Math/Sci-Fi Question
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- Cybermancer
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Math/Sci-Fi Question
I lack the knowledge and skills to find the answers to these questions on my own.
Assuming a maximum speed of 99.9999% the speed of light,
assuming a time of 365 days to accelerate to that speed (and to decelerate from that speed),
assuming a distance of 4.4 light years.
What is the rate of acceleration?
What is the 'g-force' from that acceleration?
How long does it take to cover the entire distance?
How much time appears to go by for those on the vessel due to time dilation?
Please explain your answer in simple laypersons terms and if possible, show your work.
Thank you for your assistance.
(P.S. I don't need to know things like required energy outputs but if you wish to include such, then by all means)
Assuming a maximum speed of 99.9999% the speed of light,
assuming a time of 365 days to accelerate to that speed (and to decelerate from that speed),
assuming a distance of 4.4 light years.
What is the rate of acceleration?
What is the 'g-force' from that acceleration?
How long does it take to cover the entire distance?
How much time appears to go by for those on the vessel due to time dilation?
Please explain your answer in simple laypersons terms and if possible, show your work.
Thank you for your assistance.
(P.S. I don't need to know things like required energy outputs but if you wish to include such, then by all means)
I was raised to beleive if you can't say something nice about a person, say nothing at all. This has led to living a very quiet life.
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
- Severus Snape
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Re: Math/Sci-Fi Question
Cybermancer wrote:I lack the knowledge and skills to find the answers to these questions on my own.
Google can be your friend.
Cybermancer wrote:Assuming a maximum speed of 99.9999% the speed of light,
assuming a time of 365 days to accelerate to that speed (and to decelerate from that speed),
assuming a distance of 4.4 light years.
To start: Light speed is 186,286 miles per second. Which would be 11,177,160 miles per minute (light speed * 60), or 670,629,600 miles per hour. 99.9999% of this would be 670,628,929.3704 miles per hour.
Cybermancer wrote:What is the rate of acceleration?
Well, that's a little tricky. You need to remember that acceleration is the rate at which velocity - not speed - changes. And it's going to be hard to determine the rate of acceleration. Why? Well, at the start you are not moving. You then start moving, and are attempting to get up to (near) light speed, over the course of 1 year. To calculate the rate of acceleration, we'll need to know how much speed you are gaining over every single day. If the amount of speed is the same every day, then you would be gaining 1,837,339.5325 mph every day until you reach your intended speed. We can calculate the rate of acceleration on this as:
Change in Velocity/Time for Velocity To Change
So the change in velocity is 1,837,339.5325 mph, and the time it takes to reach this amount of velocity is 24 hours. This means your rate of acceleration in this case is 76,555.813 mph^2 (71,555.813 miles per hour squared).
But this does not take into account that you are continuing to build speed through each consecutive day. Rate of velocity changes as speed increases. And you'll need a whole lot more math than I know to calculate this based on current speed, speed attempting to attain, speed gained, and distance traveled.
Cybermancer wrote:What is the 'g-force' from that acceleration?
This one is out of my reach.
Cybermancer wrote:How long does it take to cover the entire distance?
4.4 light years is what you are asking for. A light year is the distance light can travel in one year, which is 5,878,630,000,000 miles. 4.4 of these is 25,865,972,000,000 miles. That's the distance light can travel in a vacuum in 4.4 years. With me so far?
Now, you are reaching near light speed, which means you can only travel 5,878,624,121,370 miles in one year. And that's AFTER you reach near light speed. So in 4.4 light years, you would travel 25,865,946,134,028 miles. But again, this is after you've reached light speed. You have to account for the distance you travel in the first year first. And again, that math is dependent on the rate of acceleration. And that changes from day to day as you are increasing your speed. It also helps to know that the distance you can and do travel will change with each 1 mph increment in speed.
Cybermancer wrote:How much time appears to go by for those on the vessel due to time dilation?
365 days appear to go by for those on the vessel. They are travelling for 1 year per your statement, so it would appear to them that 1 year passed by.
- Cybermancer
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Re: Math/Sci-Fi Question
If it takes a year to get up to 99.9999% the speed of light and another year to decelerate from that speed and the total distance to be travelled is 4.4 light years, I'm not seeing how it only takes a year to travel that distance. At light speed, it's going to take 4.4 years to travel 4.4 light years. At less than that speed and taking into account a year to accelerate and decelerate it's going to take longer than that amount of time.
But that's the time relative to one who is not taking the trip.
I also need to know how long it takes for those taking the trip. Time will seem to go slower due to time dilation.
But that's the time relative to one who is not taking the trip.
I also need to know how long it takes for those taking the trip. Time will seem to go slower due to time dilation.
I was raised to beleive if you can't say something nice about a person, say nothing at all. This has led to living a very quiet life.
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
- Severus Snape
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Re: Math/Sci-Fi Question
Cybermancer wrote:If it takes a year to get up to 99.9999% the speed of light and another year to decelerate from that speed and the total distance to be travelled is 4.4 light years, I'm not seeing how it only takes a year to travel that distance. At light speed, it's going to take 4.4 years to travel 4.4 light years. At less than that speed and taking into account a year to accelerate and decelerate it's going to take longer than that amount of time.
But that's the time relative to one who is not taking the trip.
I also need to know how long it takes for those taking the trip. Time will seem to go slower due to time dilation.
I'm sorry if I confused you. I was originally under the impression that they were travelling only for a year.
For those on the ship, however long it takes for them to travel the specified distance is the amount of time that will pass. Meaning, they will be on the ship the whole time that they are travelling, and however long it takes is how much time will seem to pass to them.
Now, as far as how much time passes for those outside the ship, well...I'm not a quantum physics or relativistics theory professor or student, so I can't answer that. I know that, according to wikipedia:
Wikipedia wrote:Time dilation can be inferred from the observed fact of the constancy of the speed of light in all reference frames.
