The difficulty with Hard Sci-fi

I think that was his main problem with the theory: if it's a straight shot fine, but if you need any special maneuvers good luck. Space ships like that would probably cost a lot of money and would you want to risk its destruction and your death because you are solely relying on lasers?

 

Wow, I think you are really going to need to do some hand waving no matter what you choose. A beam ship sounds nice but the more you try to explain it the harder it is for me to understand. I have a couple of stories in mind to address near light speed and FTL travel. My near light speed concept is to use gravity tunnels between black holes that exist either by freak of nature or some ancient unknown alien civilization created them for a highway system. Sort of like the trade winds in the Atlantic Ocean. Gravity is a great way to hand wave since it simply defies explanation at this time.

For my FTL concept, I fall back to the Big Bang Theory, actual theory not the show. When the Big Bang occurred matter was propelled out at speeds much greater than light, much greater, I mean much, much greater. How could that happen? Simple explanation: light speed constraint only applies within the universe, which didn't exist before the Big Bang, so no problem, go as fast as you want. Then you mentioned something that fits into my concept about space being sparsely populated, which is another scientific hand wave. However my thought is that an object could move between the objects in space at unlimited speed because they are essentially outside of the universe, a hand wave of course. Things like photons move at near light speed and are limited to that since they have no means of acceleration in my own hand wave opinion. So if a ship is shaped like a dart it might travel between particles in space and of course I would hand wave a FTL beam projected out from the space craft to encounter and clear the path of any extraneous particles that would create a problem. Of course traveling FTL means you arrive at your destination before you depart which creates an issue getting volunteers for missions that didn't succeed before they were launched.

Anyway I hope you write your story, I want to read it already.

 

Sounds kind of like a hyperspace idea to travel outside of normal space. Then the travelling between particles sounds kind of like a wormhole.

In terms of an inflation drive it would be worth looking at how electro-magnetism and space-time affect one another. It might be possible to actually manipulate space-time via electro magnetism to create propulsion.

With regard to photons there is an argument that because at the speed of light time has stopped and they are of infinite mass, there is in fact only one photon in the universe existing everywhere at once.

I am not sure that time would run backwards at FTL, or more accurately that if it does the causality violation would probably preclude this type of travel. If not then getting close to light speed would result in a huge time dilation (i.e. a few days would pass on the ship, but many years on earth). Instantaneous acceleration would also liquefy the ship and its occupants so (unlike Star Trek) it would probably take many months to get up to speed.

This is an interesting alternative (which also requires a LOT of hand-waving): http://en.wikipedia.org/wiki/Alcubierre_drive

 

I believe the general sci-fi reading public will be happy with any explanation as long as it isn't obviously wrong to the layman. The sci-fi audience is not made up of Stephen Hawkins types, and trying to create a really believable method of inter solar system travel is more a matter of not saying too much since it is currently impossible , therefore not really credible. Thank goodness for the fiction part of sci-fi. As far as time dilation I am not sure what the current scientific thoughts are but when I was a kid I remember NASA had computed how many microseconds some astronauts had not experienced relative to time on Earth since they orbited for several days. If NASA believes in it, then that is good enough for me and probably 99% of the world. As far as going backwards in time, that is always just a fun thing to toy with, Superman did it by zipping around the world FTL, but as with so many comic book characters they get added powers/capability whenever they happen to need it. I believe there maybe a Deus ex machina type term for that particular situation. Please write your story and not get hung up on the transport mechanism, you obviously have already put a lot of work into the research aspect. To infinity and beyond!

BTW, I am curious what you meant that a photon has infinite mass? Did you mean that or infinitesimal mass? You make a photon sound like Chickenman: "He's everywhere! He's everywhere!" Yeah, yeah, I'm old.

 

On the topic of whether our understanding of the universe could change, it very well could. It's true that scientists from the 1800s believed some things to be true that were later proven to be false. However, there were also many things they got right. For example, our understanding of thermodynamics hasn't changed in about the last 200 years. FTL travel and our understanding of the speed of light falls in the latter category. No matter what happens, we aren't going to have FTL travel.

 

That statement falls into the category of things I don't think you can know with certainty.

 

Based on what we know and what we've known for hundreds of years, this is one of those rules that isn't likely to be broken. If FTL travel does become possible, then that means the universe fundamentally changed in some way, which is bad news for us.

 

Time dilation increases with relative speed on an exponential curve. So an astronaut at earth orbit speeds is subject to vanishingly little, but someone travelling at 0.8c is subject to a hell of a lot. At light speed the passage of time stops.

I've never even heard of chickenman

 

I don't agree with this either. Past changes in our fundamental understanding doesn't mean the universe changed, just our understanding. These statements are rooted in contemporary understanding, and maybe not even a complete one at that, given that you can find work by physicists discussing theoretical FTL options (for example: http://iopscience.iop.org/0264-9381/11/5/001/pdf/0264-9381_11_5_001.pdf).

That idea that our understanding of the universe couldn't change significantly enough that additional options might become available is short-sighted, and there's no reason for a firm belief that it must be true.

 

I am sort of torn on this. Obviously there are theoretical ways to exceed light speed, but they all rely on negative energy which probably doesn't exist.

