[EnergyUnlimited]

the above quote is true, then we will lack the space technologies to mitigate the collision risk in the mid-22nd century, whereas we have these technologies now. We need to act now so we don't have to deal with a major asteroid collision when our civilzation has collapsed and we no longer have the option of mitigation available.

Who cares what will be in late 22 nd century?
In any case 500m asteroid might wipe out large part of a reasonably sized country, not entire humanity (if anything is still left out of humanity in late 22nd century).
And there will be hundreds of large asteroids to cope with *after* technological civilization collapsed.

So move on.
Yawn.
Nothing here to see.

[Rod_Cloutier]

Who cares what will be in late 22 nd century?

My grandkids, grandkids will likely care that's who. Your planning horizion is too short. Their lives will be miserable after the collapse of civilization, lets leave them with one less thing to worry about!

[vision-master]

Now we know! New wujo. June 16, 2012 3:46am posted. Important for humans who live in coastal areas of earth.

Podcast available free ->Broken link; Required the user to download and install a file.

[EnergyUnlimited]

Who cares what will be in late 22 nd century?

My grandkids, grandkids will likely care that's who. Your planning horizion is too short. Their lives will be miserable after the collapse of civilization, lets leave them with one less thing to worry about!

These are events 7 generations away.
No one from the era of Napoleon wars have taken care about me, so there is no need for me to worry about grandkids of grandkids of my grandkids.
So lets not worry about BS, don't waste money on it and allow Nature to take its course.
There are other, more imminent issues to worry about these days and if we don't resolve these, gradkids of grandkids of my grandkids won't even exist.

[dinopello]

I went to my nephew's High School graduation yesterday and the speaker they had was Charles Bolden, the director of NASA. He didn't mention the doom scenario at all, but did mention that this graduating class would have the challenge of landing on asteroids. Apart from mining them, blowing them up or diverting their course is maybe what he was referring to.

[Rod_Cloutier]

6 year update:

The odds have increased from a 1 in 1000 chance of this asteroid from hitting the Earth, to a one in 345 chance of an impact between 2185 to 2196:

Joe Bauwens, who runs blog Sciency Thoughts, wrote: "An object of this size would be expected to punch straight through the Earth's atmosphere, impacting directly into the ground, an impact which would result in an explosion over 17,650 times as large as that caused by the Hiroshima bomb, creating a crater over 7 km in diameter and climatic effects that could last for decades.

http://www.express.co.uk/news/science/6 ... e-out-life

[Outcast_Searcher]

6 year update:

The odds have increased from a 1 in 1000 chance of this asteroid from hitting the Earth, to a one in 345 chance of an impact between 2185 to 2196:

Joe Bauwens, who runs blog Sciency Thoughts, wrote: "An object of this size would be expected to punch straight through the Earth's atmosphere, impacting directly into the ground, an impact which would result in an explosion over 17,650 times as large as that caused by the Hiroshima bomb, creating a crater over 7 km in diameter and climatic effects that could last for decades.

http://www.express.co.uk/news/science/6 ... e-out-life

Since AGW has about a 99% chance of having a HUGE impact on the entire planet by then, why worry about this? Are you that desperate to project possible doom?

If, in say, 120 to 150 years, the odds that this could hit earth look serious (say over 5%) and AGW has been dealt with by technology, never fear, technology will be directed to deal with this. OTOH, if BAU growth and fossil fuel burning continue apace, in 120 to 150 years, problems with the climate will make this long shot look like child's play.

[Newfie]

Thanks for the update. Interesting.

[Tanada]

Just too many unknowns to get real excited about this, for one thing the odds greatly favor a water impact. If it were to hit say the central Pacific it is unlikely the crater would even reach the abyssal plain. The only effects would be the Tsunami which would be focused in some locations depending on the impact point and the direction of the wave as it impacted the different coastlines. Heck if the Dino killer had impacted in deep water instead of on the continental shelf the effects would have been much different as well. Water has an amazing capacity for absorbing heat and kinetic energy. The Dino's might even have survived in some places with a deep water impact 65 million YBP. In any case none of us typing about it will be around to see what happens.

[Rod_Cloutier]

Are you that desperate to project possible doom?

