In your lifetime, find life on other planets?

Carl Sagen had a theory.As beings reach a high technology level,such as the power to destroy themeselves they probly will and that will make them harder to detect. Just look at the way this world is going.I wonder what the the odds are that we will be around in say 100 years.

 

<div class='quotetop'>QUOTE(TJandGENESIS @ Apr 27 2007, 01:26 AM) [snapback]431050[/snapback]</div>

It is not at all Earth-centered to point out that since nothing and nobody can travel faster than light, and the universe is so big, and there are so many stars, the chances of anybody coming here are vanishingly small. First, they'd have to pick us out, from billions of billions of billions of star systems, and then they'd have to travel millions of years to get here.

It makes the liklihood very small.

Perhaps the difference between us has to do with the distinction between hope and belief: the religious mindset believes that whatever it hopes is likely to come to pass. The scientific mindset recognizes that hope has no influence on reality, and therefore draws a clear distinction between what it hopes and what it believes. Even if I thought that meeting an alien would be "cool," I still believe it's not likely to happen.

I'm not sure I'd want to meet extraterrestrial aliens, though. If they're smart enough to get here, they'd probably view us as we view chickens: they'd think us so stupid that they'd feel justified in eating us. Or exterminating us and making Earth suitable for them to colonize.

I do believe that some few of those billions of billions of planets have intelligent life. But they are likely to be very far away. And however great a fan of Star Trek someone may be, faster-than-light travel is fantasy, because it requirs an infinite amount of energy to accelerate an object to the speed of light. Theoretically, you could accelerate a space ship to a speed where time dilation makes it's local elapsed time very short for a very long trip, but the energy cost is enormous, and so much time would pass on the home planet that the travellers, upon returning, would find all their friends dead, and probably find their civilization gone, or evolved into something entirely different. And a civiliztion that sent out a near-light-speed probe would not get it back until so many generations had passed that nobody would remember it had been sent in the first place. And if Sagan is right (see below) there'd be nobody home to receive it.

They're probably out there. We're probably never going to find them.

<div class='quotetop'>QUOTE(charliem @ Apr 27 2007, 04:01 AM) [snapback]431072[/snapback]</div>

I've often considered this. Technological civilizations might not last very long. This would reduce the chances of contact even further.

As for life in our solar system, it's possible, but I give it a pretty low probability.

 

<div class='quotetop'>QUOTE(daniel @ Apr 27 2007, 12:07 PM) [snapback]431230[/snapback]</div>

I don't think it's quite as bad as all that. Presumably these civilizations will be scattered about, and of course they'd look at nearby star systems to find habitable planets, kind of like we're doing now. If you could get up to 1/2 the speed of light (which we cannot, but maybe in 100 years we'd have the ability), considering half the flight would be accelerating, the other decelerating, you'd average about 1/4 the speed of light, so to get to the planet just found would take about 80 years, each way (I'm not sure what kind of G's that would produce). There are people would do that - most of the American immigrants in the 1700's never expected to get back home again, it was a one-way trip for them.

(I'm being optimistic here, it would take another Einstein to give us a breakthrough to make things like this feasible. Current technology won't work for us, and we certainly can't assume another civilization is within 20 light-years of us, but every light-year you expand that sphere greatly increases the possibility).

But I still don't think we've been visited by aliens or could reasonably expect to have that happen. The lifetime of a civilization is questionable, and a civilization would need access to metals and stored energy to be able to build radios and spacecraft. But I expect we will find life elsewhere, which is the original question. But it will likely be mats of algae producing hydrocarbons that we can detect in the atmosphere.

BTW, my understanding of the limitation of speed of light is that you can't cross the barrier, but it doesn't rule out the existance of tachyons, which already travel faster than the speed of light. If we could harness them, we could at least communicate above the speed of light, or use entangled quantum mechanics to do so.

 

It's also my understanding that, while it takes an infinite amount of energy to approach the speed of light, no one has said what happens once you actually cross the threshold... This would seem to imply that, if we could find a way to accelerate something that far, traveling faster might not be out of reach.

Of course, it's all just a pipe dream, as we have no clue how to go even that fast...

