Just a small article here ( for be any newbies) about the threat of asteroid 1950DA...

http://www.geocities.com/blobrana/features/1950da.html

Enyoy.
:)

What bothers me is the consistant way an observation like this is used to sell stories. Big headline "Earth Doomed", "Imminent Collision", "Doomsday Rock"...and then at the end the unemphasized mention that the chances are low, more observations are needed to be sure of the path, and it won't be back for generations.

What's the problem? It's more of crying wolf...it's desensifying the public to a serious matter. When funding for NEO discovery and development of techniques to stop them is brought up these days, after all the bad movies and misrepresented facts, the public shrugs the denial as no big loss, since the papers always say at the end that isn't not a problem for this generation, or the end of the movie showed a laser on a jet firing at the last minute, no big problem there. Anything space oriented is seen as a frivolous waste of resources...give the money to the military, that's much more important. So what that the military budget increase is probably as big as the total devoted monies to space. Defense is important, you say....we have to have the tools to protect our nation and the free world, right? Well, doesn't this qualify as a threat to our well being, and to life as we know it? Make the military budget pay for NEO research then!

I predict one day...it could be in the far future, or tomorrow...we will discover something heading this way. Most people will look at the headlines, and say yeah, read that before. Or maybe it'll be hushed up, to prevent riots. But at any rate, that day will come. We will either be ready enough to 1) see it coming in time, and 2) do something about it....or not. And if not...then that generation and any others that would have been after it were killed by this generation's inaction and lack of caring.

Objects do hit the earth. That's a simple fact. We're the first species to be able to do something about it...so what are we doing? Not a lot...

Lecture/rant over... :)

The collision would be the equivalent of smashing a million tons of TNT into earth We build bigger bombs.

Niribu? Planet-X? What is it that NASA has pictures of as of 2/17/03? Looks like a comet twice the size of Earth. http://www.rense.com/general35/COMET.HTM Check there or go to the Solar and Heliopsherc Observatory SOHO website.
Passing withing 5 million miles of the Sun is different.;)

Originally posted by Gifted
We build bigger bombs.
Actually, a 1 mile wide asteriod colliding with earth would create an explosion equivalent to somewhere in the neighborhood of 500 million kilotons on TNT. The human race does not make bombs anywhere near that big.

- foadi(se) de la Ter-Rani

Jaxom,

Possibly some day when a real collision is eminent people will read the headlines go "ya right" then read the fine print "1/5 chance of collision in 6 months" then they will start screaming like the sky was falling(which it is likely in this situation)

I believe nukes are the best way to deflect a asteroid or comet: we send up volley after volley, blow them up right up against the asteroid or comet to change its trajectory. we would need a least 5 years warning to send a probe up to check structural integrity and determine proper distance for the nukes to blow and time for us to prepare and launch a lot of nukes.

foadi,

The site claims two different impact values: "million tons of TNT" (1 megaton) and "44,800 megatons" for 1950 DA. I would go with the latter of 44.8 Gigatons... so then no we don't make bombs in that range: the larges production nuclear bomb was 59 megatons

sry,
fixed now...

tnx.

Originally posted by WellCookedFetus
so then no we don't make bombs in that range: the larges production nuclear bomb was 59 megatons
Tsar Bomba yeild was 59 megatons? I was under the impression that it only yeilded 50 megatons(Though was designed to yeild 100 megatons of TNT). Have a link to where you got the information?

- foadi(se) de la Ter-Rani

"Trinity and Beyond" the video bought off Discovery... or was it TLC I get those confused?

Originally posted by WellCookedFetus
"Trinity and Beyond" the video bought off Discovery... or was it TLC I get those confused?
TLC, I think. I remember watching that.

Originally posted by blobrana
sry,
fixed now...
tnx.

Blobrana thats your site?!? Very nice!
You change it to:
"The collision would smash millions of tons of TNT into the Earth and could wipe out a large city, trigger widespread fires and tidal waves."

the change I would advice is:

"The collision would be as explosive as billions of tons worth in TNT and would cause a level of destruction probably not seen since the end of the dinosaurs."

This way it just as accurate but much more ominous and scary.

Originally posted by WellCookedFetus
This way it just as accurate but much more ominous and scary.
I agree. A rock only 100 meters wide could cause an explosion yeilding more than a million tons of TNT.

(whips out calculator makes estimate of equivalent density and velocity)

That would be 33.6megatons if 1950 DA was only 100meters wide instead of 1.1km. :D

Originally posted by WellCookedFetus
Possibly some day when a real collision is eminent people will read the headlines go "ya right" then read the fine print "1/5 chance of collision in 6 months" then they will start screaming like the sky was falling(which it is likely in this situation)

And then it will get ugly, and the finger pointing and lynching will begin. The politicians who don't run away will get hung because of their inaction. And the complimentary riots will ensue. Six months, hell, six years is not enough time to do anything about even a small city killer, even if we had easy access to space.

