London, June 18 : Astronomers have, for the first time, developed a radio telescope that spans four continents, namely North America, South America, Europe and Africa.
According to a report in New Scientist, astronomers have long combined observations from individual telescopes. The process, called interferometry, produces the same resolution as a single dish as wide as the distance between the antennas.
Recently, the Arecibo Observatory in Puerto Rico joined a project called Electronic Very Long Baseline Interferometry (e-VLBI), which can make temporary radio telescopes that rival the size of the Earth.
Its size gives it 10 times the resolution of the Hubble Space Telescope, allowing the array to image objects - like the bright 'afterglow' formed when a high-speed jet of matter from a gamma-ray burst slams into its surroundings, that just look like points to individual radio telescopes, according to Chris Salter of Arecibo.
Arecibo now conducts one observing session a month as part of the e-VLBI project.
Previously, data from each telescope was recorded on discs and mailed to a central location. The fastest you could do it was the speed of Fed Ex," Salter told New Scientist.
Now, the data is sent via fiber optic cables to produce real-time images of celestial objects. That allows astronomers to easily plan follow-up observations for rapidly changing phenomena, such as supernovae.
Such observing plans, which can change quickly depending on what the target does, were hard to justify when the data was still in the mail.
"These are very expensive telescopes," said Arpad Szomoru at the Joint Institute for VLBI in Dwingeloo, the Netherlands. "They don't just give away time on the off-chance that something will happen," he added.
Boosting the amount of data that can be sent to build larger, Earth-sized arrays should vastly improve their sensitivity, according to Mark Reid of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US.
"Right now, we're limited by disc-recording technology," Reid told New Scientist. "With fiber optics, you'd be limited by the telescope itself," he added.