This constancy of the speed of light means, counter to intuition, that speeds of material objects and light are not additive. It is not possible to make the speed of light appear faster by approaching at speed towards the material source that is emitting light. It is not possible to make the speed of light appear slower by receding from the source at speed. From one point of view, it is the implications of this unexpected constancy that take away from constancies expected elsewhere.
and that
Wikipedia wrote:Thus the duration of the clock cycle of a moving clock is found to be increased: it is measured to be "running slow". The range of such variances in ordinary life, where , even considering space travel, are not great enough to produce easily detectable time dilation effects, and such vanishingly small effects can be safely ignored. It is only when an object approaches speeds on the order of 30,000 km/s (1/10 the speed of light) that time dilation becomes important.
Now, there are forumulas at wikipedia (this is the article you referenced) that tell one how to calculate the amount of time that has passed. However, and while I am pretty good at math, I am not that good. What you are trying to calculate cannot be done with simple algebra, nor can it be done by the average person. You need to go back to the original questions and figure out the following:
1. Rate of acceleration/velocity. This is the key component - Everything else pretty much depends on this.
2. Distance travelled in the first year. Remember that you don't travel the entire distance that light would travel in a year as you have to get up to speed first.
3. Amount of time it takes to travel the distance light would travel in 4.4 years.
4. The amount of time dilation relative to the passengers on the ship.
What we're talking about here is fairly advanced mathematics. And while I am quite certain there are people on these boards that may be able to tackle what you are asking, I'm also fairly certain that none of them will want to given the scope of what you're asking.
Which reminds me - why are you asking this anyhow? Is this for something in a campaign you're running/a part of?
- Natasha
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Re: Math/Sci-Fi Question
I'll give it a shot.
At 99.9999% of speed of light, the clock on rest frame (Earth, I assume) will be 1.937 years faster than clock on the ship. So if the voyage is 4.5 years on-ship; on Earth it's almost 9 years. (http://www.fourmilab.ch/cship/timedial.html)
99.9999% of speed of light = 299792158 m/s, and 1 year = 31556926 s.
So the average acceleration would be: (299792158 m/s)/(31556926 s) = 9.5 m/s^2.
That's less than 1 G; cosmonauts accelerate less than 4 G's to the so-called escape velocity (something like 11100 m/s).
Escape velocity is gravity against an object's kinetic energy (mass drops out, so velocity is what matters):
0.5 * m * v^2 = GMm/d, which simplifies as: v = sqrt(2GM/d).
Note that gravity obeys the inverse square law so gravity drops off quickly.
Note that here G is the gravitational constant (see below), not acceleration expressed in G's.
You can express acceleration in G's (a_g) by: a_g = F / mg
where F = force of accelerating ship (mass times acceleration),
m = mass of your ship, and
g = acceleration due to gravity.
As g approaches zero (get further from Earth, Sun, etc), the acceleration would likely become lethal to the passengers. Let's wave the hand of the GM here and say they survive.
Newton's law of gravitation says that the force of gravity is given by: F = GmM/d^2,
and by Newton's Second Law: Force is equal to mass times acceleration (F = ma).
So: ma = GmM/d^2
And because m cancels out, acceleration due to gravity on your planet is given by:
a = GM/d^2
where G is the gravitational constant = 6.673 * 10^-11 m^3 kg^-1 s^-2
a = acceleration due to gravity,
m = mass of your ship,
M = mass of your visited planet, and
d = distance between centers of each mass.
For me staying on the surface of earth, example:
m = (cancels out, even the Universe know better than to ask a girl this question)
M = 5.9742*10^24
d = 6378100 m
a = ((6.673*10^-11)(5.9742*10^24))/6378100^2
a = 9.799823 m/s^2 (close enough to the official answer, I think)
If I were flying away from the Earth and I reach already 55 million kilometers, it's 1.3 * 10^-7 m/s^2.
So, how long will it take?
Average velocity is given by: v_avg = (v_intial + v_final)/2
v_initial = 0, v_final = 299792158 m/s, so v_avg = 149896079 m/s.
Distance is average velocity times time: x = v_avg * t
v_avg = 149896079 m/s, and t = 31556926 s, so
x = 4.7 * 10^15 m (the distance your ship travels in a year).
4.4 light years is 4.16 * 10^16 m. Subtract the distance already traveled.
There remains: 3.69 * 10^16 m.
Again, by hand wavium, let's say that the ship covers the same distance over the year it is stopping as covered when the voyage began;
then there remains just 3.22 * 10^16 m, which the ship can cover in 107407746 seconds (going 99.9999% of speed of light), which is about 3.4 years. Add in the 2 years acceleration and decelerating: the clock on the ship says 5.4 years while clocks on Earth say 10.5 years.
At 99.9999% of speed of light, the clock on rest frame (Earth, I assume) will be 1.937 years faster than clock on the ship. So if the voyage is 4.5 years on-ship; on Earth it's almost 9 years. (http://www.fourmilab.ch/cship/timedial.html)
99.9999% of speed of light = 299792158 m/s, and 1 year = 31556926 s.
So the average acceleration would be: (299792158 m/s)/(31556926 s) = 9.5 m/s^2.
That's less than 1 G; cosmonauts accelerate less than 4 G's to the so-called escape velocity (something like 11100 m/s).
Escape velocity is gravity against an object's kinetic energy (mass drops out, so velocity is what matters):
0.5 * m * v^2 = GMm/d, which simplifies as: v = sqrt(2GM/d).
Note that gravity obeys the inverse square law so gravity drops off quickly.
Note that here G is the gravitational constant (see below), not acceleration expressed in G's.
You can express acceleration in G's (a_g) by: a_g = F / mg
where F = force of accelerating ship (mass times acceleration),
m = mass of your ship, and
g = acceleration due to gravity.
As g approaches zero (get further from Earth, Sun, etc), the acceleration would likely become lethal to the passengers. Let's wave the hand of the GM here and say they survive.
Newton's law of gravitation says that the force of gravity is given by: F = GmM/d^2,
and by Newton's Second Law: Force is equal to mass times acceleration (F = ma).
So: ma = GmM/d^2
And because m cancels out, acceleration due to gravity on your planet is given by:
a = GM/d^2
where G is the gravitational constant = 6.673 * 10^-11 m^3 kg^-1 s^-2
a = acceleration due to gravity,
m = mass of your ship,
M = mass of your visited planet, and
d = distance between centers of each mass.
