OVER the past decade, spacecraft have beamed back reports from some truly awe-inspiring destinations within our solar system. Rovers have revealed vast river channels carved by ancient floods on Mars. Probes have zipped through the turbulent geysers erupting from Saturn’s icy moon Enceladus. We have even flown past the frigid mountains of Pluto. But what if we could extend our horizons further – much further?
Let’s imagine that we could roam across the Milky Way on a sightseeing trip like no other. Where would I take you? Well, supermassive black holes, strange, pulsating stars and exotic Earth-like worlds are on the itinerary for starters. Aside from the sheer spectacles we’ll witness, we’ll discover how visiting these space oddities might offer clues to some big mysteries – from how the first stars formed to what is producing weird radio signals from outer space and whether there is life beyond Earth. Here, then, is my guide for the discerning galactic tourist.
Watch a passing parade of stars bursting with dark matter
To begin our journey, we’ll jump into a river of stars that loops right past our front door and across the entire Milky Way. To truly appreciate the S1 stream, we have to recalibrate our sense of scale, because its length and breadth are counted in thousands of light years. Our solar system, sat in the middle of the stream, is akin to a grain of sand in the Amazon river.
To find the source of the S1 stream, we need to turn back the clock nearly 9 billion years to our galaxy’s turbulent youth. Seen from the outside, the …