Interstellar Travel is Impossible

Humanity is doomed.

Even at a mere 1500 km/sec (0.5 percent lightspeed), or less than 3-times the escape velocity of the sun, the impact of a micrometeorite would destroy any spacecraft. A typical 10 gram micrometeorite would impact with the energy of 2.7 tons of TNT. The Oklahoma City bombing was less powerful between 1-2 tons of TNT. The explosion that destroyed the Russian submarine Kursk was also less powerful at about 2 tons of TNT, but it was registered by seismic stations in several countries.

Even a tapered titanium-constructed spacecraft (10 meters wide, 51000 meters long) that "brushes off" to the side any meteorite impact would still accumulate enough damage to render it garbage in far less than the 860 years needed to make it to the nearest star system Alpha Centauri. It would be too massive to get up to speed, requiring at least 3 million pounds thrust for nearly a year to reach cruise speed of 1500 km/sec.

Look at the world we live in. We have not yet come up with a way to survive that does not require a cities and urban congestion and depletion of resources. Crime is rampant. People are vicious to one another. What a 5hithole we live in.

Humanity is doomed.

 

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Never say impossible

At our present level of tech it would take a heck of a lot longer. You'd have to stick 'em inside an asteroid and use it for a generation ship. By the time they got there it would probably already be settled if settlement was possible.

We humans have a tendency to "come up with stuff" that doesn't seem like it's of any value at the time or isn't practical to use. The transistors at first didn’t seem to be of any use because we couldn’t shrink them down to make them. Now we don’t use them much as IC’s have taken over most solid state circuits. Or the computer is another one. Took a room full of equipment, blew vacuum tubes faster than could be replaced, and was a glorified adding machine. You couldn’t tell the modern computer was descended from it. Not that it isn’t aggravating but at least it runs more than a minute or two.

So while you have very good points it is not to say it will never be.

 

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Meteor impact is the easiest-to-define problem

As for getting to another solar system in sufficiently short time, well we can mine deuterium & tritium from Jupiter's atmosphere and stockpile it. After all, if we have enough propellent we can do it. The propulsion aspect is what they always talk about, but I think it is a smokescreen. We have to imagine that we understand relativity, nuclear physics, and quantum mechanics to come to believe what has been said about it too. But the easiest to define problem is completely ignored: meteorite impacts!

Every high school senior knows the equation for kinetic energy:

KE = (1/2) x (mass) x (velocity squared)

where mass is in kilograms and velocity is in meters per second, kinetic energy is given in Joules.

We also know through experiment that 1 ton of TNT yields 4.18E+9 Joules of energy. So we have an intuitive comparison for the effect of a meteorite impacting the hull of a spacecraft.

Project Daedalus starship design expected the ship to reach speed of 16 percent of the speed of light, that's 48,000,000 m/s !!! At this speed an ordinary 10 gram meteorite, whether made of solid rock or frozen water ice, would impact with the energy of 2.756 kilotons of TNT. This is almost exactly the same explosive energy as the French munitions ship that destroyed Halifax, Nova Scotia in Canada. For a description of how much destructive energy this represents read the following article about the Halifax disaster:

http://www3.sympatico.ca/goweezer/canada/blowup.htm

The human race is alone, effectively confined to this one solar system. This does not require knowledge of nuclear physics, einsteins theory of relativity, or quantum mechanics. It is easy to understand.

And we are screwed.

 

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Luckily there are not that many. If this was the case our probes within the solar system would be so much trash. And many are still going.

 

I have to say Success Machine you have a pretty good view of what the world we live in is. You're also probably right that we will kill ourselves off before anything else does. It is also an insane endever to take a ship like the ones we send into orbit to another solar system. But if I were to ignore all that, I'd say just throw on an anti-gravity nose cone and warp space infront of your ship so that it's expanded like a balloon. This will efectively deflect smaller meteorites. It won't do much if you hit a planet of course, but it will do quite well against the marbles out there. Side impacts are an infinitesimal event since, if you have the technology for anti-gravity, then you are probably moving so fast that meteors don't have the chance to hit you. Another more out there idea i've had is to increase the frequency of your ships vibration by a multiple of the resonant frequency of the universe. With some modifications to this idea you might be able to slide straight through an object. Kind of like sand (the meteor, asteroid, etc) slipping through a screen (your space ship) quite easily when you shake it back and forth. Just a vague idea i've had in the past.

