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View Full Version : How Long Would it Take to Travel to the Nearest Star?



Fraser
2008-Jul-08, 10:00 PM
We've all asked this question at some point: How long would it take to travel to the stars? And could I do it in my lifetime? There are many answers to this possibility, some very simple, others in the realms of science fiction. To make this easier to answer, we'll address how long it would [...]

More... (http://www.universetoday.com/2008/07/08/how-long-would-it-take-to-travel-to-the-nearest-star/)

GOURDHEAD
2008-Jul-09, 02:37 PM
From the linked article:
First choice would probably be Proxima Centauri, the closest star to the Solar System. Part of a triple star system called Alpha Centauri; Proxima is 4.22 light years from Earth. Alpha Centauri is actually the brightest star of the three in the system, and so the system is named after this star. Alpha Centauri is part of a closely orbiting binary about 4.37 light years from Earth, but Proxima Centauri (the dimmest of the three) is an isolated red dwarf star 0.15 light years from the binary. In some articles I have read in recent months, Alpha Centauri-A and B are orbiting binaries and the status of Proxima (Alpha Centauri-C) as gravitationally attached to the system is in doubt with Alpha Centauri applied generally to the three as a system.

I have not done the detailed engineering problem solving required to determine the total mass of such a human rated system initiating a trip from the solar system where the shielding, and recycling of water, food and oxygen masses are included. My guess is that the solution approaches in difficulty answering the question: "Can God make a rock so massive He can't lift it off the surface a planet large enough to support it?" But I have done sufficient engineering problem solving (though more devils reside in the finer details to this day) to show that it can be done with a set of ion engines capable of processing 200 to 1000 kg/sec exhaust rates powered by 10^17 or so watts power supplied by a collimated photon beam radiated from polar solar orbit inside the orbit of Mercury. There is considerable sail effect from receiving that much radiation by the beam riding 10^9 kg or so ship. Not usually addressed is avoiding crashing into galactic orbiting objects which do not radiate enough light to be detected in sufficient time for avoidance measures to be taken safely at an above ship speeds of a few hundredths light speed. My design addresses these problems. If one wishes to slow down sufficiently to orbit one of the AC stars, the trip can be made from 10 to 40 years depending on solutions to particle beaming the propellant mass to the ship (or along the path to be taken by it) and to capturing the propellant mass. Much shorter times can be achieved for flybys (6 or so years).

Interstellar flight will be hazardous however it is undertaken (no pun intended) so the largest safety margins affordable must be used.

Disinfo Agent
2008-Jul-09, 08:11 PM
First choice would probably be Proxima Centauri, the closest star to the Solar System. Part of a triple star system called Alpha Centauri; Proxima is 4.22 light years from Earth. Alpha Centauri is actually the brightest star of the three in the system, and so the system is named after this star. Alpha Centauri is part of a closely orbiting binary about 4.37 light years from Earth, but Proxima Centauri (the dimmest of the three) is an isolated red dwarf star 0.15 light years from the binary.This is confusing. As far as I know, the stars are called Alpha Centauri A (the brightest), Alpha Centauri B, and Proxima Centauri (sometimes also Alpha Centauri C).

JustAFriend
2008-Jul-10, 12:11 AM
http://en.wikipedia.org/wiki/Voyager_Golden_Record:

The Voyager spacecraft would take about 40,000 years to reach the distance of the star nearest the Sun, Alpha Centauri at a distance of 4.4 light-years, though neither craft is travelling toward that star.

Hope your family is long-lived....

BigDon
2008-Jul-10, 01:07 AM
Sorry should read before posting

Paul Leeks
2008-Jul-10, 01:28 AM
Hi

1.To get to the nearest star (Sun) would take 8.3 min travelling at the speed of light of 186,000 miles per sec!

2. if you could soul travel/OBE/astral travel you could get to the Sun instantly...at the speed of thought,go there come back to your body and then tell your friends what a lovely a place it is for a vacation!! I haven't done this, so you would have to ask a Hindu Fakir!

I have had an involuntary OBE...just try not to panic if it happens to you!!then tell me what you see with your 360 degree spiritual vision in the Astral Body!!