For me staying on the surface of earth, example:
m = (cancels out, even the Universe know better than to ask a girl this question)
M = 5.9742*10^24
d = 6378100 m
a = ((6.673*10^-11)(5.9742*10^24))/6378100^2
a = 9.799823 m/s^2 (close enough to the official answer, I think)
If I were flying away from the Earth and I reach already 55 million kilometers, it's 1.3 * 10^-7 m/s^2.
So, how long will it take?
Average velocity is given by: v_avg = (v_intial + v_final)/2
v_initial = 0, v_final = 299792158 m/s, so v_avg = 149896079 m/s.
Distance is average velocity times time: x = v_avg * t
v_avg = 149896079 m/s, and t = 31556926 s, so
x = 4.7 * 10^15 m (the distance your ship travels in a year).
4.4 light years is 4.16 * 10^16 m. Subtract the distance already traveled.
There remains: 3.69 * 10^16 m.
Again, by hand wavium, let's say that the ship covers the same distance over the year it is stopping as covered when the voyage began;
then there remains just 3.22 * 10^16 m, which the ship can cover in 107407746 seconds (going 99.9999% of speed of light), which is about 3.4 years. Add in the 2 years acceleration and decelerating: the clock on the ship says 5.4 years while clocks on Earth say 10.5 years.
- Severus Snape
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Re: Math/Sci-Fi Question
Natasha wrote:I'll give it a shot.
At 99.9999% of speed of light, the clock on rest frame (Earth, I assume) will be 1.937 years faster than clock on the ship. So if the voyage is 4.5 years on-ship; on Earth it's almost 9 years. (http://www.fourmilab.ch/cship/timedial.html)
99.9999% of speed of light = 299792158 m/s, and 1 year = 31556926 s.
So the average acceleration would be: (299792158 m/s)/(31556926 s) = 9.5 m/s^2.
That's less than 1 G; cosmonauts accelerate less than 4 G's to the so-called escape velocity (something like 11100 m/s).
Escape velocity is gravity against an object's kinetic energy (mass drops out, so velocity is what matters):
0.5 * m * v^2 = GMm/d, which simplifies as: v = sqrt(2GM/d).
Note that gravity obeys the inverse square law so gravity drops off quickly.
Note that here G is the gravitational constant (see below), not acceleration expressed in G's.
You can express acceleration in G's (a_g) by: a_g = F / mg
where F = force of accelerating ship (mass times acceleration),
m = mass of your ship, and
g = acceleration due to gravity.
As g approaches zero (get further from Earth, Sun, etc), the acceleration would likely become lethal to the passengers. Let's wave the hand of the GM here and say they survive.
Newton's law of gravitation says that the force of gravity is given by: F = GmM/d^2,
and by Newton's Second Law: Force is equal to mass times acceleration (F = ma).
So: ma = GmM/d^2
And because m cancels out, acceleration due to gravity on your planet is given by:
a = GM/d^2
where G is the gravitational constant = 6.673 * 10^-11 m^3 kg^-1 s^-2
a = acceleration due to gravity,
m = mass of your ship,
M = mass of your visited planet, and
d = distance between centers of each mass.
For me staying on the surface of earth, example:
m = (cancels out, even the Universe know better than to ask a girl this question)
M = 5.9742*10^24
d = 6378100 m
a = ((6.673*10^-11)(5.9742*10^24))/6378100^2
a = 9.799823 m/s^2 (close enough to the official answer, I think)
If I were flying away from the Earth and I reach already 55 million kilometers, it's 1.3 * 10^-7 m/s^2.
So, how long will it take?
Average velocity is given by: v_avg = (v_intial + v_final)/2
v_initial = 0, v_final = 299792158 m/s, so v_avg = 149896079 m/s.
Distance is average velocity times time: x = v_avg * t
v_avg = 149896079 m/s, and t = 31556926 s, so
x = 4.7 * 10^15 m (the distance your ship travels in a year).
4.4 light years is 4.16 * 10^16 m. Subtract the distance already traveled.
There remains: 3.69 * 10^16 m.
Again, by hand wavium, let's say that the ship covers the same distance over the year it is stopping as covered when the voyage began;
then there remains just 3.22 * 10^16 m, which the ship can cover in 107407746 seconds (going 99.9999% of speed of light), which is about 3.4 years. Add in the 2 years acceleration and decelerating: the clock on the ship says 5.4 years while clocks on Earth say 10.5 years.
And now my brain hurts. Thank you.
- Cybermancer
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Re: Math/Sci-Fi Question
Thank you very much, both Natasha and Severus Snape, that's exactly the information I needed.
The information is for use in a play test campaign that will eventually be submitted as a Chaos Earth/Rifts submission to the Rifter.
Basic concept, a colony mission was being prepped to leave for Alpha Centauri in the asteroid belt (yes, I'm aware that the odds of there being planets, much less habitible ones is abysmally small). The Rifts come and the mission is still a year from launch. The Chaos Earth portion deals with the mission trying to get underway (using tractions drives).
300 years later, the colonists, now well established, send an expedition back to the Sol system. Primary concern is the alien Arkhon's with an eye towards helping humans in the orbital community and on Earth after the alien menace is dealt with.
The information is for use in a play test campaign that will eventually be submitted as a Chaos Earth/Rifts submission to the Rifter.
Basic concept, a colony mission was being prepped to leave for Alpha Centauri in the asteroid belt (yes, I'm aware that the odds of there being planets, much less habitible ones is abysmally small). The Rifts come and the mission is still a year from launch. The Chaos Earth portion deals with the mission trying to get underway (using tractions drives).
300 years later, the colonists, now well established, send an expedition back to the Sol system. Primary concern is the alien Arkhon's with an eye towards helping humans in the orbital community and on Earth after the alien menace is dealt with.
I was raised to beleive if you can't say something nice about a person, say nothing at all. This has led to living a very quiet life.
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
Re: Math/Sci-Fi Question
Why are you people doing complicated math when you can pretty much work this out in your heads?
If it takes you a year of constant acceleration to get up to the speed of light, then your average speed during that year is half the speed of light, so you travel half a light year in your first year.
If you decelerate at the same rate, your average speed during your final year will also be half the speed of light, so that's another half a light year there.
So that's your first and last year of the voyage to cover a combined total of 1 lightyear.