I had read an interesting article a few years ago (don't have any links, sorry) that said some researchers had proven that the speed of light isn't a constant through all mediums, and that they actually observed light traveling faster than the speed of light through some gaseous cloud of exotic particles. Something to that effect, at least.

 

Think Relativity, guys, Relativity. To us watching a ship depart at lightspeed toward that planet, the journey would appear to take 40 years (as it got closer to the planet it would take closer to 20 years for the light of the receding ship to reach us). But to the occupants of the ship, the journey would last less than 1 second.

Now, acceleration of mass to 100% of C is, I believe, theoretically impossible, so the example above won't literally work, but it illustrates the principle. So, sticking with what COULD be achieved: slow acceleration to 0.5C at 1 G so the occupants don't get crushed to pulp (I don't have the math at hand - physicists out there can correct the numbers) would be only a 10 to 12 year journey for the occupants, ship's time, not earth's time.

We back on earth wouldn't find out anything for more than 60 years elapsed earth time (40 years to get there at 0.5C; 20 more years for the radioed information about what they found to reach earth), but the ship's occupants would arrive while still young enough to enjoy life when they got there (assuming they don't land in an unanticipated active volcano).

Mark Baird
Alameda CA

 

<div class='quotetop'>QUOTE(nerfer @ Apr 27 2007, 10:41 AM) [snapback]431248[/snapback]</div>

But the people who came here from Europe had a voyage of several weeks, and they expected (in some cases) to become fabulously wealthy in a few years and return home, or (in other cases) to settle in a new land where they would not be persecuted for their religion.

You are talking about a round trip of 180 years, so that the people starting out would be committing themselves to spending the rest of their lives in a space ship, with the hope that maybe they'd see a new world at the very end of their life, if they were successful, and maybe their great-great-great grandchildren would make it back to Earth, and a civilization they'd know of only in ancient tales passed down from the first generation of travellers.

<div class='quotetop'>QUOTE(nerfer @ Apr 27 2007, 10:41 AM) [snapback]431248[/snapback]</div>

Relativity does not rule out the possibility that tachyons exist. But it does absolutely rule out the possibility of any interaction whatsoever between tachyons and normal matter. Therefore it is impossible to even know if they exist, or to use them in any way. (And tachyons, if they exist, can never go slower than the speed of light.) And Relativity does not predict tachyons, it merely fails to rule them out. This will probably turn out to be an incompleteness, which will be corrected once we have a successful unified field theory.

<div class='quotetop'>QUOTE(eagle33199 @ Apr 27 2007, 11:26 AM) [snapback]431267[/snapback]</div>

There is no way to cross that threashhold, because there is no way to reach it. It would require an infinite amount of energy. The word "infinite" does not mean "really big." The word infinite means without limit. "IF" is not an argument. Nothing can reach the speed of light.

<div class='quotetop'>QUOTE(eagle33199 @ Apr 27 2007, 11:26 AM) [snapback]431267[/snapback]</div>

As used in physics, "the speed of light" actually means the speed of light in a vacuum. Light travels slower than the speed of light when it travels through any substance. A glass prism works because light travels slower through glass than through air, causing a bending at the interface. Same with water. Cerenkov radiation is the characteristic radiation given off when electrons travel through water at a speed faster than light travels through water, which is still less than the speed of light in a vacuum.

All the relativity equations use the value of the speed of light in a vacuum.

Also, please note that time dilation is not equal to the ratio of your speed to the speed of light. At half the speed of light the time dilation is virtually or entirely undetectable. I think you have to get over 90% of the speed of light before you notice a real difference, and you have to get much closer to that, at a huge energy cost, before you even cut your local travel time in half.

 

I know, I know...silly question, but what the hey: Is it not possible that we have it all wrong, or at least part of it wrong, and maybe there could be some form of life, but not as we know it, that could be out there that has figured out how to travel in space, and to do it with little to no ill effect?

And another question: Why do we assume we have it all correct in the first place? Again, I think it's rather 'earth' egotistical to think we know it all.

When the universe is so large, and there are untold billions of stars and planets, to think we are the only ones with remote controls is silly. In other words, we may think we have it all, but to some other planet out there, they may be way ahead of us, and may show up here, and laugh long and hard at our puny ideas.