Paul

Van Rijn
2008-Jul-10, 01:38 AM
Hi

1.To get to the nearest star (Sun) would take 8.3 min travelling at the speed of light of 186,000 miles per sec!


Close enough . . .



2. if you could soul travel/OBE/astral travel you could get to the Sun instantly...

That would be physically impossible. Paul, this isn't Off-Topic Babbling. Please, stick with the science here.

antoniseb
2008-Jul-10, 12:56 PM
A few interesting things to note about the article:

If we are talking about tens of thousands of years, then Barnard's Star will be the closest star for some significant fraction of that time coming to a little over 3 light years from the Sun. Perhaps we should go there.

Also, the article made the jump from low-energy ion propulsion (a la DAWN) straight up to the "Project Orion" nuclear pulse thing. There are certainly steps in between that would get to the Alpha Centauri in hundreds of years.

LotusExcelle
2008-Jul-10, 01:16 PM
We could use the Witch Drive like in Elite. And a lot depends on relativity, I think. If we humans ever create craft fast enough to arrive at another star within the lifetime of one human then it will be traveling fast enough for relativity to be a concern. Are we talking ship time or earth time? Or banker time? Or waiting in line at Wal-mart time?

DoctorScience
2009-Jan-17, 05:47 AM
[QUOTE=Paul Leeks;1279443]Hi

1.To get to the nearest star (Sun) would take 8.3 min travelling at the speed of light of 186,000 miles per sec!



??? I'm sorry to say this paul but thats inaccurate if something is 4.23 light years away such as "Proxima Centauri" it would take 4 years 3 months and 2 and a half weeks traveling at the speed of light to get there. asuming your going the speed of light of course. if you could go even half the speed of light you would make it there in 8 and a half years. now using Antimatter as fuel we could make it possible to go half the speed of light all the way up to 2 thirds the speed of light! Also using worm holes would be usefull to, if you Isolated yourself in a electromegnetic field and cross junkshined a plasma atom with an antimatter it could be possible to become imaginary mass and go anywhere in the universe instantly. Asuming we can even prove a "tachyon" exsists. Btw with modern day science it would take around 81,000 years with are best thrust technology.

JustAFriend
2009-Jan-17, 03:43 PM
The fastest space probe is the Helios2 which hits just over 150,000mph (http://www.aerospaceweb.org/question/spacecraft/q0109c.shtml) as it slings around the sun.

But the fastest HUMAN-carrying spacecraft so far is the Apollo capsules which nearly hit 25,000mph.

....the closest stars are NOT within a human lifetime with any real-world propulsion system yet.

speedfreek
2009-Jan-17, 07:58 PM
Hi

1.To get to the nearest star (Sun) would take 8.3 min travelling at the speed of light of 186,000 miles per sec!


??? I'm sorry to say this paul but thats inaccurate if something is 4.23 light years away such as "Proxima Centauri" it would take...

Hi there and welcome to BAUT!

I should just point out that Paul was referring to the nearest star to us, the Sun, which is around 8.3 light-minutes away.

tdvance
2009-Jan-17, 08:12 PM
Let's see--a big ship with a Bussard ramjet maintaining 1G halfway, then flipping over and maintaining 1G deceleration the rest of the way to Proxima, about 4.2 light years away. Solving 16t^2 = distance gives

sqrt(4.2*5880000000000*5280/2/16)*2/3600/24/365

gives 4.048 subjective years (for those inside the ship).

Of course, you'd use Einstein's equations to figure out how long it would see to someone on Earth or Proxima. I could definitely say it's more than 4.2 years.

speedfreek
2009-Jan-17, 08:56 PM
For a distance of 4.2 light-years, assuming a 1g acceleration to halfway, then flipping over and a 1g deceleration, would take around 3.5 subjective years for those inside the ship, and 5.8 years for those who stayed home and watched. I didn't do the maths myself, I am afraid I have to rely on an online calculator:

http://home.att.net/~srschmitt/script_starship.html

that agrees with

http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html

JustAFriend
2009-Jan-18, 03:11 AM
Which is great, but no one knows how to really build a Bussard ramscoop (not ramjet).

And there's been talk that they may not even be possible to build.....

You may as well wish for a Stargate.