Doesn't sound like it killed it, now does it?Chalnoth said:
Sounds more like a "moon maker"
Humans close to finding answers to origin of universe: Hawking
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Sounds more like a "moon maker"
Well, obviously by "planet killer" I mean big enough to kill all life on the planet, leaving something dead behind
Edit:
Although granted, it's rather unlikely that anything could extinguish all life on Earth. Even in a worst-case scenario, I would expect exotherms to survive, and eventually re-evolve to the current biodiversity.
Edit:
Although granted, it's rather unlikely that anything could extinguish all life on Earth. Even in a worst-case scenario, I would expect exotherms to survive, and eventually re-evolve to the current biodiversity.
Theres one thing I never quite understood in the meteor scenarios. If you hit it with say a nuke from far enough out (within our abilities), even if you dont deviate it and instead split it, each fragment will likely have significantly different spins than they did before. This will interact nontrivially with the friction in space (space is not quite a vacuum) and its own gravitational field, and could (at least naively) be enough to alter its path away from the tiny needle in the haystack that is the target earth.
I've never done the calculation, but it doesnt seem to me to be as gloomy as the pure vacuum scenarios suggest
I've never done the calculation, but it doesnt seem to me to be as gloomy as the pure vacuum scenarios suggest
Well, in the viscinity of the sun, the "friction" mostly comes from just the solar wind, which is largely just a tiny modification of gravity, so I doubt that there would be any significant difference. Also, if you fail, it becomes much harder to deflect the pieces than one big solid lump.Fred said:
Chalnoth said:
That depends on how you view things
Many things that were considered pseudo-science in the past are now accepted by science. There are no limits.
Pre-determined perception and way of thinking is the real limit.
As Einstein used to say imagination is more important than knowledge
Everything started from the big bang according to science. Including you and me as well as everything you see around you. Besides the word universe is made from the latin words uni and vertere which means turning into one.
Using a simplistic similar logic you can derive infinite numbers and infinite combinations from one number, the zero that equals to nothing.
Nesh said:That depends on how you view things
Many things that were considered pseudo-science in the past are now accepted by science. There are no limits.
Pre-determined perception and way of thinking is the real limit.
As Einstein used to say imagination is more important than knowledge
Everything started from the big bang according to science. Including you and me as well as everything you see around you. Besides the word universe is made from the latin words uni and vertere which means turning into one.
Using a simplistic similar logic you can derive infinite numbers and infinite combinations from one number, the zero that equals to nothing.
Oh please don't start this nonsense again, we've had enough threads that have degenerated into airy-fairy hand-wavey nonense about what science can and cannot rule out. If you don't want to be subject to the "limits" of science, stick to religion or science-fiction.
Look it's quite simple. Science is about finding out what is, not what might be. Yes, scientific understanding evolves, that's it's very nature. But simply because science is not currently complete that does not mean that any random semi-mystical New Age crap that someone makes up is scientifically plausible. The one is not a logical extrapolation of the other.
It's total crap to say there are no limits -- the Universe is what it is. There are a whole pile of things which one can imagine which the Universe isn't. Those things which the Universe isn't are outside the limits of what the Universe can be. Period. Having an imagination is great, but really, honestly, there is such a thing as a wrong idea.
Zero doesn't have to be equal to nothing. It depends on the context you're interpreting zero to be under.
1/0 = unpossible(undefined)
1/0 = infinite(limit theorem)
Thank you Mr RuinMyLife. I was hoping to be the universe's greatest physicists(Competing against Chalnoth here) and you've just blown my hopes.
I'm going to go to bed this morning crying. I hope you're happy.
1/0 = unpossible(undefined)
1/0 = infinite(limit theorem)
Thank you Mr RuinMyLife. I was hoping to be the universe's greatest physicists(Competing against Chalnoth here) and you've just blown my hopes.
I'm going to go to bed this morning crying. I hope you're happy.
First off, omnidirectional explosions are orders of magnitude less powerful in a vacuum than in a dense atmosphere. There is no shockwave (the main destructor on Earth), only two blastfronts, the first consisting of radiation and the second of fragments. With nukes, you generally only have the radiation blast front, which loses consistency and power very fast in space. So, you have to do it really up close, or don't bother. And the metal core of an asteroid (the dangerous part) will almost surely survive unharmed.
Second, we need to make a distinction between asteroids and comets: comets mostly consist of icy stuff, while asteroids consist of rock, with often a big metal core (nickel and iron, mostly). Some are reasonably solid (asteroids, mostly), some are made up out of many small fragments (comets, mostly), loosely held together by the minute gravity. Although the opposite happens as well. And everything in between. And some comets have a rocky or even a metal core.
