With so many dangers existing in the wider solar system from asteroids, the European Space Agency (ESA) is attempting to ensure our future survival with a planetary defence system due for testing in 2020.
Dublin: 01.04.2015 05.31PM
An artist’s rendering of what Voyager I might look like as it enters interstellar space. Image via NASA/JPL-Caltech
NASA’s Voyager I has reached mankind’s latest milestone after the agency confirmed the satellite is on the outer limits of our solar system and in the darkest depths of interstellar space.
Voyager 1 launched in 1977. Scientists have now been able to determine its location based off readings still coming from the craft, which appear to show it has sustained its third 'cosmic tsunami', which originated from our own sun.
The first recorded cosmic wave by Voyager 1 occurred only two years ago, with the next one recorded last year.
Ed Stone of the California Institute of Technology in Pasadena, California, and the mission's project scientist since 1972 described what happens during one of these cosmic tsunamis.
“The tsunami wave rings the plasma like a bell. While the plasma wave instrument lets us measure the frequency of this ringing, the cosmic ray instrument reveals what struck the bell - the shock wave from the sun."
While the deepest depths of space is rather quiet, when the sun emits a solar eruption it will take about a year for it to reach interstellar space, which this latest reading would appear to indicate.
A scale showing our solar system and its outer reaches
The region of interstellar space between stars is filled with a thin soup of charged particles known as plasma but this latest news means Voyager 1 has passed through the layer known as the heliosphere where the plasma is about 40 times less dense than the plasma that lies outside in interstellar space.