There was a time when humanity seemed content to divide the material world into four basic elements: Earth, Wind, Fire, and Water. That was the extent of it until some clever Greek pointed out that these things were not, in fact, elemental. And so, before long, we arrived at the notion of "atoms," which were posited to be the unseen but fundamental building blocks of all matter.

The word atom means uncuttable, but alas, science created a misnomer. As we now know, atoms have a nucleus orbited by a cloud of electrons. Inside the nucleus are protons and neutrons, the "hadrons" after which the LHC is named. By smashing together atomic nuclei, we have managed to drill down deeper still, getting inside the protons and neutrons to reveal quantum-level particles, such as quarks and gluons and neutrinos, that scientists believe are in fact fundamental, structureless, and dare we say it, uncuttable.

The problem is that when all these dots we know about are connected, we still don't get a satisfactory picture of the universe. Some basic forces—gravity, for example—don't quite fit. To learn more about all this, I visited theoretical physicist Michael Barnett. Among his many roles, Barnett serves as coordinator of education and outreach for the ATLAS experiment, an international effort that revolves around the cryogenically cooled, seven-story-tall, 49-yard-long ATLAS detector—one of the main particle detectors at the LHC.

The main trouble with gravity, Barnett explained to me in his office at the Lawrence Berkeley National Laboratory, is that it's so confoundingly feeble. "You would normally think of gravity as a fairly strong force. It's pulling pretty strongly on you right now. But if you imagine me putting a paperclip down here and getting a weak little refrigerator magnet and having a contest between this little dinky refrigerator magnet and the entire body of Earth, the magnet wins. And the reason is because gravity is...many orders of magnitude weaker than other forces [electromagnetism and the strong and the weak interactions]. We would like to know why that is. One thought that came up a few years ago was that there may be extra dimensions of space." According to the theory, Barnett explained while tugging at his graying beard, "gravity may be spreading out all over the place," radiating gravitons (gravity particles) into the other dimensions we aren't aware of. "And then you get to the other consequence [of extra dimensions] which is...we might be able to produce these microscopic black holes, which leave very nice signatures in our detector, which would make them very clear to us and would be a major discovery."

A fantastic discovery, I echoed while trying and failing to imagine gravity slipping through the sieve of space-time. Or whatever.

"And it leads to certain people having misunderstandings about what that means."

I was still having trouble with gravity. Why, I asked, couldn't gravity simply be what it appears to be—that is, an anomalously weak force bound by the same dimensions we experience?

"Physicists like life to be simple," Barnett answered—paradoxically, I thought, since nearly everything he said seemed to complicate matters. "The question is, why would you have three forces that are relatively similar to each other in magnitude and then one that's just completely different? That doesn't—we don't like that idea." As for microscopic black holes, Barnett confessed, "probably the most reasonable person won't believe that they exist, because there's a whole set of assumptions you have to accept to get to that point. So, most likely, they don't exist, and if they do, they're just exciting for us to study and will tell us that there are extra dimensions. When I said there were extra dimensions, by the way, it doesn't mean there are black holes, but if we see black holes, then boy! there are extra dimensions! That's a truly revolutionary idea. That would be great for us to see. But it's a long shot."

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