The 25 science fiction stories I most liked

Isaac Asimov

In the United States fiction is classified depending on the length of the work, with four subsequent stages:

1. Novel, any work that has more than 40,000 words.
2. Novella, a work between 17,500 and 40,000 words.
3. Novelette, between 7,500 and 17,500 words.
4. Short Story, less than 7,500 words.

Naturally, the limits are not strict, and in practice they depend on who classifies each book. In Spanish, however, we have fewer categories:

1. Novel.
2. Short novel, which applies to works of intermediate length.
3. Story, with few characters and a simple plot.

Wormholes

Science fiction novels make it clear that, even if we were able to reach relativistic speeds (close to the speed of light), our need to personally explore the universe wouldn’t be satisfied. We’d like to travel to other stars with the same ease with which we cross the Atlantic today. We’d like to measure in days, if not hours, the time of a trip to the center of the galaxy (which probably contains a large black hole). Is there any chance of this happening?

To do this, we should discover in the future some property of the universe, now unknown, that would help us break the speed limit of light, which seems firmly established, and which would make us spend thousands of years on trips to most stars, except the nearest.

To solve the problem, science fiction authors have used essentially two different procedures:

The age of the Nobel Prizes in science

Age of scientific Nobel Prizes, by decades

In my conference closing the 1997-98 term at the Universidad Autónoma of Madrid, entitled The myth of progress in the evolution of Science, I wrote this:

The Nobel prizes provide an interesting measurement of the evolution of scientific progress during the twentieth century. These prizes award the most important advances in the fields of Physics, Chemistry, Physiology and Medicine. Statistics show a few worrying trends, such as the progressively higher age of the scientists who have received the Nobel Prize: the average age has gone up from 47 in the first decade to 60 in the last. The number of Nobel prizes awarded to people below 40 has gone down from nine in the thirties and fifties to zero in the nineties. Not one person born after 1950 has yet received a Nobel prize.

The problem with hierarchical multiverses

Lee Smolin

In an earlier post in this blog I mentioned a list of theories about multiverses, independent and often mutually contradictory, prepared by George Ellis, the cosmologist. These multiverses can be divided into two large groups:

• Non-hierarchical multiverses: such as the chaotic inflationary multiverse, where each universe is supposed to be a bubble that has stopped its inflationary growth, amid a permanent and total inflationary environment.
• Hierarchical multiverses: like Smolin's (which Ellis does not mention) and the multiverse of universe simulations (in other words: that we live in a simulation). In this post I speak exclusively about this type of multiverses, which share a property that, in my opinion, makes them implausible, if not impossible.