VIDEO: Gregory Benford and Larry Niven @Google

Larry Niven & Gregory Benford, two of the most respected authors of hard science fiction, talk about their new book Bowl of Heaven and the concept of stories about “big dumb objects” as a sub-genre. They review prior stories (including Ringworld by Niven) and then talk about the physics of the “big smart object” that is the Bowl of Heaven — a half dyson-sphere steering a star on an interstellar voyage.


La ucronía es un género literario que también podría denominarse novela histórica alternativa y que se caracteriza porque la trama transcurre en un mundo desarrollado a partir de un punto en el pasado en el que algún acontecimiento sucedió de forma diferente a como ocurrió en realidad (por ejemplo, los vencidos de determinada guerra serían los vencedores, o tal o cual rey continuó reinando durante mucho tiempo porque no murió fruto de las heridas recibidas).

La ucronía especula sobre realidades alternativas ficticias, en las cuales los hechos se han desarrollado de diferente forma de como los conocemos. Esa línea histórica se desarrolla a partir de un evento histórico extensamente conocido, significativo o relevante, en el ámbito universal o regional. Ese momento o acontecimiento común que separa a la realidad histórica conocida de la realidad ucrónica se llama punto Jonbar.

Un punto Jonbar es un acontecimiento singular y relevante que determina la historia futura. Se denominan así en honor a John Barr, personaje de un relato de Jack Williamson de los años 1930 donde se crea un mundo si escoge un guijarro y otro diferente si coge un imán y se convierte en un gran científico.

Las ucronías son una rama completa de la ciencia ficción que especulan acerca de las posibles consecuencias de que un punto Jonbar hubiera tenido un resultado diferente al que tuvo en nuestra línea temporal.

Existe una gran cantidad de puntos Jonbar recurrentes, y algunos de ellos son:

  • La no extinción de los dinosaurios. (Al oeste del Edén, de Harry Harrison).
  • La inexistencia del cristianismo. (Roma eterna, de Robert Silverberg).
  • La destrucción de los nazis (Inglorious Basterds, de Quentin Tarantino).
  • La victoria de la Armada Invencible sobre Inglaterra (Pavana, de Keith Roberts y Britania conquistada, de Harry Turtledove).
  • La construcción exitosa de la máquina diferencial por Charles Babbage y la supervivencia de Lord Byron (La máquina diferencial, de William Gibson y Bruce Sterling).
  • La derrota de los aliados en la Segunda Guerra Mundial (Hitler victorioso, de Gregory Benford, El hombre en el castillo de Philip K. Dick y Patria, de Robert Harris).
There was a blithe certainty that came from first comprehending the full Einstein field equations, arabesques of Greek letters clinging tenuously to the page, a gossamer web. They seemed insubstantial when you first saw them, a string of squiggles. Yet to follow the delicate tensors as they contracted, as the superscripts paired with subscripts, collapsing mathematically into concrete classical entities– potential; mass; forces vectoring in a curved geometry– that was a sublime experience. The iron fist of the real, inside the velvet glove of airy mathematics.
—  Gregory Benford
Gregory Benford's Guide to Terraforming the Moon

When it comes to remaking a celestial body in Earth’s image—“terraforming” it—the moon has clear advantages: It gets twice the sunlight of Mars. It’s a three-day trip with current technology, while getting people to Mars would take six months. Furthermore, the moon is dead and it’s small, so it needs less work and investment to build an atmosphere. Mars has slightly less than the total area of Earth’s dry land; the moon has a quarter of it—a bit smaller than all Asia.

Still, engineering any planet or satellite, including Earth, is a huge job. We will probably encounter the true scale of it in this century, as we build defenses against climate change. Thinking through how we might thrive on other worlds, even in the far future, can make us reflect on how terraforming Earth or other worlds will alter the human perspectives.

Terraforming our moon will take many decades and vast abilities. Before we can begin, we’ll have to master the resources of our solar system—especially transporting raw masses over interplanetary distances. That means nuclear thermal rockets (which we already developed by the 1970s), advanced robotics and communications, biotech, and sustainable closed environments. Once those come, we can reach higher. Here’s how the terraforming process might work.

Our moon was born too small to harbor life. It came from the collision of a Mars-sized world into the primordial Earth. From that colossal crunch spun a disk of rocks that condensed into a satellite. The sun robbed its gases, and that bully Earth slowly stole the moon’s spin, locking it so that one face always smiles at us.

The moon’s closeness is a huge advantage: To make it habitable, we would first have to bombard it with water-ice comets, a tricky endeavor best attempted with the many resources waiting on and near Earth. Using incoming comets will be worth the challenges, because they can deliver both an atmosphere and momentum.

