DETERMINE DUE DISTANCE
Near Earth's surface,
free falling object's velocity increases with time.
Thus, one can describe velocity as a function of time v(t).
v(t) = g × t
free falling object's velocity increases with time.
Thus, one can describe velocity as a function of time v(t).
v(t) = g × t
Simple Calculus
To describe distance traveled by a g-force,
integrate above velocity equation to
describe distance as a function of time.
d(t) =∫v(t) dt = g × t2/2
Above "Newtonian" equations work well for short distances.
Examples of G-force Distance
However, interstellar travel needs another equation
to describe distance traveled by Thought Experiment's (TE's) notional g-force spaceship.
Perhaps More Calculus .....Recall Einstein, c is always observed as consistent value, c, regardless of the observer's velocity.
Different durations of g-force produce different velocities; thus, observers might observe each other traveling at different speeds, but a few facts stay steadfast:
1. Nothing ever exceeds c, light speed. 2. All observers at any speed consistently measure photons at the same velocity,
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Previous work leads to following equation to model velocity of g-force spacecraft:
V(t) = (1 - (1 - Δ)t) c
where:
Following Method could approximate distances without calculus:
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A Little Calculus...... |
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(Many thanks to Wolfram Integrator)
Compute g-force distance: HOW?
Recall basic calculus, the integral, ∫, an elegant way of summing the area under the curve under consideration.
Calculus and Motion Problems.
Integration has many practical applications; perhaps the best known is for motion problems. For example, integrating a velocity function is known to yield distance.
For example:
∫ab V(t) dt = d(b) - d(a)
is the general form of a velocity function (with time, t, as the independent variable) being integrated to produce distance traveled from time, a, to time, b.
Most common functions are of the form:
∫k × tn dt = k × tn+1/n+1
EXAMPLE: CONSTANT VELOCITY. Most of us commonly ride automobiles at a constant velocity, such as 60 miles per hour, or cruise in aircraft at 500 nautical miles per hour (knots). Using the latter example:
∫0t k dt = k × t - 0
∫02 500 NM/hr dt = 500 knots × 2 hrs - 0 = 1,000 NM.
EXAMPLE: CONSTANT ACCELERATION. A more interesting integration might involve g-force acceleration. Let's consider two such examples. First example involves an object free falling from a great height toward the Earth for 10 seconds. Use traditional g=9.8 m/sec2. ∫010 g × t dt = g t2/2
∫010 9.8 m/sec2 (10 sec)2 dt = 9.8 m/sec2 (10 sec)2/2 - 0 = 490 m Second example involves our notional spacecraft g-force accelerating from Earth toward Jupiter for 2.5 days. Use TE's g=0.49 AU/day2. ∫02.5 g × t dt = g t2/2
∫02.5 0.5 AU/day2 (2.5 day)2 dt =.5 AU/day2 (2.5 day)2/2 -0 = 1.5625AU
Above examples show cases where distances can be easily validated via other computation methods.
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However, the case under consideration
( V(t) = (1 - (1 - Δ)t) c)
needs more sophisticated integration
to determine the corresponding distance function.
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INTERPLANETARY RANGES | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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After 50 days of g-force acceleration,
methods start to noticeable diverge. | For initial 10 days of g-force acceleration, Newtonian values resemble Einsteinian values. EXAMPLE: For tenth day of g-force acceleration, both methods show velocity about 5 AUs/day and a total distance of about 24 AUs. |
BEYOND INTERPLANETARY Short range (10 days) chart contrasts starkly with a longer range chart. After 500 days of g-force acceleration, velocity charts show enormous divergence. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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After one year (365 days) of g-force, Newtonian velocity exceeds c. IMPOSSIBLE!!! Thought Experiment's solution shows g-force vessel at 64% c after one year of g-force.
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Newton's equation is no good for larger values; above chart shows Newton's equation (g × t) exceeding light speed (c) after a year. IMPOSSIBLE!!! | On the other hand, Thought Experiment assumes an Einsteinian version is adequately modeled by an exponential equation which shows at 500 days, a velocity of 131 AUs/day and a total distance of about 40,000 AUs (≈ 2/3 LY). |
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VOLUME 0: ELEVATIONAL |
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VOLUME I: ASTEROIDAL |
VOLUME II: INTERPLANETARY |
VOLUME III: INTERSTELLAR |
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