Rees notes that some experiments, say launching of single nuclear weapon, are known to render threat to life on Earth. However, the magnitude of the impact of such experiments may not be amply intense to destroy the whole world. On the contrary, the author asserts that there are some physics experiments performed mainly for the purpose of pure scientific inquiry that could possibly pose global or even cosmic threat.
For instance, device known as particle accelerators have been created to aid in the study of particle composition of the world. This machine is primarily utilized to investigate about most extreme energies and temperatures. Unbeknownst to many, such experiments that entail the smashing of atoms are said to possibly have disastrous effects on the universe.
The author elaborates that this type of experiments may generate unprecedented concentration of energy which may lead to different catastrophic scenarios. This first scenario entails the formation of black hole that sucks in everything around it. However, Albert Einstein disputed this claim as the energy requirement for the formation of black hole is significantly greater than the amount of energy generated with the collision experiment. The second scenario involves the formation of strangelet, which is described as reassembled quarks. A strangelet is deemed harmless in itself but it said to possess the ability to convert anything it encounters into a new strange form of matter. With this, it could transform the entire planet into an inert hyperdense sphere. The third theory concerning vacuum is considered as the most disastrous. Some have speculated that the concentrated energy when particles crash together may set off a "phase transition" that would rip the fabric of space itself.
Although experts have expressed that the likelihood of these scenarios occurring is minimal, Rees asserts that we cannot be completely sure of the outcome. This is because the probabilities assigned to these scenarios are deemed subjective due to the absence of comparison to a similar occurrence in the past.
According to Rees, one way of checking whether an experiment is safe would be to examine if such has occurred naturally. For example, the negligible probabilities posited by experts may be acceptable in light of the fact that particles randomly crash into other atomic nuclei in space. This shows that space is not as "breakable" as envisaged by physicist. However, the mechanics change once the accelerators become more powerful, thus, no longer replicating what naturally occurs.
The same concerns are encountered with the plans of Brookhaven National Laboratory in the United States and CERN Laboratory in Geneva to crash atoms more forcefully. Issues regarding safety is raised since no adequate reassurance is established considering that the conditions are different from what occurs naturally. Even if two notable theories were asserted in relation to the improbability of strangelet formation and characteristics, many experts still question the sufficiency of such claims.
In view of the above, Rees opines that it is not reasonable to conduct an experiment if the downside may entail finality and completeness of extinction. As such, experiments with "doomsday downside" should not be permitted unless the general public is assured that the risk such undertaking may entail is within