posted on Jul, 3 2013 @ 02:36 AM
Originally posted by yorkshirelad
Originally posted by reject
If we say 5% of 3 billion had developed interstellar travel, would that be a conservative estimate? That would be 7.5 MILLION sources of
let's not even think of other galaxies
300 billion stars in our milky way.
7.5million with spacecraft (using your estimate)
That means 7.5 space faring civilisations per 300,000 solar systems
Or 1 space faring planet per 40,000 solar systems
Now assuming we can travel between solar systems in 1 day !
The odds of us arriving at a space faring solar system is 1 in 40,000 hmmmmm
We would have to visit 20,000 solar systems before the odds match the toss of a coin !!!!!
At 1 per day and taking into account rest, repair etc etc this works out a travelling around
the milky way for about 70 years and having a 50:50 chance of meeting an alien !
The odds are the same for them. This means that only way of an alien visiting us or us visiting them, even assuming near instant travel, is for them
and/or us to already know of each others existance. Roaming around Star Trek style is pointless event at warp 10!!! So, we, and they, have to have the
technology to detect each other before deciding on our respective destinations.
So forget about inventing star ships. If we can't detect them the star ship is pointless as a means of visitation. Instead our first objective has to
be to find a way of detecting remote civilisations. Now we know of the limitation of light or rather EM waves. So any viable detection method MUST be
faster then light. Therefore if aliens are indeed visiting us they are detecting our presence using a faster than light method before coming
Thank you for a very sensible post. I don't understand why everyone is so down on earth on this thread and this site. The effort and odds of
actually terraforming another planet and making it habitable for humans are immensely low. For those that think we are about to destroy the Earth, I
would think that the odds of successful terraforming should be zero since those planets are much worse off to begin with.
With respect to finding civilizations, I think we are going to be stuck with light speed travel issues for a very long time, if not forever. However,
I think detection techniques will improve such that through light waves we will eventually be able to detect the existence of life on a planet albeit,
it is a detection of life at a point in time in the past. However, I think the odds of finding intelligent life are a lot lower than those suggested.
If you look at our own solar system, there are three planets near the habitable zone and only 1 has life that we know of. There are so many things
that can go wrong, planet develops greenhouse gases and becomes a furnace (Venus). Planet loses its atmosphere and becomes a cold lifeless desert
with high amounts of radiation (Mars). Planet is struck repeatedly by meteors that wipes out life. Planet's magnetic fields do not protect life
from radiation etc. Bacteria is hardy and I would guess it exists on 25% of the 60B worlds, 15B. Plant life on 20% of those, 3B. Animal life on 10%
of those, 300M. Intelligent life that I will define as capable of written language ,5%, 15M. (And that is probably optimistically high.) Space
faring,25%, 3.75M civilizations. Space faring is a long way from interstellar travel, if it is even possible given the resources. Lets say 5% of
those achieve it at some level, i.e. they are capable of getting to one star. That is about 180,000 civilizations out of 400 billion stars or 1 per
every 2.2M stars! There are approximately 1.8M stars within 500 lights years of the earth. Therefore, there really isn't even a 1% chance of
finding one interstellar space faring civilization within 500 light years. There would be about 1 space faring civilization per million stars which
is about 1 every 180 lights years. Obviously these calculations are guesses like everyone else, but, the point we are both making is that this will
I think we should try to do three things. Figure out if there is animal life on Europa. That may give us a better idea of what to look for. Try to
make Mars habitable. That is the first step to making survivable interstellar travel reality and this will be very hard to do, if it is possible.
Refine detection techniques for finding habitable planets and potentially life so as travel techniques improve, we know where to go. If we can
accomplish those three things in the next 100 years, it would be a good start.