That leaves 3.4 lightyears of the voyage left, but since you're travelling at roughly the speed of light you can just call that a travel time of 3.4 years in the middle.
So there you go, total travel time of roughly 5.4 years to travel 4.4 lightyears. Or almost but not quite 5 years and 5 months.
And I'm going to go out on a limb here and not even bother looking up the math, and say that to those on board it felt like roughly one year of subjective time (technically a little longer, since the middle of the voyage was spent at slightly below lightspeed).
As for acceleration, by a happy coincidence it just so happens that accelerating at 1G (9.8 metres per second squared) will get you to the speed of light in approximately one year (not exactly one year, but close enough that it'll feel almost like Earth gravity to the people on board for most of the trip).
If it takes you a year of constant acceleration to get up to the speed of light, then your average speed during that year is half the speed of light, so you travel half a light year in your first year.
If you decelerate at the same rate, your average speed during your final year will also be half the speed of light, so that's another half a light year there.
So that's your first and last year of the voyage to cover a combined total of 1 lightyear.
That leaves 3.4 lightyears of the voyage left, but since you're travelling at roughly the speed of light you can just call that a travel time of 3.4 years in the middle.
So there you go, total travel time of roughly 5.4 years to travel 4.4 lightyears. Or almost but not quite 5 years and 5 months.
And I'm going to go out on a limb here and not even bother looking up the math, and say that to those on board it felt like roughly one year of subjective time (technically a little longer, since the middle of the voyage was spent at slightly below lightspeed).
As for acceleration, by a happy coincidence it just so happens that accelerating at 1G (9.8 metres per second squared) will get you to the speed of light in approximately one year (not exactly one year, but close enough that it'll feel almost like Earth gravity to the people on board for most of the trip).
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Re: Math/Sci-Fi Question
Rallan wrote:Why are you people doing complicated math when you can pretty much work this out in your heads?
If it takes you a year of constant acceleration to get up to the speed of light, then your average speed during that year is half the speed of light, so you travel half a light year in your first year.
If you decelerate at the same rate, your average speed during your final year will also be half the speed of light, so that's another half a light year there.
So that's your first and last year of the voyage to cover a combined total of 1 lightyear.
That leaves 3.4 lightyears of the voyage left, but since you're travelling at roughly the speed of light you can just call that a travel time of 3.4 years in the middle.
So there you go, total travel time of roughly 5.4 years to travel 4.4 lightyears. Or almost but not quite 5 years and 5 months.
That's exactly what I did, nothing complicated about it, I think.
Rallan wrote:And I'm going to go out on a limb here and not even bother looking up the math, and say that to those on board it felt like roughly one year of subjective time (technically a little longer, since the middle of the voyage was spent at slightly below lightspeed).
Meh. I just looked it up.
Rallan wrote:As for acceleration, by a happy coincidence it just so happens that accelerating at 1G (9.8 metres per second squared) will get you to the speed of light in approximately one year (not exactly one year, but close enough that it'll feel almost like Earth gravity to the people on board for most of the trip).
That's correct as long as they're close to Earth, but it won't take long to get to microgravity where the G's will go up quite a bit.
- glitterboy2098
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Re: Math/Sci-Fi Question
Cybermancer wrote:I lack the knowledge and skills to find the answers to these questions on my own.
Assuming a maximum speed of 99.9999% the speed of light,
assuming a time of 365 days to accelerate to that speed (and to decelerate from that speed),
assuming a distance of 4.4 light years.
What is the rate of acceleration?
What is the 'g-force' from that acceleration?
How long does it take to cover the entire distance?
How much time appears to go by for those on the vessel due to time dilation?
Please explain your answer in simple laypersons terms and if possible, show your work.
Thank you for your assistance.
(P.S. I don't need to know things like required energy outputs but if you wish to include such, then by all means)
assuming constant accelleration, to reach the speed of light (or infinitely close there to) in one year would require an accelleration of about 10 m/s^2, or about one gravity.
light speed is 299,792,458 meters per second. at 10 meters per second per second, reaching would take ([[[299,792,458/10]/60]/60]/24) = 346.9 days. a little less than a year, but close enough for roleplay.
for distance covered, that tricker. each second you'd be going faster, and thus cover a bit more ground.. the formula is to find the average velocity based on starting and finishing velocity, then multiply by the time. (V2-V1)/2
in this case, ((299,792,485 -0)/2)*29,972,160 = 4,492,714,163,608,800 meters
or 4,492,714,163,608.800 kilometers. or about 0.00449lightyears... or about 30,031.9 astronomical units
energy use is going ot depend on your drive system and it's efficency.
please also note this ignores alot of the effects of reletivity past .6c
for the crew, the elapsed time would be two years under one gravity of accelleration (one to get up to speed, one to decellerate), and 4.39 years of coasting, IE weightlessness.
the main problem with this approach is that once you get close to c, space dust hits like an atomic bomb. and even in the local bubble, densities are such you'd be hitting one speck a each second during the coasting phase, where one speck would hit like half it's mass in antimatter.
frankly, it would make more sense to build the ship as hollowed out asteroid based o'neil colony that can be spun to generate artificial gravity, and then use the traction drive at a much lower accelleration, such that you'd reach alpha centauri after a 50 year trip (25 years accellerating, then 25 years decellerating.)
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Author of Rifts:Scandinavia (current project)
* All fantasy should have a solid base in reality.
* Good sense about trivialities is better than nonsense about things that matter.
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Visit my Website
- Cybermancer
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Re: Math/Sci-Fi Question
glitterboy2098 wrote: the main problem with this approach is that once you get close to c, space dust hits like an atomic bomb. and even in the local bubble, densities are such you'd be hitting one speck a each second during the coasting phase, where one speck would hit like half it's mass in antimatter.
frankly, it would make more sense to build the ship as hollowed out asteroid based o'neil colony that can be spun to generate artificial gravity, and then use the traction drive at a much lower accelleration, such that you'd reach alpha centauri after a 50 year trip (25 years accellerating, then 25 years decellerating.)
