Asteroid 'gives Earth a close shave' on Monday

[Baub]

How is the Kepler Mission more important that "saving the world"? I suppose that it is a low probability that Earth will get destroyed, or suffer a significant impact (comparable to Tunguska) over the next few hundred years. Although that recent object gave us a close shave by missing Earth by 45,000 miles, that is not too close for comfort among the experts.

 

The lazer spread is an issue at long distance. I believe lazers shot at the moon spread out to miles wide, and that is only 240,000 miles away.

I think it all comes down to funding. I am sure that it is easier to allocate funding for something "warm and fuzzy" like finding another earth than for something as frightening as addressing doomseday scenarios. Most people will hear that an object passed 45,000 miles from Earth and think....so what.

[moth]

beam divergence is a tech hurdle no doubt, but by making the amplification area of the laser long to collimate the beam and choosing a beam diameter suitable to the wavelength of the photons used, maybe we could get close to having a good beam.

the weapon potential would probably make it impossible to build something like this though.

[Airbrush]

Moth quote: "...the weapon potential would probably make it impossible to build something like this though."

 

Which leaves the only option kinetic impactors. Unless we can put beam devices or nukes into orbit discreetly, our only option for short-term defense will be to hit the asteroid with a rocket-propelled calculated mass. By "calculated mass" I mean the mass of the asteroid is estimated. Then orbiting rockets that carry nothing but weight can shed excess mass, like ballast, so the impact is just massive enough to change the asteroid's tragectory. You don't want to hit that thing too hard so it breaks into pieces.

[SH3RL0CK]

The laser can't really hurt anyone immediately if it can only be pointed into space whereas a kinetic impactor could be launched into a sub-orbit to crash on a city within a few minutes time. But then, this technology has already existed for a long time.

 

Both have the potential, in the wrong hands, to alter the trajectory of an asteroid such that it could land on a city. Hopefully, there would be sufficient time to respond and move the asteroid away should this unfortunate event happen.

 

If we want to develop the abillity to harness these technologies for good purposes (i.e. saving the earth), then we need to accept the challenges of preventing its use for harm. I'm not of the opinion that we should not develop technology because it "might" harm others, as long as it also has potential to help others as well.

[Baub]

The laser can't really hurt anyone immediately if it can only be pointed into space whereas a kinetic impactor could be launched into a sub-orbit to crash on a city within a few minutes time. But then, this technology has already existed for a long time.

 

Both have the potential, in the wrong hands, to alter the trajectory of an asteroid such that it could land on a city. Hopefully, there would be sufficient time to respond and move the asteroid away should this unfortunate event happen.

 

If we want to develop the abillity to harness these technologies for good purposes (i.e. saving the earth), then we need to accept the challenges of preventing its use for harm. I'm not of the opinion that we should not develop technology because it "might" harm others, as long as it also has potential to help others as well.

Exactly why such a venture would need to be undertaken by a group of countries, under the unifying banner of species preservation. These countries would need to share the responsiblities, from design through oversight.

[cameron marical]

just like the iss.

[Airbrush]

Exactly why such a venture would need to be undertaken by a group of countries, under the unifying banner of species preservation. These countries would need to share the responsiblities, from design through oversight.

 

A group of countries is the best way. Since everyone on Earth would benefit, there should be a way to pass the costs along to every country on Earth, according to an equitable scale or responsibility. The wealthy have the most to lose, so the US would carry a heavy share of the costs. Transparancy about it all the way so no country would feel threatened by weapons in space.

[YT2095]

well there`s ~6 billion humans here, if you were to tell each of them they we going to die for sure! and a fiver could ensure their safety, I`m sure most would pay up.

 

that`s 30 Billion quid, I reckon That would cause a dent in any space bearing intruder!

[Sisyphus]

that`s 30 Billion quid, I reckon That would cause a dent in any space bearing intruder!

 

I'm thinking it would be more effective to actually spend it on some sort of preventative measure.

