Soapbox:Time we stop acting like an asshat of a species before we go out like dinos

I think a few posters really have no idea how big even the space between Earth and the Moon's orbit really is.

 

In class - will respond to questions and quotes directed towards me ASAP.

Please knock off the religious and news source stuff - this is a soapbox thread. I mentioned god for rhetorical purposes, this isn't a theology thread.

Edit:
I specifically brought up people not paying attention in the OP. Stupid me. Apologies.

 

Yup, there's no debate about that. The questions are, how much and how good?

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.

You can try different masses, velocities, angles, and compositions in this Asteroid Impact Simulator.

I don't know what the 1000 Hiroshima-bombs (1000 x 15kT = 15 MT ) relates to, but certainly not to a kitchen-table sized rock, which would have to move at roughly 3200 km/s - in other words 1% the speed of light or 44 times the maximum orbital velocity of an abject orbiting the Sun - to have that kind of kinetic energy equivalent.

Actually, you can. In the end, it is a simple cost-benefit analysis.

Will you spend 1 billion dollars on a massive anti-smoking campaign which will save thousands of lives per year and save the health care systems billions in return, or will you spend the same amount of money on developing a cure for a rare genetic condition that only affects a few hundreds of individuals?

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.

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.

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.

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.

Exactly - and the fact is that metre-sized rocks hitting Siberia are an acceptable danger of living on this planet. Only the bigger ones are a threat which warrants spending a lot of money to get prepared against them.

 

From the asteroid mining company Planetary Resources:

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.

We cannot, at the present time, make that accurate of a prediction. There is no hard laws that say we cannot, however.

I agree and the thought that this may not change anything wrt R&D in this field.

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.

But it's not impossible and it certainly would be much easier if we got serious about this and started sending up more satellites, telescopes and devoted more ground-based observation time to this issue. Luckily, we do have some efforts and there are new companies such as Planetary Resources who will shortly be launching new telescopes and probes to find asteroids.

Still, the public needs to be made aware just how lucky we all are that this didn't land on DC, London or some place else with lots of people.

We need to get serious about this.

 

Maybe time to look for a more reliable one.
The MPC begs to differ.

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.

PR will be spinning that for, well, PR purposes (pun intended).
15Mt is the ballpark of the Tunguska event, almost a third of the Tsar Bomba. Don't you think the news would look quite a bit different by now if this would be the case?

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.

Edit: First real data coming in:
http://www.nature.com/news/russian-meteor-largest-in-a-century-1.12438

"Infrasound data suggests in the hundreds of kt range", i.e. about halfway between the initial reports and Tunguska, equivalent to a medium yield nuclear warhead.

 

I plugged that into the Asteroid Simulator (I assumed a diameter of 2.0 m ):

0.00021 MT = 0.21 kT = 210 tonnes of TNT. Or, 1.4 kT equivalent before the atmospheric entry. Certainly not 15 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.

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).

Shoot KE=.5mv^2.
Divide the above by 2.

So definitely not 15MT, but still nothing to laugh at.

Edit: This is a straight up KE calculation on a scrap of paper, not a sophisticated meteor-impact analysis converter equation I pulled from the web.

Edit Edit: While I clearly misread an earlier email about 1000 Hiroshima's, there is a lot of conflicting reports. But it's safe to say this was at least in the size range of a small tactical nuclear weapon.

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.

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.

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.

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 there exactly are, how many will strike the Earth or where they will strike. 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.

 

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.

 

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!

 

Exoplanets generally stay in the same section of space. Asteroids don't.

 

Maths correct, or at least equally incorrect as mine

But really, why do you think PR has access to informations the rest of the public doesn't have?
At this point in time no one can know the size of that rock, and what floats around are just generic numbers.

Airbusts in the range of nuclear weapons happen once every few years, exact data is probably still classified (the superpowers have satellites specifically designed to look for explosions of that size, i.e. nuclear explosions/tests)
90% of the earth's surface is uninhabitated, and typically there's next to no damage.
This one was the biggest since the Tunguska event a century ago.

Problem is, the damage for really large ones approaches infinity, i.e. at worst this means the extinction of our species.

 

Well fine, I don't care about the math that applies to paying taxes, insurance, and bills in pubs, but sadly, it cares about me. You can't really ignore the fact that these events rarely if ever kill anybody. They are therefore acceptable risk which, in terms of severity, is roughly comparable to being killed by one of those storms where it rains frogs. Tough luck.

We need a system that will reliably warn us against large asteroids which can impact Earth. Nothing more, nothing less.

When did they last kill anyone?

Define harm - a few shattered windows? A rock the size of football damaging a roof of a suburban house? I am sorry, but there FAR GREATER threats to people's lives.

Again, cost-benefit analysis.

A whole ton?

Because spending money on fighting hyped-up threats does more damage to your cause than not spending it at all.

And we can do all this without having to find all metre-sized rocks which pose next to no threat to this planet and its inhabitants. Case closed.

Agreed. Then we deal with the threats which are credible.

What you come out as advocating is an overreaction to this event. Or at least that's what it looks like.

Perhaps you should again and in more specific and detailed manner explain what it is that you want the world to do, against what, and for what money

I am going on the known facts - in the last several hundreds of years, impacts of meteorites killed very few, if any, people. Tunguska could have killed a lot if it had happened over densely populated urban area, so there the risk is at least credible and nobody is proposing to ignore it.

 

Kennedy's Ghost: We choose to go to the moon, we choose to go to the moon and do the other things, not because it is easy, but it is hard.

Today: But...but finding asteroids is hard ! And expensive !

I guess we should re-lable asteroids "commie-rocks" and then people would support finding them. By the way, we spent a big fraction of GDP to beat the commies back then but now give a pittance to asteroid searches. Oh that money wa well spent then, it lead to many technologies - this could give us that and a space infrastructure to boot.

Or I guess we can just change our speciesnames to homo stupididous or neo-trilobites and pack it in.

 

Jesus

Stop and breathe for a moment before you say something else you will regret.

 

I think you're way too emotional here hobbs. I too do hope that we expand our space infrastructure significantly, but we can't prevent every single asteroid from reaching Earth and most asteroids are too small to do damage anyway (also the chance of one hitting a densely inhabited place are what, 1%?)

 

Instead of trying to track smaller asteroids, I suggest exploring and expanding to the deep sea.

 

Heh, cheer up, this IS a soapbox thread, after all

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.

It certainly sounds nice to suggest some unnamed wonder breakthrough technologies, what about actually putting something specific forward

The limit is that earth leaves a given volume of space long before it could be scanned completely for NEOs. Putting more telescopes to the task would help, putting the existing numbers of telecopes on probes scattered around the solar systems won't help one bit.

 

Isn't that what photomultipliers are for?

 

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?

Well, that's kind of difficult to do until you track them for a long time and get some precision into their projected orbit. You can't calculate the orbit with enough precision until you've spent a lot of time viewing it. So once you find it, you have to keep an eye on it and not lose it.

So you have to look through all 360 degrees of sky - not just along the ecliptic. It's a big challenge, and they are already working on it, as I'm sure you know:

http://en.wikipedia.org/wiki/Near-Earth_asteroid#Near-Earth_asteroids
http://en.wikipedia.org/wiki/Spaceguard

Coincidentally, I just finished reading Rendevous with Rama last weekend

 

If your detector is already good enough to detect all photons, what's the point?
Okay, not all, but AFAIK modern CCDs have a photon efficiency in the ballpark of 50%, and I doubt you could fabricate a photomultiplier with several square decimeters of detector area and a few µm resolution.