While you've raised some good points, 50 years won't work for a one way trip, at least not for what I'm setting up. Because there needs to have been a probe launched to determine that a suitable planet exists before an expedition could even start being planned. I actually have no problem with the colonists taking 50 years to get there (bigger ship=more time; makes sense in my laymen's mind). But I need to have a way for a probe to get there much faster. Twenty-five years or less (with less being quite preferable).
The time constraints are based on a few factors. The first is that I figure the mission would have had to be almost ready to go by the time the Rifts come. The second is I figure any probe would have to be launched 2050 or later. So in that 48 years or less, a probe has to make it to the destination, make the required observations and send them back. There also has to be a reasonable (by Rifts standards) amount of time for planning and construction.
So it looks like I'm going to be looking at solutions to the high speed impact delima that could possibly be implemented.
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Re: Math/Sci-Fi Question
http://www.nyu.edu/pages/mathmol/textbook/scinot.html
If that's true, then we have the energy of a dust particle being:
0.5 x (7.53 x 10^-10) x (3.0 x 10^8)^2 = 33,885,000 Joules of kinetic energy per particle.
Or 33.885 MegaJoules.
I think that glitterboy2098 has elsewhere attempted to calculate how many MegaJoules to 1 point of MegaDamage. If that's a compelling case, then you just pack on enough armour to see you through. How much armour is that? Well, you're the Game Master. So you could as well say that dust particles, no matter how fast, do not do M.D.
Do you know this number, 300,000,000 m/sec.?
It's the Speed of light !
Do you recognize this number, 0.000 000 000 753 kg. ?
This is the mass of a dust particle!
If that's true, then we have the energy of a dust particle being:
0.5 x (7.53 x 10^-10) x (3.0 x 10^8)^2 = 33,885,000 Joules of kinetic energy per particle.
Or 33.885 MegaJoules.
I think that glitterboy2098 has elsewhere attempted to calculate how many MegaJoules to 1 point of MegaDamage. If that's a compelling case, then you just pack on enough armour to see you through. How much armour is that? Well, you're the Game Master. So you could as well say that dust particles, no matter how fast, do not do M.D.
Re: Math/Sci-Fi Question
Natasha wrote:http://www.nyu.edu/pages/mathmol/textbook/scinot.htmlDo you know this number, 300,000,000 m/sec.?
It's the Speed of light !
Do you recognize this number, 0.000 000 000 753 kg. ?
This is the mass of a dust particle!
If that's true, then we have the energy of a dust particle being:
0.5 x (7.53 x 10^-10) x (3.0 x 10^8)^2 = 33,885,000 Joules of kinetic energy per particle.
Or 33.885 MegaJoules.
I think that glitterboy2098 has elsewhere attempted to calculate how many MegaJoules to 1 point of MegaDamage. If that's a compelling case, then you just pack on enough armour to see you through. How much armour is that? Well, you're the Game Master. So you could as well say that dust particles, no matter how fast, do not do M.D.
That last explanation will have players screaming "WHYYYYYY?" the moment they realise that every energy weapon in Rifts does damage using much smaller particles than dust, and most of them are travelling a lot slower than virtually lightspeed.
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Re: Math/Sci-Fi Question
I'm thinking that there are other ways of dealing with these particles.
For example, an electromagnetic or electrostatic ion scoop could be used to gather these particles for fuel as with a Bussard ramjet. Since traction drives have been chosen as the hand wavium technology to move the vessels at relavistic speeds, the problems of the ramjet are less pronounced. Such a device may also prove useful for deceleration at the target star.
For example, an electromagnetic or electrostatic ion scoop could be used to gather these particles for fuel as with a Bussard ramjet. Since traction drives have been chosen as the hand wavium technology to move the vessels at relavistic speeds, the problems of the ramjet are less pronounced. Such a device may also prove useful for deceleration at the target star.
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Re: Math/Sci-Fi Question
Rallan wrote:Natasha wrote:http://www.nyu.edu/pages/mathmol/textbook/scinot.htmlDo you know this number, 300,000,000 m/sec.?
It's the Speed of light !
Do you recognize this number, 0.000 000 000 753 kg. ?
This is the mass of a dust particle!
If that's true, then we have the energy of a dust particle being:
0.5 x (7.53 x 10^-10) x (3.0 x 10^8)^2 = 33,885,000 Joules of kinetic energy per particle.
Or 33.885 MegaJoules.
I think that glitterboy2098 has elsewhere attempted to calculate how many MegaJoules to 1 point of MegaDamage. If that's a compelling case, then you just pack on enough armour to see you through. How much armour is that? Well, you're the Game Master. So you could as well say that dust particles, no matter how fast, do not do M.D.
That last explanation will have players screaming "WHYYYYYY?" the moment they realise that every energy weapon in Rifts does damage using much smaller particles than dust, and most of them are travelling a lot slower than virtually lightspeed.
Without a doubt; you're absolutely correct.
Still, they've already accepted that such a weapon can be held in the hands of a toddler, so they would just have to accept the mystery, I suppose.
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Re: Math/Sci-Fi Question
Cybermancer wrote:
While you've raised some good points, 50 years won't work for a one way trip, at least not for what I'm setting up. Because there needs to have been a probe launched to determine that a suitable planet exists before an expedition could even start being planned.
actually, probes aren't required, since golden age tech would suffice to detect planets via telescope. we can already do this and take spectroscope readings to determain if the world is habitable or not.
plus, if you really want probes, you could send a probe much faster than a manned ship. not only i a probe unmanned, and thus expendable, but they'd also be somewhat smaller, and thus less likely to be hit. they're also safer to use things like magnetic feild based particle defenses on. (use a UV laser to ionize particle in your path, and a ultra massive magnetic feild to repel them. the problem being that unless you line the ship with a superconductor material for Em protection, it'll destroy electronics and kill living beings at the strength needed. probes are smaller, and can thus be so sheilded. manned ship would have to settle for weaker feilds to protect against radiation only, and use physical armor and slower speeds for dust and stuff.)
I actually have no problem with the colonists taking 50 years to get there (bigger ship=more time; makes sense in my laymen's mind). But I need to have a way for a probe to get there much faster. Twenty-five years or less (with less being quite preferable).
