In elementary school, during astronomy class, we were taught all about the Big Bang and how scientists roughly agreed how the universe began. How it was to end, though, that was up for grabs. There were two possibilities: either the universe would eventually begin contracting in on itself, ultimately collapsing into a fiery point; or it would continue expanding, forever, with galaxies growing so far apart they would no longer be visible to each other. It was a powerful and, apparently, memorable lesson; the universe would end either in heat or cold.
But now, at least according to the BBC, we know how the universe’s final fate: cold.
A paper published in Science reports that scientists used the Hubble Space Telescope to observe how light from distant stars was distorted by a large galactic cluster. From this they were able to work out the distribution of the universe’s dark energy, “a mysterious force that speeds up the expansion of the Universe” (I smell a new Dan Brown thriller).
How does that work, exactly? That’s above my pay grade — but not PhysOrg.com’s. They have a thorough yet accessible description, including:
As dark energy pushes the Universe to expand ever faster, the precise path that the light beams follow as they travel through space and are bent by the lens is subtly altered. This means that the distorted images from the lens encapsulate information about the underlying cosmology, as well as about the lens itself.
So why is the geometry of the Universe such a big issue?
“The geometry, the content and the fate of the Universe are all intricately linked,” says Natarajan. “If you know two, you can deduce the third. We already have a pretty good knowledge of the Universe’s mass-energy content, so if we can get a handle on its geometry then we will be able to work out exactly what the fate of the Universe will be.”
I don’t know about you, but I don’t plan on sticking around that long.
[Side note: When did we start capitalizing Universe?]