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Could Experimental Physics Accidently End the World?

A section of the Large Hadron Collider showing the pipe containing the two "tracks" where the particles build up speed and energy. (Photo by Julian Herzog licensed under the Creative Commons Attribution-Share Alike 3.0 Unported)

It's a scenario right out of a bad science fiction movie: Scientists working in multi-billion dollar facility tamper with the tools of creation and accidentally make a tiny black hole. It sinks to the center of the earth, sucking in matter furiously. In a few hours the core of the earth is consumed. Earthquakes rock the planet and tsunamis sweep across the continents. Then suddenly the world flattens out into the shape of a giant Frisbee and then collapses in on itself. Out in space the astronauts on the International Space Station watch in shock as they now orbit a small, invisible black hole which they cannot see, but has just consumed everyone and everything they know and love. Left alone they contemplate their fate. Will they asphyxiate when their air runs out first, or freeze to death when the power fails…

So is the story even vaguely possible? Could scientists accidently create a black hole in the laboratory that would consume our planet?

When people think of black holes they usually think of an object in space many times the mass of the sun whose gravity is so powerful that even a beam of light cannot escape its grasp. These monsters are the remnants of supernova explosions. Anything that gets close to them, a space ship, a planet, or even a star, gets sucked in by the black hole's gravity never to be seen again. Scientists think there is a huge one a million times the mass of the sun located right in the heart of our galaxy.

The minimum size of these black holes in space are at least three times the mass of the sun, so it would seem to require a lot of matter to create a black hole. Physics theory suggests, however, that it might be possible to create a microscopic black hole by slamming two sub-atomic particles together at extremely high velocities.

Making Black Holes

And that's what has some people worried. Particle colliders, like the Large Hadron Collider (LHC) in Europe and the Relativistic Heavy Ion Collider (RHIC) in Brookhaven, New York, are designed to do precisely that: slam sub-atomic particles together at tremendous speeds and energies. These particle accelerators usually include a ring-like "track" where the particles are accelerated to speeds near that of the speed of light. In the case of the LHC, the main ring is 17 miles in diameter and sends particles down two parallel tracks in opposite directions. When they have obtained enough energy, the particles are switched onto different tracks that take them on a collision course so they strike head on. The impact tears the particles apart into their component pieces and some of the energy involved converts into a hot, soup-like plasma of quarks and gluons. When it condenses it becomes matter again with new types of particles being formed as per Einstein's famous formula E=mc2. This allows scientists to study the universe at it smallest and most basic pieces.

Sub-atomic particles are subject to a number of forces. Gravity is one we are very familiar with. Though it is weak when compared to other forces, it is tenacious and operates over great distances. Gravity causes all pieces of matter to be "pulled" toward each other. The more massive the object is and the closer the object is the more pull it has. That's why something large like the earth attracts you. It is also why (if you were standing on the moon, which is only 6th the mass of earth) you would have only one 6th your weight.

Even small particles have gravity, but other forces resist them being pulled very close together. If, however, you slam them together with enough speed so you can get the particles close enough, gravity will overcome the resistance and the two particles will form a tiny, black hole. For many years it was thought that the energy necessary to do this was many, many times more than a particle accelerator could ever provide.

Scientists working on string theory (a theory about how the universe is put together), however, have suggested our universe has more than just the three familiar dimensions. Extra, small dimensions might be curled up in the big three that we can't see. If this is the case, as two objects get very close to one another, their attraction due to gravity might skyrocket. With this extra gravity helping, the LHC just might have the necessary power to make microscopic black holes.

Black holes are believed to be the result of a large supernova explosion, but could a tiny one be made in a laboratory? ( By Alain r licensed under the Creative Commons Attribution-Share Alike 3.0 Unported)

So if these theorists are right, can the LHC create a black hole that will eventually eat the world? One of the strongest arguments against this happening is something known as Hawking Radiation. A few years ago the famous physicist Stephen Hawking came to the conclusion that a black hole should emit radiation. His arguments have become widely accepted and this means that any black hole under a certain size should simply "evaporate." Microscopic black holes made by a particle accelerator would probably be around for only a fraction of a second before they would disappear.

But what if Hawking is wrong and they don't evaporate? Or don't evaporate as quickly as we think?

Most of the black holes created by a particle accelerator would be moving so fast that they would simply leave the planet and head out into space. Perhaps only one in a million would be moving slow enough that it would get trapped by Earth's gravity.

What about one of those then? A tiny, black hole would be pulled to the center of our planet. However, the gravity it would have is so low it would rarely interact with other matter. Physicist Greg Landsberg at Brown University believes it would only absorb about one proton (the positive particles at the center of atoms) every 100 hours. This growth rate is so small that the tiny, black hole would only have absorbed a few milligrams of Earth's matter by the time the end of the universe arrived.

As it is, the HLC has been operating for a while now and so far nobody has seen any signs of any microscopic black holes. This might be actually a bit of a disappointment for those betting on string theory as it seems to make the possibility of those extra dimensions less likely. The HLC will not be up to full power till 2014; however, there is still a chance they may be found during later testing.

Strangelets Danger

Black holes aren't the only things that a particle collider might make that could get out of control. Normal protons consist of smaller particles known as quarks. Quarks come in several flavors including "up," "down," and "strange." Regular matter is composed of up and down quarks. Some exotic particles (known as "strange matter") are thought to contain all three types of quarks, but are usually unstable and decay quickly into just regular matter. There is a theory, though, that if a piece of strange matter were made large enough it could reach a critical size (about the weight of 1000 protons) where it would actually become more stable than regular matter. Such an object would be called a "strangelet," though at this point nobody is sure if such a thing could actually exist.

