Light Speed and Artificial Gravity.... killing 2 birds?

Question

I am curious how difficult would be to obtain light speed with a constant acceleration of 1g.

At a constant acceleration of 32.2 ft/ sec (1g), artificial gravity would be created for the humans traveling inner stellar space. According to my calculations (which could be wrong) it would only take 355 days to reach 186,000 miles per sec (light speed).

I would think that decelerating at this rate (from light speed) would also cause artificial gravity on the opposite side of the ship. The nearest star can be reached in less than 6 years, and the human would be healthy.

Is this idea possible considering there in nothing in space to inhibit acceleration?

Answer 1

to reach the speed of light? an infinite amount of time.

your not factoring in relative mass. as something accelerates energy is added to it (obviously). if you were to add one joule of energy something that joule would carry it onward forever. but where did it go? it cant just disappear. it added to the total energy of the object, and therefore it added to the total mass. as something gets faster it also gets more massive. if it were to reach light speed it would have an infinite mass.

the equation for relative mass is M = M0 / sqrt( 1 - ( v^2 / c^2 ) ). so if an objects velocity were the speed of light the denominator would become zero, meaning the solution becomes infinity.

so traveling at light speed is impossible.

Answer 2

Your calculations could be verified only by the travelers.  Observers on earth would grow old and die waiting for the arrival at the other star system.

While there is nothing in space to inhibit acceleration, there is also nothing to cause it to occur at values approximating g.

Answer 3

You need Relativity for this.  As you gain speed, mass increases and time to an outside observer slows down.  The energy requirement becomes greater and greater.  So you will run out of energy before you got to light speed.  At the same time it is taking longer and longer to get the next increment of speed.  Assuming it was possible, yes, to you on the ship it would take 6 years.  To the outsid observer it would take centuries.

Answer 4

You cannot travel at the speed of light, you will have trouble with the adjusting mass and gravitation, you will turn into a spoilt matter

Answer 5

what causes this acceleration?

are you also aware that (relativistically) speeding objects also increase in mass?  so as the speed increases, so does the force required for acceleration, and so the energy input for the propulsion...

so while there's nothing in space to inhibit the acceleration, the universe inhibits it anyway :P

Answer 6

I had a prof as an undergrad give a great lunch talk that demonstrated why what you say is, if not impossible, not exactly practical.

Your calculation to get to light speed isn't quite right (it uses nonrelativistic mechanics), but it will do as an order of magnitude to get you up to relativistic speeds (a significant fraction of c).  Of course you have an equal period of deceleration at the end of your trip.  You'll have to rotate the ship so your gravity is the way you want it, but that's cool.  So far so good.  In fact, your travel time gets cut somewhat by time dilation.  Old pilot and Steve have it backwards--the trip is on the order of 6 years to the observer and SHORTER for you.  All the better!  And you get to enjoy gravity during the acceleration and deceleration and zero g during the cruise time.  It's sounding pretty cool, right?

There are two wet blankets that get thrown on the idea.

1)  The amount of energy needed to get you up to relativistic speeds is staggering.  Even if you had an absolutely perfect engine that converted matter to antimatter and propelled you with massless propellant (photons), you need to carry many times the mass of your ship in fuel to slow down.  And then square that "many times" number to get you (and the fuel you need to slow down) up to speed in the first place.  And for anything resembling a real propulsion system--fusion power, for example, the amount of fuel you need to get up to relativistic speeds is completely ridiculous.

2)  Your notion that there is nothing in space to slow you down is not exactly correct.  There is a proton here and there.  That might not seem like much, but when you travel at relativistic speeds, it creates a serious drag that will slow you down.  You have to overcome that drag AND shed the energy somehow that you pick up when you hit it AND protect yourself from what is, in effect, some seriously boosted high-energy cosmic radiation.  It turns out you need a lot of shielding.  And a lot more shielding means a lot more fuel.

So don't hold your breath waiting for the engineering details of interstellar flight to be resolved.

This talk was hilarious.  He played it like he was an interstellar used car salesman.  He had all the exact numbers worked out for the travel times and the amounts of fuel required and the propulsion technologies needed and the radiation dose that would be absorbed by the passenger--they are pretty simple calculations that you can do after an undergraduate course in relativity.  So he would say these ridiculous things, but the delivery was totally straight.  Like yes, we've build an antimatter device and a fuel container to hold umpteen gajillion kgs of antimatter.  Sure, you'll only be exposed to hundreds of times your lethal dose in the first year of travel.  But look at rich Corinthian leather.

Maybe you had to be there. ;)

Answer 7

The problem arises when you get closer to light speed.. Remember, e=mc^2. A constant acceleration requires energy, and energy has a very small amount of mass. For this reason, you will have more mass as you begin to accelerate, and you will require more and more energy to accelerate that 32.2ft/sec. It is impossible, no matter how much energy you have, to travel at the speed of light.