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A Giant Comet Heads Towards Earth
Hundreds of miles across, the icy giant has travelled half a light year to get here.
The edge of our Solar System is a still unknown region. Scientists are confident a ring of dwarf planets and comets lies roughly four billion miles from the Sun — something known as the Kuiper Belt. But beyond that, things get murky. Many astronomers think there should be a cloud of scattered, icy objects surrounding the Solar System and stretching far out into interstellar space.
Hard evidence for its existence has so far been lacking. The outer solar system is an area of unbroken darkness, with the light of the Sun no brighter than any other star. Out there, small comets and planets can spend an eternity drifting invisibly through the gloom.
A handful of objects have been discovered that may belong to the inner regions of this cloud. Certain comets, for example, originate incredibly far away, hundreds of billions of miles from the Sun. One small planet, Sedna, appears to drift between the Kuiper Belt and the clouds lying further out — by lucky coincidence it is currently close enough to the Sun for our telescopes to faintly pick it out.
Now, however, astronomers have discovered something that clearly does come from those outer reaches of space. The object, named 2014…
