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Asteroid Impacts Bigger Risk Than Thought
Rambo Tribble (1273454) writes "The B612 Foundation, a U.S.-based nuclear test monitoring group, has disclosed that their acoustic sensors show asteroid impacts to be much more common than previously thought. Between 2000 and 2013 their infrasound system detected 26 major explosions due to asteroid strikes. The impacts were gauged at energies of 1 to 600 kilotons, compared to 45 kilotons for 1945 Hiroshima bomb."
Is the Earth basically getting nuked (in terms of explosive yield) about twice per year without anybody noticing?
The B612 Foundation is a private venture dedicated to finding NEOs that will impact the Earth. They used nuclear test monitoring equipment to find the explosions resulting from asteroid impacts.
8/25/2000 (1-10 kilotons) NORTH PACIFIC OCEAN
4/23/2001 (1-10 kilotons) NORTH PACIFIC OCEAN
3/9/2002 (1-10 kilotons) NORTH PACIFIC OCEAN
8/9/2006 (1-10 kilotons) INDIAN OCEAN
9/2/2006 (1-10 kilotons) INDIAN OCEAN
10/2/2006 (1-10 kilotons) ARABIAN SEA
12/9/2006 (10-20 kilotons) EGYPT
9/22/2007 (1-10 kilotons) INDIAN OCEAN
12/26/2007 (1-10 kilotons) SOUTH PACIFIC OCEAN
10/7/2008 (1-10 kilotons) SUDAN
10/8/2009 (>20 kilotons) SOUTH SULAWESI, INDONESIA
9/3/2010 (10-20 kilotons) SOUTH PACIFIC OCEAN
12/25/2010 (1-10 kilotons) TASMAN SEA
4/22/2012 (1-10 kilotons) CALIFORNIA, USA
2/15/2013 (>20 kilotons) CHELYABINSK, OBLAST, RUSSIA
4/21/2013 (1-10 kilotons) SANTIAGO DEL ESTERO, ARGENTINA
4/30/2013 (10-20 kilotons) NORTH ATLANTIC OCEAN
yyeeeah, those are technically all between 1-600 kilotons.
Also, between 1 kiloton and 600 gigatons.
First, the Hiroshima bomb was 13 Kilotons, not 45. Nagasaki was roughly 20 Kilotons.
600 kilotons TNT is about 2.5e15 J. In comparison, the sunlight incident on the Earth is around 174 petawatts, meaning it takes roughly 20 milliseconds for that much solar energy to be absorbed (clouds, oceans and land masses) by the Earth (taking into account the ~30% reflected power). In comparison, the total world annual energy consumption is around 5e20 J. So, I wouldn't be too worried about added heat due to asteroids.
Sources:
https://www.google.com/search?...
http://en.wikipedia.org/wiki/O...
http://en.wikipedia.org/wiki/S...
blame the asteroids for global warming!
have you seen my sig? there are many others like it but none that are the same
Little Boy clocked in at ~15 kilotons, not 45 kilotons per TFS. Fat Man was ~21kilotons, though it was dropped off target and ended up doing less damage than Little Boy.
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
Right - if we find out that these are happening much MORE often than previously thought, and yet damage is rare, then it seems like they're LESS of a risk than previously thought. Sort of like finding out that when you swim at the beach, sharks are close by more often than you realized - meaning the risk of them attacking you is lower. If anything this indicates that the Earth's natural asteroid defenses are more robust than previously realized.
Besides, I remember reading that kiloton-scale atmospheric asteroid detonations happened once every month or two, but this indicates it's less often than that, so they're actually LESS common than I thought. I could have misremembered that stat, though.
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I'm, you're, he's/she's/it's, we're, you're, they're
They're nothing to do with nuclear test monitoring, they just happened to use data from the monitoring network to count the number of kiloton scale events in the last decade or so.
The B612 Foundation is a non profit organization trying to raise money for a asteroid discovery spacecraft, a telescope that will sit down near Venus's orbit and look outwards, enabling it to see asteroids near earth without the sun dazzling the optics (half the asteroids passing near earth are invisible because they are too close to the sun). It's not an unreasonable goal when you consider that high profile museums and educational institutions regularly raise hundreds of millions of dollars in donations.
I don't think anyone is implying that we are doomed because of _these_ impacts.
However, in general the frequency of an impact event is inversely proportional to the size of the impacting body. Smaller impacts happen more often than the larger ones. Counting the smaller ones precisely gives you an idea of what the risk of a big event is.