 

<div class='quotetop'>QUOTE(nerfer @ Apr 27 2007, 09:41 AM) [snapback]431248[/snapback]</div>

I could not resist.... If you accelerate at 1.6 ft/sec^2 you would achieve 1/2 the speed of light in about 10 years. That would translate to 0.05 G - which is very comfortable. For reference, that would be the same as going 0 to 60 in your car in 37 seconds - even a Prius can do that....

 

<div class='quotetop'>QUOTE(TJandGENESIS @ Apr 27 2007, 11:42 PM) [snapback]431577[/snapback]</div>

I will apologize in advance for seeming harsh in my tone, but you have hit on a pet peeve of mine: A complete misunderstanding of science, all too common (though not universal) among religious-minded people.

There is a completely false notion, common among religious people and sci-fi fans, that science progresses by periodically discarding everything thought previously, and adopting an entirely different view of the world. In this false view, scientists don't really know anything at all, because next year the new view will point in exactly the opposite direction.

This false view is promoted by sensationalist media that publicise preliminary studies as if they were conclusive, and then publicise contrary data as if it has disproved an established theory, rather than presenting both as raw experimental data that has not yet established any clear conclusions.

The false view is also supported by considering pre-scientific beliefs as if they were in the continuum of scientific study: In the popular imagination "everyone" thought the earth was flat, and then "everyone" believed Aristotle, and then "everyone" believed Ptolemy... etc. etc.

Some sciences, like paleontology, are so young, that it's easy to view pre-scientific models as if they were in the scientific continuum, reinforcing the erronious idea cited above, that science continually trashes old theories in favor of radically different ones.

And finally, and saddest of all for me, is the general mathematical illiteracy, which leads a lot of people to disregard the very simple mathematical formulas that explain, in simple terms, such things as the impossibility of achieving travel at the speed of light, or the mind-boggling quantities of energy needed to achieve speeds where time dilation becomes significant.

Science (especially physics) proceeds by continual refinements of theory, each of which fills in a gap in the earlier theories. As an example, Newtonian physics fails to account for relativistic effects, but is an accurate description in most cases. Newton himself knew that there was a problem with his formulas because they produce a tiny error in predicting the orbit of Mercury. Einstein's formulas, by introducing relativity, produce very small differences from Newtons, wherever the speed is close to that of light, or gravitational fields are immense. Nothing was thrown out, merely refined. Quantum mechanics, which so revolutionized classical physics, intruduced a way of explaining effects on a size scale so miniscule that they were irrelevant at "normal" (i.e. human) size scales. Quantum mechanics did not reject Newtonian mechanics, it merely clarified what happens at very small scales.

So now I come to your question: Isn't it possible, with so many worlds out there, that aliens on one of them have "figured out" how to circumvent the basic laws of nature?

No, it is not. Because the question itself presupposes that the basic laws of nature are subjective, and that a sufficiently-advanced technology would not be bound by them. There is a very great deal we do not yet know. But there are cerain basics that we do know. And the fact that it would require an infinite amount of energy to accelerate anything that has mass to the speed that light has in a vacuum, is one of those basic facts, explained in Einstein's formulas, and confirmed in particle accelerators, where the energy:velocity curve for a sub-atomic particle exactly matches the curve predicted by these formulas!

Not only can no object reach the speed of light, but information intself cannot travel faster than light. And, FWIW, light travelling in a vacuum cannot travel slower than light.

If people spent as much time reading books on science as they spend watching Star Trek, we wouldn't even be having this kind of conversation. Fantasy can be fun. But it is pathetic when people are so utterly and completely uninformed that they consider television fantasy to be as valid a description of the world as is science.

It is not impossible that aliens may visit us. But the fact of the limiting factor of the speed of light, and the fact of the immense distances involved, and the fact of the astronomical number of planets a space traveller has to choose from, make it extremely unlikely that anybody will come here from another planet during the short period of time that humans are likely to continue in existence. And finally, those same factors reduce to near insignificance the usefulness of Earth to any alien civilization, just as an Earth-like exoplanet would be useless to us except as an object of study, and in the time we could get a probe (much less a manned ship) there and back, we'd probably have gone extinct.

