All other planets acording to calculations are billions of lightyears away, we today tend to think of the world as limitless if we can think it then it can be done we just need to know how, but this logically this has to be wrong just as we ourselves cannot seem to fly without assistance what makes people believe that theere is technology to travel to other worlds or other worlds to travel to us, will we ultimately be capable of all things we can dream, or could even tomorrow be the last day for inovation?, This seems to be an important discussion, due to the fact that logic should prove their to be aliens but will technology allow interaction this are we traped on our own planet and moon, and if their are technologically advanced does that mean their are invvincible, does science allow sci-fi style laser or plasma weapons,or sub-space travels?

as long as you have an open mind, you are never trapped .any thing and every thing is possible.only you can limit your possibilities.

Yes.

That's pretty but like my previouse example, you may want to fly but as hard as you flap your arms you will not

It is a very interesting question you have there. The human mind has no limits save the imagination and experience of the owner. Not all that can be thought of can be done, and not all that can be done is thought of. But in looking for something we want to be we might explore things we did never imagine before...

Will we be able to fly to the stars? Perhaps if we exist long enough. Perhaps not if we do not develop a new society? Current science would allow travel, but current mankind and humans do not. A question I pose myself sometimes is: Will there be adaption of human species to environments like space someday?

ok i give you that. i may not fly physically, but i do fly.

Not true. Earth-like planets could very possibly exist in great abundance throughout our galaxy, which measures only 100,000 lightyears across.

What kind of 'logic' is this? Logic says that any 'proof' of extraterrestrial intelligence has to be based on certain assumptions. The validity of those assumptions is open to debate. So, ultimately, logic says the existence of ETs is an open question.

to me the existence is undeniable but though i doubt they have presence here, I read an article in my local newspaper about microorganisms beleived to be on mars when they found that rock that had been eroded by water, there is nothing to prevent life elsewhere and this is a more than justifiable assumption though admittedly not proven, though not the purpose of the discussion(this was included because this was in the ufo section i hadn't noticed this one ariane nicely moved it

And i supose I am wrong with the billions of lightyears things, but 100 000 lightyears is still more than anyone can travel even if we gain light speed technology is it not

You obviously haven't met Major Tom on this forum have you??? There a few others that would claim 100 000 light years was well within their reach but hey, if it's any comfort...I'm with you.

Ben

Well, if other organisms don't breathe oxygen then spending 100 years travelling 100 lightyears wouldn't be so much... Oxygen is the reason our life span is so short (compared to non–oxygen breathing organisms like trees).

Question to Hodge: Are you sure you can compare animals' and plants' life span just on what they respirate? What about cell-life span and devition?

Anyway... The only limits would the physical ones, whitch can change as our knowledge of them expands.

Einstein himself said something along the lines of (I paraphrase) "I expect that within 100 years all my theories will be proven wrong."


I'm comparing them! If we breathed carbon dioxide like plants we'd live much longer... Maybe not as long as trees because they don't lose cells at the rate we do (thus creating that whole telomere problem thing), but we certainly wouldn't suffer the ill effects of free radicals.

I was asking- keep yer pants on. It's been a while since I oriented myself on free radicals. How is it that oxygen respiration makes us more prone to attack from free radicals? Oxygen travels through plants just as much as within us, just that we have different end-results after the process. And infact, they flip over to oxygen respiration during the night. Again, I'm just asking what you base your comparison on?

Because our bodies actually use oxygen to create energy, whereas plants use photosynthesis. Our mitochondria are what create free radicals as they process food into energy, and then those free rads start smacking our DNA around. Plants do use respiration! You learn something every day... They don't use it on the same scale as we do, however. Maybe this is why some plants are so rich in antioxidants...

So agreeing that plants have to convert to oxygen respiration during the night, how could the oldest trees get to live up towards 4000+ years, compared to our 120 years? It seems to me that free radicals isn't what causes death for plant life (at least not more than a part of the cause). So my guess is that one then can't compare plant cells' and animal cells' life span just on what they get energy from.

Nope, I guess we can't. But it stands to reason that if our primary aging factor does not exist in other lifeforms, then they will live much longer than us. Hell, there's even an Orscon Scott Card short story about a race of aliens that doesn't ever die and study us because death is interesting and new to them.

Well, I am not knowledgable enough to comment on the biochemistry, so I will ignore that part. But, 100 years travel time in whose frame of reference? If for the traveller then fair enough, they would be travelling at speed of c/√2 by my reckoning (I wouldn't put much stock in it!) and in the rest frame they would take around 140 years to travel that distance. If for the stationary observer, then they would be travelling at lightspeed (not possible), or a good approximation thereof (possible). If it is, say, .99c they are travelling at then they would appear to take 101 years to travel there to the stationary observer. As far as the organisms are concerned however the journey took 2 years.

You see the need precision in specifying your frames of reference when you are talking about these things?

One would have to travel pretty far anyway, so any humans inside the space ship could likely die of old age before finding anything. Then of course there is the problem of acceleration to the speeds required to get a significant distance. It would take a long time to reach a speed close to light speed if we're sending people. We can't stand that many G's at once.

But this is not deduced from available evidence. It is your personal belief.

Well, assume you had the technology so you could travel through space at as high a fraction of the speed of light as you desired. Then as far as you are concerned you could travel across the galaxy in as little time as you liked. But more than 100,000 years would have transpired in the rest frame. Whether this is a practical means of spaceflight is debatable.

That is incorrect. As Andrew said... the reference frame is the important thing. You can easily reach speeds near lightspeed if you accelerate at only one g (~1 year to reach 90% lightspeed...). And for the traveller the time would be quite short at such speeds. For you as a stationary observer it would take him perhaps thousands of years... for him only a few....


What a logic... if our skin was made of iron and our eyes made from diamond we would have not always those itchy spots everywhere and we would never need glasses... heaven... the human metabolism is totally different and to compare it to plants is like comparing a bird to an elefant and to say: Look if the elefant had wings it could fly. It is not that easy... really not. We do not use that principle for good reason, Hodge. We would not exist as intelligent species if we had not developed a much more powerful and faster metabolism. Plants have similar DNA problems as we have. Only their metabolism is much slower and their biological systems are simpler in most ways.
Humans are not at the end of evolution anyway... who knows what there will be in one million years?