So far people underestimated these smaller ones that is being reported. The wikipedia article I linked to earlier, suggests one impact every five years at the level of 5 kT of TNT. These guys being right would imply a risk of at least a magnitude higher than previously estimated. That increases the risk for the really big ones too.
The article authors say that most of the dangerous asteroids are already being tracked (additional tracking efforts under way), and can potentially be deflected since collisions can be predicted decades into the future. That's only a half-truth. Comets in the outer solar system are too dark to detect in their present locations, but can arrive at Earth very quickly. There will not be enough time to deflect them... Statistically, what percentage of impacts are from objects originating in the outer solar system? Is that even possible to determine?
We don't have enough history to gauge what actually has happened over time, so we have to estimate.
We approximate by finding big rocks or chemistry on earth, looking at craters on the moon, or this.
In all these cases we are using the small but frequent to infer the distribution of big but hugely problematic events. Our best answer the question about the likelihood of a killer impact is grossly changed if this tail is changed.
Think about it like floods. We ask how likely a 10,000 year flood is going to happen next year. We have ~100 years of rainfall data. We fit it to a distribution that is appropriate and then use those fit parameters to make a best guess. If our rain gauge was only measuring half the rain, we might under-estimate the actual risk by a factor of 10x or 20x.
There is good correlation between "killer impacts" and location of the sun in the galaxy (yes it moves around). We are starting to enter a higher risk region (transition to edge of arm) and perhaps the fundamental distribution is changing. In that case the history of craters on the moon or other might not be meaningful indicator of the near future.
Considering this I think good tracking is not a bad idea and should be thought out well and properly considered.
the whole solar system is covered with asteroid collisions..... shouldn't take a damn genius to get it's a real possibility to be hit by something a little too big to go unnoticed.... and the best solution ,as dear C.Sagan said, is to become a spacefaring race...the sooner we move our asses to mars (and beyond) the better....
it's our duty as a specie to at least colonize the solar system.... ...when they will stop laughing about it...
I came here to say something very much like this. Thanks for saving me the need to log in and... Oh, wait...
Garry Knight
No. The B612 people's math is demonstrably wrong, or at least very misleading.
26 explosions happened in the atmosphere in the last 13 years. Some of them broke windows but none had significant impact on cities, and would not have no matter their location. I don't know how they predicted once every hundred years, but they're wrong for two reasons. First, predictive analytics just doesn't work that way with any high confidence. If I flip a coin -- one that I know is cheating -- 26 times and it comes up heads every time, what are the odds that it will come up tails? You don't know... You can't know. You can make some educated guesses, but there is no real confidence. In the case of these explosions I'm sure they can model the size, altitude, and some other things, but still, they can't really know this, and they seem to fail to account for things like the impact of jupiter and the moon and sun on larger asteroids (which does actually affect the math). Second, you can compare the numbers to recorded history. The earth has certainly been hit by asteroids that would destroy a city. The last one probably happened off the coast of New Zealand around 1400 BC and caused a tsunami wiping out some local villages. There are only a few hundred noteworthy craters on earth over the past few hundred-million-years. That works out to "not one per century".
Make no mistake -- I think we should prepare for and defend against them, and I'm in favor of the satellite and conversation on the topic. But the numbers in this study are difficult to swallow and I accuse the hopefully well-intentioned people behind B612 of some under-founded alarmism.
"asteroid strikes more common than thought" would have been interesting enough to get me here
...but it would still be dishonest and I would still take offense. "...more than thought" implicitly implies "...more than the scientific community knew about". This is false. Nothing in this story suggests that science was not aware of this frequency. An honest headline would be "frequency of asteroid strikes underappreciated by the general public". Which doesn't say all that much. Also, as pointed out elsewhere in this thread, the risk of large-scale loss of life is minimal. This is all fear-mongering to get a product sold. It's a bit scandalous how media fall over themselves to repost this non-story without the smallest amount of background research. BBC is this close to losing its status as my primary news source.
The problem lies in their highly misleading use of the phrase "than previously thought". The scientific community has been aware of the time and energy distribution of these strikes for a long time. They actually meant "than appreciated by the general public". More on that here.
Orbiting body surrounded by other orbiting bodies occasionally gets smacked by an orbiting body, news at 11.
NASA had nothing to do with this. Private organization. Kindly remove your head from your posterior and re-insert it into the sand.
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