Top 10 technologies we'd like to see

2. Space Elevator
Iain Thomson: The concept of a space elevator is over 100 years old. Konstantin Tsiolkovsky's idea for such a structure has been adapted extensively since, but is one of those concepts that relies on materials.

There are many current theoretical plans for such a structure, but the basic idea is the same. If you can run a cable from the surface up to an object in geostationary orbit you can reduce the cost of getting stuff into orbit to a fraction of current levels. A space elevator is really a smart investment for any civilisation looking to get out of the gravity well.

However, it's quite likely that you could see the concept put into action on the Moon before it's tried on Earth. It should be theoretically possible to build an elevator on the Moon using current technology, and Nasa is already funding experiments into building climbing robots that could be used to transport equipment to the lunar surface.

Looking ahead, some have suggested that the elevators could eventually be built into towers if strong enough materials become available. They could become huge 'arcologies' extending into orbit that would free up space on Earth and remove the need for satellites.

But there are serious practical problems to be overcome. Carbon nanotubes have been touted as a solution, but there is no way currently known to mass produce them to the length required.

There's also the human factor. Simply moving people up and down would be a slow process that would take days and may include too much radiation exposure. And there's so much junk in orbit right now that it would either have to be strong enough to resist an impact, or the spacefaring nations will have to hoover up all the junk.

Shaun Nichols: The rising cost of sending craft into space, combined with the looming retirement of the US Space Shuttle fleet, is only further advancing the case for a space elevator.

Eventually it might just become more practical to invest in the construction of an elevator system than to keep shooting rockets into space. Keep in mind that the rockets we use today are pretty similar to those from the 1960s, and 50 years is a lifetime in the technology and aeronautics worlds. We need to find a better way to get into space.

Remember earlier when we talked about the strength of nanotubes? This would be one of the truly revolutionary applications for them. Once the manufacturing hurdle is overcome, an elevator system could be a highly valuable asset for no other reason than the ability to get new orbital craft into place.

Manned travel might prove a bit more difficult, but if solved it could make the concept of space tourism an exciting reality.

1. Clean energy
Shaun Nichols: To many people, the development of clean energy in the immediate future is about the only chance we have to avoid a catastrophic environmental transformation.

Even if you don't agree, there's not much argument that we don't need to find a way to harness the power of renewable and sustainable resources far more efficiently than we do today.

Ee are working to harness the power of wind, solar and hydroelectric systems to generate energy, but such systems are often far less efficient than either nuclear power or the combustion of fossil fuels, and generate only a small percentage of the world's total power.

This is an area where IT could have a direct impact. To generate the precision engineering and modelling data needed to produce more efficient equipment requires a huge amount of computing power.

While getting such immense computing muscle once required hugely expensive supercomputer installations, these days you can build a respectable cluster by hooking together a few dozen gaming consoles.

As supercomputing power becomes easier to obtain, the chances of scientists solving the top item on our list become better and better.

Iain Thomson: This is really the panacea that the world is looking for. After the disappointment of cold fusion, oil stocks that are going to run out eventually (and even faster if certain companies in the Gulf of Mexico don't get their act together soon) and ever-increasing energy demands we need a clean, cheap reliable power source.

There is some promise in nuclear power, but too many people find the topic too emotive and it's difficult making any headway, although Bill Gates is funding a rather interesting system that generates power by burning radioactive waste. Nevertheless, the quest for a clean, cheap power supply goes on.

Renewable energy is all very well, but it's not reliable and can't supply fluctuations in demand. Better energy efficiency would be a start, and fuel cells are showing some promise, but fusion looks to be the most likely candidate to supply our energy needs in the future.

However, as we can't sustain a reaction yet for more than a second, we may have some wait yet.