We didn't build rockets and travel to the moon before we made airplanes.

However I really think the drake equation is way way too strict, and assumes that civilizations destroy themselves easily, which I think is HIGHLY improbable.

we haven't been close to extinction ever during modern times, even during the cold war

I'm pretty sure once you can feasibly deploy ICBM's then you're too intelligent collectively to ever destroy your own entire species.

The Drake equation doesn't assume anything. It's just a form for filling in numbers, an accounting of all the necessary variables to answer the question. Only the person inputting the numbers into the equation can make assumptions. I've seen people run the drake equation and get <1, and I've seen people run the drake equation and get millions, as Carl Sagan famously demonstrated in the 12th episode of Cosmos.

There actually were a couple of times during the Cold War when we were literally a hairsbreadth from a full nuclear exchange, which would have absolutely ended our global civilization.

The technical skill required to construct a lethal weapon is unrelated to the temperance and foresight necessary to avoid using it

The area in which that bomb would be lethal is up to 50 times the area in which it achieves "complete destruction".

As for the number of nukes needed to end civilization: if the theory of nuclear winter first outlined by Sagan et al. is correct, then the number could be a low as 100.

Even if you say that to destroy civilization you would need to destroy every city in the world with a population of at least 100,000 then you would only need 4600 nukes.

Can you elaborate on when and why that would ever happen? The biggest nuclear exchange possible would be between Russia and the USA, and they wouldn't aim for any other countries if it ever happened. Why would a single country aim for all other countries cities?

The bottom line is, it's impossible to cause the extinction of mankind completely in any sort of logical scenario, could you kill off a large percentage? Yes. Could you cause extinction? No.

But that's just wrong. Can you provide a source for that statement? Or did you just make it up?

The United States conducted 1,054 nuclear tests between 1945 and 1992, you think if 100 nuclear warheads were detonated at once it would cause a nuclear winter (if it even caused one) that would cause the extinction of mankind?

I find it hard to believe Carl Sagan even said that.

Also keep in mind that there are TONS of nutjobs that are completely self sufficient, just because you can't go to walmart and buy food doesn't mean the entire world will starve and die.

Can you elaborate on when and why that would ever happen?

Also, there are millions of other cities around that have less then 100,000 people, you literally can't nail every single city on Earth with all of the worlds nukes, it's impossible. I hope you realize this.

This would lead to a declaration of war form the USA's allies against Russia and Russia's allies against the USA. In a global society this would not end well at all.

And it will never happen, I'll bet you millions.

Well I won't bet against you there, but even if I did and I won I wouldn't be able to collect

It's not the nuclear detonations themselves that cause nuclear winter, it's the smoke and particulate matter lofted into the stratosphere by fires burning in cities.

This has no bearing on the fate of civilization. You are confusing that with human extinction, which is a separate matter.

This is correct. Any attack against the USA would automatically involve NATO, which has most of the rest of the nukes.

Well I won't bet against you there, but even if I did and I won I wouldn't be able to collect

From what I'm getting you're trying to say that a nuclear exchange would end civilization and humans would not be able to recover at all and eventually die out.

You think Britain and France would launch all their nukes at Russia if USA and Russia had a nuclear exchange? I highly doubt that at all because if they did that they know that Russia would have leftovers to respond with, and they wouldn't want to risk that for their population.

And after long term effects probably 70-90% of the human population would be killed. But that's more then enough left to survive and preserve the knowledge of our civilization and rebuild humanity.

Humans don't need sun light to live, we can grow plants with artificial light.

You can't win a nuclear war (against a country with nukes). That's why we're never had a nuclear exchange. And that's why it will never happen.

And they have saved more lives then they have killed.

why would you be so choosey? Your nation is sunk anyway, might as well take everyone else down with you.

They would have to, because in all likelihood Russia would launch at them

More pessimistic predictions argue that a full-scale nuclear war could potentially bring about the extinction of the human race, or at least its near extinction, with only a relatively small number of survivors (mainly in remote areas) and a reduced quality of life and life expectancy for centuries afterward.

I'm saying that human civilization would end. I don't make any predictions about whether it will ever get started again, or whether humanity would go extinct. I just say that civilization ends in that scenario.

the vast majority of knowledge possessed by that civilization was lost, and human progress was set back by nearly a thousand years.

Those are very pessimistic views, yet they still admit that it would be very hard for a full-scale nuclear war to extinct us.

Can you define what you mean by "civilization ending"?

I wonder when Space Engineer comes back from his trip. I want to hear his views on this subject as a Russian.

because of nuclear terrorism. I think it is only a matter of time until the US, Israel and maybe even Russia will be subject to nuclear attack by extremist groups (also, you must realize that if such an event was to happen, global tensions and mistrust would rise sharply, and any small incident or crisis could escalate to war or even a nuclear exchange).

1. If it is impossible to move at the speed of light, because it takes infinite energy to reach the speed of light..... then how is light moving at the speed of light?

2. Wasn't it discovered that some particles can in fact move faster than light?

I suppose that this discussion would have benefited greatly if we had defined the word "civilization" at the outset.

So any world in which nearly everyone is concerned with survival and finding food could not possibly be civilized