If time travelers and extraterrestrials exist where are they?

I don't think you can rule out the possibility of time travel based on the apparent lack of visitors. I know that from our perspective the last century or so has seen an incredible surge in scientific understanding but it may be that, far into the future, there isn't anything of interest to see today.

I can imagine being interested in having a look at what the planet was like 200 million or so years ago before dinosaurs became extinct. And possibly a couple of hundred thousand years ago, when we started the slog out of Africa and began using tools to our advantage. But maybe everything from the last 50,000 years or so ago to several thousand years into the future is just considered a long boring patch while we got a handle on the universe and bickered with each other. If time travel requires a great deal of energy/effort this era might just not make the cut.

 

there is the theory that if you go back in time you create a new timeline and the current one keep going as if you just disappeared while you now live in the new one, maybe we the original timeline

 

There is no shortage of conjecture that they have. Basically all of it is anecdotal but there is some compelling stories of UFO's from government officials, veteran pilots, military pilots etc.

Of course a UFO doesn't necessarily mean aliens but it's interesting none the less.

 

There's no indication that faster than light speed is possible so it's more likely than not that the vast majority of folks out there haven't even gotten the spam we started sending out 70 or 80 years ago. There's a hypothetical bubble around the earth and it's expanding at almost the speed of light. Its surface contains the very first amplified electromagnetic information we deliberately generated. And compared to where i's going it's hardly started.

We've found so few planets so far that it's clearer just to say we've found a total of one. In the same way that someone visiting earth and taking 1500 grains of sand back with them doesn't count as a good start on clearing the planet of sand.

In other words we've not even scratched the surface in terms of investigating the universe. And we've been at it a few hundred years already. But we only started making noise 70 or 80 years ago, and we've only been a planet with covered in humans for maybe 200 000 years. So the bubble is about 400,000 light years in diameter. That's big to us but we're still talking about noticing a raisin somewhere in the Grand Canyon.

 

Speaking of which, have you ever seen the film "Primer"? From 2004 or so. If not I highly recommend it. Warning: may contain time travel.

 

I'm always wary of the anthropic principal for the same reasons I wouldn't use the word "designed" like you did there. It seems like putting the cart before the horse, right, although not if you consider the issue of God's existence as having been resolved, I suppose.

But the anthropic argument makes claims about other hypothetical universes and states that unless some things are true in precisely the same way they are here those other universes would cease to exist, or all life would vaporize. But isn't all we can really say, since we don't know what an alternate universe looks like, that it seems likely that we, born and raised in the land of Planck Einstein, wouldn't last long in the other place? I'll grant you that, but I'd have to add that it doesn't seem impossible that in other upside down worlds where 2+2=5 nobody's ever heard of an inverse square, that something else could pop up in a few places, something that would find our universe as treacherous as we theirs?

If you allow that then there isn't much left that's interesting about the anthropic principal, in my opinion. Douglas Adams put it much better than I have:

"... imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact, it fits me staggeringly well, must have been made to have me in it!' This is such a powerful idea that as the Sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be all right, because this World was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for."

 

Well I'm a time traveler. That's the good news. Things are still as f***ed up in 2521, that's the bad news. I'd wish you all, good luck, but I know better.

 

Interesting.

 

If the universe were even slightly different evolution and therefore adaptation could never have occurred.

quote: There are many other finely-tuned constants of nature besides the strengths of these forces. Consider the ratio of masses for protons and electrons, as a final example. The mass of a proton is roughly 1836.1526 times the mass of the electron. Were this ratio changed by any significant degree, the stability of many common chemicals would be compromised. In the end, this would prevent the formation of such molecules as DNA, the building blocks of life. But with regard to the development of life on Earth, it is sometimes claimed that natural selection would find a way for life to develop no matter what the circumstances. In this way, nature is sometimes said to tune itself. However, the fine-tuning of carbon is even responsible for nature’s ability to tune itself to any degree. As professor Alister McGrath has pointed out:

"[The entire biological] evolutionary process depends upon the unusual chemistry of carbon, which allows it to bond to itself, as well as other elements, creating highly complex molecules that are stable over prevailing terrestrial temperatures, and are capable of conveying genetic information (especially DNA). […] Whereas it might be argued that nature creates its own fine-tuning, this can only be done if the primordial constituents of the universe are such that an evolutionary process can be initiated. The unique chemistry of carbon is the ultimate foundation of the capacity of nature to tune itself."

LINK

 

That's a pity.

 

Wow. Possibly the best timed conversation closer ever. What are the odds?

 

He's making a very fundamental mistake here. He can't conclude, after pondering what would happen here if all the rules when haywire, that a universe bound by those different rules would self destruct. The stuff just doesn't work here, up against our rules. I mean, since we're all just making stuff up here anyway, why don't we imagine a universe notable mainly for the odd fact that anything stable or logical or reliable here goes off like a rocket over there. And vice versa? My point is nobody, not even someone willing to do a little math like this guy, has any inkling of what a different set of constants imply. Certainly to say that destruction is inevitable is to presume far too much knowledge about how things work here. The best answer we have for a lot of things is still "it works that way because as far as we know it always has." Newton's laws of motion are basically just statements like this. Do we have a clear idea why entropy seems so pervasive in some cases and rare in others? Or why something, if it is something at all, isn't also nothing?

We don't, we've just kept lots of notes. And we are making progress. But these kinds of claims are a little premature when we haven't run at least a few alternate universes into the ground to see what happens. We just don't know enough.

 

I still use my original view to this topic.

If 'aliens' have mastered technology and the minds capable of it. To change time and travel where they wish by mere whim. Then why would they bother visiting a young planet called Earth that is still in its infancy, lost in wars and not mature enough to handle their arrival.

 

Its possible that your existence, and mine, was ensured just 10 minutes ago due to a group of time travelers who copulated with our mothers...

In 10 more minutes someone might go back in time and kill our grandparents which would cancel my past, as well as yours, and this entire thread.

So it might not be possible to see or know of the time travelers.

Now for aliens, maybe they've got better things to do than to come here and explore. maybe they will explore in the future, maybe they already did. you can't expect too much, their priorities could be different than ours at every level.