Speed, acceleration, distance, time question

[texasman1979]

I thought i would post what yall helped write.
It is relatively simple but will go a long way toward me getting realistic numbers in my story.
I am going to add a bit more to it as the story requires it.

I think you will all enjoy the very realistic technology as well as some a bit more imaginative making the things in this story possible.

Now I can begin again. :)

 

[texasman1979]

Something that I would like to include is defeating Earth's gravity well.

http://en.wikipedia.org/wiki/Escape_velocity

That is for more info concerning various exit velocities. In order to figure the math properly, the gravity wells need to be accounted for.

This won't change my numbers by terribly much, but I'm wanting to be as accurate as I can.

All the trips in my book start in Earth orbit with an initial velocity of 3.07 m/s^2.

As an aside, I did the math and you would be shocked at how little thrust is needed for a ship of 344730 kg mass to go 6083288.935 miles per hour. Its shockingly little effort once you get to around the Kuiper belt. According to my math, we have the technology right this very minute to send probes to the nearest stars and they would get there before 2075. Then they could beam back lots of lovely information for our kids and grand kids.

 

[Drakkith]

As an aside, I did the math and you would be shocked at how little thrust is needed for a ship of 344730 kg mass to go 6083288.935 miles per hour. Its shockingly little effort once you get to around the Kuiper belt. According to my math, we have the technology right this very minute to send probes to the nearest stars and they would get there before 2075. Then they could beam back lots of lovely information for our kids and grand kids.

We have the propulsion technology. Kind of. I don't know how well solid or liquid propellant holds up after up to 60 years in space. Not to mention the issue of keeping the electronics working for so long. Cosmic rays play havoc with spacecraft electronics, and I think we've had multiple spacecraft fail because of faulty electronics, possibly from cosmic ray strikes. The issue of interstellar travel, even by unmanned probes, is a complicated one, and there are no easy solutions or shortcuts to getting to even the nearest star.

 

[meBigGuy]

Sounds like you are having fun with this. Nice script you built.

You are forgetting that kinetic energy = 1/2 MV^2. Saying you are providing thrust is one thing, but where will that energy come from.

Maybe you are also forgetting that you must carry your fuel that provides the thrust. You are required to expel mass to accelerate the ship.

You also need to slow down at the other end which requires fuel also. (but you have less mass then, so that helps)

Redo your numbers to calculate and include the mass you must expel to get the thrust at each end.

http://exploration.grc.nasa.gov/education/rocket/rktpow.html is the ideal rocket equation

http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

http://en.wikipedia.org/wiki/Spacecraft_propulsion

http://en.wikipedia.org/wiki/Interstellar_travel

Here is an interesting narrative:
http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html

 

[texasman1979]

The only time expelling mass for propulsion is mandatory is when one is using chemical rockets.

Solar derived Electricity and electromagnetism work on entirely different principles. Remember, like poles repel one another.

I could have figured out the things this thread was about just fine given time. It's just been so long since I took math that I wasn't to be sure.

Yall will like my book. :-)

 

[Drakkith]

The only time expelling mass for propulsion is mandatory is when one is using chemical rockets.

Solar derived Electricity and electromagnetism work on entirely different principles. Remember, like poles repel one another.

I don't know what kind of propulsion you're talking about, but all forms of propulsion that I know of either depend on expelling mass (or shooting light, which has momentum) or absorbing/reflecting radiation from a star. I've never heard of any realistic propulsion involving "like poles repel one another" except in ion drives. Which expel mass.

 

[meBigGuy]

I was keying on your statement
"According to my math, we have the technology right this very minute to send probes to the nearest stars and they would get there before 2075"

What non-mass ejecting technology that we have right now were you referring to?

 

[texasman1979]

The closest thing to perpetual motion that we know of is the electron revolving around the nuclei of atoms. That most basic of energies is available to exploit.

Electricity and magnetism are the things that make it possible.

The core of the Earth is a big glob of a ball of random churning that generates an enormous magnetic field. A magnetic field that does indeed modify the trajectories of billions of tons of mass coming from the sun. If the Earth had a mass of only a few million kg, the force with cosmic matter would out shine gravity.

A ship the size of an aircraft carrier has the size to house a generator of enough efficiency to make a magnetic field comparable in size to the Earth's field.

Space is a lot more dense with matter than we have the ability to test for and this matter is more than sufficient to provide, a massive enough magnetic field, resistance to push against. That in association with a channeled magnetic field can cause enough propulsion for any size vessel.

You don't necessarily have to eject mass, you can eject focused magnetism for thrust.just imagine a vessel the size of an aircraft carrier pulsing out a magnetic field equal to that of the earth's. There is an amazing amount of power there.

The clincher really is only limited to a sufficent and efficient means of generating electrical power.

Atoms have all the power we need and I'm not talking about nuclear, I'm talking about a whole new look on generator technology. But until then, the sun has all the electricity we need to propel a probe to our nearest star neighnors. As well as all around the solar system.

 

[Dale]

Sounds like a good science fiction device.

