Galactic census
SCIENTISTS have long been perplexed by a question: how many galaxies are there in the universe? Taking a census of the galaxies is like counting the grains of sand on a beach.
But thanks to the Hubble Space Telescope, they have now come up with an estimate: 125 billion.
Arriving at a consensus is probably impossible as the numbers can be :stronomical', say scientists of the American Astronomical Society. Just three years ago, the count was only 50 billion. It was subsequently updated to 80 billion.
Scientists say the new figure does not mean that there has been an increase in galactic births, but is an improvement in the Hubble telescope's ability to look further into the universe, even to the first epoch in which matter coalesced into stars and stars congregated in vast galaxies.
The latest observations have detected some faint galaxies so far away that scientists say they were probably formed when the Universe was no more than one billion years old.
"The new estimate was derived from the Hubble telescope's observations of a small patch of southern sky taken over a 10-day period in October," said Henry Ferguson, an astronomer at the Space Telescope science Institute in Baltimore, USA called the Hubble Deep Field South, the pictures were a sequel to a similar survey of a part of the northern sky in late 1995.
These pictures were possible only because of the two new instruments of the Hubble telescope. One is a camera for recording objects that can detect galaxies otherwise obscured by dust. The other is an imaging spectrograph that produced some of the deepest optical pictures ever taken, say scientists.