New Results From Venus Express

Riding with Robots writes "For the past two years, Europe's Venus Express orbiter has been studying Earth's planetary neighbor up close. Today, mission scientists have released a new collection of findings and amazing images. They include evidence of lightning and other results that flesh out a portrait of a planet that is in many ways like ours, and in other ways hellishly different, such as surface temperatures over 400C and air pressure a hundred times that on Earth. The article lists seven papers that will be published today in Nature."

Comments

Re:Can Venus be made habitable?

[kebes]

I would think the first step would be to boost the planet to an orbit further away from the sun. Changing the orbit of a planet is not really an option. The energy required to do is ridiculously large. Not to mention the difficulty of actually applying the required forces to a planet (without ruining it). Attach rockets? Launch asteroids into it (and bit by bit change its velocity)? In any case it would be very, very costly, and would require a long, long time.

But all that is unnecessary anyway, because Venus' orbit is not too far outside the habitable zone. One could, I suppose, eject a large percentage of the Venutian atmosphere in order to reduce atmospheric pressure, temperatures and greenhouse effects (via controlled explosions, perhaps?). To further reduce and control temperatures would require some geo-engineering. For instance, one could place a huge number of thin solar reflectors at the Lagrange point between the planet and the sun. These thin floating mirrors would reflect away some percentage of the sun's rays, thereby casting a "shadow" of sorts on the planet and reducing temperatures. This would of course be ambitious, requiring billions of lightweight reflectors to be placed into the proper orbit, but it's not unthinkable to do it. (Actually, some people are even suggesting it as a potential solution to control Earth's climate.)

After stabilizing the temperature there would still be many other things to deal with: the atmospheric makeup isn't very hospitable, and it would probably require millenia of active modification to bring it even close to being hospitable to simple forms of life (e.g. extremophiles). Presumably one would engineer these initial life forms so that they would convert the atmosphere as required (especially, to generate oxygen). So, it's probably possible in principle to make Venus habitable... but by no means easy.

Re:Can Venus be made habitable?

[sckeener]

I think we have time to make Venus habitable....we just need to colonize it first.
http://en.wikipedia.org/wiki/Colonization_of_Venus

Aerostat habitats and floating cities

Geoffrey A. Landis has summarized the perceived difficulties in colonizing Venus as being merely from the assumption that a colony would need to be based on the surface of a planet:

        "However, viewed in a different way, the problem with Venus is merely that the ground level is too far below the one atmosphere level. At cloud-top level, Venus is the paradise planet."

He has proposed aerostat habitats followed by floating cities, based on the concept that breathable air (21:79 Oxygen-Nitrogen mixture) is a lifting gas in the dense Venusian atmosphere, with over 60% of the lifting power that helium has on Earth.[4] In effect, a balloon full of human-breathable air would sustain itself and extra weight (such as a colony) in midair. At an altitude of 50 km above Venusian surface, the environment is the most Earthlike in the solar system - a pressure of approximately 1 bar and temperatures in the 0C-50C range. Because there is not a significant pressure difference between the inside and the outside of the breathable-air balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates, giving time to repair any such damages. In addition, humans would not require pressurized suits when outside, merely air to breathe and a protection from the acidic rain. Alternatively two-part domes could contain a lifting gas like hydrogen or helium (extractable from the atmosphere) to allow a higher mass density[5].

Cloud-top colonization also offers a way to avoid the issue of slow Venusian rotation. At the top of the clouds the wind speed on Venus reaches up to 95 m/s, circling the planet approximately every four Earth days in a phenomenon known as "super-rotation".[6] Colonies floating in this region could therefore have a much shorter day length by remaining untethered to the ground and moving with the atmosphere. While a space elevator extending to the surface of Venus is impractical due to the slow rotation, constructing a skyhook that extended into the upper atmosphere and rotated at the wind speed would be comparably difficult to constructing a space elevator on Earth.

Since such colonies would be viable in current Venusian conditions, this allows a dynamic approach to colonization in stead of requiring extensive terraforming measures in advance. The main challenge would be using a substance resistant to sulfuric acid to serve as the structure's outer layer; ceramics or metal sulfates could possibly serve in this role. (The sulfuric acid itself may prove to be the main motivation for creating the structure in the first place, as the acid has proven to be extremely useful for many different purposes.)

Landis has suggested that as more floating cities were built, they could form a solar shield around the planet, and could simultaneously be used to process the atmosphere into a more desirable form. If made from carbon nanotubes (recently fabricated into sheet form) or graphene (a sheet-like carbon allotrope), the major structural materials can be produced using carbon dioxide gathered in situ from the atmosphere. The recently synthesised amorphous carbonia might prove a useful structural material if it can be quenched to STP conditions, perhaps in a mixture with regular silica glass. According to Birch's analysis such colonies and materials would provide an immediate economic return from colonizing Venus, funding further terraforming efforts.