Quote from: meberbs on 07/26/2017 07:24 pmSo now you are reduced to disputing the credentials of the people who study this for a living. ... Your arguments are equivalent and just as wrong as the people who doubt that the Earth is getting warmer ... If YOU understood the topic, you wouldn't question their work unless you had something specific to question about it. Did I just get called a GW-denier? Stay classy.
So now you are reduced to disputing the credentials of the people who study this for a living. ... Your arguments are equivalent and just as wrong as the people who doubt that the Earth is getting warmer ... If YOU understood the topic, you wouldn't question their work unless you had something specific to question about it.
They may have great credentials and spent their lives on the topic, but that doesn't make them right - only the truth can do that.
I have not questioned others' credentials,
only their conclusions and pointed out credentials don't matter.
I'll also point out hop, like other topic pundits, have led you astray with false promises, flawed reasoning, worthless studies and his inability to defend those subject/quotes is proof of his ignorance of it.
First and foremost; all studies to date are without merit as the physical properties of meteors is unknown - specifically their tensile strength, shear strength and elasticity. Shoemaker-Levy 9 disentigrated from tidal forces that are comparatively minor, suggesting anything but compressive forces with containment or minute forces over decades would be disasterous. But making assumptions about how to affect them would be like making environmental or atmospheric predictions without actually knowing the atmosphere's composition. DART will fill some voids current "experts" ignore while making speculative and uneducated theories.
In the complete absence of actionable data, but a wealth of irrelevant glad-handing and statistics,
we can realistically only rely on the total vaporization of a meteor as defense. That limits our defense to 100m or less,
but the path of parliamentarians and statisticians has concluded we should only focus on larger objects, with fungible "completeness" or "risk reduction" assertions. In truth nothing has been accomplished as no defense -from any size or distance- has been made. Only empty, and foolish promises.
That limits our defense to 100m or less, but the path of parliamentarians and statisticians has concluded we should only focus on larger objects, with fungible "completeness" or "risk reduction" assertions. In truth nothing has been accomplished as no defense -from any size or distance- has been made. Only empty, and foolish promises.
Moreover, "completeness" under 100% isn't complete and even if it was, wouldn't actually be complete just like "risk reduction" doesn't actually reduce the risk of a city or planet being anhiliated. These are meaningless statistics used by people who don't understand the problem, but like to justify their participation.
First and foremost; all studies to date are without merit as the physical properties of meteors is unknown
Nukes are insufficient.
So if a nuclear mass generator was a viable / non-fictional concept,
I'd guess that would be more practical than the above two concepts (nukes & tethers).
Actually I said we should focus on finding asteroids/meteors we can currently stop (100m down to 20m equivalent to ICBMs) that can cause massive destruction, while awaiting data (DART) to inform us on the properties of asteroids instead of wildly speculating on what to do, how effective it would be, calling it "expertise" and trying to con Congress into funding it. Notably, finding 20m meteors means we found the 20mi ones as well and provides more future options to test redirect concepts.
If one is spending money to save lives and property, concentrating on finding small asteroids/meteors makes very little sense from cost/benefit point of view.
Quote from: as58 on 07/29/2017 03:39 pmIf one is spending money to save lives and property, concentrating on finding small asteroids/meteors makes very little sense from cost/benefit point of view. Why, when small asteroids are the only ones we can stop? Programs to find large meteors have no benefit as we have no actions against them. And the cost of finding small asteroids is almost no different than finding large ones if the cost of scaling up a telescope is minimal. Previously I mentioned telescopes haven't advanced in 350years - the date when reflection replaced refraction in large scopes. Sure, we've managed to ease production and reduce weight by combining multiple mirrors into a larger primary and surface-coat rather than back-coat the mirrors, but that's embarrassingly minor for 31/2 centuries.Building better telescopes is something everyone can get on board with. From asteroids, to the Solar system and deep space - even downlookers want better scopes. That's the squeaky wheel which actually benefits mankind and provides smaller, more numerous options to test redirect methods in the future.
