Only the third interstellar comet ever to be seen contains material from other star systems that can be observed close upYou wait ages for an interstellar comet to arrive and then three come along at once. Or at least over the space of a decade. The latest interloper from another star system is the 3I/Atlas comet, which was first detected in July. As space agencies track the speeding object, here’s what we know so far. Continue reading...