I have read and heard about this possibility (theory?) since my pre-teenager sci-fi craze...

For some reason, this is the 1st time that I have actually grokked it. I have re-read your post a dozen times or so to try to figure out what you said (or how you said it) that made this seem like a genuine possibility.

For this to be true (seems to me) we'd have to be approaching the point in time that mankind starts getting a foothold in time travel. ... Otherwise, these little teasing "visits" could alter the timeline in some subtle way like the butterfly effect.

Also agree, that if a future mankind were sharp enough to manage time travel, there'd have to be super beyond strict controls on the who-what-when-where... There'd be no "corrections" of things like genocide.
Also, would like to point out that there would be no way for us to know that WW2 and The Holocaust is not the less horrible alternative to whatever might have happened before it was prevented.
Perhaps the alternative was the complete annihilation of all Germans or Japanese or ... ?
Trying to play the guessing game about what a future more technologically advanced and (hopefully) more thoughtful civilization should have, would have or even COULD do is akin to cavemen giving computer advice to us while they scratch in dirt.

Time is treated like any other factor in chemical and physical reactions in theory and mostly practice too : Reversible. IRL, not so much.

Okay, so let's just play this out for a moment. Time machines. At first they would be novel and limited, like nuclear weapons. Then, in a few decades, they would become common and all first world nations would have them. We can speculate on various treaties or agreements but they would ultimately be used to further the goals of the individual nations. Sort of a "war" to rewrite history.

Future Germany would have a time machine. Don't you think leaders of future Germany would be tempted to go back and reverse the TWO travesty and embarrassing and costly involvements and responsibility and setbacks of both WWI and WWII? I tend to think they would.

Or how about England. Maybe England would go back and assassinate key leaders of the US revolution? Or go back in time to discover and colonize America first.

Or Japan. Surely Japan would opt to alter history and stay out of the devastating losses of WWII. Remain neutral or even change sides to fight for the Allies and avoid costly humiliating defeat.

Surely all nations might agree to go back and prevent proactively the atrocities of WWI and WWII thru future agreements to go back and stop these wars before they started.

Surely the US would opt to not get involved in Vietnam, which was a costly black eye on our nation. Or imagine going back and erasing our black eye of African slavery which was wrong and divided our nation in civil war, and still is problematic today. Or surely future Americans would go back and prevent the disaster Pearl Harbor or 9/11/01. The temptation would be too great.

I don't think they'd have the wisdom to NOT interfere and the temptation would be too great. Man has always wanted great power and to play God, and this would be the ultimate way to play God and alter time and events.

Every nation would have huge self interest to rewrite blemishes in their own history. Or to control the history of OTHER nations.

This would seem to follow the self-interests of the parties that you named...
But there is no way for us to know if any single one of those potential "fixes" would cause much worse (or unpredictable) futures.
Mightn't there be enough self-control to preserve the past?

I think that technology does not necessarily lead to cheaper/smaller and available to everyone. There might be something about time travel that is simply impossible to scale down to less than planetary or even star-system energy levels. (Google the Kardashev Scale)

I wasn't even thinking about time travel earlier... I still think that it would be "easier" to wrinkle space than time, but I am a caveman with a pointy wooden stick drawing in the dirt.

You guys are being silly...the Dem/Millenials are re-writing history every day, so eventually, the truth will be blurry and inconceivable

One thing overrides all the above what-if time re-write scenarios: one power being "first" to monitor and police all others' use and access to time travel by using time travel to destroy or nullify others' time travel technology.

For all we know it's already happened and the Power In Charge has decided that the timeline we have is the "least harmful" per PMB's above stated logical analysis.

Re time travel. It's an interesting discussion and of course total speculation.

Playing the other side of the coin for a moment, maybe lots of interfering in earth's alternate course in history WERE tweaked and what we got instead was the result of the tweaking...

For instance, we've come very very close to total thermal nuclear war a few times. Maybe out fate was a massive nuclear war. And future humans who survived and developed time machines went back and altered that event and what we have today is the result.

But I could argue against that theory too. If I were a future human with time travel and I wanted to eliminate all threats of nuclear war, I'd go back in time to the events that lead to nuclear technology. Even if it cost me my life and maybe even the evolution of time travel.