The time constraints are based on a few factors. The first is that I figure the mission would have had to be almost ready to go by the time the Rifts come. The second is I figure any probe would have to be launched 2050 or later. So in that 48 years or less, a probe has to make it to the destination, make the required observations and send them back. There also has to be a reasonable (by Rifts standards) amount of time for planning and construction.
So it looks like I'm going to be looking at solutions to the high speed impact delima that could possibly be implemented.
a laser Broom comes to mind. though at the strength needed, you'd be able to blow craters into the moon from the earths surface if you focused it as a weapon. but sweeping the path ahead with a laser to "push" the particle out of the way....it could work.
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Re: Math/Sci-Fi Question
A probe is required for two reasons.
One, while telescopes and spectral analysis will indeed tell a lot about a planet, you're not going to want to risk your life and the lives of your children and grand-children on that data alone. You're going to want to have detailed information about microbes and so forth. You're going to want to have as much specific data as you can get before departing.
Two, it proves the technology necessary to make the trip. Because again, you're risking your life and those of your fellow colonists.
Compared to human life, probes, even those that span interstellar distances are cheap and expendable.
One, while telescopes and spectral analysis will indeed tell a lot about a planet, you're not going to want to risk your life and the lives of your children and grand-children on that data alone. You're going to want to have detailed information about microbes and so forth. You're going to want to have as much specific data as you can get before departing.
Two, it proves the technology necessary to make the trip. Because again, you're risking your life and those of your fellow colonists.
Compared to human life, probes, even those that span interstellar distances are cheap and expendable.
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Re: Math/Sci-Fi Question
Cybermancer wrote:A probe is required for two reasons.
One, while telescopes and spectral analysis will indeed tell a lot about a planet, you're not going to want to risk your life and the lives of your children and grand-children on that data alone. You're going to want to have detailed information about microbes and so forth. You're going to want to have as much specific data as you can get before departing.
Two, it proves the technology necessary to make the trip. Because again, you're risking your life and those of your fellow colonists.
Compared to human life, probes, even those that span interstellar distances are cheap and expendable.
Meh. Change your alignment.
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Re: Math/Sci-Fi Question
Natasha wrote:Cybermancer wrote:A probe is required for two reasons.
One, while telescopes and spectral analysis will indeed tell a lot about a planet, you're not going to want to risk your life and the lives of your children and grand-children on that data alone. You're going to want to have detailed information about microbes and so forth. You're going to want to have as much specific data as you can get before departing.
Two, it proves the technology necessary to make the trip. Because again, you're risking your life and those of your fellow colonists.
Compared to human life, probes, even those that span interstellar distances are cheap and expendable.
Meh. Change your alignment.
Or get stupid colonists.
Or both.
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Re: Math/Sci-Fi Question
Remember, the probe doesn't need to return, it only need to get to it's destination and make it's observations then beam back its findings. The findings will get back to Earth long before the probe will (by about a year or so).
And sleekjag is right, why bother with all of these details? All you really need is a ballpark estimate and hand wavium it from there.
And sleekjag is right, why bother with all of these details? All you really need is a ballpark estimate and hand wavium it from there.
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Re: Math/Sci-Fi Question
dragonfett wrote:Remember, the probe doesn't need to return, it only need to get to it's destination and make it's observations then beam back its findings. The findings will get back to Earth long before the probe will (by about a year or so).
And sleekjag is right, why bother with all of these details? All you really need is a ballpark estimate and hand wavium it from there.
I don't agree that sleekjag is right.
These details may not be important to you or sleekjag but they are to some players and readers. It's also important for writers to research their material so that any hand wavium applied is used judiciously. Too much hand wavium can ruin an otherwise good story for some. Considering the information was easily gained simply by asking for it, I don't see the issue.
As to the probe, I never said anything about it returning. But the information does have to return and is limited by the speed of light just like everything else in the universe. In this case it will take 4.4 years for information to return to Earth after the probe arrives.
Although all of this is pretty much academic at this point. The question was asked, answered and then used in the campaign. The first submission to the Rifter was also sent about two weeks ago.
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Re: Math/Sci-Fi Question
More power to you then. Some people like it, others don't. And I also said just get a ballpark figure and pretty take it from there. In reality, there are so many more factors and variables that we haven't even thought of yet that would concern a trans-solar voyage.
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Re: Math/Sci-Fi Question
I thought in Star Wars, they go into Hyperspace, which bends space and does not conform to normal rules of Time and Space.
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Re: Math/Sci-Fi Question
And this is why, for my ship design material, I have pretty much thrown time dilation effects out the window for all Palladium space settings. Otherwise, you need something like PtP or "wormhole" technology to create a space opera setting that is both involved and compelling in my humble opinion. Thus, if my stuff ever sees print and goes into canon, expect the need for the accounting for time dilation to go out the window (i.e. the laws of astrophysics simply work differently within the Megaverse than our own universe, thus eliminating some of the need for us hard-corps versimilitude guys and gals to try and enforce "real world" standards of science on a fantastical setting).
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Re: Math/Sci-Fi Question
actually, time dilation's not really a problem until you get over .6c, at which point it becomes an asymptomic problem.
this means that no palladium space setting ever has to worry about it, since there are no settings where speeds get over .6c. (phase world has fluf stating .6c is the max for contragravitics, the old robotech never got above .6c, and most of the rest barely even get to .01c)
any travel over .6c is thus inviarably using a faster than light drive, which being 'handwavium', can simply ignore Reletivity.
this means that no palladium space setting ever has to worry about it, since there are no settings where speeds get over .6c. (phase world has fluf stating .6c is the max for contragravitics, the old robotech never got above .6c, and most of the rest barely even get to .01c)
any travel over .6c is thus inviarably using a faster than light drive, which being 'handwavium', can simply ignore Reletivity.
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Re: Math/Sci-Fi Question
What is .6c?
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Re: Math/Sci-Fi Question
dragonfett wrote:What is .6c?
60% the speed of light.
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Re: Math/Sci-Fi Question
Thanks
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Re: Math/Sci-Fi Question
dragonfett wrote:Thanks
You're welcome.
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Re: Math/Sci-Fi Question
paxmiles wrote:dragonfett wrote:In reality, there are so many more factors and variables that we haven't even thought of yet that would concern a trans-solar voyage.
