I am saying we need to go beyond what we have now and invest in better detection systems overall.
Also your point on size and its relation with damage is flawed. The engery scales linearly with mass but with the square of velocity. I haven't had time to fact check but I got an email from the asteroid miners at Planetary Resources and they say it had a blast equal to 1000 Hiroshimas. The only estimate on size I have seen yet is table sized. While it sounds like that isn't possible, all it means is it was going very fast.
It is worth the cost to find them all, period. You can't put a value on lives saved.
Plus, you are assuming that we would be doing this with technology of fixed capability (bad assumption) and that there will be no economic returns from the endevour(bad assumption). Already, Planetary Resources is making a business case to launch lots of asteroid finding telescopes and making money of the data and mining the juicy ones.
This is why we need to start getting serious about this problem.
You may have heard of the meteorite that struck the Russian Chelyabinsk region at about 09:15 local time in the region about 1,500 km (930 miles) east of Moscow in the Ural mountains. The damage caused by the shock wave has been extensive. As reports continue to stream in, the number of people injured has been increasingly steadily and nears 1,000, mostly caused by window glass blown out by the shockwave. The amateur videos and pictures illustrate the power that a small object entering the atmosphere at high speed can have.
Estimated at about 10 tons, and about 2 meters across, this object (called a bolide when they are this bright) streaked through the sky at a speed of 54,000 kph (33,000 mph), and due to the extreme forces of atmospheric entry, broke apart between 30-50 km (18-32 miles) above the ground. Despite the coincident timing, the Russian meteorite has nothing to do with 2012 DA14, as the objects have decidedly different trajectories. A fragment from 2012 DA14 would have been moving from south to north, the path of the meteorite is from northeast to southwest. We will certainly learn more about the nature of this object when fragments from it are recovered and studied in laboratories.
In our previous update, we mentioned that many asteroids pass by Earth with little or no warning. We were not exaggerating. Despite considerable progress in asteroid detection, only about one in ten close-approaching asteroids are known about ahead of time. While not every approaching asteroid may be detected, and with little warning not all can be prevented, in this case a little warning would have prevented many injuries, and quelled the panic that followed.
Today's events, both with 2012 DA14 and the Russian meteorite, are a reminder that our Solar System is a crowded place. Today was unnerving indeed, and scary and unfortunate for those near Chelyabinsk. We dont know when the next one of these might appear, but were working to see it coming!
Actually, I was referring to directly imaging exo-planets. While those planets are already found when they were imaged, the imaging is still an extremely difficult thing to do. But it's doable, and I suggest it's harder to do than finding an asteroid.Yes, but this is using specific techniques like measuring the gravitational perturbation of the parent star or observing the planet's transit. It hardly follows from this that we can easily detect small dark objects close to home.
We cannot, at the present time, make that accurate of a prediction. There is no hard laws that say we cannot, however.I don't know if we can actually determine an object's trajectory with the degree of accuracy needed to say, issue a meteor impact warning for a specific city with enough warning to evacuate it. And objects entering the atmosphere often break apart in stages, scattering debris over a wide area. When the Mir space station was deliberately deorbited in 2001, they had to issue cautionary statements for a large chunk of the south Pacific, for example.
I agree and the thought that this may not change anything wrt R&D in this field.However, I ultimately agree with your overall sentiment. It's worth investing some money and effort to better understand, predict, and mitigate the threats posed by near-Earth objects of all sizes.
We can actually detect quite small ones. The difference is that when we find ones that small, it's usually by accident. We do have some half-hearted searches (which are better than none) for the larger ones, but ones this small are only ever picked up basically when the conditions are perfect and we happen to be looking in that area.Hobbs, how small of space debris/asteroids can we detect currently? Any reason why this bit wasn't detected?
I said amateurs in my news source
It not a question of "better", the only thing making a difference would be many more of those medium sized wide-angle telecopes with really large CCD chips looking out for NEOs.I am saying we need to go beyond what we have now and invest in better detection systems overall.
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I am not talking about current ground based systems only. I am talking about making investments to build new, more capable, space based systems. My point is about our future and this problem going forward, not about current capabilites.
PR will be spinning that for, well, PR purposes (pun intended).I haven't had time to fact check but I got an email from the asteroid miners at Planetary Resources and they say it had a blast equal to 1000 Hiroshimas. The only estimate on size I have seen yet is table sized. While it sounds like that isn't possible, all it means is it was going very fast.
By the way, (usually reliable) German public radio was citing Russian sources mentioning a relative velocity of about 30 km/s, and observers feeling a heat pulse from the explosion.
Energy before atmospheric entry: 5.65 x 1012 Joules = 0.14 x 10-2 MegaTons TNT
The energy of the airburst is 8.84 x 1011 Joules = 0.21 x 10-3 MegaTons.
Velocity is the most important factor. However, as per the email I posted above, it was roughly 2 meters wide (roughly a large kitchen table's width), weighed 10 tons and hit at roughly 54,000kph.Well of course velocity is a factor, but since we're speaking mostly of near-Earth objects, their orbital velocities don't vary that much. The impact velocity then depends on the angle at which they strike Earth. Typically it's about 11-20 km/s I believe.