[cameron marical]

ya. i dont think we should wait until the time comes when we actually need it, i think we should start some stuff up today. with total transparency, as mentiones above, of course.

[Mr Skeptic]

Yes, we need preventative measures. You can't build a rocket out of money, no matter how much you have. Also as my dad would say, You can't make a baby in less than nine months no matter how many women you assign to the task.

[cameron marical]

mr. skeptic-im getting to like you, you seem to have the same veiws as me, judging by other posts and this. kudos man.

[Airbrush]

They should start working on something soon. I love to hear about the Kepler mission, but let's face the fact that Kepler will not save our planet from destruction, nor will it save anyone from a Tunguska-sized impact.

 

First things first. More and better methods for detecting such objects, and a short-range, "last resort" defense system that can deflect the smaller objects. I envision something like a "rocket with weight" to simply crash into an asteroid at high speed to deflect it. Over time we can add redundant safeguards and longer range systems which will take much more time for development and deployment.

 

The United Nations needs to start talking about a global tax to finance these defense systems. It may be that a common cause can bring the nations of the world together in peace. Some argue that WWII helped pull the US out of the great depression. Maybe the jobs created by Planetary Defense projects can help pull the world out of this global recession. And there much more to do. What about global warming and the energy crisis? Anyone looking for a job? I'd rather work on planetary defense than continue this lousy job as bookkeeper for a restaurant for the rest of my life.

 

As Skeptic's Dad would say "You can't make a baby in less than nine months no matter how many women you assign to the task." Hahaha! But you can assign a number of women to work on different babies, and each baby can contribute to the overall mission of "saving the world". Unless you can find an "Octomom" to help out.

Edited March 12, 2009 by Airbrush

[cameron marical]

airbrush-thats one of the best ideas ive heard so far. i fully agree.

[Sisyphus]

A "global tax" is never ever ever going to happen, especially not one levied by the UN. Nor should it, nor is it necessary. The spacefaring nations have already managed to work together remarkably well, with things like the ISS and astronauts sharing rides on other nations’ vehicles.

 

You're not going to see the level of investment you're asking for, though. It’s just not important enough in the short term*, and our ability to deal with NEOs will inevitably increase naturally, as space tech in general improves.

 

*I know you think it’s the most important thing ever, but again, risk vs. reward. Tunguska sized impacts happen on average about once every thousand years or so, and when they do happen, they’re mostly harmless. Yes, harmless. The Tunguska event was a release of energy about equal to a midsize nuclear weapon. Enough to wipe out a city if it’s a direct hit, but we’re not talking about tsunami-causers, which are orders of magnitude rarer. And hitting a city is very unlikely. Most of the Earth is ocean, and most of the land is sparsely populated. Almost certainly, several have hit the Earth over the history of human civilization, and nobody noticed.

[Airbrush]

Tunguska sized impacts happen on average about once every thousand years or so, and when they do happen, they’re mostly harmless. Yes, harmless. The Tunguska event was a release of energy about equal to a midsize nuclear weapon. Enough to wipe out a city if it’s a direct hit, but we’re not talking about tsunami-causers, which are orders of magnitude rarer. And hitting a city is very unlikely. Most of the Earth is ocean, and most of the land is sparsely populated. Almost certainly, several have hit the Earth over the history of human civilization, and nobody noticed.

 

I agree with most of what you are saying and Tunguska-sized events, or larger, are very rare, maybe once in a thousand years, as you say. But Wikipedia estimates Tunguska as an air explosion 3 to 6 miles high and comparable to a very large nuclear weapon 10-15 megatons, or about 1,000 Hiroshimas, and it was only a few tens of meters across (about 100 feet in diameter).

 

Consider an object only 10% the mass of the Tunguska object, and those impact Earth more frequently. If it is able to penetrate the atmosphere and hit ANY ocean, it WILL cause devastating tsunamis which will destroy high populations along coastlines. Such an impact happening hundreds of years ago would go unnoticed, except locally. But now with high population densities along coastlines, the results will be very noticeable, as we saw with the Dec 26, 2004, Indonesian earthquake tsunamis, results was 200,000 plus dead.