 

[texasman1979]

All inventions are fiction until they are fact. :-)

 

[Dale]

Sure, as long as you understand that this is not even remotely close to "we have the technology right this very minute". Not only is this not technology that we have now, it is not even on the technological horizon. It would not even be classified as hard science fiction currently.

The only way it can be discussed here on PF is in that context and with that recognition.

 

[meBigGuy]

Pretty much everything you said shows you have no understanding of what magnetism is and how it can be utilized. Great hand waving, though. But not precise enough for even a hard SF novel.

But, if you need more help with f=ma, etc or the rocket equations, feel free to ask.

You should probably stay away from expounding your beliefs in the magnetism stuff in this thread, or it will get shut down.

 

[texasman1979]

I suppose I did make the mis-step of implying this technology is potentially possible. It will be soon enough though.

But yes, with what we have now, and a little imagination, and the concept of making it important to society, we could have a probe in the alpha centauri system within 30 years. It would take multiple sling shots around Jupiter and the sun. Then a solar assisted ion stream geared toward maximum thrust. Achieve the highest speed possible. Then fire laser beam powered by the sun into a titanium plate pushing the probe until the distance becomes unpheasable.

The speed attained by those steps on a roughly 1000 kg probe is enough for the craft to get there within the typical working span of a generation.

If humanity wanted to do it and decided to take the steps necesary, we could do it.

 

[texasman1979]

Let's cruise back to the original question then.

Being that the vessels in my book are all starting in geosynchronous orbit of Earth or the moon, how would gravity manipulate the equations above in there initial departure from orbit. If you will suspend disbelief, I am purposely ignoring relativistic effects, but I do wish to figure how the Earth and moon would effect acceleration and thrust. (Relativistic effects as in time travel and the warping of space/time)

I really would hate for this thread to die over a difference of opinion. Star trek and star wars and a great many others have technology that, according to popular science, are impossible, but that doesn't necessarily make the book or movie any less interesting to watch. Not all inventions have been invented yet. I would hope we can agree on that.

 

[Evo]

I suppose I did make the mis-step of implying this technology is potentially possible. It will be soon enough though.

But yes, with what we have now, and a little imagination, and the concept of making it important to society, we could have a probe in the alpha centauri system within 30 years. It would take multiple sling shots around Jupiter and the sun. Then a solar assisted ion stream geared toward maximum thrust. Achieve the highest speed possible. Then fire laser beam powered by the sun into a titanium plate pushing the probe until the distance becomes unpheasable.

The speed attained by those steps on a roughly 1000 kg probe is enough for the craft to get there within the typical working span of a generation.

If humanity wanted to do it and decided to take the steps necesary, we could do it.

Please do not make claims that you cannot substantiate.

 

[texasman1979]

Let's cruise back to the original question then.

Being that the vessels in my book are all starting in geosynchronous orbit of Earth or the moon, how would gravity manipulate the equations above in there initial departure from orbit. If you will suspend disbelief, I am purposely ignoring relativistic effects, but I do wish to figure how the Earth and moon would effect acceleration and thrust. (Relativistic effects as in time travel and the warping of space/time)

Also, do any of you know of a forum where I can dicuss theoretical physics? Without billions of dollars I can't substantiate much but I still would like to discuss my theories in a more open minded setting. I also have some theories about dark matter and the similarities between gas giants and stars.

I spent two years in school for software engineering before I had to go to work to support my child. In a few years he will be old enough where I can go back. Maybe then I won't sound so crazy.

 

[texasman1979]

But, if you need more help with f=ma, etc or the rocket equations, feel free to ask.

Being that the vessels in my book are all starting in geosynchronous orbit of Earth or the moon, how would gravity manipulate the equations above in there initial departure from orbit? If you will suspend disbelief, I am purposely ignoring relativistic effects, but I do wish to figure how the Earth and moon would effect acceleration and thrust. (Relativistic effects as in time travel and the warping of space/time)

What you say meBigGuy?

Do any of you know of a forum where discussions on theoretical physics is allowed? According to the rules here, anything that might contradict or refute what is maintained in popular science is banned. Okay, I can live with that. Where do people like Edison, Tesla, or the Wright brothers go to talk about new ideas? Like my belief that time travel via relativity is complete and utter nonsense. Where can that be discussed?

 

[texasman1979]

Just for giggles I did the math on that 1000 kg probe.

And I added some functionality for my program I'm writing for data for my book. If anyone would like the source, just holler at me.

 

[texasman1979]

http://science.howstuffworks.com/electromagnetic-propulsion.htm
http://www.sciencetimes.com/article...tary-travel-on-electromagnetic-propulsion.htm

Those whom suggest that my theory has no base in fact can take a look at this. There very well could be a variation of this that would work marvelously.

With that being said, my being deemed a crackpot can be revised a bit I think.

So, how does my equations need to change to account for the gravity of Earth, moon, other bodies?
How can i graph the data in such a way where i can pull speeds at various times considering acceleration?
And anything else you might think may help me write this book scientifically accurate.