jueves, 21 de marzo de 2013

Voyager-1 enters new region of space

The Voyager-1 space probe has entered a new region of space, but earlier claims it had left the solar system entirely have been questioned by Nasa experts.

The American Geophysical Union (AGU) announced on Wednesday that the Nasa probe, which was launched in 1977, had left the solar system after detecting sudden changes in radiation. But Nasa scientists later questioned the claim because the probe's magnetic field has not yet flipped, which the agency said should indicate its entry into interstellar space. Instead the craft is passing through a region known as the "magnetic highway", where the effects of radiation change, before leaving the solar system entirely, they argued. The American Geophysical Union (AGU) later corrected its announcement to say the probe had entered a "new region of space" to reflect the uncertainty. The initial claim was based on research to be published in the Geophysical Research Letters journal, which appeared to show that the probe had exited the so-called "heliosphere", the region of gas and magnetic fields released by the Sun, and passed beyond the influence of the star entirely.Results showed that the intensity of particles reaching it from the Sun dropped suddenly while the intensity of cosmic rays coming from interstellar space had suddenly increased. But Edward Stone, Voyager project scientist based at the California Institute of Technology, Pasadena, said: "The Voyager team is aware of reports today that NASA's Voyager 1 has left the solar system. "It is the consensus of the Voyager science team that Voyager 1 has not yet left the solar system or reached interstellar space. In December 2012, the Voyager science team reported that
Voyager 1 is within a new region called 'the magnetic highway' where energetic particles changed dramatically. "A change in the direction of the magnetic field is the last critical indicator of reaching interstellar space and that change of direction has not yet been observed."The measurements which prompted the announcement reveal that the spacecraft has travelled an estimated 18 billion kilometres (11 billion miles) from Earth – 123 times the distance from our planet to the Sun. Prof Bill Webber, who wrote the paper, accepted there were doubts over whether the craft had definitively left the solar system but said it had certainly entered a new region of space and passed beyond the "normal heliosphere". Voyager-1 had been designed to return information on the outer planets in our solar system, but kept travelling towards the centre of our galaxy. The next star the probe will come near to on its journey is known as AC +793888, but Voyager-1 will not arrive for another 40,000 years and even then it will only approach to a distance of two light years.

source and credit a telegraph