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Author
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Topic: Accelerating at 1G to the speed of light
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Mercury7
Member Posts: 360
From: Greenville, SC, USA
Registered: Aug 2006
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posted 05-17-2008 12:11 AM
  
I have wondered about this question for years but never knew the mathematics to figure it out so I thought maybe someone here might know.The question is: Assuming you had a propulsion system that could constantly accelerate you to 1G, how long would it take to approach the speed of light. I wonder this because short of any significant development of warp drive or some other super sci-fi invention, I think that in the far future when we decide to set off to distant stars we will use this formula to determine how long it will take to get there. Basically accelerate at 1G and then at an equal distance start to decelerate at 1G until you arrive. thanks Scott |
cspg
Member Posts: 6210
From: Geneva, Switzerland
Registered: May 2006
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posted 05-17-2008 12:11 AM
I hate maths but...If 1G is equal to 22mph and that each additional second will add 22mph; considering that the speed of light is 670,616,629 mph, divide it by 22, then by 3,600 which will give you the number of hours required; then divide by 24, and you get 352.8 days. (Wikipedia). Again, I hate maths so it's probably wrong  - or not! Chris. P.S. And, amongst other variables, you'll need to consider the fact that the universe is expanding.... |
Mercury7
Member Posts: 360
From: Greenville, SC, USA
Registered: Aug 2006
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posted 05-17-2008 04:11 AM
Well you did better than I could have done.  I have to say though, that is much shorter than I thought, with roughly two years for acceleration and deceleration according to your calculations then we could reach the nearest star in a lifetime (isn't the nearest star 43 light years away?) seems like I read that anyway.Cool breeze! |
star61
Member Posts: 294
From: Bristol UK
Registered: Jan 2005
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posted 05-17-2008 04:55 AM
Unfortunately, it's not quite as simple as that. As you approach a appreciable fraction of the speed of light, you have to take account of special relativity. The maths is a wee bit tricky to post, but it means your mass will increase as you get faster and faster. Hence, you need more and more thrust to maintain 1g acc. Only a massless particle, such as a photon can actually attain the speed of light. If you look at the new particle accelerater at CERN, the LHC, and see how much power is needed to get a proton (which has mass) to about 99.999% speed of light , you'll see the problem.Nearest star, Proxima Centauri approx 4.3 light years. Phil |
Rodina
Member Posts: 836
From: Lafayette, CA
Registered: Oct 2001
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posted 05-17-2008 08:41 AM
quote:
Originally posted by Mercury7:
we could reach the nearest star in a lifetime (isn't the nearest star 43 light years away?) seems like I read that anyway.
While the Alpha Centauri system is about 4.3 LY away, some of the potential interstellar ships that are reasonably within our grasp (Orion, Daedalus) might reach about 10 percent of light-speed, so by that we'd take about 43 years to go to A Cen, which is where you likely heard the "43 year" figure. |
cspg
Member Posts: 6210
From: Geneva, Switzerland
Registered: May 2006
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posted 05-17-2008 08:56 AM
And to complicate things further, those 43 years are the ones spent by the inter-stellar travelers or by the observers on Earth? The two will differ as time "slows" down for someone on the move (and a by-product of this is that it's a one-way ticket).Oh, and make sure there's a planet orbiting Alpha Centauri! - none has been detected as of today! Chris. |
Blackarrow
Member Posts: 3118
From: Belfast, United Kingdom
Registered: Feb 2002
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posted 05-17-2008 11:26 AM
There is a great science fiction short story (Clarke? Asimov?) about the first interstellar mission. After many years in suspended animation, the crew reach their destination, to be greeted by the crew of the second interstellar mission who had launched many years after the first crew, but had overtaken them using a much faster propulsion method. I can't help thinking that this will actually happen one day. |
Mercury7
Member Posts: 360
From: Greenville, SC, USA
Registered: Aug 2006
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posted 05-17-2008 06:24 PM
quote:
Originally posted by Blackarrow:
There is a great science fiction short story (Clarke? Asimov?) about the first interstellar mission.
I believe I heard Carl Sagan make the same argument as this... however I don't think it should ever be a reason for not attempting the trip, one never knows what the future holds. My opinion is the trip should be attempted at a point when we are able to build a self sustaining "city" sized spacecraft, many generations may be born and die in space before a world is found we could inhabit. But it is our destiny, The earth has finite resources and eventually we will have to make the trip... If I had to guess though all of this would take place several hundred years from now, assuming we are not wiped out by then by natural disaster or one of our own doing. |
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