Re: are we alone in the universe?
 

I could accept the idea of life spreading from one planet to another within the same solar systems, organic material being blasted off one planet, frozen in space, and managing to land on another planet and carry on there.

But I find that much less likely to happen between star systems, where the nearest inhabitable star/planet might be 20 or 50 light years away. For life to be moved from one star system to another by natural forces, the time involved would be tens of thousands of years in transit, and the acceleration required to obtain those speeds would shred the cells.

But if intelligent life is colonizing the galaxy, with sub-light speed space craft, then studies have shown our entire galaxy could be colonized in about 2 million years.

Which is another argument for a lifeless galaxy/universe. The galaxy is 16 billion years old. If it only take 2 million years (0.0125%) to colonize the galaxy then, where are they? Where are the other colonies and why are we not in contact with them? Every inhabitable planet in the galaxy should be colonized by now.

Re: are we alone in the universe?
 

Ah, but it hasn't had all of the 16 billion years, present theory has it taking 3 generations of stars to go supernova before the elements required for life as we understand it came into being, so I guess the question is what is the mean time to failure of a star. We also suffer a second interesting phenomena, and that is the cyclic nature of the solar system oscillating up and down though the galactic arm creating the potential for extinction events. And unfortunately this doesn't even begin to address our most pressing issue: intelligence may not be a long term survival strategy. Look how long the dinosaurs lasted; 20 thousand years ago Neanderthals were still wandering around.

Re: are we alone in the universe?
 

Ok, then let the galaxy stew for 8 billion years for the first intelligent life to evolve. 2 million years to colonized the galaxy is still only 0.025% of the remaining 8 billion years. Our galaxy could have been completely colonized 4,000 times by now

Re: are we alone in the universe?
 

Well, I'm not necessarily talking about dropping off living things, just the beginnings of it. We decided that getting the correct chemicals going is hard enough, so why not drop those off?

Re: are we alone in the universe?
 

I was thinking, wouldnt it be ironic if some advanced alien life was colonizing the galaxy, and they discovered you cant put higher lifeforms on a lifeless planet, because there is no organic material for plants and such

so you have to start out by maybe introducing algee into the waters, let that take for a few million years, then maybe seaweed and some plankton, wait another 10 million years

then add fish, and maybe some smaller land based plants and animals, slowly working your way up

so that after 50 million years you would have a planet that was stable and suitable for intelligent lifeforms to colonize

wouldnt it be ironic if they were doing that here on earth, and humans evolved by chance, or by mistake

and they show up someday and say "What are you doing here? you totally screwed up the whole planet!"

we may have to start all over now!

they walk away muttering "Oh man! you turn your back for 100,000 years and look what happens!"

Re: are we alone in the universe?
 

Well, I'd assume there's only a few inhabitable planets. Therefore, there's only a few other colonies. I feel safe saying that some of them would have destroyed themselves by now - look how close we are... The remaining ones may have forgotten we're here.

Another likely scenario is something out of Stargate. Some advanced civilization wanted slaves, so they grabbed humans (or maybe other humans took human slaves). With their development stunted, most of the colonies aren't capable of interplanetary travel/communication. They don't necessarily have to be slaves either. Maybe some crackpot or a facist government was running an experiment...or trying to get rid of people...

Re: are we alone in the universe?
 

makes me wonder, how advanced would our science have to be to take a planet that is not suitable for life - totally unsuitable, and make major corrections

for example - we discoved this solar system, and the most ideal planet was between mars and jupiter

it was the right size, but its orbit was too far from the sun, and it had two moons, one of which was so large it caused destructive tidal forces

so major adjustments were needed.

1. obliverate the massive moon (resulting in the asteriod belt)

2. drop the planet into a better orbit, between Venus and Mars

3. Introduce basic life forms

4. Let the planet stew in its own juices for 50 million years

and Walla! Earth!

Advanced terraforming 527. For this course you will be required to alter the orbit of a class M planet....

Re: are we alone in the universe?
 

I think you're talking about the Planck length. It's not exactly evidence that space is digital; it's just that quantum effects mean you can't meaningfully measure a smaller distance. The "snap to grid" idea is amusing, though you have to account for the fact that exactly which gridpoint gets snapped to is a probabilistic choice, and things can sometimes jump from one point to another even if there's something else in the way.

Even if space is quantized, the number of directions from one intersection that eventually lead to another on a regular grid is unlimited -- you can always point between two destinations and find another one farther away. Even with a finite number of roads, the number of different trips one can take is unlimited -- you can always add another loop or round-trip down a path.

Re: are we alone in the universe?
 

Bacteria survived on Surveyor 3's camera for a year and a half before the Apollo 12 crew brought them back from the moon.

Re: are we alone in the universe?
 