What lead to nuclear power and atomic weapons? WWII and the scientists that fled Germany as a result, such as Oppenheimer and Einstein. To ensure that nuclear weapons wouldn't be developed and used, at least not for maybe a century, you'd eliminate Hitler to prevent the start of WWII. Then you'd eliminate the great minds that invented nuclear weapons, systematically. That would at least delay for decades the invention of nuclear weapons.

Now, maybe there would be worse consequences; perhaps the Russians secretly would invent it and use it as first strike against the USA. Dunno. I'd bet future humans with time travel would have a sophisticated "war game" machine that would give alternate realities...

Let's look at smaller tragedies or ones with lesser implications. The sinking of the Titanic. What harm would there be in erasing that from history? Or the Oklahoma bombing? And so forth. Seems a little erasing here and there would be harmless... and yet all those still exist. Further proof in MY mind that no time travel has happened.

For some reason I really dislike using the term, "time travel". It implies that we could jump in some Delorean branded vehicle with a flux capacitor and away we go. I don't think it will be that simple. It will somehow involve the manipulation "warping" (don't really like using that word either) of both space and time in a manner that it can be harnessed for the use of travel through both space and time.

When I listen to Stephen Hawking talk about quantam physics and the space time continuum it really just boggles my mind with the implications and possibilities. The understanding and harnessing of these ideas will eventually come to pass if humankind doesn't end up destroying itself first.

Thanks for jumping back into the conversation PMB, I appreciate your intellectual perspective, and I mean that sincerely.

Eh, nobody ever claimed to meet a time traveler. And wouldn't the mere time visitors risk altering the future by all their visits?

Lots of people claim to have seen or been abducted by aliens.

Put whatever weight to that as you will.

Of the two, I believe alien life visitors are far more probable. The universe is unending. Races with a billion year head start could easily reach us, having mastered physics.

I've met a few time travelers. They flew in from Australia to LA.

I prefer to subscribe to the infinite universe theory. Any paradoxical alterations to the reality of a specific timeline simply begin a new reality split from the last reality.

For those not familiar... A time paradox is what happens when alterations are made to a timeline which would prevent the originator of said changes to have ever existed.

So basically what that concept boils down to is that for any time a change is made through time travel influence, a whole new reality is created, with a full history which matches the previous history up until that point.

The real noggin scratcher is whether the addition to the time-space continuum is "discovered" by the action, or rather created at the moment of change, or even just by the arrival itself.

Earth may be nothing more than a Petri dish. The thousands of years of recorded human history may account for no more than a galactic bacterial smear.

To me it seems fairly evident that visitors from outside this world have been here. Theres just too many relevant religious beliefs going back throughout recorded history, and it would seem to me to be pure hubris to deny the complete body of evidence.

Adding a little more.

Energy Waves and the butterfly effect:

A boat slips its moorage, and 200 miles away, another boat moves a fraction of an inch and crushes a spider against the dock. Said spider which would have otherwise killed the mosquito carrying the plague virus which subsequently wiped out most of mankind on the European continent.

It's imaginable from a mathematical standpoint, that a single physics shattering attempt, successful or not...Could change the fabric of space and time. For all we know, our civilizations concepts of physics are ass backwards.

Imagine the following scenario if you will.

Someone, somewhere, at some time, successfully breaks the laws of physics. Imagine any sci-fi trope you like. FTL, anti-gravity, transmutation, etc. That single point of change, could have far-reaching effects which observed singly, are unexplainable.

When we first began to experiment with"faster than speed" aircraft, part of that equation was discovering that approaching the "SOS" quickly built up a high frequency vibration, which was extremely destructive.

In the same manner, any experiments which stretch the understanding of physics could feasibly cause echoes of energy which we don't currently understand.

Say the Aurora project successfully demonstrated that a ramjet platform could make the SR-71 performance look like a push-cart. Imagine that by pushing through new boundaries could effect future and our past physics permanently or even temporarily.

Say a mach-1 testbed is shooting across the salt flats of Utah in 1960-something......

The crew stands there breathless, binoculars pressed hard to their eyes and fighting to see through the heat waves. All praying for the sound wave which they know prove that all their blood, sweat, and tears put into the effort will be rewarded.

The driver meanwhile... streaking across the earth with his ass strapped to a 3 wheeled rocket, is saying his own prayers as he pushes faster and faster toward what may amount to his own oblivion.

As the g-forces build, his brain does its best to concentrate on the minute movements necessary to keep this screaming deathsled from ripping apart as it hurdles closer and closer to the sound barrier.