I believe nukes are the best way to deflect a asteroid or comet: we send up volley after volley, blow them up right up against the asteroid or comet to change its trajectory. we would need a least 5 years warning to send a probe up to check structural integrity and determine proper distance for the nukes to blow and time for us to prepare and launch a lot of nukes.

Nukes are most likely the method, specially if it's a last minute shove, but the technique depends heavily on the type of structure. If it's a large iron chunk, then a close nuke in an enclosed crater would provide a good shove...a stony asteroid may allow the same thing, but it could also potentially fracture, and then the fragments may or may not be a problem. Comets are the hardest to predict...It looks as if most of these bodies are fragile, so a close nuke could just make a shower of fragments too numerous to deal with. All nukes in space would create thrust by the vaporization of a part of the body, but to do so with a comet without breaking it apart would require to practice. That and the fact that comets are much faster incoming due to their usual orbits. Little warning and hard to move...

Either type, if we have warnings of 20 or more years, could be easily moved enough by simple engines, a few nukes, or even a solar sail. Time is the key...the more time, the less of an angle you need to change.

For the record:

metric ton = 1000 kg

megaton = 10^6 x 10^3 kg = 10^9 kg

kg TNT = 4 x 10^6 joules

megaton TNT = (10^9 kg) 4 x 10^6 joules / kg = 4 x 10^15 joules

10 km asteroid:

density = mass/volume = 2.5 g/cc or 2,500 kg/m3

V = 4/3 pi R^3 = 5.22 x 10^11 m3

V x M / V = M = 5.22 x 10^11 m^3 x 2.5 x 10^3 kg/m^3

Þ mass = 1.3 x 10^15 kg

Earth: velocity = escape velocity (11 km/sec) +

typical relative velocity (9 km/sec)

400 x 10^6 m^2/sec^2

Þ velocity = 20 km/sec

km / sec = 10^3 m/sec

E = 1/2 m v^2 = 1/2 (1.3 x 10^15 kg) (20 x 10^3 m/sec)2 = 2.6 x 10^23 joules

2.6 x 10^23 joules / 4 x 10^15 joules/megaton = 6.5 x 10^7 megatons

Or 1.1 million of our biggest bombs.

And 10 km is average, but hardly a big asteroid...

Estimates based on the Hellas impact area on Mars predict that was an object around 12 km in size.

And lastly, a comet the same size would likely have less density, but be moving much faster...it averages out. :)

Jaxom,

Nice with the explosive force and all... I was just saying how much a 100m would be at the same density and velocity of 1995 DA.

As for nukes on comets considering what a comets made of blowing it to snow flakes would be a good thing! Its the dust clad asteroids we need to worry about... hard to move and hard to destroy. True though anything thing under ~5 years is going to be very hard to deflect! As for your dooms day prediction: I think in 6 months time the whole world would have collapsed and gone to hell… and then the comet would hit!

Well, here's the problem...we really don't know what a nuke would do to an average comet. It may act just as a solid body, it may totally vaporize it, or something inbetween (which would be the worse case scenario, but also the most likely:eek: )

We are seriously lacking research in these things...and it could come back and bite us if we don't begin to take the threat seriously. Some days I reluctantly wish for a small impact to give us a wake up call...but the smaller ones tend to detonate in the upper atmosphere, so there's no evidence to the general public, only to setups like NORAD.

There is a relationship with the spin of an asteroid and its composition.

1950da spins quite fast, this implies that it is composed of a rocky/metallic material.

If it were made of loose rock/ice then nuclear explosions would be absorbed by the object and not be be diverted.

The bad thing is that most of the asteroids are slow spinning.

We know of most of the 10km near earth asteroids. but we probably only know about 50% of the 1 km sized ones...

(The dinosaur killer was probably 10 km).

Jaxom,

Answer to your question may come from here: http://deepimpact.umd.edu/

Here is a nice site... I just felt real nice: thought I should share it to the world: http://spacescience.nasa.gov/missions/

Yep, that's a good mission to watch for. The mission objectives are a few of the points I've touched on. Using data from this, they could get at least an idea on what a nuke/impact effort would do.

Then again...every body out there is different. Fetus, you mentioned going out to examine the body before determining what to do...I think that is critical to be a success. Of course, if there's no time, we have to guess, and hope for the best. :bugeye:

Blobrana, spin is yet another issue. We'd have to determine how offset the vector would be from the explosion, or despin the body...

