Time Travel Is Tricky
In the popular mind and in many so-called "scientific" minds, time is often thought of as a dimension of space. Because of this there is a strong tendency to think of the past as a place where we have been in time, and the future as a place where we will be in time.
Along with this come ideas that the past is affecting us right now, just as sunlight is affecting us from a great distance in space, and the future is an existing place that we can catch glimpses of through dreams, intuition, and perhaps clairvoyance.
Of course, if time is a dimension of space, then it ought to be possible somehow to travel to the past and the future. This, then, brings up fears of interfering with the past in ways that might have negative repercussions in the present and the future, just like an earthquake might cause a tsunami to damage a distant location.
These ideas have produced a great many stories about the effects of time travel, as well as many scientific speculations and experiments.
However, all these ideas about time mentioned so far share a highly significant logical flaw. For some reason they all assume that the earth is standing still.
H. G. Wells' story, The Time Machine, can serve as a good model here. In the literary and movie stories there is a machine that is supposed to travel through time. To the observer's eyes the machine and its occupant naturally disappear when they travel to, say, the future space. And from the occupant's point of view there is a constant parade of natural and man-made changes going on outside the machine--all in the same place!
In the objective world it can't possibly happen that way, because the earth is constantly moving in many directions at once.
The essential misunderstanding comes from the fact that time is not a dimension of space at all. It is a measure of movement through space. Let's look at some of the movement that time is a measure of first.
When we say that an hour of time has passed, what we are really saying, whether we realize it or not, is that the sun has apparently moved 15¼ of arc in the sky. Since ancient times we have divided the day/night cycle into 24 periods that we call hours. These periods can also be defined as 24 units of 15 degrees each, which gives us a complete circle of 360 degrees. So an hour can also be defined as 1/24 of a solar day/night cycle (I am ignoring obscure variations in the movements of the sun and the earth).
The important point here is that an hour only has meaning in relation to the apparent movement of the sun, which is due to an actual movement of the earth. Now we're getting somewhere, believe it or not (and pun intended). It's time to consider the movements of the earth.
The most important earth movement, as far as our daily life is concerned, is its rotation, because this is what gives us the apparent movement of the sun across the sky from horizon to horizon. The earth is rotating at approximately 1000 miles an hour. This means that during the period in which the sun seems to move 15 degrees of arc in the sky, the point on which you are standing or sitting (or even lying down) on has moved 1000 miles from where it was.
Next, we have to consider the earth's movement in its orbit around the sun. Looking at the sun relative to its background of stars, it appears to move about 1 degree per day, using a 360 degree circle for the earth's orbit. It actually takes about 365.25 days for the earth to move around this circle. The circumference of this orbit is about 608 million miles (940 km) and the earth has to move at a speed of about 69,000 miles per hour in order to make it on time.
Wait! It gets even more complicated.
While rotation and orbiting are going on, the sun and all its planets are moving toward the constellation Hercules at 42,000 miles per hour. At the same time the whole system is moving upwards at about 15,000 miles per hour. And also at the same time as a system we are are orbiting the Milky Way galaxy at a speed of about 446,000 miles per hour.
Putting all these movements together, each of us as individuals on this earth are moving at about 575,000 miles per hour within our galaxy. Not only does this make space navigation extremely difficult, it plays havoc with the whole idea of time travel.
Here is the gist of it. We are over half a million miles from where we were an hour ago. The place where we were is empty space (or filled with an asteroid or a nebula or a black hole or dark matter or whatever). To move "back in time" would necessarily mean to go backward in space to where we were previously. If we were to go backward for only one minute it would put us about 9,600 miles from where we are at this moment, and the result would most likely mean instant annihilation.
So "time travel" is not only impractical, the whole idea is merely a trick of language. Among people whose language does not include a past or future tense you will never find stories of time travel.
On the other hand, all of the above is only valid from within the worldview that we call "objective," or "scientific." From a subjective (psychic), symbolic (shamanic), or holistic (mystical) worldview everything might be different.