the Webb, we can expect much more impressive celestial photography to come.

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