According to Mother Nature Network, Voyager 2 has reached interstellar space.<br />The deep space probe launched 41 years ago, making it NASA's second-longest mission to date.<br />The first Voyager probe entered interstellar space about six years ago.<br />But Voyager 2 is equipped with an instrument that the maiden craft lacked.<br />Known as the Plasma Science Experiment, the Voyager 2 has a sensor for detecting the speed of solar wind particles emitted by the Sun. <br />
