Thread: The begging = 1st dimension, the past = second dimnsn, the present is in the

3rd dimnsn, future is in 4th dim? As 3 dimensional beings percieving time, we cannot "fit" in the present, and only truly experience the future.

Does that make any sense; discuss why or why not please.

If the magnitude of the velocity vector remains the same, and only the direction changes, you can get the magnitude of h like that:

h = r x v
->
|h| = |r| * |v| * cos(a)

Your orbit energy, remains constant, as your radius and the magnitude of the velocity remains constant.

So, your semi-major axis remains constant, but your eccentricity should change.

You want to change the eccentricity as such, that your periapsis distance is half the semi-major axis.

r/2 = Sma/2 = Sma(1-e) ->

0.5 = e

So, the question is now: Which angle is needed, so that e is 0.5? We can get this over h.

|h| = sqrt(p*µ) = sqrt(Sma(1-e²)/µ)

|h| at a circular orbit is, as you have initially is:

|h(0)| = sqrt(Sma/µ)
You want:
|h(0.5)| = sqrt(0.75Sma/µ)

we remember from the beginning:

|h(0.5)|/|h(0)| = cos(a)/cos(0) = cos(a)

sqrt(0.75Sma/µ)/sqrt(Sma/µ) = sqrt(0.75) = cos(a)

cos(a) = sqrt(3/4)

a = 30°

If the magnitude of the velocity vector remains the same, and only the direction changes, you can get the magnitude of h like that:

h = r x v
->
|h| = |r| * |v| * cos(a)

Your orbit energy, remains constant, as your radius and the magnitude of the velocity remains constant.

So, your semi-major axis remains constant, but your eccentricity should change.

You want to change the eccentricity as such, that your periapsis distance is half the semi-major axis.

r/2 = Sma/2 = Sma(1-e) ->

0.5 = e

So, the question is now: Which angle is needed, so that e is 0.5? We can get this over h.

|h| = sqrt(p*µ) = sqrt(Sma(1-e²)/µ)

|h| at a circular orbit is, as you have initially is:

|h(0)| = sqrt(Sma/µ)
You want:
|h(0.5)| = sqrt(0.75Sma/µ)

we remember from the beginning:

|h(0.5)|/|h(0)| = cos(a)/cos(0) = cos(a)

sqrt(0.75Sma/µ)/sqrt(Sma/µ) = sqrt(0.75) = cos(a)

cos(a) = sqrt(3/4)

a = 30°

We use 3 numbers, to locate an object space, ONLY 3 numbers are necessary to locate something in space. Therefore we say that space has 3 dimensions. We can use more numbers, but ONLY 3 are necessary.

If the object has limited existance, we can use a forth number to locate it in time also. Ergo, we can say there are 4 dimensions.

Every dimension consists of 2 directions, we can go forward or backwards along a dimension. If I go North, that is one direction, if I go South, that is another direction. But North and South together would be a dimension.

You can have an infinite number of dimensions in space alone, but you will still ONLY need 3 numbers to locate an object in space, ergo, we say there are 3 dimensions.

We can only go forward in time, not backwards, ergo, it may be, that time is not a full dimension, but only one direction, towards the future.