It's not often that astronomy goes well with the book of Genesis. But this is a theory that evokes the line, "But of the tree of the knowledge, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die." In this theory, knowledge doesn't just kill you — it kills the entire universe. Indeed, one physicist speculates that continuous observation of the universe might put it into a state that will destroy us all.
Illustration by Ron Miller
The Curse of the Big Bang
Our universe's eventual demise, in this case, springs from the fact that it wasn't properly created. The big question has always been, how does something come from nothing? If, in the beginning, there was nothing but a vacuum, devoid of energy or matter, where did the universe come from? As it turns out, not all vacuums are alike - some of them are what's called "false vacuums." They are "bubbles" of space that look like vacuums, but aren't actually at their bottom energy state. They can collapse at nearly any time, and go into their ground energy state. The collapse of such a false vacuum releases energy. At first, many physicists thought this is how our universe began. A false vacuum collapsed down to a true one, and the matter and energy of our universe was the result of its collapse.
It's also possible that the collapsing false vacuum didn't create a true vacuum. It simply created, along with all that matter and energy, another false vacuum. The universe we live in now might simply be a long-lived bubble of false vacuum that's not really at its lowest energy state. If you have trouble believing that the vacuum of space that astronomers observe isn't at its lowest energy state - ask yourself what dark energy is if not a higher-than-expected energy state for the universe. We might be in a fragile, and unstable, bubble of universe that could collapse at any time.
But There's Hope! (Unless We Screw It Up)
It's unpleasant to think the universe might collapse out of existence at any moment. Especially since, as the collapse won't exceed the speed of light, we'll probably see it coming for us, knowing we're unable to escape it. Fortunately, we have (theoretical) options. Dark energy drives the expansion of the universe. Although bubbles decay, they decay along different lines according to the energy state they're in when they start collapsing. If they're in a high energy state, the rate of decay is also high. If they're in a low energy state, the rate of decay is slow. Put the fast rate of decay in a race against the expansion of the universe, and we are all winked out of existence. Put the slow rate of decay in that same race, and we all have the chance to live productive lives.
The problem is, when we observe a system, we can keep it in a certain state. Studies have shown that repeatedly observing the state of an atom set to decay can keep that atom in its higher-energy state. When we observe the universe, especially the "dark" side of the universe, we might be keeping it in its higher-energy state. If the process of collapse happens when it is in that state, the universe will cease to exist. If we stop looking, and the universe quietly shifts to a state at which its decay is slower, then we're all saved. The more we look at the universe, the more likely it is to end.
The Unsettling Truth
At least that was the theory that Lawrence Krauss, a well-known physicist and author, playfully put forward. He was applying the idea of quantum mechanics in small systems, like atoms, to large systems, like the universe. It's a fun idea, but not practical reality. Although Schrödinger's cat is a good thought experiment, the cat doesn't need us to observe it in order to die, and the universe doesn't need it either. (Even if it did, humanity probably isn't the only race looking out at the universe. If we see our little bubble collapsing, we could easily blame it on curious extraterrestrials and their observations.)
Krauss re-stated his position after his paper on the subject came out and made a bit of a stir. He doesn't truly believe that we might end the universe by looking at it too closely. The truth is even more unsettling. The data that led to the false vacuum universe theory came from observing a supernova in 1998. Given the data about the supernova, Krauss believes that the universe is likely to be in its high-rate-of-decay state. So although we might not be the reason the universe ceases to be, we still might be the victims of its collapse.
[Via The Late Time Behavior of False Vacuum Decay, Ars Technica, The Telegraph.]