With all those discussions why not put your energy into practice? There is only one way to find out..Join SETI@Home (http://setiathome.berkeley.edu/) :P

We don't know how big our universe is, but one thing we are certain is that univserse is huugggee. It contains trillions and trillions of stars and one of them must have a planet that could have condition that could support life and I have a feeling that we are not alone.

Re: are we alone in the universe?
 

well thats sorta the point Ive been trying to make. From what we are able to observe about astromony and biology, SETI not likely to find anything.

Im hoping that once it starts to sink in that theres nobody else out there, then humanity will start to take ownership of life seriously, and put our collective energy as a species into an effort to find ways to spread life as far and wide as we can.

The first step is to understand our real situation. Not what we wish it to be. What it actually is.

Re: are we alone in the universe?
 

This sort of comes back to my points. If we're supposed to spread out, who's to say that we're not the result of another civilization that decided to do the same? Not having contact with them doesn't mean anything. There's orphans out there that have no idea who their biological parents are, much less talk to them. That doesn't mean that they don't exist.

Again, evidence can be interpreted any way that you want to. Just because everyone sees that the earth is a sphere doesn't mean that it is. It just means that everyone is having the same delusion. Maybe it actually is flat but some sort of Einstein-like space-time curvature makes it appear to be round. There's no such thing as conclusive evidence, just evidence strong enough to make a very good guess. Your version of reality only exists in your mind.

Re: are we alone in the universe?
 

there you go now you know. slightly off topic but has anyone seen this http://www.mirror.co.uk/printable_ve...siteid=947 62. Before people say its far fetched. Everything on this is being studied and have had plenty of success. I know this because i looked up each one and some like medicine fruit already exists and is working its way through testing. nice to know i was born in time for immortality! :D

Re: are we alone in the universe?
 

if we were part of this effort to spread life, and the 'project' has already been underway for thousands or millions of years, then breaking the continuity of knowledge of the project would be counter-productive to the project itself.

That would be like us deciding as a society, instead of teaching each generation of our children all the things we know (language, science, math, medicine) we will let each of them find their own language, and re-invent everything from scratch. If we did that we would keep humanity in the stone age forever.

On the other hand, if we were placed here without our own knowledge, then our situation remains the same: as far as we can tell we are alone.


as a scientist and engineer I must disagree with this. One of the foundations of science is that the universe is knowable, and the laws of physics are predictable. If I design a circuit, and it does not work correctly, the logical thing to do is test and debug based on what I can observe and measure. If I tell my boss that reality only exists in our minds, and the circuit may or may not be actually working, I will be out on the street so fast my head would spin.

If reality is unknowable, then science is a waste of time.

All we can ever do is make our best observations and measurements, and proceed towards our goals with the information we have.

Re: are we alone in the universe?
 

Of course it would be. But think of how much knowlege has just been lost over time. Wars have spured the burning of libraries. Anything held in these libraries is lost. If stuff disappears, people start to forget it and it becomes myth. I'm sure that with some slight modification, most creation stories could support an interplanetary colonization project. I also recall something about the only copy of a book by Archimedes being erased because some monks needed paper. In it, he had the beginnings of calculus (the concepts of infinity and integrals) and some very advanced geometry. We didn't have the technology to read the erased ink until recently. With this knowledge gone, Newton had to reinvent calculus from scratch.

You are right in that all we can do is make our best guess. If we didn't, we wouldn't be doing anything. I'm just trying to point out that concrete evidence is only as strong as the wrecking ball that tries to destroy it. There used to be solid evidence that the world is flat. At the time, there were people that believed that and people that believed it was round. Current evidence supports that it's round. Future evidence may support that it's actually a cube. Until then, we have to pick one.

You have to realize, however, that science and religion are the same thing. They are merely different ways of arriving at the same place. The ultimate goal of both is to understand the universe. The only difference is that one resides in observations and the other resides in thought. So your notion of an unknowable universe would invalidate both. The reason that both are valid, however, is that the universe is knowable; you just can't be sure if what you know is true.

One following says that candles emit light. The heat excites the electrons in the atoms and they spit out photons. Another train of thought says that candles suck darkness. The black stuff on the wick is the collected darkness. Shadows are a result of the candle's dark sucking capability being blocked by an object. Combining this theory with some form of areodynamics could explain defraction. The photon theory is just an illusion, like the flat earth notion that people used to have. Both theories have valid points. The best we can do is pick one and see where it takes us. Like science and religion, some will choose to follow one path, some will choose to go another.

Someone mentioned earlier that there are infinite paths between two points in space. The same holds true in this journey to understanding the universe. How you get to the end doesn't really matter as long as you do. Some paths will be longer, some will be shorter. As long as everyone ultimately arives at the same place, it doesn't matter how they get there.