Regular matter coming into contact with a strangelet might be converted itself into strange matter because the strange matter would be more stable than regular matter. This has led some people to theorize that if a particle collider could made a large enough strangelet with a negative charge (so it would be attracted to other matter), it might convert the whole planet to strange matter which would be hot, dense and fatal to all human life.

The result of a gold ion collision as recorded by the Solenoidal Tracker (STAR) instrument at RHIC showing the charged particle debris. ( By Argonne National Laboratories licensed under the Creative Commons Attribution-Share Alike 3.0 Unported)

There is no proof, however, that the strange matter theory is right. Or that large strangelets would actually be stable. And if they were it would be very, very unlikely that they would be negatively charged. If the theory is right, however, it is likely that almost all neutron stars (collapsed versions of stars not quite big enough to become black holes) should actually be made of "strange" matter as naturally occurring strangelets would have collided with them and converted them to strange stars. No evidence for this exists. In fact, most observations made so far suggest that neutron stars are just made up of regular neutron matter.

In theory the Relativistic Heavy Ion Collider (RHIC) that started operating in Chicago in 2000 should have been much more likely to produce strangelets then the LHC. Scientists at the RHIC have not seen any strangelets of any size or type appear however, which puts the whole strange matter theory into question.

Vacuum Bubbles and Magnetic Monopoles

Another concern raised by particle colliders is the possibility that they might generate a bubble of vacuum at a lower level than currently exists in the universe. If that was the case, the whole of the universe would suddenly be converted to that level destroying any life.

There is also the possibility that a large collider might be able to produce a particle known as a monopole. Most magnets have two poles, north and south. In theory there might be particles that have only a single magnetic pole (therefore the name "monopole"). If monopoles exist and are heavy enough they could cause protons to decay into electrons /positrons and unstable mesons in a chain reaction that would destroy the earth. However, even if monopoles do exist, ones that are heavy enough to do such damage couldn't be made at LHC or any other collider now in operation. The energy required to make such heavy monopoles just can't be generated by today's colliders.

The bottom line is that almost anything that current particle accelerators are capable of doing has been done in nature already through natural high-energy, cosmic-ray collisions with earth's atmosphere or a more solid object, like the moon. These collisions happen hundreds of thousands of times each day. Because of this black holes, strangelets, monopoles and vacuum bubbles should have already been created by nature, but they haven't, or if they have, they turned out not to have planet-destroying capability.

Future Threats

This doesn't mean that experimental physics or another scientific discipline might not, in the future, be capable of doing experiments that might threaten the safety of humanity. The possibility has long been on the mind of some scientists. During the early atomic and hydrogen bomb tests, a few researchers were initially concerned that the blast might set the earth's atmosphere on fire, reducing the planet to a charred cinder. Calculations made before the test showed that this was impossible, though there are some rumors a few scientists were still extremely nervous about such a thing at Trinity, the first atomic bomb test in 1945. Perhaps they were thinking "what if those calculations are wrong?" Scientists are fallible like anyone else. At Castle Bravo, an early hydrogen bomb test in 1954, researches expected the weapon to yield a 5 or 6 megaton blast. Instead, because they miscalculated what would happen with the lithium-7 isotope included in the bomb, it generated a 15 megaton blast with a dangerous increase in fallout that poisoned several Pacific Islands in the area along with a Japanese fishing boat.

Can society guard against the possibility of a highly dangerous scientific experimentation without hampering research that might benefit humanity? Up to this point in times our science hasn't had the capability to trigger a doomsday disaster. This will change in the next century. Just one example is which nanotechnology holds the promise of cleaning up the environment, ending water shortages, providing green power and curing deadly illnesses, but it might also be capable of accidentally reducing the planet to "grey goo."

Usually when a project is proposed the chance of something going wrong is weighed against the amount of damage that might result. We do this type of thing everyday: we evaluate the chance of being in a car accident against the cost to us if it does occur. There is a fair chance I might be in a collision on my way to work, but even if I am, the chances are I will not be killed or even seriously injured, so I accept the risk.

In the case of a doomsday experiment, however, the chances of anything going wrong might indeed be tiny, but the cost - the destruction of all human life - is enormous. What is the acceptable probability of such an event? One in a million? One in a billion?

Science and the Courts

Before the LHC went on line a number of lawsuits were filed in order to stop its operation. Most of the claims the plaintiffs made were based on faulty scientific data and ideas, but the merits of these arguments were never tested in court. The cases were simply thrown out based on jurisdictional problems.

Eric E Johnson, a lawyer at the University of North Dakota, has written a paper arguing that the courts have a place in stopping hypothetically cataclysmic experiments. Others argue that such an approach could bog down important research with frivolous lawsuits. There is also a question of what kind of court would have the necessary jurisdiction. A case against the LHC was brought in Switzerland but was dropped because the LHC straddles the Franco-Swiss border and treaties with France and Switzerland guarantee the research center immunity from the legal process in both countries.

So what court would have the right jurisdiction? A future threat might come from any laboratory in the world. How could a plaintiff in South Africa get an injunction to stop an experiment being run in the People's Republic of China if he had good evidence that it might destroy the planet? And even if you could get a case into a courtroom could a judge really understand the arcane scientific arguments that might emerge in such a lawsuit?

There is currently no clear cut way these concerns can really be addressed except by safety reviews done by the scientific organizations sponsoring the research. Many people are concerned however, that such reviews will be biased unless done by an outside entity. After billions of dollars have been spent and scientific careers are on the line, the temptation to fudge the facts and proceed with a dangerous experiment might be irresistible. So how we will protect the world from dangerous experiments remains an open question. A question the human race needs to address before something goes badly wrong.

Copyright Lee Krystek 2011. All Rights Reserved.