 

<div class='quotetop'>QUOTE(daniel @ Apr 28 2007, 06:56 AM) [snapback]431661[/snapback]</div>

Remember, we can't account for 80% of the mass in the universe.

Secondly, your certainty is based on the facts as you know them... we all agree and understand the limitation of the speed of light. However, what if there is a completely new set of rules that have not yet been discovered?

So - within the bounds of physics as we understand them today - everything you said is correct. However, we know we do not know everything... therefore, it is possible that a breakthrough could occur in the future which would completely change the rules of the game.

Acknowledge the above fact - and we are in complete agreement.

 

<div class='quotetop'>QUOTE(John in LB @ Apr 28 2007, 11:18 AM) [snapback]431746[/snapback]</div>

It is true that we do not know everything. But we do know some things. And the impossibility of travelling faster than light is one of those things.

Your view is exactly what I'm talking about: People who imagine that because we don't know everything, we really know nothing. I call it the Star Trek syndrome: believing that what is shown on Star Trek "could" be true, because there's so much yet to be learned that everything is possible.

It's a very anti-scientific attitude.

 

<div class='quotetop'>QUOTE(daniel @ Apr 28 2007, 09:56 AM) [snapback]431661[/snapback]</div>

You have hit on a pet peeve of mine: Assuming that all people that believe in God are of one mind.

Including renowned scientists.


<div class='quotetop'>QUOTE(daniel @ Apr 28 2007, 09:56 AM) [snapback]431661[/snapback]</div>

We also, just about 100 years ago, thought traveling to the moon would be impossible. That traveling in a plane with hundreds of people and tons of weight, impossible. Heck, that I could type words out here, on my Blue Tooth enabled keyboard, have them transmit to my Apple computer, and then speed along wirelessly to a modem, that enables me to hook up to the Internet, was seen as stuff of fantasy, if seen at all, 100 years ago.

What does the future hold? What changes that we think are impossible today, will be reality tomorrow?


<div class='quotetop'>QUOTE(daniel @ Apr 28 2007, 09:56 AM) [snapback]431661[/snapback]</div>

How rude of you. To assume that I spend a lot of time watching Star Trek, and that I get my information solely from that. You don't know me, or where I get my science. Could be that I happen to have spent time reading scientific journals. Perhaps I watch the Discovery channel. Maybe I just dabble here and there in science.

Or none of the above. But I don't think I said, ever, 'based on Star Trek'. No, I did not. I will admit, to being a person who thinks, that things change, laws change (like defying the law of gravity; happens every day); I think that it's possible that the very things you speak of not happening, will happen someday. And it could happen in my lifetime; who knows. My late father, born in 1920, lived a life where he personally saw many changes in the way things run, and things once written in Buck Rogers comic books come to life.

It's somewhat sad, IMO, to just sit there and pontificate that there is no way that things can change.
Man might just break some barriers that were thought to be impossible to break.
Who knows?
Dreamers dream, and sometimes those dreams become reality. It does happen.

 

<div class='quotetop'>QUOTE(daniel @ Apr 28 2007, 04:14 PM) [snapback]431876[/snapback]</div>

I never said anything about going faster than the speed of light - that's YOUR simpleton, linear thinking.

 

Not to take sides or get in the middle, but this would seem an appropriate time to mention Clarke's Laws:

1) When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

2) The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

3) Any sufficiently advanced technology is indistinguishable from magic.

 

<div class='quotetop'>QUOTE(hyo silver @ Apr 28 2007, 10:18 PM) [snapback]432025[/snapback]</div>

AHA... I have one person on my side....

 

On a lighter tone-

Ok.----so whats the speed of dark?

 

<div class='quotetop'>QUOTE(TJandGENESIS @ Apr 28 2007, 10:52 PM) [snapback]432017[/snapback]</div>

I have said that there are religious people who do not fall into the mode of thinking I have described.

<div class='quotetop'>QUOTE(TJandGENESIS @ Apr 28 2007, 10:52 PM) [snapback]432017[/snapback]</div>

This paragraph illustrates, opnce again, what I am talking about. In this case, a misunderstanding of how, and why, the word "impossible" gets used. To take your first example: Scientists calculated how many thousands of pounds of fuel it would take to get a rocket to the moon, and some of them used the word "impossible." Others figured out a way to burn that many thousands of pounds of fuel.

