Earth Will Continue To Exist, But Maybe Not Koalas

High-Energy Physics Gadget

The world will not end in August when the switch is flipped on for the Large Hadron Collider (LHC), an enormous HIGH-ENERGY PHYSICS GADGET, say officials at the European Organization for Nuclear Research (CERN). When the LHC, located underground near Geneva, starts up this summer, its proton beams will collide at higher energies than have ever been produced in a particle accelerator.

Scientists will use the accelerator to gain more insights into the universe and maybe even catch a glimpse of the Higgs boson, a never-before-observed particle thought to give matter its mass.

But some critics of the collider have exotic concerns that microscopic black holes, strangelets, vacuum bubbles, and/or magnetic monopoles could end Earth as we know it. The LHC Safety Assessment Group, whose conclusions were endorsed by an independent panel of scientists, countered the doomsday speculations succinctly in its report last month: “Over the past billions of years, Nature has already generated on Earth as many collisions as about a million LHC experiments—and the planet still exists.”

On the basis of “the well-established properties of gravity,” the Safety Assessment Group discounted the notion of microscopic black holes forming in the LHC. But should a black hole pop up unexpectedly, theorists predict that it would not be able to survive long enough to start swallowing everything up, as black holes are wont to do.

Also of concern to LHC critics is the potential creation of strangelets—hypothetical particles containing strange quark matter. In theory, strangelets could coalesce with normal matter and change it to strange matter. Again, the safety group discounted strangelet concerns with the it-hasn’t-happened-yet argument. The Relativistic Heavy Ion Collider at Brookhaven National Laboratory, in Upton, N.Y., faced this same concern when it opened in 2000. In its eight years of operation, no strangelets have been detected. And the CERN scientists point out that conditions in the LHC are less favorable for strangelet production.

A vacuum bubble—a theoretical more stable state of the universe, but one in which we can’t exist—and magnetic monopoles—hypothetical particles with a single magnetic charge that could cause protons to decay—are also discounted in the safety report. Neither situation has ever been observed, conditions in the LHC are not theoretically conducive to their creation, and if vacuum bubbles and magnetic monopoles existed, Earth probably wouldn’t. And as the Safety Assessment Group put it, Earth is still here.

Eucalyptus Leaves

Although Earth is safe, in theory, from particle accelerators, things might not be so rosy for koalas if atmospheric carbon dioxide levels continue to rise. A study in Australia determined that increasing rates of CO₂ could be making EUCALYPTUS LEAVES, a staple of the koala diet, toxic. Ian Hume, emeritus biology professor at the University of Sydney, and his students determined that increases in CO₂ affect the nutrient level of eucalyptus leaves by increasing the amount of antinutrients present.

Hume classifies antinutrients as carbon-based compounds that are either toxic or interfere with the digestion of nutrients. For example, eucalyptus leaves may have high protein content, but antinutrients, such as tannins, bind with the protein, thereby preventing absorption by the koala.

Even though all eucalyptus species are fairly poor in nutrients, koalas are highly particular about which eucalyptus species they eat. And different species contain different ratios of nutrients to antinutrients. If those nutrient-to-antinutrient ratios tip in favor of the antinutrients, koalas could find even fewer palatable plants.

Hume, who presented his research at the Australian Academy of Science’s New Fellows seminar in May, thinks that koalas don’t have enough time to adapt to changes in eucalyptus nutrient levels and that we may see koalas disappearing “within our lifetimes.”