Relatividade

Astronomers’ latest estimates put the age of the universe at about 13.7 billion years. That is three times as long as the Earth has existed and about 100,000 times the lifespan of modern humanity as a species. The true size of the universe is still unknown. Its age, and the finite speed of light, means no astronomer can look beyond a distance of 13.7 billion light-years. But it is probably bigger than that.

Nor does reality necessarily end with this universe. Physics, astronomy’s dutiful daughter, suggests that the object that people call the universe, vast though it is, may be just one of an indefinite number of similar structures, governed by slightly different rules from each other, that inhabit what is referred to, for want of a better term, as the multiverse.

In “As important as Darwin” published on August 15th, we said that no astronomer can look beyond a distance of 13.7 billion lightyears. This was incorrect. The universe has expanded during the 13.7 billion years that light has been zipping across it and, as a consequence, astronomers can see to distances of perhaps as far as 47 billion lightyears.

[The core of the spectacular globular cluster Omega Centauri glitters with the combined light of 2 million stars. The entire cluster contains 10 million stars, and is among the biggest and most massive of some 200 globular clusters orbiting the Milky Way Galaxy.]

According to a recent study, smoking kills an average of 55 Iraqis a day, compared to a current average of ten deaths daily from terrorist shootings or bombings. So the government argues that it is perfectly reasonable to outlaw smoking on public-health grounds.

The capital of Haiti, Port-au-Prince, suffered a devastating earthquake measuring 7.0 magnitude on Tuesday January 12th. Much of the city was flattened and at least hundreds-and probably thousands-of people have been killed.