It is well known that in order
For a given desired outcome
To be possible, the arrow
Of time must be preserved for all
Observers throughout the process.
This results in what is known as
“The expense” for time travel, and
It must be payed twice. First by the
Package, and second by the near
Matter of the destination.
The package sees the universe
Return to a high energy
State, and therefore, must observe an
Equal loss in energy from
Itself in order to preserve
Its arrow of time. This loss, or
“Expense” is paid from energy
Sent with the package from the point
Of departure. Similarly,
The destination would observe
The newly arrived matter as new
Energy, and so it must lose
An equal amount of local
Energy to get the package.
This has the appearance of the
Package arriving super cooled,
Which causes it to syphon the
Local heat as it is received.
In order for time travel to
Be possible the expense must
Be finite. For the receiving
Locality, the expense is
Generally trivial, but
The expense paid by the package
Can be immense depending on
The size of the universe in
Question. Obviously if the
Universe were infinite then
The expense to restore it to
A previous time would also
Be infinite. Thus time travel
Is only possible in a
Finite universe. Furthermore,
The recieving expense of time
Travel packages can add up
Causing reduction of the life
Span of a finite universe,
So the number of trips should be
Be kept to a bare minimum.
In general, time travel is
Not wise, especially if
It is found to be possible.
