Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror

Comment: Re:Effect of nukes on NEOs (Score 1) 272 272

No, because those millions of small pieces release the same amount of energy into the Earth system, just now into the atmosphere now rather than the planet surface

You start with an incontrovertible claim,

Rather than ejecting material, earthquakes, tsunamis, you flash fry the hemisphere

And you use it to justify pure poppycock?
The atmosphere is big. The earth- it's also really goddamn big. The energy required to raise a hemisphere's atmospheric temperature enough to "fry" us is so goddamn big that there's no point in worrying about it. If something the size of Texas is about to hit us, we're just fucked.

The beast that (I guess contentiously, now?) knocked out the dinosaurs, spread across an entire hemisphere would yield about 193MW/m^2, to dissipate through a 100km column, giving us... 1.9kW/m^3 of dissipation, assuming impossibly worst case scenario (instantaneous thermal conversion across entire air volume)... which is quite survivable.

Realistically, the dissipation will be far better distributed over time and area (a lot of impactors will take long paths through the atmosphere, being not direct hits, better improving their dissipation at high altitudes)

It's not a... "good" thing, for sure... But it's not the total annihilation of a hemisphere.

Comment: Re:Effect of nukes on NEOs (Score 1) 272 272

What sort of nuclear engine are you envisioning that would match the thrust of bombs boiling off the asteroid's surface in a big plasma wave?

I'm pretty confident that absorbing half of the energy output of a significantly sized fusion explosive (say, dozens of megatons) is going to do a lot more for you than just the ablative propulsion effects of the vaporized surface.

You're still going to send a pressure wave through that rock that is going to be a very formidable force in comparison to the very weak gravity holding it together.
This obviously isn't too helpful for a world-ending impactor (hundreds of miles+), but I'm guessing highly dangerous ones of that size and smaller could be reduced to buck shot.

One NASA-funded plan involved hitting it with an impactor first and then having the nuclear explosive follow it in. Even more energy absorption, and even more fertile ground for a very serious pressure wave.

The 5MT device detonated 1.8km deep on Amchitka lifted the ground at the surface by 20 feet. Imagine what that'd be like without 9.8m/s^2 of force pulling it back together, and without the weight of nearly 2km of rock to fight the expansion.

Comment: Re: Effect of nukes on NEOs (Score 1) 272 272

Some of them will go in the opposite direction

Unlikely. This isn't a stationary object, and the velocity of it is almost stupid. Sure you'll slow a lot of pieces down a lot, but I sincerely doubt you'll reverse their trajectory.

That's assuming that the nuke actually blows it up. Nukes are FAR less effective in space because there's no atmosphere for the thermal energy to create a big shockwave, and there's no solid ground beneath it to amplify the intended direction of said shockwave.

That's ok, rock absorbs high energy photons and neutrons even better than air. The shockwave of a nuke causes the serious damage away from the fireball, but I assure you the people within the area of atmospheric ignition due to high-energy radiation couldn't give two squirts of piss about the pressure of the atmosphere there. Definitely detonate close to the bolide.

IMO if you want to blow up an NEO, you'll probably want some kind of kinetic weapon akin to a giant bullet, maybe a space born railgun or something.

You could be right... But I doubt it. Someone would have to do the math to see what portion of the energy output of a large hydrogen bomb would hit the object, how much the object would absorb, and how it would react to the incidental heating. (my guess is very traumatic explosion of the object itself)

Still though, nudging is probably a better approach.

I think we all agree here

Comment: Re:Effect of nukes on NEOs (Score 1) 272 272

Come on, now.
Your second sentence is certainly correct, however, your first couldn't be more wrong in its conclusion.

Which would you rather be hit with? A ~150J .22LR round, or a ~320J baseball?
Contact area of the kinetic energy matters. The atmosphere is going to do a great job of absorbing nearly ALL of the kinetic energy of a large impactor, if you can reduce it to small enough rubble, while it isn't going to do shit against a big dense bolide with a minimal contact area.

I'll take atmospheric buck shot over a .50 cal any day.

Comment: Re:Icehouse Earth (Score 1) 637 637

Give that a little thought.

Done. Still stands. Your argument is vindicated because you argued with someone who disagreed with you, and used information from their side against them. They lost, but you sure as hell didn't win.

By that bizarre logic the earth itself is an infection.

That's so non sequitur I'm unsure how to respond to it. An infection upon what? The solar system? For the destabilizing influence it has upon it? The Universe? Help me.

Given that the earth has never had a stable climate, your notions are entirely alien to nature itself.

This is nonsense. The glacial/interglacial oscillation of the current ice age is quite stable. The fact that catastrophes have occurred to destabilize it on 2-3 occasions in the last million or so years does not unstable make.

No, you refer to watermelons, the leftist interpretation of environmentalism - which has very firm roots among the monied classes of the 19th century, to say nothing of conservationism whose earliest manifestations can be tracked back a full thousand years earlier. Much like social welfare systems and every other ostensible social good Marxists have latched onto since Karl hoisted the first of many, many alcoholic beverages, this stuff has been around for a very long time. You'd think you people would learn, I mean Russia has wound up somewhere to the right of Genghis Khan and China's busily returning to its imperial roots, complete with caste system. What you do is create reactions which eventually end up consuming any gains you might have made, a process which will inevitably end up being replicated even in the enlightened and much reviled (by the left) west. Leftists believe me to be a conservative reationary, conservatives call me a progressive swine, I'm quite content to watch all of you idiots get hoisted by your own petards.

