[katieHaylor (OP)]

David says:

If it were possible to travel forwards in time (and you didn't move in space), then what would happen if you moved to a time where the space you occupy is taken up by another object (a mountain or a volcano for example)?
What would happen to you?

What do you think?

[evan_au]

If it were possible to travel forwards in time...

It is easy to move forward in time. In fact, we are all doing it now, at a rate of 1 second per second.

If it were possible to travel forwards in time (and you didn't move in space)...

Physicists would say that the concept of an unqualified "not moving" is flawed - you always have to measure your position relative to something else.

But let's say that you want to remain where the Earth is now (relative to the Sun), while the Earth continues on its orbit at 108,000 km/h....
- You would immediately start accelerating towards the Sun, and hit it in around 3 months
- So you would need an incredibly powerful rocket (with some amazing fuel) to maintain you in the same position, despite the Sun's gravity
- When the Earth comes by again in a year, you will become a puff of vapor as you enter the upper atmosphere at a relative speed of 108,000km/h

Of course, if you measured your position relative to the center of the galaxy, the Earth would miss you by a long way, because the Sun (and Earth) are orbiting the center of the galaxy at around 800,000 km/h. Any piece of dust hitting you at these speeds would turn into plasma, and the shock wave would blow you into little pieces.

the space you occupy is taken up by another object

But I assume you mean moving faster than 1 second per second...
And you mean that you suddenly disappear and reappear somewhere else...

If you reappeared in air, you would have about 70 liters of air (about 100g of air) suddenly appearing in your body - but the electrons and nuclei would be in all the wrong places - a very unstable situation. I expect that there would be an intense burst of X-Rays as the electrons and atomic nuclei find new orbits, which would fry your DNA. Molecules of oxygen and Nitrogen suddenly appearing in your cells would break your proteins. You would be very dead.

If you appeared inside a rock (eg granite), your already densely-packed atoms would need to make room for even denser atoms that make up the rock. This would normally cause an explosion to double your normal volume.

However, granite is strong enough to hold in the explosion, so I expect that you would have perhaps 100 liters of shattered granite containing a high level of organic impurities, all well-baked by X-Rays.

If you were going to design a mythical time-machine, you may as well have it exchange the matter from the destination with your current location (and while we are doing the impossible, equalize the velocities too).

That way you would suffocate after being entombed in granite, leaving behind a granite statue at your point of departure to commemorate your demise.