See, in this case, the word "impossible" was used not because there was an absolute mathematical limit, but because the technological barriers appeared insurmountable. The lesson of history, is that if something is theoretically possible, technology may be able one day to accomplish it. But when it would violate the basic laws of nature, then it cannot happen.

Travel of any particle that has mass, or transmission of any form of information, faster than the speed of light in a vacuum, is mathematically impossible because the amount of energy needed to acceleate an object rises exponentially as the speed of that object nears the speed of light, and the speed of light itself is never reached. There is no amount of energy that can accelerate an object to the speed of light.

When you say, "Maybe we'll find a way to do it," you are speaking not about overcoming a great technological obstacle, but about violating the basic laws of nature. And that is the basic misunderstanding which I am criticising. Not all believers in god fall into this trap, but many do.

<div class='quotetop'>QUOTE(TJandGENESIS @ Apr 28 2007, 10:52 PM) [snapback]432017[/snapback]</div>

I did not say that you watch Star Trek. I called your mode of thinking about science and technology the Star Trek syndrome because it is so common among
trekkies," though, as with religion, there are Star Trek fans who do not fall into it.

<div class='quotetop'>QUOTE(TJandGENESIS @ Apr 28 2007, 10:52 PM) [snapback]432017[/snapback]</div>

Dreams do often become reality. And technology produces marvels. But the basic laws of nature do not bend. When you dream of overcoming technological barriers, you may well succeed. When you dream of breaking the basic laws of nature, you are doomed to failure.

The dream of travel at the speed of light is much like the dream of a perpetual-motion car. It violates the basic laws of nature and it won't happen. It's curious that everybody on PriusChat understands the law of the conservation of energy, which means you need a source of energy to propel a car. Nobody here says, "Maybe some day we'll figure out how to make a perpetual-motion car." And yet there are people here who do not understand that you cannot travel at the speed of light because that would require an infinite amount of energy, and there is no such thing as an infinite amount of evergy; or to put it another way, no matter how much momentum you impart to an object, it will never reach the speed of light because, at higher speeds, more and more of that energy becomes mass, rather than increasing velocity. This is scientific stuff as basic as the conservation of energy.

I know people will take offense at me. Especially people who do not understand the fundamental difference between a technological difficulty and a basic limitation imposed by the laws of nature. I said that when I began. So be it. Unpopular views have that effect. But there are some views that are opinions and everybody's opinions are valid, such as in politics, discussing who would be the "better" president, which is a value judgement. And there are other views that are demonstrable by the methods of science, such as evolution and the laws of physics. Then there are correct and incorrect views.

 

Is the speed of light the ultimate?
Readind a scientific article on the expanding universe, where the red shift of some outer galaxies were actualy exceeding the speed of light.That kind of knocked me for a loop becuse i like most of you,and for all my life believed 186217miles per sec. was the ultimate speeds.

 

<div class='quotetop'>QUOTE(charliem @ Apr 29 2007, 12:17 PM) [snapback]432165[/snapback]</div>

The universe can expand faster than the speed of light. It apparently did so during a period of hyper-expansion early in its history. What you read may be refering to this. But no object can move faster than light. Also, no information can move faster than light. But space can expand faster than light. This is kind of weird, and I'd rather it wasn't so. But nobody consulted me when the big bang was being planned.

So, yes, what you read is true, but is a different issue, and does not help anyone who wants to travel faster than light.

Now me, I'd rather be able to breathe under water without artificial equipment than travel faster than light.

I can travel through time, though. I travelled several minutes just while typing this reply.

 

I have to say, anytime I hear the word "impossible", I shake my head. As I get older, words like "impossible", "never", "always", etc. become less apart of my vocabulary. The gray is expanding, those black and white extremes tend to get farther away.

We operate at the limits of our understanding. We learn as a function of our own paradigms, and are thus limited by what we know.

To say that something is impossible or can never happen is one thing. To argue it begs the question - how do you prove something is impossible?