The process begins by steering a comet nucleus, which some call an iceteroid, from the chilly freezer beyond Pluto. Nudge it from its slow orbit with a mile-per-second velocity change and swing it near any gas giant planet for a momentum swerve. By hooking the comet adroitly in a reverse swing-by around, say, Jupiter, we can loop it into an orbit opposite to the way that worlds orbit the sun. The grimy, mountain-size iceteroid soon will loom in the moon’s night sky.

Mere days before it strikes, scientists will have to blow it apart—brutally and carefully. Ice shards come gliding in all around the moon’s equator, small enough that they cannot free themselves from gravity’s grip. (We can’t let big chunks of comet scatter off the moon to rain down as celestial buckshot on Earth.) Within hours of the first incoming comet, the moon will have a crude atmosphere. With one-sixth of Earth’s gravity, it can hold gases for tens of thousands of years.

As more comets arrive and pellets pelt down, the moon spins faster. From its lazy “day” cycle of 28 days, it speeds up to a 60 hours—close enough to Earthlike, as they say, for government work.

For most of its life, the moon’s axial tilt has been a dull zero, robbing it of summers and winters. But if they are angled just so, the incoming ice nuggets can tilt the poles while shortening the days. From such simple mechanics we conjure seasons.

All told, we’ll need about 100 comets the size of Halley’s, which will bring water and carbon dioxide, with smidgens of methane and ammonia. We’ll need nitrogen, too, and some magic from the biochemists, who will pepper the moon’s old, gray rocks with blue-green algae that can exhale oxygen.

For centuries the moon’s dark plains had carried humanity’s imposed, watery names: Tranquility, Serenity, Crises, Clouds, Storms. Now, thanks to the “rain” of iceteroids, these lowlands of aged lava catch the rains and fatten muds into ponds, lakes, true seas. After billions of years, the ancient names come true.

Genetically engineered plants will create the first greenery. Like Earth’s tropics now, at the moon’s equator heat drives moist gases aloft. Cooler gas flow from the poles to fill in. The high wet clouds skate poleward, cool, and rain down.

On Earth, such currents are robbed of their water about one-third of the way to the poles, creating the worldwide belt of deserts. Not so on the moon. The new world has no chains of deserts, just one simple circulating air cell grinding away in each hemisphere. Moisture forges climate. Northerly winds sweep poleward, swerving toward the west to make the occasional mild tornado.

The moon, once “the lesser light that rules the night,” now shines five times brighter, casting sharp shadows on Earth. Because of the reflection of the seas, when the alignment is right, people on Earth’s night side gaze up at Earth’s image.

The moon has no soil, only the damaged dust left from 4 billion years beneath the solar wind’s anvil. Making soil from gritty grime is work best left to the biologists. Our moon can brew its own, in fast-forward. Bioengineered minions can till the dirt, massage the gases, build an ecology.

In the one-sixth gravity, humans can fly, with flaps on arms and feet. At last we will be at one with the birds—big rude beasts who will challenge us among the thick decks of pewter cloud.

This exotic Floridalike globe with the land mass of Asia will have mostly cloudy days. It’ll be warmer, too, from greenhouse effects. Earth will still hold sway over a moon revolving much faster, making its presence felt even if you can’t see it most of the time. The tides will be 20 yards high—and so can be surfed. With lesser gravity, a boarder can skate over hundreds of miles, a daylong ride. Of course, when that tide slides up the shore of a lunar lake, there’ll be plenty of tourists scampering away from it.

This sobering step to a higher level could mark a defining role for an emergent humanity, securing its future with a new, distant habitat. We may finally become, millennia after the Old Testament commanded, true stewards of the Earth—and no doubt, more.

We cannot have a future that we do not first imagine. Historians often convey the impression that the past, since it is now fixed, was a neat, cut-and-dry time. This mistake makes the present seem messy. The past is a far country, but the distance should not confuse us about its turbulent nature. […] We shape our future with incomplete information, then must live with what results.

Gregory Benford,

The Wonderful Future That Never Was

AUTHOR: Gregory Benford & William Rotsler
TITLE: Shiva Descending
ISBN: 0-7221-1577-3


An asteroid swarm, twice Earth’s diameter, in elliptical orbit around our planet Earth.  And in the centre of the swarm, a vast chunk of space rock, codename:


Two kilometers in diameter, the giant asteroid will collide with Earth in precisely 11 month’s time, with a staggering impact force equivalent to a 250,000 megaton fusion bomb.


While scientists desperately world round the clock to divert the lethal cannon ball, civilization explodes into a blaze of riots and mass murder, as the day of the final apocalypse draws nigh.