Let's forget about the small ones and only look at the big ones (say, 500 meters diameter and upward), with enough energy to cause a new extinction event. How many of those are there? We really have no idea. Although, since we started looking, we see more and more of them all the time. And the more and better we look, the more we see.
How often does one of them hit the Earth? That depends on three things, mostly:
1. The size of the meteor and the impact we count as our baseline.
Depending on that, we can say that we have had five huge major extinction events in the last 600 million years by collisions with bodies that had a diameter of around 5 km for the upper bound, and a "minor" colission with the energy of the Hiroshima bomb or more about ten times each year (actual observations) for the lower bound. And, we see large asteroids (500+ m) pass very close to the earth more often all the time, up to four each year from 2004 onwards, most of them only a few days before they would have hit the Earth. And considering the small part of the sky observed, there are many more.
A serious event that can completely level a big city is estimated at about once every three hundred years, and one that can completely wreck a small country every few thousand years. The thing to notice here, is that we have very little data, and only saw the evidence historically if it impacted close to a center of civilization, which were very sparse compared to the total surface of the Earth. Most of the guesses for those events are based on at most a few actual observations.
2. The total amount of asteroids and comets.
This is a big problem, as many of the early ones have impacted by now, but there are plenty left that enter the inner Solar system all the time. Comets mostly from the extremely huge Oort cloud, and asteroids mostly from the very large asteroid belt. Everything moves, and trajectories are diverted all the time. But nobody knows how many there really are, not even the right order of magnitude. The Solar system is HUGE, and those bodies are extremely small. Especially asteroids are very hard to see, as they emit very little radiation (light and such).
3. Can we divert it?
Detonating one or more very big nuke(s) on or below the surface of a loose comet that is inbound towards the Sun is a good idea. The comet will shatter, and offer a much larger surface to the heat it collects from the Sun when it's close. But that requires us to see it years or even centuries before a likely impact is eminent. And there is no guarantee that would reduce it enough. And when it would come around, it might still offer a big risk.
A better idea for comets of all kinds that are inbound towards the Sun is to paint one side of the surface white or metallic with a sticky plastic. That will make the outgassing occur mostly at the other side, and divert it's course. But that still requires spotting it far in advance.
An idea that might work for asteroids as well, is to pull a net around it and attach a solar sail to it. That might even work if we spot it only a few months before impact, but only if the rocket with the sail is ready to launch.
Otherwise, the only thing that can be done is try and nuke one side of it as often as possible, and as Chalnot said, that might actually make things worse.
Most everything else, like attaching rocket engines is very unlikely to succeed. For starters, because it would have to be a huge engine and carry massive amounts of fuel, and you cannot do it remotely (for now). You need people over there, who are sure to die. And (Hollywood aside), who thinks we can do an engineering project on that scale in those conditions?
Second, we need to make a distinction between asteroids and comets: comets mostly consist of icy stuff, while asteroids consist of rock, with often a big metal core (nickel and iron, mostly). Some are reasonably solid (asteroids, mostly), some are made up out of many small fragments (comets, mostly), loosely held together by the minute gravity. Although the opposite happens as well. And everything in between. And some comets have a rocky or even a metal core.
Let's forget about the small ones and only look at the big ones (say, 500 meters diameter and upward), with enough energy to cause a new extinction event. How many of those are there? We really have no idea. Although, since we started looking, we see more and more of them all the time. And the more and better we look, the more we see.
How often does one of them hit the Earth? That depends on three things, mostly:
1. The size of the meteor and the impact we count as our baseline.
Depending on that, we can say that we have had five huge major extinction events in the last 600 million years by collisions with bodies that had a diameter of around 5 km for the upper bound, and a "minor" colission with the energy of the Hiroshima bomb or more about ten times each year (actual observations) for the lower bound. And, we see large asteroids (500+ m) pass very close to the earth more often all the time, up to four each year from 2004 onwards, most of them only a few days before they would have hit the Earth. And considering the small part of the sky observed, there are many more.
A serious event that can completely level a big city is estimated at about once every three hundred years, and one that can completely wreck a small country every few thousand years. The thing to notice here, is that we have very little data, and only saw the evidence historically if it impacted close to a center of civilization, which were very sparse compared to the total surface of the Earth. Most of the guesses for those events are based on at most a few actual observations.