For example, the speed of light is measured in a vacuum. Space isn't a perfect vacuum. If it were, planets wouldn't be possible.
Even if you could go 99.9999% the speed of light, there still might be slow points and fast points. Not to mention the typical inability to slow down when your going that fast - honestly, that's the most amazing part of Star Wars or Star Trek - they can stop after going that speed...
-Pax
Well no it's not amazing, because in Star Wars and Star Trek they're using "sufficiently advanced technology" that does whatever the writers want it to. And since that sufficiently advanced technology isn't even described as working the way you seem to think it works, there's nothing particularly amazing about what you've just mentioned
Re: Math/Sci-Fi Question
glitterboy2098 wrote:actually, time dilation's not really a problem until you get over .6c, at which point it becomes an asymptomic problem.
this means that no palladium space setting ever has to worry about it, since there are no settings where speeds get over .6c. (phase world has fluf stating .6c is the max for contragravitics, the old robotech never got above .6c, and most of the rest barely even get to .01c)
any travel over .6c is thus inviarably using a faster than light drive, which being 'handwavium', can simply ignore Reletivity.
And there you're wrong, since Traction drives (available both in Mutants In Orbit and in Phase World, althoug it's an obsolete low-tech way of doing things in Phase world) allow for indefinite acceleration up to the speed of light. As you would've known if you'd bothered to actually read this thread
And it's particularly problematic in Mutants In Orbit, because traction-drive ships there are able to reach any planet in the solar system in a few weeks at most, and a long range mining or scouting trip to the outer reaches of the Oort Cloud would only be a few months either way. And since in the current setting (where the writers never sat down and did the math) people are described as being perfectly willing to travel via chemical-drive ships for several months just to reach the asteroid belt, then it stands to reason that if any NPC in Mutants In Orbit ever magically gets better at highschool physics than Kevin Siembieda, they'll be quite willing to go on voyages to the outer solar system which will involve travelling at high enough fractions of c for time dilation to become pretty darn noticable.
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Re: Math/Sci-Fi Question
What he said.sleekjag wrote:It's your game just make it up. Is it scientific no but are you playing with a bunch of physicist that will call you out on it probally not. There's plenty of math to work with in the thread so just go with what works for the campaign. No big deal. But have to give a big thinks to those that did the math.
"Forget" the Science.
For just one thing....don't they say somewhere that due to extreme time dilation on the part of the lightspeed traveler, that it only takes a single hour of lightspeed travel for a thousand years to pass for the rest of us not on the ship??
Even the indestructible walls of Center in the Three Galaxies will start rusting by then, the journey will take so "long!"
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Re: Math/Sci-Fi Question
cornholioprime wrote:For just one thing....don't they say somewhere that due to extreme time dilation on the part of the lightspeed traveler, that it only takes a single hour of lightspeed travel for a thousand years to pass for the rest of us not on the ship??
Something like that. As you approach the speed of light, the amount of time dilation you get increases exponentially, which means that the amount of time you get approaches zero.
At 90% of the speed of light, you could travel for a thousand years and experience about 450 years of subjective time.
At 99% your thousand year voyage feels like about 140 years subjectively.
At 99.9% it's only about 45 years.
If we were to kick it up a notch and travel at 99.99999999999934% of the speed of light, you'd get your thousand year voyage that feels like an hour.
And at lightspeed itself (which in theory is impossible, rather than just insanely difficult like those previous speeds), your thousand year voyage feels like no time at all. To the outside world you've travelled at the speed of light for a millenium. To you, you've travelled a thousand lightyears in an instant.
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Re: Math/Sci-Fi Question
Abub wrote:OH MY GOD I CAN SEE FOREVER
You can save yourself all this trouble by declaring they hit an asteroid in the 10th month of acceleration and all die.
Rocks fall and everybody dies?
Bad form, poor GMing and general jerkiness all wrapped up and rolled into one.
Thanks but no thanks.
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Re: Math/Sci-Fi Question
Cybermancer wrote:Abub wrote:OH MY GOD I CAN SEE FOREVER
You can save yourself all this trouble by declaring they hit an asteroid in the 10th month of acceleration and all die.
Rocks fall and everybody dies?
Bad form, poor GMing and general jerkiness all wrapped up and rolled into one.
Thanks but no thanks.
It is something that you might have to find a way around though. If this sort of epic space voyage is just a very occasional thing, then you can sorta gloss over it and hope nobody asks questions. But if puttering around with ships that can travel at almost the speed of light is a common part of your campaign, you'll need to come up with an explanation for why nobody ever faceplants into a planetoid that they didn't see, or nobody gets ripped apart when they impact a golfball-sized piece of debris with the relative mass of the Titanic.
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Re: Math/Sci-Fi Question
The voyage out at light speed is going to be pretty much a singular, once in human history event. I'm using a MacGuffin that basically moves particles and debris around the ship as it moves through space. The ship will also use laser brooms and then just avoid anything too big.
I have other plans for the voyage back. They won't be travelling in normal space at all.
I have other plans for the voyage back. They won't be travelling in normal space at all.
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Re: Math/Sci-Fi Question
Cybermancer wrote:The voyage out at light speed is going to be pretty much a singular, once in human history event. I'm using a MacGuffin that basically moves particles and debris around the ship as it moves through space. The ship will also use laser brooms and then just avoid anything too big.
I have other plans for the voyage back. They won't be travelling in normal space at all.
In that case, don't fret the details too much. Whatever handwavium you use to justify the lack of crashed is good enough.
All you have to do is figure out what they'll do during the voyage. Because even if their top speed is so close to lightspeed that it seems almost instantaneous, you've still set yourself a long acceleration/deceleration time at either end.
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Re: Math/Sci-Fi Question
even at lightspeed, a trip to alpha cent would be a bit under 5 years. plus the year or so on each end to speed up, slow down. so at least 7 years to get there. at a speed where getting hit with a stray cosmic ray is like being nuked, and even dust can gut a ship. and there is no mechanism to "move debris around the ship" that doesn't completely break physics, even more than traction drive does. even traction drive is constrained by conservation of energy and momentum..it just uses spatial warping to go from energy to movement directly.
if this trip is a onetime only deal, slow it down, use armor and laser brooms, and put the whole thing on a mobile asteroid so you have a large enclosed setting before you even reach alpha cent.
if this trip is a onetime only deal, slow it down, use armor and laser brooms, and put the whole thing on a mobile asteroid so you have a large enclosed setting before you even reach alpha cent.