It's funny that you make it political. Your colors are showing :)
I'm no leftist. I would classify myself as socially liberal, for sure, however, I'm as capitalist as the next guy.

Both leftists and conservatives should call you what you are- A person who thinks only in partisanship. The very problems of the world for you can't be seen as anything but right-wing or left-wing.
I don't care who Big Oil votes for today. Their loyalty lies only in the price of their commodity. They have no ideology beyond that. But they and their blind supporters (which admittedly do tend to be conservative, however, that's simply because that's who the conservative football team is playing for right now. It could change next election.) are the opposing side I referred to.

Comment: Re:Icehouse Earth (Score 1) 637 637

Dry fact sadly. The reality is that the information I linked to above comes as a major shock to many anthropogenic global warming proponents when it should already be widely known, one fellow I was discussing it with lately proudly declared that we're going through the quickest global warming in 45 million years while earnestly claiming the imprimatur of science. Ask yourself why that might be the case.

Erm. Ignorance by people on my side of the debate certainly doesn't debunk my side of the debate. Since the information you pulled was from a panel that can most certainly be characterized as an "anthropogenic global warming proponent," I think that makes your paragraph entirely circuitous.

The problem is people who regard this notion as a good thing and refer to human civilisation as an infection.

Only when it behaves as such. The Earth is our host. If we seek to alter its ecosphere uncontrolled, then we most certainly are an infection. If we seek equilibrium and stability, we're not.

Who do you refer to when you say "our"?

I refer to any of the people who are not included in the group of people who believe that we should pull every fucking ounce of carbon sequestered in the dirt and inject it wholesale into the extant cycle. You'd think the opposed group of people would be small, as that viewpoint is shamelessly reckless and narrow, but it's not. Legislatively speaking, it's quite massive. Moneyed interests and all that.

Comment: Re:Icehouse Earth (Score 1) 637 637

Your weak link here is the assumption that science is in any way clear about what caused relatively recent drastic climate adjustments. Which leads us inevitably to the conclusion that we can't really go making any definitive statements about the comparitively placid warming we're currently experiencing.

Poppycock. Sure, it's no slam dunk, but forensic experts often determine the trajectory of a bullet without ever seeing it, either. I suppose you're going to argue that CFCs weren't causing ozone depletion, as well. After all, the actual full causal link there is pretty hypothetical.

And placid? Sure, compared to the leading hypothesis for the Younger Dryas ending and such, I guess it's placid. For human civilization, we may look back on it and find it to be not very placid at all.

It's much ado about not a whole lot anyway, fossil fuels are being scaled back to nothing and will be out of mass usage in a couple of generations, and no economies need be wrecked in the process either.

Yes, they are. Only by our efforts. You point to our success as evidence that we should stop? Like it won't flip? There's still a *lot* of coal left.

Comment: Re:Icehouse Earth (Score 2) 637 637

I know the guy you were responding to was wrong.
Your citations are even good.

But certainly you don't think these were non-causally linked random events caused by God sneezing or some shit, right?
All kinds of horrible shit has happened to this planet over time to wipe out massive portions of its population, toss its climate way out of its regular cycle, and generally really make the place a shitty place to be for anyone expecting stability.

The problem is that the only current traumatic event the planet seems to be going through at the moment to cause this particular geologically rapid climate shift is an acute infection of industrialized ostrich-human hybrid civilization. If we can't find something else to explain it, it seems safer to assume that the gigatons of carbon we're pulling from outside of the carbon cycle and injecting into the goddamn gaseous portion of it might possibly be related, rather than assuming it's just a random fucking coincidence.

Comment: Re:the world was supposed to end years ago (Score 2) 637 637

Argh. I was about to mod you insightful, then:

No one who has ever read the Bible believes that God is going to personally intervene to prevent you from screwing up in your current life

That's too much bullshit to cope with. I had to sacrifice my mod-points to tell you that you are terribly, terribly wrong. I have family in the midwest and the east coast.
My Uncle literally believes that humans can't possibly alter the climate, as God says that the Earth is unchanging. He's not a... stupid man. He retired recently from a life-long career as a network engineer at the Census Bureau; he just really believes his cultural interpretation of the vague writings in that damned book.
He absolutely believes that God does intervene to help him with his fuckups.

I know anecdotes are general pretty poor data, but he's not alone. http://www.motherjones.com/env...

I think where you went awry, is that people who do believe in Jehovah the bipolar micromanager are actually the majority, not whatever minority you belong to.

Comment: Re:Rand who? (Score 1) 294 294

That provision was going to expire regardless of whether the Freedom Act was passed that night or the next day. It's not like a vote to reauthorize it was going to happen that night, then get kicked back to the House for reconciliation.
Again- all he did was prevent McConnell from putting in a vote for extending the Patriot Act, which wasn't going to happen. Nobody thought that was going to happen.
To begrudgingly quote Ted Cruz, "It is abundantly clear that a clean reauthorization of the PATRIOT Act ain’t passing this body, and it certainly ain’t passing the House of Representatives."

So again, kudos to Paul for at least being noisy about all this nonsense, but he ultimately did nothing but that.

"There is such a fine line between genius and stupidity." - David St. Hubbins, "Spinal Tap"

Working...