Nature recently revealed research that will please the nihilists among us, from astrophysicist Teppo Mattsson, who says that dark energy, the stuff that keeps the universe from imploding, might just be emptiness. That’s a subscriber-only article now, but it’s summed up (with a link to the original research) over here:
If this guy were right, the required changes would be tiny. Dark energy would go away, 90% of the mass would be dark matter, 10% would be baryonic, and the age of the Universe would jump to 14.8 billion years.
He says that as you observe distant objects, the Universe is getting emptier, due to a hierarchical clumping of matter, and in these emptier regions, the Hubble constant increases, mimicking the accelerating effects of the cosmological constant.
In other words, nothing is keeping us from imploding. We’re just a lot emptier and clumped a little differently than we think.