Author of Rifts: Deep Frontier (Rifter 70)
Author of Rifts:Scandinavia (current project)
* All fantasy should have a solid base in reality.
* Good sense about trivialities is better than nonsense about things that matter.
-Max Beerbohm
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Author of Rifts:Scandinavia (current project)
* All fantasy should have a solid base in reality.
* Good sense about trivialities is better than nonsense about things that matter.
-Max Beerbohm
Visit my Website
Re: Math/Sci-Fi Question
glitterboy2098 wrote:even at lightspeed, a trip to alpha cent would be a bit under 5 years. plus the year or so on each end to speed up, slow down. so at least 7 years to get there. at a speed where getting hit with a stray cosmic ray is like being nuked, and even dust can gut a ship. and there is no mechanism to "move debris around the ship" that doesn't completely break physics, even more than traction drive does. even traction drive is constrained by conservation of energy and momentum..it just uses spatial warping to go from energy to movement directly.
if this trip is a onetime only deal, slow it down, use armor and laser brooms, and put the whole thing on a mobile asteroid so you have a large enclosed setting before you even reach alpha cent.
Um, dude? We already covered all of that. Including the bits that you either forgot to mention or didn't know about, like the time dilation effects of travelling almost as fast as the speed of light which would make the journey seem much shorter for the people on board.
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Re: Math/Sci-Fi Question
glitterboy2098 wrote:even at lightspeed, a trip to alpha cent would be a bit under 5 years. plus the year or so on each end to speed up, slow down. so at least 7 years to get there. at a speed where getting hit with a stray cosmic ray is like being nuked, and even dust can gut a ship. and there is no mechanism to "move debris around the ship" that doesn't completely break physics, even more than traction drive does. even traction drive is constrained by conservation of energy and momentum..it just uses spatial warping to go from energy to movement directly.
if this trip is a onetime only deal, slow it down, use armor and laser brooms, and put the whole thing on a mobile asteroid so you have a large enclosed setting before you even reach alpha cent.
1. The MacGuffin is linked to the traction drive and frankly, doesn't break physics any more or less than the traction drive. Both do equally impossible things. In that something either is possible by physics or it is not. There are no degrees in between.
2. So far as the Rifter article, it's written as an optional feature which a GM can ignore or not include. The option for a longer trip is also included. Either for GM preference or due to failure of the players to get the MacGuffin.
3. Already mentioned that I'm using laser brooms on it. Look up thread for that.
4. It is an armored asteroid.
5. How it has played out in my campaign and the baseline assumption for the article (already submitted) is that it will be accelerate at 1G until reaching nearly the speed of light. Then it will coast for most of the journey before decelerating at the other end.
I needed to know the length of actual time and time dilation effect for the crew in order to work out a timeline (and optional alternate timeline) to fill the gap between departure (the conclusion of the orbital Chaos Earth adventure) and current Rifts era.
BTW, to all. I could have sworn I read about a Neptune mission in a Rifter someplace set in the Chaos Earth timeframe but haven't been able to locate it since. It had a real horror feel to it. Maybe I dreamed it after watching Event Horizon or something. I have all the Rifters (except 52 which just came out) so I'm wondering if I'm just not seeing it or something. Is this article real and if so, what Rifter did it appear in? Page number too, if you can. Thank you.
Just as a general update.
The Chaos Earth adventure has been run in my group, they enjoyed it. I've begun play testing some features of what I'll be including in the follow up article. The players have enjoyed it and it seems to be working out from a game balance perspective. I'm still filling in the 'in between' details between the two eras although I have a fairly broad outline done. Just some details to sort out. I'm including alternate notes and timelines so that it can be ran to taste. It seems like a good way to take advantage of the fact that the Rifter is not canon material. I'm also seeing it as an experiment in having player actions effect meta-plot. Orbit also serves well in this respect as the setting is isolated from the rest of the Rifts world.
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Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
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Re: Math/Sci-Fi Question
Recently came up with a new idea of how to build the colony vessel. It's going to be a constructed spacecraft on the same engineering scale as the space stations in orbit. I originally had planned for the hollowed out asteroid concept but ultimately I liked this design better. And based on the scale of engineering projects already taking place during the golden age of man, it seemed feasible. The best part of this is that it allows me to reuse the design and indeed the very ship for a return voyage to earth in the current time (109-110 PA)
I have slowed down the speed of the journey to Alpha Centauri significantly. This is part due to the deletion of the traction drives. I've replaced them with nuclear pulse drives instead.
Basically the new design is a space station with engines added and designed to establish an extra solar colony.
I also changed the name to the United Nations Colony Vessel (UNCV) Jupiter.
Here are the basic stats I wrote up for it last night. Still a work in progress at this point.
I'd like to thank everyone who has contributed ideas thus far. I'd like to single out glitterboy2098 for special thanks in his assistance both in this thread and in PM. I haven't used all your ideas and suggestions but I have toned down the 'fantastic' and dialed up the science. Plus I've learned a lot of interesting things along the way.
Just hit the spoiler tag to see the stats and history.
I have slowed down the speed of the journey to Alpha Centauri significantly. This is part due to the deletion of the traction drives. I've replaced them with nuclear pulse drives instead.
Basically the new design is a space station with engines added and designed to establish an extra solar colony.
I also changed the name to the United Nations Colony Vessel (UNCV) Jupiter.
Here are the basic stats I wrote up for it last night. Still a work in progress at this point.
I'd like to thank everyone who has contributed ideas thus far. I'd like to single out glitterboy2098 for special thanks in his assistance both in this thread and in PM. I haven't used all your ideas and suggestions but I have toned down the 'fantastic' and dialed up the science. Plus I've learned a lot of interesting things along the way.
Just hit the spoiler tag to see the stats and history.
Spoiler:
I was raised to beleive if you can't say something nice about a person, say nothing at all. This has led to living a very quiet life.
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?
Someone who tells you what to think is trying to control you. Someone who teaches you how to think is trying to free you.
WWVLD?