How fast does the ship travel? How is acceleration/deceleartion achieved?

If we assume a 1G acceleration (modified in flight to the gravity of the destination) how long does it take to go 1000 light years? What is the elapsed time taking any relativistic time dialations into account? |Distance |1000 | Light Years |10,000 |Light Years| |Acceleration |1G | 0.0001G |1 G |0.0001G| |Subjective time |13.48 |6210 |17.94 |18950| |Earth time |1003 |6316 |10002 |22105| |Maximum speed |c |.31c |c |.75c|

• It doesn't make sense to depart until the technology is advanced enough so that you won't be over taken in flight. Relativity makes that strange. For accelerations above 0.001G on long flights, or high (near 1G) you reach nearly the speed of light and you get there sooner if you leave sooner. If your acceleration is weak than it gets close if you should wait for the technology. For example, If your starting acceleration is 0.01G and it improves 30% every ten years, and your trip is 100 light years, then it takes between 193 and 210 years to get there (earth time) reguardless of when you leave. With weaker accelerations (0.001G) it pays to wait. This all depends on the acceleration and the assumptions made about how it improves in time. --DaveK

• I was amazed at how the numbers turned out. But if we want that story to be possible we will have to choose our starting conditions with a bit of care. CM, there is a book called _Rare Earth_ by Ward Brownlee. Its premise is that the occurance of habitable worlds is very low. So worlds may be very valuble. But then it is our universe we get to decide. Probably an entry for the background section. -- Main.DaveK - 25 Jun 2004 ---

• Great numbers, but they all assume we want to get to the destination in a hurry. If we need a long time, we can work the math out so it takes us nearly a million years to get 59 light years. (Again, plugging a destination I sort of like 70 Virginis and it gas giant "Goldilocks") We need to decide the level of technology we want for our drive, or do we hollow the asteroid, set it spinning, give it a good nudge and let it coast? If it isn't obvious already this is the meathod I prefer, and will likely write some stories using this regardless of how we go with this project. Also, I think that the argument that it doesn't makes sense to leave until the technology improves is counter intuitive because it negelects alot of variables. For instance if a group of people decide to do this project, and they have the will power, the funding, et, then decide to wait say a hundred years because technology may make speed faster what guarentees can they have that 100 years into the future anyone will even want to go? Why not put it off indefinately until FTL is discovered? Buzz Aldrin and John Barnes addressed this nicely in their novel Encounter with Tiber in which an alien race at Alpha Centauri know their world is doomed in a certain period of time, and have to plan an exodus. The argument is made why not wait till the technology allows a maximum amount of people for a minimum amount of time, but politics being what it is, no one ever gets around to doing it and they die off. The same might happen here on Earth. Why wait for technologiocal advances when politics and public interest might cancel the idea all together? Also, as I've said before, I like the idea of the ship being over taken along the way. Its one of the ideas which draws me to this project, and will likely be one of the story ideas I use. I hope to persuade everyone to leave this option open for such stories, but if not, I will write the thing anyway. Only outside the context of this Universe. ---Main.EmptyKube - 24 Jun 2004

• In one of my bboard posts, I argued perhaps a governing body would pass a law forbidding a second ship from pursuing a chosen planet. With billions and billions of stars in the galaxy, why would any "good" government/group sponosered trip go to a star already being colonized? I certainly envision some rebel faction (pirates?) eventually developing and then passing earlier colonists by, even pillaging them. However, I would argue, these developments should be later in the universe construction, not during the first handful of ship constructions. -- Main.CmAmidon - 24 Jun 2004