If time travelers and extraterrestrials exist where are they?

These aliens are standing beside you!

But not in this time. On future earth with technological progress so advanced that this forum actually works and never crashes....

 

If they are real, why don't they just make themselves known. Obviously it appears they have advanced knowledge and technology. So what's their problem?

 

Same reason wildlife film crews hide from gorillas/tigers etc...

 

The time scales involved would greatly exceed the time any person spent in high school, and would no doubt require hundreds of generations of people at the very least.

This is the issue with studies into the origin of life. The time scales are too immense for traditional experimental methods to simulate. How do you perform an experiment that will take thousands or tens of thousands of years to conduct? How about a million years?

Honestly, the building blocks have already been demonstrated to self-assemble in the lab. The problem is time. There is insufficient time for any researcher to follow an experiment to its conclusions without substantial manipulation of the conditions of the experiment.

We have not even collected detailed photographs of any "Goldilocks" planet outside of our solar system. We have never even done the most basic level of investigation. Declaring that life in the universe must be uncommon because we have not found it anywhere else is a bit like someone who's looked at a beach through a spyglass insisting that there could not possibly be sand there because it is not uniformly white.

 

We haven't even looked in the most likely places in our own solar system (Europa, Titan, the atmosphere of Venus, etc); his proposal that it is improbable in the rest of the galaxy--to say nothing of the universe--based on such limited data... is quite wrong.

 

Then my point is made. We've no evidence that the few goldilocks planets we've discovered could be habitable, and we can't duplicate making life in the lab.

You say because the time scales are too big, but how do you know? You can't know how long it's supposed to take to cook up a batch of life. Again, someone who wants me to prove a negative.

 

A few hundred randomly selected stars would be sufficient, statistically speaking. Of course, travel requirements would prohibit us from taking an actual random sample of the stars in the universe.

The Earth's surface has been explored enough to discount a reasonable possibility of a large land mammal like unicorns existing. That is why the default position is "no unicorns"--because we have a significant body of research cataloging animals and no unicorns were found. It is that context of a large amount of data that lets us make that assertion. In a situation where you have a literally insignificant sample size to draw from, the best you can manage is theory.

 

Hardly. You are noting that experimental difficulties preclude the experiment from being conducted, and therefore incorrectly assume the results would be false. The more limited research into the subject on time scales that are reasonable for experimentation do show a promising line of research. What research we do have strongly suggests that abiogenesis is almost a foregone conclusion if theoretically common conditions are met. Granted, the experiment has not been conducted in its entirety, and taken to a conclusion, because that would take longer than the entire time that human societies have existed, far longer. It would take longer to actually conduct this experiment than we have had agriculture.

Expecting complete experimental results for such a proposal is unreasonable. What is reasonable is to conduct more limited experiments to demonstrate that the theoretical basis for the common abiogenesis proposal is sound. That research is being conducted, and for the most part shows fairly promising results so far.

I don't believe that anyone is claiming that being in the Goldilocks zone is the only requirement for life, merely one of many theoretically common conditions. However, current methods of actually finding exoplanets are severely limited. It is doubtful that we can even detect most planets at this time, let alone make a reasonable guess about their properties and composition enough to predict the probability of life on them.

But have demonstrated that the pieces of life can occur abiogenically in a lab. The problem is that there is insufficient time to actually watch those parts become life.

Theory suggests that the time scales are too long, observational studies have shown that it does not occur in a short time frame (otherwise it would have been observed in the experiments that have been conducted). There is no theoretical basis for the claim that there is some incredibly rare condition required for life; even if we assume that a planet must be almost exactly like Earth, there's probably many other planets with the same sort of configuration.

No, but theory can suggest a time scale based on more basic research. And in this case theory suggests a very long time scale, and this time scale has not been contradicted by observations of a more rapid pace of development.

I don't want you to prove anything. There is insufficient data to operate on the basis of anything but theory, and there is no theoretical basis for the claim that life requires an improbable unobserved condition.

 

They"ll Eat Us??

