Let's talk about time travel

This is a fascinating area of thought that I'm sure everyone has as much to say about as all the other mind boggling puzzles discussed here : is your future already pre-destined? Do you fear death? Is there a God?, etc...

Do you believe time travel will ever be possible one day? Do you think memories of all the things that happened in your life are like a time-capsule sitting somewhere in your brain? Do you wonder where the images form when you think about your past? Do you believe that people you've once loved that have now left this earth are still 'alive' in your memory when you think about them? Do you look at old photographs and videos and can you re-live those moments again very vividly? Do you put yourself in photographs and videos quite deliberately with the intent that you may live on in them, after you're gone?

Do you accept that the Earth is 4.5 billion years old (as is popular opinion according to science) or do you have your own ideas about the true age of the Earth? I know for a fact that it ain't gospel

Finally, on a lighter note, if you had a time machine and could go back to any moment in history, where/when would you go to, and why?

I'm not much help because my answer to nearly all your questions is "No."
As for going back in time, there is nowhere I'd like to go. Looks like I'm a complete washout on this.

Of all the SciFi speculations, time travel is the least likely.

Why, because if it is ever invented in the future, allowing people to travel in time, they'd be showing up here.

The fact they aren't is a pretty good argument against future development of time travel.

Time travel is possible in that the known laws of physics allow it. According to the theory of relativity, when an object moves through space, its motion through time slows down relative to an object that's not moving. The effects are not noticible unless the object is moving at a significant fraction of the speed of light. This would, in principle, allow for time travel to the future (fly in a spaceship at close to the speed of light for a period of time and more time will have elapsed on earth than has on your spaceship, so when you return, you'll have traveled to the future). Gravitational fields are another posibility for time travel. According to the theory of relativity, a gravitating mass will bend space and time, therefore time moves more slowly for an object inside a gravitational field than for one outside it. The effect would not be noticible unless the gravitational field was very strong, as in a black hole or neutron star. Spending time in such a gravitational field (if that were possible) would also provide time travel to the future. Time travel to the past, now that's considerablly harder and involves complex paradoxes. One hypothetical way to travel to the past would be to fly a spaceship at a speed greater than light. Due to time dilation predicted by the theory of relativity, if an object were to travel at the speed of light, it would have a speed through time of zero relative to a stationary object and at speeds faster than light, the object's speed through time would be negative. There are many problems, however, an object would requier an infinate amount of energy to reach the speed of light (therefore to exceed the speed of light would requier an amount of energy greater than infinity) and the object's length in the direction of motion would compress to zero at the speed of light. Even if you could somehow get past these hurdles, there's still the paradox If you travel faster than light, you go back in time to a time before you were traveling faster than light, therefore you never were traveling faster than light, therefore you never went back in time, and on and on it goes. Another hypothetical way to travel back in time would be a negative gravitational field. This has its own problems, as it requiers an object with a negative mass (weighs less than zero) and it would have a negative gravitational field equal in force to the positive gravitational fields emmited by black holes and neutron stars for an appreciable effect. Negative mass requiers negative energy density (remember matter and energy are equivelent E=MC[squared]). That means the total system must have an energy content of less than zero. Imagine an object that weighs less than zero....wierd! No one knows how to create negative mass, much less the massive quantities of it needed for any meaningful time travel.

Now for the easier question to answer. The age of the earth is 4.5 billion years, give or take 100 million or so years. Scientists know this by using radiometric dating techniques on crystals found in ancient rocks. Carbon dating doesn't work on things older than 50,000 years due to carbon 14's half-life of 5,730 years. To date these ancient rocks, scients use uranium-lead dating. They look at the ratio of uranium to lead in the crystal and knowing the half-life of uranium (about 4.5 billion years) they are able to calculate how long it would take for enough uranuim to decay into lead to account for the amount of lead in the crystal. It is posible for these radiometric dates of the earth to be off by a few hundred million years, but for the earth to be only a few thousand years old (less than 10,000) as some religious groups teach is a scientific imposibility. There is reason beyond radiometric dating to believe the earth is more than a few thousand years old. Calculating based on known rates of erosion, structures like the Grand Canyon could not be formed in a few thousand years and calculating based on known rates of uplift, none of the worlds major mountain ranges could have been formed in a few thousand years. There is good reason to believe the earth is aproximately 4.5 billion years old.

Ahad,

You do not want to hear my theories about the age of the earth or anything else. I don't know how old the earth is, but do not believe it evolved.

I believe in creation. I realize that most folks evolved, but I didn't. I am Rh negative and so are my husband and children.

Do you wish to hear more?

I personally believe that the creation and the creator are one and the same entity.

ooooo, good one.

One reason time travelers from the future are not showing up in our time period may be that when they travel in time they actually enter a parallel universe (in fact it may be entirely posible that we enter a parallel universe every time we have a thought). The idea of parallel universes makes sense because it eliminates all the temporal paradoxes and it allows for the realization of all posibilities. I personally believe in the many worlds intrepretation. The idea that there are parallel universes just makes logical sense to me.

Got to agree with that last post, Gordon. When I think of the meaning
of time, and time travel, I keep coming to a weird thought that time
only exists in the physical world, created by humans to try to
understand the impossible.

I think that all time exists at once - past, present and future. The great I AM mystery.

Like the guy said, Time is what keeps everything from happening at once and Space is to keep everything from being in the same place.