The driver cannot be faulted for not realizing that as the vibrations build to a crescendo..his rocket car suddenly streaks through a bubble, or string of energy released from an F-14 tearing its way across the Gulf of Mexico 20 years in the future.

Neither the crew of the rocket car, nor it's driver are to blame for failing to realize that for the last 30 seconds of their run....the events were also plainly visible to some dude, riding a burro across the desert in 1835.

Same same regarding "time travel." Warping is overused in sci-fi, but it comes closest to what I picture will be the far distant ability to travel between stars. Light speed (~186,272 miles per second) is just way WAY too freaking slow.
When I was in the US Navy I wrote several sci-fi short stories... Never tried to get any published.
One of them was of an attempt at just such a time travel. The engineers built a machine that actually worked for extremely short jumps backwards or forwards but the item would always be displaced from its original location, but more frequent failures as the length of time attempted increased. (I moved the point around a little bit depending on the time of day, in regards to the spinning of the Earth and its orbit.) Sometimes the item would show up several feet away or it would just disappear altogether.
I wrote several different versions of this story, and one of them was of the traveler trying for a 1 hour time jump as his first manned attempt.
The unfortunate gentleman forgot to pack a spacesuit, and his successful time jump "landed" him 800,000 miles away from his lab...
Because?
The sun orbits the center of the galaxy at 500,000 MPH...
The Earth orbits the sun at 67,000 MPH
The Milky Way Galaxy is moving something around 1 Million MPH (skipping relativity.) (I did a very rough description of the time of year to show where he ended up in relation to the moon.)

In real life the engineers would know this, so it was more of a gotcha joke for people who think that time travel could be as simple as twisting a clock like dial backwards and hitting the red button.
Where you are right now is over 1,000,000 miles away from where you were 1 hour ago.
Is there something about a gravity well that can lock time "in step"? I don't think so... I think it would have to be calculated, and it would be a terrifically complicated calculation, and the consequences for getting a digit wrong down at the 10th decimal place could land the time traveler at the molten core of the planet or in interstellar space light years from home or anywhere in between.


Agreed! We live in really interesting times for several reasons... Politically and scientifically we're in major motion!

Thank you for the kind words Ron...

If they are truly ETs that are unrelated to us, then why do they look like us? Arms, legs, a head, two eyes, a mouth, etc.? The chances of life evolving like ours on a different planet are infinitesimally small.

I am not confident that we've seen real ETs...

Does a .Gov have guests or corpses from crashes? So far nothing but National Enquirer and rumors.
Have people been abducted and returned? Lots of stories for sure, but I have way more questions about those.

So far to my way of thinking, these are all in the unverifiable realm... Can't deny, can't verify. I hope so, but no trust no verify.

Let's say that even one of them is real and those aliens were humanoid, even if vaguely. Possibilities :
1. Their appearance is presented in a way that humans can vaguely identify with, so basically for approachability.
Think of "V" and also the 1983 series.
I prefer the 2009 series because Morena Baccarin. That'd be a good face to paste on a reptile if they wanted to get at me for sure.

2. Panspermia. (Still leaves a ton of questions.) Hominid Panspermia Theory

Spoiler: show

Quote:

I apply the Hominid Panspermia Theory theory to pretty much every sci-fi series I encounter that involves multiple alien species that are hominid. For series in which the species are distinctly hominid but not mammalian, such as Mass Effect, I just modify the theory so that the First Intelligent Species was arbitrarily dumping seed genetic code into every splash of primordial soup they could find with no intent to reproduce themselves and/or that their explorations recklessly forward-contaminated the universe. Life with a very similar genetic base still gets scattered about, but less planning leads to much less parallel evolution.

Also : https://io9.gizmodo.com/is-there-any-pl ... 1638235680

3. Maybe our shape makes good sense for a primitive species to make the leap to tools... ?
a few hypothesis

Spoiler: show

Quote:

The upright-walking, bipedal, two-armed posture "seems to have evolved independently in various unlikely contexts, from meerkats to velociraptors," notes Slonczewski. "Maybe it just makes sense to have two feet to move, two hands to manipulate something, and a sensory 'head' with as wide a view as possible. Then again, that's what we have, so it makes sense to us."

The bottom line is that we really don't know what the chances are... We have a scientifically testable sample of ONE.
I surely hope that humankind makes first contact before I turn to worm food, but that seems like the real infinitesimally small chance.