47. VOYAGER-1

♤ Voyager-1 was a space probe launched by NASA to study the outer Solar System.

♤ Thirty-six years after being launched and having travelled about 19 billion kilometres from the sun, Voyager 1 has become the first human-made object to venture into interstellar space.

♤ Voyager 1 has been travelling for about a year through plasma, or ionised gas, present in the space between stars.

♤ Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident.

♤ Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft.

♤ Why In News: In 2012, Nasa's Voyager 1 spacecraft was believed to have achieved what was once unimaginable - becoming the first manmade object to breach interstellar space and move beyond mankind's solar system - more than 11 billion miles distant and 36 years after it was launched.

♤ But, in the nearly two years since that historic announcement, it has become increasingly uncertain about whether Voyager 1 really crossed the threshold.