Quote from: as58 on 07/29/2017 03:39 pmIf one is spending money to save lives and property, concentrating on finding small asteroids/meteors makes very little sense from cost/benefit point of view. Why, when small asteroids are the only ones we can stop? Programs to find large meteors have no benefit as we have no actions against them. And the cost of finding small asteroids is almost no different than finding large ones if the cost of scaling up a telescope is minimal. Previously I mentioned telescopes haven't advanced in 350years - the date when reflection replaced refraction in large scopes. Sure, we've managed to ease production and reduce weight by combining multiple mirrors into a larger primary and surface-coat rather than back-coat the mirrors, but that's embarrassingly minor for 31/2 centuries.Building better telescopes is something everyone can get on board with. From asteroids, to the Solar system and deep space - even downlookers want better scopes. That's the squeaky wheel which actually benefits mankind and provides greater options to test redirect methods in the future.
Quote from: hop on 07/28/2017 04:50 pmWe have observations of many hundreds of thousands of asteroids, and many of these provide significant insight into their structure and physical properties. ... Physical properties are a significant source of uncertainty, but to say we know nothing just shows total ignorance of the field. No, you really don't know anything. Six months ago the 40-90m asteroid "2017 BS5" was discovered in an orbit nearly identical to Earth's and flew past last weekend. This is an obvious orbit to detect, like a dim star following the Earth, and yet it wasn't detected until the point no redirection theories could have avoided a possible collision, only total vaporization of the object at the last minute. Fortunately it missed.Thankfully pundits and "the field of experts" who focus on "risk reduction and completion" have enough "studies" of the physical properties to handle this, right?Dr. John S. Lewis - "Until we know what the body is made of, hazard projections are nonsense. It could be a dustball, a snowball, a loose collection of rocky rubble, a monolithic soft rock, a monolithic hard rock, a giant steel cannonball, et cetera. It could, at the extremes, fall apart into dust at high altitudes or penetrate hundreds of meters into Earth’s crust and explode like World War III." http://deepspaceindustries.com/asteroid-profile-2017-bs5/Quote from: meberbs on 07/28/2017 02:27 pmSince the only thing you count as progress is successfully deflecting an asteroid, we should give up all searches for asteroids and research into deflection methods right now, because none of them are producing progress. Actually I said we should focus on finding asteroids/meteors we can currently stop (100m down to 20m equivalent to ICBMs) that can cause massive destruction, while awaiting data (DART) to inform us on the properties of asteroids instead of wildly speculating on what to do, how effective it would be, calling it "expertise" and trying to con Congress into funding it. Notably, finding 20m meteors means we found the 20mi ones as well and provides more future options to test redirect concepts.Quote from: hop on 07/28/2017 04:50 pmStatistics are a fundamental and extremely successful part of science, and impact risk is based on quite simple statistics. If you have to cross a mine field, and have a choice of knowing where ~90% of the mines are, or not knowing where any are, which do you chose? I wouldn't cross the minefield, duh. I also wouldn't play Russian roulette or buy into a "~90% completion in ten years" scheme. I'd actually try to identify all the hazards, find out their properties and remove the threat rather than waltzing through with my fingers crossed, waiving a study and professing expertise.Quote from: meberbs on 07/28/2017 02:27 pmCredentials don't matter? Lets go ask a 5 year old to resolve this for us then.and Did you just say that statistics aren't data? If someone's entirely wrong and peddling myths, credentials only show who was foolish enough to give them credentials. If a 5yr old had credentials, does that make them right? And no, statistics aren't real data. Observed, recorded information is valuable, but not after it's gone through a blender with ample assumptions, categorization and reconfigurations to become stats, marketing or whatever you want it to be.
We have observations of many hundreds of thousands of asteroids, and many of these provide significant insight into their structure and physical properties. ... Physical properties are a significant source of uncertainty, but to say we know nothing just shows total ignorance of the field.
Since the only thing you count as progress is successfully deflecting an asteroid, we should give up all searches for asteroids and research into deflection methods right now, because none of them are producing progress.
Statistics are a fundamental and extremely successful part of science, and impact risk is based on quite simple statistics. If you have to cross a mine field, and have a choice of knowing where ~90% of the mines are, or not knowing where any are, which do you chose?
Credentials don't matter? Lets go ask a 5 year old to resolve this for us then.and Did you just say that statistics aren't data?
What size of fission fission/fusion device would be need?Would the current less than 1mT devices be sufficient, or would we need to revisit some 9-15mT weapons of the past?
