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No, I'm gonna give a longer reply to that.

To get a dilation factor of 10 one must go at 9/10 the speed of light. Since most of the Class M stars are of the order of 1000 or more light years distant we will not live long enough to get there. We have not even a hint of suspended animation and freezing does not work. Generation ships are a pipe dream. Submariners cannot stay cooped up more than 6 months. In addition to which the lack of gravity will cripple the crews and cosmic rays will riddle their bodies with cancer. Our species was not evolved for long periods in zero g. And we cannot take the radiation for too long.

We don't know generational ships won't work bc we've never tried them. Submariners don't have women, they're on short tours away from home, and aren't planning to reproduce and raise families on their sub marines.

You can simulate gravity by spinning a ship.

And you can protect from radiation with the proper shielding.

Both of which increase the rest mass of the ship. The fuel expenditure would be humongous. The prospects of very long duration space flight are not all that bright. But the real show stopper is the speed of light. All of the available evidence indicates that the speed of light in vacuo is limited and no material object can be accelerated from rest to the speed of light with any finite amount of energy applied to the vehicle. The best we have done with massive objects is to accelerate sub-atomic particles to near light speed at very great expenditures of energy. If one goes strictly by the known facts sending a manned vehicle at light speed is simply not doable with currently know physics and current technology. And there is no reason to expect to able to get around Einstein's equations either. Conclusion: we are not going to be travelling to the stars in the foreseeable future.

If we are fortunate and develop ion-drive engines that will produce much faster speeds than have been produced so far we might be able to colonize the solar system. The fastest vehicle ever launched by man (an unmanned space vehicle) went under 70,000 mph. That is not quite three times escape velocity. And the energy budgets are such that the only way to get a vehicle Out There is to use the sling shot effects going around the large planets. That is a roundabout trip which is why it takes years to get a vehicle as far as Pluto.

I would urge that one make a clear distinction between science fiction and the physical facts of the cosmos.

Ba'al Chatzaf

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Fred is right. You can live inside an asteroid and have a solar sail. You can live to be 1000, also. The theory is that if we can get past 120, there is no limit. It's the dying we do not understand. There is no metaphysical reason for death. We just need to find the genes. Or put the mind into a better package. Instead of living -in- ships, we would -be- ships.

As for the Minkowski contraction, you set v/c as 1/2 arbitrarily. What you meant was v = c/2, i.e., suppose we go half the speed of light. If v = c/2, then the contraction term is ((c/2)^2)/c^2. That numerator of the complex fraction is now c-squared over 4. That over c-squared, or 1/4. 1 minus 1/4 is

three-fourths and the square root of that is about 1.7 over 2 or about 0.8, like I said.

And 1.15 is the reciprocal of 0.8, which is close enough, and as you know it shows that the new Delta-T is 15% greater than the observed. You call that 1/7 contraction at half the speed of light negligible, but it means an extra 15 years in a hundred. That's measurable. And that's at half-c.

We do not need G-stars or M-class planets. Any mass can be used for conversion. Gas giants would be oases. In fact, brought to Earth in a jar, a cup of Antares would seem like a vacuum. Yet it dominates the summer southern sky right now.

"It is estimated that 10% of the stars in our galaxy are sun-like; there are about a thousand such stars within 100 light-years of our Sun ... " Wikipedia_Astrobiology (http://en.wikipedia.org/wiki/Astrobiology)

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We do not need G-stars or M-class planets. Any mass can be used for conversion. Gas giants would be oases. In fact, brought to Earth in a jar, a cup of Antares would seem like a vacuum. Yet it dominates the summer southern sky right now.

"It is estimated that 10% of the stars in our galaxy are sun-like; there are about a thousand such stars within 100 light-years of our Sun ... " Wikipedia_Astrobiology (http://en.wikipedia....ki/Astrobiology)

Even so, the speed of light is the upper bound on the velocity of massive objects. We ain't going to the stars. We simply do not have the energy to speed very massive objects up. We had better learn to live in the solar system while the sun lasts and when it dies we are done for. Given that suns must explode or cool off eventually, death is a physical inevitability. Not only that, the Cosmos is heading toward the Big Rip. Nothing lasts for forever. See second law of thermodynamics. Entropy always increases until Total Disorder is reached.

Ba'al Chatzaf

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  • 5 months later...

Instead of starting a new topic, I decided to just append this one with another question that is tangentially related to my creative writing.

I am trying to determine which formula I'd like to use to measure advanced civilizations. There are a few different theories out there, including:

The Kardashev scale, which measures civilizations by the energy they consume;

Gerhard Lenski's scale which measures civilizations by the amount and use of information;

Robert Zubrin's scale which measures civilizations by how wide-spread the civilization is in space.

I am wondering which of these three posited scales is superior to the others, if there such exists. Let me know what your thoughts are.

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Instead of starting a new topic, I decided to just append this one with another question that is tangentially related to my creative writing.

I am trying to determine which formula I'd like to use to measure advanced civilizations. There are a few different theories out there, including:

The Kardashev scale, which measures civilizations by the energy they consume;

Gerhard Lenski's scale which measures civilizations by the amount and use of information;

Robert Zubrin's scale which measures civilizations by how wide-spread the civilization is in space.

I am wondering which of these three posited scales is superior to the others, if there such exists. Let me know what your thoughts are.

Energy is not consumed. See conservation of mass-energy. What is reduced is the Gibbs Free Energy of a system, that is the energy capable of doing mechanical work. See http://en.wikipedia.org/wiki/Gibbs_free_energy

Ba'al Chatzaf

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Instead of starting a new topic, I decided to just append this one with another question that is tangentially related to my creative writing.

I am trying to determine which formula I'd like to use to measure advanced civilizations. There are a few different theories out there, including:

The Kardashev scale, which measures civilizations by the energy they consume;

Gerhard Lenski's scale which measures civilizations by the amount and use of information;

Robert Zubrin's scale which measures civilizations by how wide-spread the civilization is in space.

I am wondering which of these three posited scales is superior to the others, if there such exists. Let me know what your thoughts are.

Energy is not consumed. See conservation of mass-energy. What is reduced is the Gibbs Free Energy of a system, that is the energy capable of doing mechanical work. See http://en.wikipedia....bbs_free_energy

Ba'al Chatzaf

I knew this. Semantics is a bitch.

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