 

Impossible?

I'd have to agree with wet1, S_M.

Unlikely? Improbable? Maybe. Impossible? No! I've just seen too many things that were 'impossible' come into being in my lifetime. From vacuum tubes to diodes to transistors to integrated circuits to today's computers on a chip. And that's just in one area.

As for this planet being a 'shit-hole' - Hey, it's our shit-hole, and the only one we've got. Try getting out into the country, even ten or twenty miles from anywhere, and you might change your attitude. That's why I left NYC and never went back except to visit. And even then, only when I had to.

One other thing: Yes the impact bit has merit, but once clear of our system, when you'd twist the throttle, how much of a problem would it be? If I'm not mistaken Voyager made it out there.

Time to sign off, need the zzzzz's.

 

with current tech, no, but....

you cannot say what we will or wont be able to do even in the near future. at the rate technological advancement is increasing, homosapiens sapiens will not be the dominant species on the planet long before 2500 (thats a REALLY conservative guess. we will be replaced by hyper intelligent, strong and agile genetically engineered cyborgs.) or maybe nano robots will have turned the entire solar system into more nano robots! who knows what crazy tech we'll have to allow us to bypass such problems. maybe we will just warp. or, a solution that is semi pratical with today's tech: vaporize anything the comes near the ship with a laser. the point is, nothing is impossible (and don't flatter yourself- nasa has thought of this problem.)

 

Success_Machine,

I'm sure that as egine tech advances so will shielding tech. After all they once belived we could not travle faster than 15MPH in a car, becuase we would sufficate.

Have you stepped out side and tried to do anything about it today? I find that those complain and call down humanity are the ones who wont even give old clothing to a charity, but want some one else to do some thing about the current state of humanity.

If any thing is going to be acomplishe in this area it will take every one to take part in it not just the goverment.

 

definately a problem of BIOLOGY

yup

 

Something finally triggered in the old grey matter that might be applicable to this subject:

As speed approaches the speed of light, time approaches zero and mass approaches infinite.

It was an equation that I had fun playing with a good while back, like fifty or so years ago. Resulted in some rather interesting conclusions:

1) Nix on light speed travel, too much mass to accelerate those last few mph's - would need almost infinite energy;

2) For those making the trip, time compression would effectively make it seem that they were in a status field;

and 3) Anything in its path would be annihilated because of the density of the matter as its mass approached infinite.

Maybe it was from an SF story, but I'm pretty sure it was from a serious paper.

 

Well I read this post earlier in the day and it got me thinking. Back in the time of the ancient greeks and romans people thought that to fly you'd have to have artificial feathered wings and you'd have to flap them to fly. There's even a myth about it somewhere, I think it involves this guy named Demetrius who flies out of the labyrinth with wings glued on with honey but loses his son because he flies too high and the honey melts. Anyhoo the answer to flight is simply speed and a curved wing, therefore the answer to flying safetly at 1/8 light speed may be simpler than projecting a 'gravity shield' in front of your ship. We just haven't found it yet. Also I think someone said on this thread that it would be impossible for a marble to hit a ship traveling at about 1/8 the speed of light, but it is possible if BARELY, but I always noticed back when I was a lil' kid that whenever I dropped a lego on the floor it seemed to somehow roll out of my reach somewhere where NO ONE could get it. Even the most minute chances must be taken into effect, since when a rock the size of a fingernail moving at a billion miles per hour can turn a planet into a crescent I'd think a 'gravity shield' on the sides of your ship is necessary. It's just a theory, after all.

 

Whipple Shield may enable interstellar travel

Shielding was a problem, but a few years ago the Whipple Shield was invented and used on Canada's RadarSat to protect from orbital debris. This shield technology may be adapted to an interstellar spacecraft in a very positive way, reducing the mass of the hull, and relieving geometric constraints on its shape. The idea with the Whipple Shield is that the meteorite impacts the first metal plate and punches through. It leaves a hole in the plate, but itself is reduced to a fine particle shower (still high speed) that spreads out with a far larger cross-section. The fine particle shower then impacts a second metal shield doing little or no damage.

