14 DAY TRIAL // According to an announcement made by officials at the American space agency yesterday, December 13, the NASA Voyager space probe is nearing the edge of the solar system, and could make the crossing into the interstellar space within less than four years.
In all fairness, it took a while for the spacecraft to get to its current position. Since its launch, it spent more than 33 years in space, and has traveled an estimated 11 billion miles (17.7 billion kilometers).
The reason why the announcement was made yesterday is that it coincides with the fact that the space probe reached an area in our solar system where there are effectively no charged particles from the Sun.
The speed of the solar wind from this location forward is zero, NASA experts say. One of the main reasons why the wind may not exist here is that it is pushed sideways by another, more powerful wind, blowing in the interstellar medium.
“The solar wind has turned the corner. Voyager 1 is getting close to interstellar space,” explains California Institute of Technology (Caltech) Voyager project scientist Ed Stone, from Pasadena, California.
The Voyager 1 launched on September 5, 1977, and was originally destined to perform flyby studies of Jupiter and Saturn. But the mission was extended, and so it managed to pass through the termination shock in 2004.
This is a boundary in the solar system where the supersonic solar wind emanating from the Sun is slowed down suddenly, and begins heating up. This achievement had never been done before.
The spacecraft, currently traveling at a speed of about 38,000 miles per hour (61,155 kph), is getting ready to pass through the heliosheath, the area where it entered after passing the termination shock.
Beyond the heliosheath lies the heliopause, which is basically where the Sun's sphere of influence ends. Once it reaches that location, Voyager will officially be in interstellar space.
Investigators at NASA believe that this frontier can be reached and exceeded by 2014. This was announced in San Francisco on December 13, at the fall meeting of the American Geophysical Union.
Using the Low-Energy Charged Particle Instrument aboard Voyager, experts detected that solar winds reached a speed of zero at the probe's current location, Space reports.
Back in August 2007, the spacecraft was battered by a stead, 130,000 mph (209,214 kph) gale. For the next three years, the speed has decreased by 45,000 mph (72,420 kph) yearly. In June 2010, the recorded speed was zero.
“When I realized that we were getting solid zeros, I was amazed. Here was Voyager, a spacecraft that has been a workhorse for 33 years, showing us something completely new again,” says Rob Decker.
The expert is a senior staff scientist at the Johns Hopkins University Applied Physics Laboratory (JHU-APL), in Laurel, Maryland, and also a co-investigator of the Voyager Low-Energy Charged Particle Instrument.