Good points, Lin. For matter to exist there must be space for it to
exist in. Time then comes into play as a tool to measure how far apart
things are.

So which came first... time, space, or matter?

Space is the distance around, between, and within objects. Objects are made of matter, which is really just highly condensed energy in an organized structure and energy is the ability cause a change in the state of an object's motion, resulting from a differnce in the potential of forces. Wthout time nothing could move (motion requiers time) and if motion were impossible, there could be no chances made to the state of an object's motion, therefore energy could not exist in a world without time. If there was no energy, there would be no matter, as matter is really only condensed energy in an organized structure. No matter would mean there would be no objects and therefore no distance around, between, and within objects, meaning space would not exist. Time, Space, Matter, and Energy are all interdependent, not one can exist without the other three. You either have all of them or you have none of them.

Say that three times real fast. LOL

Just think, that could describe the Universe or a single atom!

I am glad I am here now. Houses are more comfortable and clean.

Cars are better, people are better parents. Doctors have more training and knowledge.

Life is good now.

When people can't come up with a comprehensible answer to a situation or problem, they exclaim, GOD!
It is a good word to use in the context of the unknown or unfathomable. How does one calculate infinity?

Then there are those who explain everything with EVOLUTION.
Or BIG BANG.

Concepts they understnad just as loosely and just as much based on faith.

Meanwhile, can they answer what came immediately after the Big Bang?

They are both theories. I was not there so I can't state for certain what happened.

I believe in God so I beleive HE created the world when and how HE felt like it.

As to how old it is--who cares?

I honestly con't care. God could have created a chicken full-grown. When a person looked at it they would have judged it to be much older than 5 minutes old.

All of this controversy comes down to faith. Where do you put your faith in God or man?

I put my faith in God.

Still no answer to what came after the Big Bang

In my opinion, the big bang is just a horizion we can't see beyond. For time to have a beginning or an end makes no sense at all. Thinking you could fall off the edge of the earth makes as much logical sense as time having a beginning or an end in my opinion. There is a serious problem with thinking there could be a beginning or an end to time. In order for there to be a beginning there would have to be a before the beginning and if there was no time before the beginning, there could not be a before the beginning and therefore there could not be a beginning. This I call the before-the-beginning paradox and a simalar situation would apply to an end of time. If time has no beginning or end, that leaves two posibilities. Either time is infinate in extent or it is finite, but looped back on itself. If the second of those posibilities is true, then it would be possible to reach the past by traveling unimaginabally far into the future, just like one can go east by traveling west if one circles the globe.

lin wrote:

Still no answer to what came after the Big Bang

According to present consensus among cosmologists, the big bang happened some 14 billion years ago. The 'bang' itself is thought to have been an explosion that caused bits of the primordial fireball of matter to be sent flying-off in all directions into space. This is the notion of an 'expanding universe', whose rate of expansion is measured by the Hubble Constant. These 'bits' of matter originating from the big bang eventually condensed into galaxies, to form stars, solar systems, planets and, finally, to *us* living creatures.

With an average lifespan of a human being limited to only 70 to 80 years on this earth, we can't really visualise timescales running into billions of years all the way back to the Big Bang - or even to the relatively more recent birth of the Earth. To me, it doesn't really surprise me at all that "at the limits of knowledge" science merges with religion, and believing in either takes just as much of a leap of faith as empirical reasoning (with very large numbers and complicated equation-based proofs )

Dear Ahad,
As simple as this may seem, I was thinking about infinity the other day while trying to make a straight line on a poster board to write some words. I used a straight edged ruller. As I was drawing the line I knew that that straight line goes on far past the board on which I drew. The concept of infinity explained made me smile.

I imagine that so little of the power of the human brain is used. But power there is in the kenetic energy of the brain. To harness that would be a big step in the time travel experience. I think that the closest we come to that energy is in dreaming. We each hold our own electrodes. How to plug them in is the missing factor.

Love,
Betty

Betty,
Simple ideas with simple thoughts and having simplicity in all that we do is often the best way to understand the world - as you found drawing that line toward infinity on the board. Otherwise it gets more complicated than it need be.

When you take a photo, a split-second exposure of the world by the camera lens to photographic film captures a frame in time. A unique moment in history is then in that picture. If it can be preserved for all eternity to come, then whomever looks at that picture will in effect be looking back in time to that unique moment.

The advent of video made those still camera frames move in succession to create a 'movie'. Maybe time travel is just that, making the mind relive a past moment in history simply by exposing our senses to 'movies' of past events and there is no need for anyone to travel physically back into time.

If your parents had captured their wedding ceremony on video - long before you were born - by you watching that video today, you would in effect be experiencing a moment in time that happened before you were even conceived on this earth, let alone having been physically born.

Time travel...

Ahad & Betty. Love your answers and thoughts. Your examples makes sense and can be easily comprehended.

Regardless of whether we can travel through time or not, I believe as authors we can create ripples in time that may ultimately alter the course of the future of the world through the butterfly effect.

I doubt if L Ron Hubbard would have guessed at the time, if his writings would one day lead to the Church of Scientology and the Scientology movement.

Be careful what you write! It may stir something deep!

He would more than have guessed. He took a science fiction story and built it into a huge financial empire through a series of cold-eyed calculations. He wrote one book for no other purpose than shifting Scientology/Dianetics from a mental health practice to a relgion. (It was taking heat from the American DEA, and MUCHO heat from medical licensing authorities in Australia)