 

lol

Where are they? That's the question. Unless they are under the heel of some authoritarian organization/government wouldn't at least one of them make a public appearance?

It's called the Fermi paradox.

It's seems like the sort of future envisioned in Star Trek & Star Wars & Dr. Who and so much other Sci Fi will never be realized.

 

So basically your position is that unicorns could exist in the universe. Since we don't have a large amount of data on the universe.

 

I didn't suggest that it was impossible to cook up life in the lab, merely that we have not done it yet, so it's not that simple to do. Since we know that life is here on Earth, we know it happened at least once, but we have no data to guide us on the likelihood of it ever having happened before anywhere else in the universe.

So you have no data to make any sort of calculation on the probability of life.

You know, I thought my position was the default position, based on our level of scientific understanding is at this moment, but it seems there is a lot of pushback that's based simply on a desire to believe. You must have Mulder's poster hanging up in your living room.

If you want to believe, that's fine, but stop trying to pretend science backs up your belief.

 

A few hundred, statistically speaking, is no different than one, given the huge number of stars. You are saying that .000000000000000000000000000000000001% is unacceptable, but .000000000000000000000000000000000002% is good?

I didn't say unicorns on earth, I said in the universe. Until a unicorn is found, ET or not, the default is "no unicorns".

 

Poor analogy. One "unicorn" has been found; here on earth. Life on earth exists.

 

Key word is 'surface'

But the earth is 70% ocean, and what lies in the deep oceans is still a mystery.

 

My position is that unicorns almost certainly do not exist on Earth, but might possibly exist elsewhere. We lack sufficient data about other planets to determine if they might exist elsewhere. It's possible, I suppose. Theoretically it doesn't make a whole lot of sense, but it cannot be discounted because we have not conducted sufficient research to draw conclusions about their existence on other planets.

 

There are two types of aliens, angels and demons. Demons are the ones that kidnap people and do experiments on them, like the ones in the movie "Fire in the sky". BTW that movie was supposedly based on a true story.
Angels are the ones that took Elijah and Enoch up to heaven in a fiery chariot. Fiery chariots is what they call ed UFO's back in the old days.
I've been within 100 feet of a UFO, only fifty miles from where the guy in "Fire in the sky" was kidnapped, so I don't have to believe, I know.

 

Statistically speaking, the size of the population matters very little to the determination of intended sample size. It's the same reason you can accurately poll the opinions of a population of millions with a few hundred phone calls. The math works out, though people continually refuse to believe it. Granted, this is making some assumptions about confidence; how accurate do we need to be to talk about life generally speaking? Sure, the larger the sample the better the results, but there are very sharply diminishing returns. A few hundred truly random stars would produce fairly meaningful results, though ultimately such a survey would be impossible to conduct (due to travel constraints).

Correction; without sufficient data, the default position is "not enough data to draw a conclusion." You can then clarify with predictions based on existing tested theory, though again it should be clarified that it is a theoretical position.

 

It could simply be a matter of creating the conditions and watching for several hundred thousand years. That would be a very simple experiment, though complex to organize because of the immense time scale.

Well, we can try to understand how it occurred on Earth, and use that example to derive at least one set of conditions under which life does occur. While the total number of condition sets that result in life may be larger, it is at least as large as the conditions found on Earth, which means that it is very likely that life does exist elsewhere--simple probability would suffice as an explanation for that.

Not so. If we can establish the conditions under which life occurred on Earth, and we can build a sufficient understanding of other solar systems, we can actually make those calculations--for that one set of conditions under which life does exist. Maybe there are more sets, but at least that one is viable, and that means the problem is solvable.

So far, there hasn't been any particularly uncommon (from a theoretical standpoint, based on what we know of stellar characteristics and planetary formation) condition found to be essential to the formation of life on Earth. You're ignoring the role of theory in this endeavor.

The default position is "insufficient data to draw a conclusion," usually followed by a discussion about theoretical predictions based on what we do know. Which is what we're discussing--that theory portion of the default position. Theory is important in science, and in this case there is enough data to at least make tentative theoretical predictions about the probability of life elsewhere. That's not sufficient to make predictions about where it will be found, or what forms it will take, or any specifics of the matter.