I don't care for that kind of math really. Besides, it's obvious we need to begin searching for big ones and the little ones are also highly exploitable resource commodities. I don't see a good reason to make a cutoff for what we should and shouldn't look for, especially since the infrastructure needed to find the big ones isn't far removed from the infrastructure needed to find the little ones and you can make money off of all of them.Actually, you can. In the end, it is a simple cost-benefit analysis.
One of these little ones (2m) can kill thousands. They are worth looking for.Ask that question to the people who decide what to spend money on. They'll have a look at how many people normally die from the rare genetic condition - one or two a year. How many people die in the same period because of smoking-related illnesses? Tens of thousands. Easy choice for them.
No that's not the logic that applies at all.The same logic applies in defending against asteroids - focus on those which can do really big damage, accept the fact that you won't see the smaller ones until they get really close.
No it's not, see above. And no, I wouldn't bother with ones that are outside of orbits capable of intersecting the Earth in the next hundred years or so. That still leaves a ton of objects.Not really. I am saying that there is a limit to our capability to map everything that flies around in the Solar system, which is a fact, and that spending too much money finding every metre-sized rock is a serious overkill. In other words, it is not worth it.
Why spend less money exactly?Spending considerably less money on a project of an advanced warning in near-Earth space, which can be done comparably easily and will still give us a few hours warning against impacts of even metre-sized rocks, is a better way of addressing the severity of this threat.
We didn't know this was coming, and we certainly didn't know it was going to hit Siberia. Currently, we have no way of knowing exactly what size asteroids can cause damage, how many there exactly are, how many will strike the Earth or where they will strike. We need to put resources into answering those questions.Exactly - and the fact is that metre-sized rocks hitting Siberia are an acceptable danger of life on this planet. Only the bigger ones are a threat which warrants spending a lot of money to get prepared against them.
Again, you're assuming basically taking what we have and marginally increasing the capabilities of that. I'm talking a radically different approach: creating whole new technologies to tackle the problem in a serious way and in a hurry and launching lots of probes to go out and find stuff.It not a question of "better", the only thing making a difference would be many more of those medium sized wide-angle telecopes with really large CCD chips looking out for NEOs.
We are already pretty much at the limit of what's physically possible with optics and detection electronics, and for that purpose going into space won't make much of a difference, apart from making it much more expensive.
I suggest it's harder to do than finding an asteroid.
Maths correct, or at least equally incorrect as mineVelocity is the most important factor. However, as per the email I posted above, it was roughly 2 meters wide (roughly a large kitchen table's width), weighed 10 tons and hit at roughly 54,000kph.
I rechecked my email and the quote about 1000 hiroshima's was based on the Tunguska asteroid, not this one.
For this one, I worked out (check my math):
10kg*(54000[km/hr]/3600[hr/s]*1000[m/km])^2=2250000000J=0.000537763kt (from this converter).
How often does this kind of thing occur and what are the typical casulties, costs to infrastructure / economic activity? It may be so insigifnificant that something like a flood defense would be a better thing to spend 100m on!
I don't care for that kind of math really.
Besides, it's obvious we need to begin searching for big ones and the little ones are also highly exploitable resource commodities. I don't see a good reason to make a cutoff for what we should and shouldn't look for, especially since the infrastructure need to find the big ones isn't far removed from the infrastructure needed to find the little ones and you can make money off of all of them.
One of these little ones (2m) can kill thousands. They are worth looking for.
No that's not the logic that applies at all.
Here is the logic we should be using:
What size can survive entry?
What size of entry-survivors can cause harm to a city?
=> Find all the asteroids of that size that are in orbits capable of hitting the earth.
Oh and make money, expand our species into outer space and develop a bunch of technologies while you're saving lives.
That still leaves a ton of objects.
Why spend less money exactly?
That means less infrastructure, less new tech and less stimulus.
Don't forget every dollar we'd spend on this would be spent right here on Earth and would flow back into the economy, with the added benefits of new infrastructure, new tech, new jobs and oh yeah, saved lives. Oh and then when you've got all this infrastructure, you can start exploiting these things.
We didn't know this was coming, and we certainly didn't know it was going to hit Siberia. Currently, we have no way of knowing exactly what size asteroids can cause damage, how many their exactly are, how many will strike the Earth or where. We need to put resources into answering those questions.
You are making dangerous assumptions with your logic that could get people killed. We need to find the answers to these questions before we determine what exactly constitutes an 'acceptable danger' dude.
Jesus
Stop and breathe for a moment before you say something else you will regret.
Again, you're assuming basically taking what we have and marginally increasing the capabilities of that. I'm talking a radically different approach: creating whole new technologies to tackle the problem in a serious way and in a hurry and launching lots of probes to go out and find stuff.
No, I'm talking fundamental physics. You cannot detect more than all photons impacting onto your detector, and you cannot increase the transmission of your optics beyond 100%. Present technology is reasonably close to that.
I think it's a little more complicated that just size, right? Doesn't the velocity also affect how long it can survive in the atmosphere?Here is the logic we should be using:
What size can survive entry?
What size of entry-survivors can cause harm to a city?
=> Find all the asteroids of that size that are in orbits capable of hitting the earth.
And no, I wouldn't bother with ones that are outside of orbits capable of intersecting the Earth in the next hundred years or so.
If your detector is already good enough to detect all photons, what's the point?Isn't that what photomultipliers are for?