@Jaxom
sry, i didn`t put it clear enough.

We can determine the composition of an asteroid by measuring it`s spectra and spin.

Denser asteroids have a faster spin. (generally)

You send a probe armed with nukes. Upon arrival, it surveys the asteriod to determine where the best places t obut it would be. It puts the nukes(probably some sort of laser-guided missile) on the surface, and moves out of the danger area before it detonates. Armed with several nukes, if one or two didn't do the job, you can try again without too much trouble. You could even try to put it in a stable earth orbit.

Probably more effective could be to make physical contact with the asteroid before the blast. Then the heat could also be passed directly by contact, possibly evaporizing a lot of the asteroid. That might or might not induce enough disturbance in the trajectory. THat's the idea!:rolleyes: Most likely the bomb would penetrate several meters before detonating.
But if we would have the technology to land a nuke on the surface of a asteroid, why not land a rocket engine upside down instead, ignite it and push the asteroid out of its trajectory. Some problems with that: mass of the engine(putting something that big on the proper trajectory), the fuel, and having sufficient power to move an asteriod wieghing several million tons fast enough to alter its course in time.

BTW soft landing a ~100 ton engine, and smashing a hardened laser-guided rocket(less than 3,000 lbs) into the thing are two very different stories.

Andre,

Does not several hundred kilograms of fusing plasma traveling at a good percentage the speed of light not have any force?

Does trillions of watts of light not have any force?

Does heat and vaporized asteroid matter not have any force especially when if flies of the surface of the asteroid with Newton’s 3nd law and all?

A nuclear detonation just above a asteroid could still change the asteroid’s vector as well as a direct impact, but without the damage and chance of fragmentation.

Since there is no friction even the slightest blast is having effect according to Newtons third law. If I recall my physics correctly, first you have to overcome intertia as well. How much inertia does 2 million tons of rock have?
Well you better bring your drill and drill that hole first. Have you any idea how extremely sensitive a nuke is to deformation. We are talking about microns. Penetration by force would most certainly kill the nuke before it killed the killer asteroid. And we were thinking of building nuclear bunker busters, which would, due to their low yield, be even more sensitive.
but without the damage and chance of fragmentation. This would be why you survey the asteriod first, to find out the where and how big for the explosion. The probe would carry as many as half a dozen warheads so that you can start as soon as you've figured out where your going to hit it.

Hum, I say we survey it with a probe and launch up nukes separate. A single probe with that many nukes would weigh a lot it would take a very big boost like Energia to get it of the ground. We might not be able to get it up in time. A small probe and volley after volley of nukes pummeling the thing like paint balloons against an anti-abortion poster, is the way to go.

I think that's the consensus, that many small nukes would be more effective and controllable than one big bang. I do think planting them rather than impacting them would be better, but it all depends on the type of rock and how much time you have to play around with it.

A comet, while fragile, would vaporize as thrust better than a rocky body. But again, better to use small thrusts than try and do it all in one big one.

Only the probe would come in slow.

The idea behind launching the nukes with the probe was that you wouldn't be spending two months waiting for the probe to get there, spend two weeks surveying and analyzing, and then a month and a half waiting for the nukes to get there. I agree, seperate would be easier to get off the ground, but you don't want to wait too long. The warheads can stay in orbit around the rock until ou decide where to put them.
but it all depends on the type of rock and how much time you have to play around with it. That's why you survey it first, and already having the nukes there gives you some extra time.

The time difference can be control... in fact the time it would take to get such a large probe there and the time needed to place all the nukes would take longer then by getting a small probe there an hamming it with nukes days or weeks later.

Let's face it, if a few weeks would make a big difference, it's already too close, and we're screwed. It takes both time and effort to move a few million metric tons. Six, twelve, eighteen months is a collision window we never want to see.

The point of rendevous time is a good one. Whatever method we use, whether it be planting engines or nukes, we should have them in stationkeeping far outside the inner solar system, along with the monitoring systems. That way the course is always vectored similarly to the rock, and it's just a matter of optimizing the meeting place. Especially for comets...nothing launched from Earth would ever be able to get out there and then reverse to match the comet's speed before the angle of deflection is too great to deal with.

It would take months to get a volley of nukes to a NEA, the nukes don't need to worry about velocity change though because all they need to do is aim and explode before impact. But even so how much of a change in course are we going to get here? If the asteroid is large maybe a few centimeters a second! So we need to do these years before impact. Comets on the other hand: if the things going to impact in its first detected orbit then we would only have months or just weeks before we die: no time for a counterstrike! If its going to impact after several orbits that might give us the time we need to get some nukes to meet up with it.