It's not nothing to do with a desire to believe, it's entirely based on the apparent lack of any observable barrier to the formation of life when conditions are met, and the observation that Earth's conditions are not theoretically uncommon.

In other words, to propose that life is uncommon in the universe, one must assert that there is something preventing life from occurring where the conditions are known to have produced life on at least Earth. There is no observed mechanism by which life would be prevented under such conditions, meaning that theoretically the proposition that there is "probably life elsewhere in the galaxy, and certainly the universe" is valid.

 

The practice of polling always carries a margin of error proportionate to the sample size(vs. total population). So if a few hundred calls can only predict within +/-5% accuracy for a population of a few million, then it doesn't take too many orders of magnitude for the margin of error to be 100%. If you consider that there are like 10 to the twentieth power (or something like that) stars, there is no way that less than a thousand stars could be truly representative.

OK, maybe "default position" was bad wording, I just used it because the phrase was being thrown around. I would instead say that the hypothesis should be that there are no aliens. As stated, it is the observable position. But it is also the falsifiable hypothesis. Show me a space alien and you win. However, if you begin with the assumption that they do exist, there would be no proving it wrong. Aliens could always be just around the next star. So by "default position", what I meant was that the onus of proof is on the "yes to aliens" side.

 

From nothingness came a huge explosion! The singleurity put forth the building blocks (If you are religious, place your 'god' here)

Over the next billions of years, molocules and atoms created entire galaxies. Planets and suns formed. The chaos of creation continued, stars to supernovas to blackholes. This great cosmic soup created our world.

A giant, red hot, rolling boiling sea of molten rock until life began to form, First simple cells, they changed via photosynthesis to complex cells. Multicellular life took over until the fish crawled out of the oceans. Life changed, adapted, evolved. Whole species feeding on each other. Finally the first human stood and looked up, towards the universe from whence he came.

---------

Now are we alone? or has the same accidental dissorder produced life in galaxies which number beyond our comprehension.

 

You can extract components/organelles from different donor cells, put them into a single cell and get a microorganism. Similarily, you can splice together genes from different species and create a new species. The trick is to simulate the conditions and the process of how life originated from organic compounds. What ever molecule has made this breakthrough or anything like it is no longer around to be seen today, although the ribosomal RNA may be its closest descendant. The problem concerns coming up with a very simple 1 or 2 gene RNA molecule that would catalyze the synthesis of its own functioning polymerase. I.e. it would need to be both an enzyme and a replication template. The odds of such a molecule that would encode a 2000-base pair sensible information arising spontaneously at random is slim. However, given the immense span of time and an Earth-wide laboratory with trillions of organic molecules participating at any one time, these odds vastly increase. You should also remember that before biological evolution, there was a so called chemical evolution, with different molecules/proto-enzymes competing for resources while preserving their structures on clays and such.

 

Scientists have catalogued quite a few habitable planets in our galaxy. Why haven't advanced civilizations in our galaxy done the same, and then contacted us? If faster-than-light speed is possible why haven't advanced civilizations in other galaxies contacted us?

Alien planets get pigeonholed

Looking for Earth-like Alien Planets? Focus on the Blue Ones

 

Based on what we do know on how life arises from inert matter:

Life is probably pretty common in the Universe.

Based on the Seti, inteligent life is another story.

And no, nothing can travel faster than the speed of light.

 

About right. The universe seems designed to produce life.

Quote: The fine-tuning of the universe is seen most clearly in the values of the constants of nature. There are many such constants, the best known of which specify the strength of the four forces of nature: the strong nuclear force, the weak nuclear force, the electromagnetic force, and gravity. If these forces took on even slightly different strengths, the consequences for life would be devastating. Two of these in particular, the strong and electromagnetic forces, are responsible for the unusually efficient production of carbon, the element upon which all known life is based.

LINK

Probably much less common.