Venus’s continents and terraforming

The planet Venus already appears to have continents, Ishtar in the north and Aphrodite on the equator. They may be a remnant of a time when Venus had plate tectonics like on Earth, which means that the crustal plates were able to slip over the mantle and to collide with each other or be sub-ducted under each other to create mountain chains. However this process needs water, plentiful on earth, but almost non-existent on Venus. It may be that billions of years ago Earth, Mars and Venus all had water and the conditions necessary for life. But Mars went into deep freeze and Venus became a roasting hell.

When the day comes for our descendants to transform Venus from its present hyper-hostile state into a planet where life can prosper; a number of steps have to be undertaken to make this possible. The first is the removal or transformation of the atmosphere. That’s the most difficult step, and trying to envisage how that might be done is like someone in the tenth century imagining how people today would get from York to Jerusalem in three hours.

However let’s try anyway, and imagine that physicists in a thousand years understand a good deal more about space, relativity and particle physics than we do today. Already they are starting to say that even a vacuum has structure, and that three quarters of the particles which make up matter are missing. If this is correct, then they may have ways of bending space or even of creating holes through it into other regions of space or other dimensions. This then might allow Venus’s atmosphere to be removed to somewhere it wouldn’t cause any contamination problems for Mars or Earth.

The next steps would the correction of Venus’s spin, which at present gives Venus a day length equivalent to 225 earth days. This would also mean a night of 225 earth days, during which any plants added to Venus’s surface would die. Therefore correction of this slow rotation is essential if life is to exist on its surface. This would best be done using large asteroid strikes, delivered as twins with one on each side of the planet to speed up its rotation. Increasing the rotational momentum of an object as massive as a planet would take a terrific amount of energy and therefore that additional momentum would need to come from large chunks of rock sourced from the asteroid belt and accelerated to have sufficient energy to do the job. This would of course mean multiple twin asteroid strikes, as too few would either not increase rotational speed sufficiently or might cause the break up of the planet. Additionally these impacts, all on the equator, would produce new continents right around Venus’s circumference. This is because no single spot should be hit more than once as that could also cause planetary breakup. Once this step is complete, the surface may need to be left to cool before moving onto the final step.

Earth has seasons, Venus does not. This is due to the 23 degree tilt of the earth’s axis. Venus does have a very small 2 degree tilt, but this would need to be increased to be as close as possible to Earth’s. Here again twin asteroid impacts would need to take place to correct this. However this is a case in which the same places near Venus’s north and south poles would need to be struck repeatedly until the correct tilt had been achieved. The impacts would need to be small and regular to avoid punching holes through the crust into the mantle and initiating massive volcanism. However the outcome would be the creation of two new continents.

So with the string of three or more continents along the equator, two new continents near the north and south poles, plus the existing Aphrodite and Ishtar landmasses gives us an approximation of six continents on a future terraformed Venus.

Moons! Who needs them?

We evolved on a planet with a large moon. It gives us our seasons, our oceans tides and helps to reduce our planet’s wobble. Without a moon our weather would be less effective at mixing oxygen and nitrogen, our oceans might stratify and be less able to support life and our seasons might be so variable that living things might not be able to survive at all.

So when we come to terraform other planets should we add a moon before we do anything else to a planet? The reality is that we probably won’t have the technology to move moons around for at least a thousand years, which means we won’t be able to do this before we terraform Mars or Venus.

However the danger of not having a moon is that a planet’s wobble is so extreme that a single place may be at a frozen pole at one point and on the super hot equator at another. This would almost certainly sterilise the planet and kill all life on it.

For Mars and Venus we have a window during which we can terraform without having to worry too much about wobble. However we will need to understand the history of a planet’s wobble and how long it will be before it needs to be stabilised.

Mars at least has two small moons, which could be brought together as a way to avoid having to bring a third chunk from the asteroid belt or from elsewhere in the solar system.