2. The total amount of asteroids and comets.
This is a big problem, as many of the early ones have impacted by now, but there are plenty left that enter the inner Solar system all the time. Comets mostly from the extremely huge Oort cloud, and asteroids mostly from the very large asteroid belt. Everything moves, and trajectories are diverted all the time. But nobody knows how many there really are, not even the right order of magnitude. The Solar system is HUGE, and those bodies are extremely small. Especially asteroids are very hard to see, as they emit very little radiation (light and such).
3. Can we divert it?
Detonating one or more very big nuke(s) on or below the surface of a loose comet that is inbound towards the Sun is a good idea. The comet will shatter, and offer a much larger surface to the heat it collects from the Sun when it's close. But that requires us to see it years or even centuries before a likely impact is eminent. And there is no guarantee that would reduce it enough. And when it would come around, it might still offer a big risk.
A better idea for comets of all kinds that are inbound towards the Sun is to paint one side of the surface white or metallic with a sticky plastic. That will make the outgassing occur mostly at the other side, and divert it's course. But that still requires spotting it far in advance.
An idea that might work for asteroids as well, is to pull a net around it and attach a solar sail to it. That might even work if we spot it only a few months before impact, but only if the rocket with the sail is ready to launch.
Otherwise, the only thing that can be done is try and nuke one side of it as often as possible, and as Chalnot said, that might actually make things worse.
Most everything else, like attaching rocket engines is very unlikely to succeed. For starters, because it would have to be a huge engine and carry massive amounts of fuel, and you cannot do it remotely (for now). You need people over there, who are sure to die. And (Hollywood aside), who thinks we can do an engineering project on that scale in those conditions?
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K.I.L.E.R said:
I agree but I was refering to 0 alone as an absolute stand alone number. Also I used that example as a simple reference just to give a better idea of what I ve been trying to say.
nutball said:
1)You misinterpreted my points and misunderstood my intentions. You also mixed 2 different things like my reference to imagination and limits and came with a wrong understanding. I didnt imply that everything you imagine automatically converts to a fact because the universe is "infinite"
My reference to knowldegde and imagination was that knowledge is often based on theories, it is not always right, and there are various variations of it. Some choose specific parts of it, others take the available knowledge which contains possible errors, restrains and misconceptions as the only guide and the only acceptable explanation. Not everything that is knowledge is a fact, and not all knowledge is expanded enough. Knowledge is created from human experiences, understanding and observations. No human is perfect to find the absolute and perfect knowledge.
Taking that available knowledge as the absolute guide, rejecting everything else that might suggest previously undiscovered, unobserved data that could contradict previous knowledge, without even studying it just because of the contradiction is a limit.
Many things that were previously accepted as scientific knowledge are today not accepted, because they have been replaced by other observations.
2)Your reply isnt what I d call...polite
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Well, I'm sorry, but I'm really tired of people on these forums who go to great lengths in an attempt to say something, but in the end it just amounts to so much babble, because there's no direct connection to reality. There's just no basis for discussion if you can't say something specific.
Chalnoth said:
Well I said a few specific things in my first post. A couple of things I collected from magazines and books (or even from something my professor told me) but I got the same reaction
. And no the sources werent religious. One for example was a book refering to the unknown history of man, and some others were a few references from documentaries and magazines similar to Discovery and National Geographic. (Or was it from these magazines? I cant remember)It seems the problem isnt my lack of connection to reality. Its how each person perceives things and how open minded he is.
arjan de lumens
Veteran
One problem with ideas that contradict existing knowledge is that there are a large number of people who keep outputting such ideas all the time, and often consider themselves geniuses because of it - giving the proper scientific attention to all these people and their ideas, to experimentally test them etc, could easily be enough to keep busy 100x more scientists than what we have today, as well as making the life of all these scientists seriously miserable (not just because they end up doing tons of dull work that they strongly feel won't bring them anywhere, but also because of all the strife that arises from telling these self-proclaimed geniuses why their ideas are wrong, when they are in fact wrong) - it is mainly for this reason that the scientific community, when presented with a "new" or "revolutionary" idea, usually dismisses it with prejudice if the person behind the idea doesn't possess any relevant credentials, and otherwise treats the idea with deep skepticism if it makes too large logical leaps (e.g. the fibonacci->stock market idea you mention would be an example of a large logical leap, unless you can make a good explanation of what the underlying mathematical connection would look like).Nesh said:
No, I'm saying that you need to post something real, or it's of no use as a basis for discussion. Anecdotal, "I remember seeing something like this one time," isn't very useful, because memory changes over time, and you may well have misinterpreted the original author's statements anyway.Nesh said:Are you implying that I pulled everything out of my ass?