At a lunch conversation someone mentioned that a famous science fiction writer had been complaining that humans travelling into other planets was not realistic and would probably never happen. While the barriers do seem quite high due to the problems of travelling too slowly and transporter systems not likely to function properly without one built on the other side I do think people will appear in other locations. Here are my theories for how.

1. The spore strategy: Spores from mushrooms and mold have been thought to be able to leave the atmosphere and wander through outerspace. These little guys are so small that they fly on their own but the idea of a spore is to have lots of them shoot and float in random directions. When one lands it then colonizes a piece of rotting fruit. We will sooner or later create systems that can grow an embryo from a simple 2-4 cell thing into a full human. So we just need to send a few billion of these flying in womb sized pods that can survive impact on a foreign planet. Inside the pod would be all the machinery to grow the embryo and some seeds for tomatoes and other interesting edible plants. The pod lands, plants the tomatoes, waits 1,000 years - not too long or else the vegetables will evolve out of growing nutritious snacks, and then activates to grow the human. The newborn eats the tomatoes and the special milk-fruit. The pod also contains a video ipod with Jor-el style instructions about the home planet.

2. Beam the codes - construct there: We just assume that there are aliens on other planets and they can read signals from us transmitted through electromagnetic waves. We also assume they are good at organic chemistry since most good universities on the alien planet offer EE and Organic chemistry majors. The instructions we send are the basic blue prints for life on earth. We start with the machinery to build DNA and the core functions that allow for replication including ribozomes for making proteins, RNA, and possibly a whole mitochondria. Essentially they are going to have to synthesize the minimum set of materials to make a self sustaining cell without having a cell to begin with (an interesting science project that we can keep working towards while waiting for the sun to explode). The other instructions would be to send out the entire genomes (both male and female - probably Brad and Angelina) for people and cows. We'll need some burgers when we get there. This approach is preferred since vegetarians generally are less interested in space travel. Some genetic instructions for making tomatoes, grass for the cows, and a ten page human care and feeding pamphlet would also be helpful.

3. Space can: We read about this in grade school. Just build a big nuclear powered asteroid. It can have it's own atmosphere and renewable resources. It can periodically collect some new nuclear fuel and can always jettison bad stuff out the back. It just wanders around looking at solar systems until it finds something cool. We probably need 10 of these going in random directions and in communication with each other and Earth to keep up to date with the latest gadgets and news. The upside to them is that if we accidentally start using nuclear weapons on earth or screw-up the atmosphere these arks can preserve our genetic material and culture.

4. Travelling Robots: We figure out how to transfer intelligence into robots. They have no issues with 2 million year lay overs in alpha centauri. Alternatively we genetically engineer people to have similar attitudes to long flights.

5. Good enough planets: With terra forming all we need to do is get to the nearest star with a few planets which is a lot closer than going to a solar system with a good planet like Earth. We can figure out how to make a planet work from a lifeless hulk of volcanoes and sulphuric acid rain showers after we fix ours after we break ours.