But there are several major issues that simply aren't explained: -

• The incompatibility of classical physics and quantum mechanics.
• Almost everything about inflation in the early universe.
• The fact that gravity is insufficient to hold galaxies together (leading to the invention of dark matter to balance an equation).
• The fact the universe is expanding at an ever increasing rate (leading to the invention of dark energy to balance an equation).

These are just such huge unknowns; I mean vast areas of wilderness in our understanding. I think the theory of everything is likely to result in quite a fundamental shake up of our current understanding.

But then again special relativity is experimentally confirmed and we have to go with what we know.

 

We have a good understanding of the speed of light and what happens as you approach that limit. The fact that no particle can be accelerated to the speed of light or travel at the speed of light is a sound assumption that allows us to formulate certain results in relativity, and these results are backed by experiments or observations. While I admit that our understanding of the universe is constantly improving, there are certain physical laws that are unbreakable.

 

Doesn't this violate the Wanted movie bullet flight's curviture?

 

I feel for you. I had to give up trying to do hard sci fi. I just did not have the requisite educational background/knowledgebase to do it and I found myself spending an inordinate amount of time researching.

 

Fortunately it is an interest of mine anyway (the science part)- so it is a "two birds, one stone" situation.

 

I understand... for me, I've actually hired an astrophysicist to do calculations on the dimensions, centripedal acceleration, tonnage, etc. of my fictional space station. Lol.

 

Fair play, my brain just doesn't work the right way for complex formulas(ae). The more I work at this the more it moves towards space opera (but with realistic-ish science). I just find myself discarding the hard science because it is too dry for a novel. However, I want the science to be consistent so it is useful.

 

Hope necroposting is not frowned on here. I found the discussion interesting and am curious about the lenses?

How do they work?

 

I think the point is to use the lenses to focus a laser beam in the direction of travel (a sort of escalator) which the spacecraft "collects" as energy and is driven forward at a steady acceleration.

Google "Lightsail" for some real (as opposed to theoretical) science behind the idea of photon-powered spaceflight.

Also, Deep Space Nine, episode 68, Explorers for a more fictional account.

The big problem that I perceive with solar-powered spaceflight is what you use for energy in the inter-stellar void? Can you get up enough speed from the sun (before you get out of range) to coast to the next star? I think the lenses and directed laser beams are a means to obviate this problem.

 

I already know about light sails but thank you for the suggestion. I think they were described in a book I had 30 years ago.

I have also been following Bill Nye who has successfully run a recent kickstarter campaign to raise money to prove / explore the concept. You can read about it here:

I also read OP, so understand the intended mechanism for propulsion.

I was hoping the words "am curious about the lenses" would provide sufficient clues as to my point of interest, namely the 1km diameter lenses - the ones focusing solar powered lasers. How do they work - ie
* are the lenses in geosynchronous orbit around the sun?
* is the route to the destination solar system outside the orbital planes of all our solar system planets / moons or do you somehow switch off the beam as planets, etc cross it?
* how do you switch off the beam? if the laser is off do you need to rotate the lens also so it does not send a concentrated beam of sunlight into an earth satellite or planet?

That kind of stuff

 

Just ran across this informative and intriguing article on the importance of software to interstellar travel, and the ways to build safeguards into it. Basically, no matter what else happens, if your onboard software fails, you'll need to repair it fast, or else you're dead:

http://www.space.com/29509-software-borg-starship-greatest-threat.html

 

My trilogy includes spaceships and travel to another solar system, hence my interest in the subject. As a programmer, I could not agree more with your article link, jannert, both in space and here on our ship called earth

 

Hi,

I think it's fascinating that you want to create this craft and put all this hard science design into it, but at the snd of the day science fiction is a story. It's about people. And who the hell would get into this craft? Fifteen years each way to a star that we know little or nothing about, stuck in a little tin can? Honestly murderers get better sentences!

Cheers, Greg.

 

Me. And exploratory types like me.

 

Hi,

Honestly I doubt it. That's thirty years of your life (or at least the world's assuming relativity) with maybe one or two people to talk to for all that time, stuck in a little tin can, the very real chance of death, and when you get back your family gone or at least largely having forgotten you. Very few would sign up for a mission like that.

As I say even murderers get time off for good behaviour, walks in the exercise yard, visitors and phone calls. And they're the people we're punishing!

Cheers, Greg.

 

You doubt it therefor that's it? An adult with significant life experience confidently tells you they would do something and you simply disagree? I find this a little arrogant, to be honest. Or are you calling me a liar?

It's 15 years of your life. Who said anything about coming back? You don't lose it, either, you get to do something completely novel with it.
Who says I talk to more than 2 people now?
Who says I spend that much time outside my bedroom / lab / office now?
Who says I do not have a very real chance of death now?
Who said I have any family?
If I do have family, who says they should hold me back from experiencing the life I wish to experience?

Do you think Christopher Columbus was 100% confident he'd ever get home again? Or Hannibal?

Could not agree more - just me and explorers like me. But apparently that's wrong...

Based on the premise that people who have no choice in being incarcerated have "a better deal" than the people who do have a choice and choose to do something out of this world? I am really not following your logic here.

Is it possible that you are simply projecting your own fear and/or distaste for this journey onto others? I get that, that's very understandable. Disagreeing with someone about what actions they would take seems somewhat remiss and has clearly pushed a button. I apologise if my response has been too harsh or direct.