I wouldn't cross the minefield, duh. I also wouldn't play Russian roulette or buy into a "~90% completion in ten years" scheme.
Why, when small asteroids are the only ones we can stop?
I think nukes are insufficient because of the overall business case.If there are an unknown quantity of objects to annihilate
The probabilities of successfully achieving the outcome is uncertain. The cost is too much.
The global politics is just too complex.
The risk of failure is high.
Previously I mentioned telescopes haven't advanced in 350years - the date when reflection replaced refraction in large scopes.
I see NEOs as tremendous resources. I'm hopeful that within the next few years we can begin discussing them in those terms, rather than strictly as hazards. With the appropriate orbital infrastructure, we can begin pulling material off of asteroids each time they cross, which will lead us to more infrastructure, which in turn will increase the demand for more material.
Quote from: Mr. Scott on 07/29/2017 04:20 pmHowever, the conditional probability of most of us dying, if a ~2 km asteroid is to impact anywhere on Earth, can be fairly well estimated to be close to 100%.I'm willing to pay "high" cost of having several dozen megaton-class warheads and corresponding spacecraft to be stored and ready to nuke it, if it will be found.The big asteroids, the "world killers" are easy to see years in advance, and are now a mostly known topic. People are seriously discussing the best way to deal with them, which is more complex than it appears on the surface, as disrupting a ball of rubble is a very bad idea.But you have a lot of time to deal with the big asteroids, since you can find them years in advance. Due to the time before impact, you only have to give them (relatively) small nudges, potentially over a long period to miss Earth; in fact at a low enough rate that their minimal internal gravity may keep a asteroid that is a rubble ball together.Whether nukes will be a piece of the asteroid solution, is not clear to me (I've not studied the problem). There are serious people trying to figure that out, and meetings and proceedings you can study. Both Bomb Builders from the national labs, astronomers and others are trying to figure that out.But firing a nuke at a small asteroid nearby earth, on one of the last days before impact, will require large impulse. This seems very likely to often result in turning the small asteroid into a MIRV that would inflict more destruction than a single, larger impact. That this is a serious issue, is clear from videos of the incoming Chelyabinsk (and other smaller entries into Earth's atmosphere of asteroids). Just take a look at the fireballs. These asteroids often fall apart.So hold your nukes: it isn't clear yet they can/should play an role.
However, the conditional probability of most of us dying, if a ~2 km asteroid is to impact anywhere on Earth, can be fairly well estimated to be close to 100%.I'm willing to pay "high" cost of having several dozen megaton-class warheads and corresponding spacecraft to be stored and ready to nuke it, if it will be found.
The problem with small asteroids is that you can't see them in time to do anything (except to provide warning).
We don't even know how common they are.
Note several other things: IR is *not* necessarily better or necessary for detection.
Bigger telescopes are not a feature: what you need to do is observe the whole sky multiple times/night (something ATLAS is doing), so you can distinguish asteroids from stars.
Quote from: jg on 07/30/2017 02:06 pmQuoteWe don't even know how common they are.The error bars are large, but it's not totally unconstrained. We know the rate of impacts of very small bodies from nuclear weapon monitoring and fireball networks. Populations can also be estimated from surveys that only see some of them, as long as we have a good understanding of the efficiency and biases. The DECam paper I linked earlier is a good example https://arxiv.org/abs/1707.04066It's notable that estimates for the >100 m class seem to be converging pretty well.QuoteNote several other things: IR is *not* necessarily better or necessary for detection.
QuoteWe don't even know how common they are.The error bars are large, but it's not totally unconstrained. We know the rate of impacts of very small bodies from nuclear weapon monitoring and fireball networks. Populations can also be estimated from surveys that only see some of them, as long as we have a good understanding of the efficiency and biases. The DECam paper I linked earlier is a good example https://arxiv.org/abs/1707.04066It's notable that estimates for the >100 m class seem to be converging pretty well.QuoteNote several other things: IR is *not* necessarily better or necessary for detection.
But firing a nuke at a small asteroid nearby earth, on one of the last days before impact, will require large impulse. This seems very likely to often result in turning the small asteroid into a MIRV that would inflict more destruction than a single, larger impact.
That this is a serious issue, is clear from videos of the incoming Chelyabinsk