 

But you are mostly correct, and not much will be invested in defense until one does damage. It will be in the news. Thanks for setting my mind at ease.

 

http://en.wikipedia.org/wiki/Tunguska_event

Edited March 12, 2009 by Airbrush
New info

[Sisyphus]

I agree with most of what you are saying and Tunguska-sized events, or larger, are very rare, maybe once in a thousand years, as you say. But Wikipedia estimates Tunguska as an air explosion 3 to 6 miles high and comparable to a very large nuclear weapon 10 - 15 megatons.

 

Consider an object only 10% the size of the Tunguska object, and those impact Earth much more frequently. If it is able to penetrate the atmosphere and hit ANY ocean, it WILL cause devastating tsunamis which will destroy high populations all along coastlines. Such impacts hundreds of years ago would go unnoticed. But now with high population densities along coastlines, the results will be very noticeable, as we saw with the Indonesian earthquake tsunamis, 250,000 plus dead.

 

No, it really won't. You're vastly underestimating the kind of energy involved in a "devastating tsunami." By many orders of magnitude. Nuclear bombs cannot cause tsunamis. Especially not in the upper atmosphere. And frankly, the idea that every few decades one or another ocean's coastlines is swamped with tsunamis hundreds of feet tall, and nobody has realized it because we only just started living on the coasts (?) is, well, kind of ridiculous.

 

But you are mostly correct, and not much will be invested in defense until one does damage. Thanks for setting my mind at ease.

 

You're welcome.

[Airbrush]

Not every few decades. It is possible there have been smaller impacts a few hundred years ago that went unnoticed. Not all explode miles high. Some reach the ground, or more likely the ocean. I'm not an expert, and I would like to get expert opinion on what kind of tsunamis would be experienced along the Southern California coast caused by a meteor 30 feet across impacting the ocean at a speed of 10 miles per second, 1,000 miles off the coast of California. Anyone want to venture a guess?

Edited March 12, 2009 by Airbrush

[Sisyphus]

Not every few decades. It is possible there have been smaller impacts a few hundred years ago that went unnoticed. Not all explode miles high. Some reach the ground, or more likely the ocean. I'm not an expert, and I would like to get expert opinion on what kind of tsunamis would be experienced along the Southern California coast caused by a meteor 30 feet across impacting the ocean at a speed of 10 miles per second, 1,000 miles off the coast of California. Anyone want to venture a guess?

 

Objects that size hit the Earth at an average rate of about 1 per year. So, the answer is "zero tsunamis."

[Mr Skeptic]

When talking about the ocean surface, a 2D object, the impact would lose energy as roughly [math]1/r[/math] rather than as [math]1/r^2[/math], where r is your distance from the explosion. Even though the waves would lose energy at a far slower rate, at a significant distance you wouldn't even notice it unless your asteroid were truly huge. If you like, consider how much energy you want your tsunami to have, and at what distance. Then you can calculate how much energy an asteroid would need to have to generate that tsunami. I think you'll need a pretty big asteroid to make big waves.

[Airbrush]

Objects that size hit the Earth at an average rate of about 1 per year. So, the answer is "zero tsunamis."

 

You hear that folks? Relax, enjoy life, buy a beach house. We have hundreds of years to prepare for the big one.

[PrinceOfDragons]

How about 4 rockets with a net attached made out of Carbon nanotubes. This can be used to slow it down or even stop it before it reaches earth.

[Airbrush]

We are only worried about real big ones. For big ones it takes far less energy to deflect it, ever so slightly early on, than to try to slow it down. Probably impossible to stop it.

[cameron marical]

i like the idea of just a hopped up satelite with weight and speed. ram it a little to make it move out of direction of earth. send it to another planet so it doesnt come back.

[DrDNA]

How about 4 rockets with a net attached made out of Carbon nanotubes. This can be used to slow it down or even stop it before it reaches earth.

 

Don't need no rockets with the space elevator made out of CNTs.