Finally a strong description of how this will work! :-D

I have yet to determine if the Whipple Shield is feasible at speeds of up to 30 percent lightspeed. I'll be working on this, so stay tuned...

 

Shield construction

Whipple Shield may work for impact energies exceeding some gigajoules - if the kinetic energy converts with high efficiency to radiation escaping into free space.
A multiple hull shield will be necessary for this job. Impact energy (pressure waves, radiation) will be reflected between the hulls possibly destroying the latter. So the shield construction must be very large and spacious.
To replace the outermost hulls I suggest to use a laser. By using an array of phase shifted lasers/radar antennas the critical area can be scanned. Upon detection of a particle a series of powerful laser pulses breaks the particle into bits and eventual these bits in even smaller ones.
The inner Whipple Shield needs only to absorb the remaining impact energy from splints too small to be tracked by the laser scanner. All bigger bits pass aside the ship creating no impact energy at all.

---- BUT----
This is NMD technology - and I don't like this system and the philosophy behind... I prefer to renounce a laser shield and the possibility to travel to Alpha Centauri - for less armament in our *not* 5hithole world!

Eckhard Siegmann, Aachen, Germany

 

meteorites

If there is all this energy released when meteorites impact whatever craft it is we are flying, then perhaps an answer would be to find a way to harness that energy and use it for propulsion instead of obliterating it.

 

Excellent thought! But what could we use to hold such energy until it could be used?

 

Other solar systems and manic depression

Success Machine,
Are you the geezer I saw in Picadilly-Circus last week with the "The end is nigh" plackards front and back??

Chagur,
Time slowing when you approach the speed of light...

Hmmmm, yes I had this thought, once upon a time. Could this be the final nail in the light-speed coffin (aside from running into micrometeorites and mass increase problems that is)?

Time slows down as you approach the speed of light yeah? And when you actually reach the speed of light it stops yeah?
So who hits the big red "OFF" button then? If time isn't passing then no-one.

Another interesting question is do you actually use any fuel once you're at light speed? After all, time isn't 'passing' and therefore you ain't got fuel travelling down the tubes have you.

Quote (since it seems to be the 'in thing' on this forum)...
Terry... "Don't lie to me"
Arthur Dailey... "When have I ever lied to you?"
Terry... "Well maybe you haven't lied, its just that you never let the truth get the better of you!"

 

...

LOL

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Nice to see some people appreciate a bit of sarcasm every now and then...

Bye!

Crisp

 

You do!

Remember Sid, you're inside the 'star ship'! As far as you're concerned, everything is 'normal', so when it's 'time' you hit the big red button!

Also, time doesn't slow as you approach the speed of light, it's slowing from the moment you begin moving. And as to what happens when you attain the speed of light - you don't. It's like trying to attain absolute zero: you can approach it, but you can not attain it. If you graphed it you'd end up with an asymptotic curve (like graphing the tangent function).

As far as the fuel bit: again, you approach the speed of light, but you never attain it so you need enormous fuel to go just a little bit faster because of the almost infinite mass that you're trying to accelerate.

Hope that clears up the matter.

 

Sprout that is an excellent idea, immense 'free energy' is released when a meteorite strikes another body in space, but I'm guessing that if NASA or any private organization ever attempts to harnesse the energy from such an explosion that it would be quite tricky to actually figure out how to do so. Anyone who can figure out how to create some kind've magnet or vacuum tube (a bit worthless in space though) to suck that stuff up should post their idea RIGHT NOW! It would turn into quite an interesting debate.

 

Doh!

I am smart I am Smart,
s.m.r.t
doh, I mean S.m.a.r.t - H.Simpson & Sid!

Ahhhhh keep getting that bit the wrong... Ta for correction... back to brief history of time for me... Learn all my physics from Red Dwarf obviously!

In this case I'll go for the "if you can't reach the speed of light or beyond, then don't bother. 'Just' find a way of getting where you want to go without having to travel as far - wormholes, 5th dimension etc"

Either that or if there's goona be a 'big crunch' then go to sleep for a 'while' and wait for the place you want to go to, to come to you - take plenty of lime jelly with you because there's bound to be a shortage at the end of the universe...

OK I'm being silly now, but hey I didn't start it, god did!