No just bored at home with the post holiday's blues; I revived a dead thread from 2010

[KaiserJeep]

I say don't worry about it - the near Earth asteroids and these objects in cometary orbits that intersect the Earth's orbit are a treasure trove of materials that don't need to be lifted into space or moved all the way from the asteroid belt. They are the main source of the ores that will build the space habitats at the LaGrange points, and the water and methane ices that will enable orbital farming.

Just mine the thing until it is a hollow shell of ore tailings, and blow up the remnants. The small pieces will make a spectacular display in the night sky, for the few AGW survivors on the ruined Earth.

[dolanbaker]

I think I'll put this one near the bottom of the worry list.

My opinion hasn't changed one bit since I wrote this.

[onlooker]

http://www.purdue.edu/impactearth/
Wow I found this neat site that allows users to specify with many variables and criteria the results of an impact from a given asteroid, comet or meteor. For all you scientific wonks this should be very intriguing.

[onlooker]

the quarter mile circumference of this asteroid is close to the 1/2 mile some scientists consider large enough to cause an extinction event. Just one more thing to worry about or not depending on your inclination.

[KaiserJeep]

Let us not forget basic geometry. Half the diameter is 1/8th the mass of the larger sphere - not very close even if it turns out to be of solid nickle-iron composition.

I mean, it can still make a heck of a bang - the nickle-iron body that formed Meteor Crater in Arizona is estimated to have been 150 feet in diameter and to weigh 300,000 tons. It struck the Earth at 20 miles/sec, had a mechanical energy yield equivalent to 2.5 megatons of TNT, and made a crater a mile across.

[onlooker]

Any theories Kaiser about the Tungaska event in the early 1900's. From what I heard it was probably a comet that whizzed by very close to the surface which created those devastating effects over there.

[Tanada]

http://www.purdue.edu/impactearth/
Wow I found this neat site that allows users to specify with many variables and criteria the results of an impact from a given asteroid, comet or meteor. For all you scientific wonks this should be very intriguing.

I played around with your calculator link and if the Dinosaur killer had hit in the deeper plain of the Pacific Ocean 10,000 meters deep AND you were in Europe about as far away as you could get and still be on the planet the worst immediate effect would be the 10.1 Earthquake arrive 60 minutes after impact. The air blast would arrive 15 hours after impact as a 13 mph breeze. The Tsunami effects will arrive 16 hours after impact and would range from 150 to 300 feet above sea level depending on the local terrain, so a beach is not a good place to weather the storm.

Crater data

The crater opened in the water has a diameter of 163 km ( = 101 miles ).
For the crater formed in the seafloor:
Transient Crater Diameter: 83.8 km ( = 52.1 miles )
Transient Crater Depth: 29.6 km ( = 18.4 miles )
Final Crater Diameter: 150 km ( = 93.1 miles )
Final Crater Depth: 1.34 km ( = 0.83 miles )
The crater formed is a complex crater.
The volume of the target melted or vaporized is 4340 km^3 ( = 1040 miles^3 )
Roughly half the melt remains in the crater, where its average thickness is 785 meters ( = 2580 feet ).

The way I understand it the impact would vaporize a large volume of water and then also vaporize a large volume of the underlying sea floor ooze and rock creating the deep round crater. Then the sea would rush back in from all sides washing a much wider circle of sea floor into the deep center area making the final crater almost twice as wide but only 1,340 meters deeper than the sea floor was before the impact. The plume would take the classic mushroom cloud shape as vaporized rock and water would rise high above the atmosphere and then condense into ice crystals and rock flour crystalline dust that would shroud the Earth for 3 to 5 years causing an impact winter. Something to keep in mind, this probably happened many times in the history of the planet, but the sea floor is not a permanent feature. If this had taken place in the deep Pacific 65 million YBP there is a high probability that the moving continental plates would have crossed that spot by now and the crater would be subducted back into the Mantel and gone forever without a physical trace other than the Iridium layer where the crystallized vapor settled to the surface. The only reason we can see the Chicxulub crater now is it impacted on the continental shelf in 300 feet of water and it is on the trailing edge of the North American plate, not the leading edge. If it had been a few minutes later and hit in deeper water west of the North American plate it would have been erased a long time ago.

[onlooker]

Impressive Tanada.

[Tanada]

An actual meteorite hit Australia 27 November 2015 and their new tracking network was able to help them locate it right before a thunderstorm would have obscured the surface evidence of its impact point. Needless to say it was not a large rock and it wasn't going incredibly fast, but it was buried over a foot down in the mud where they found it. More at link,

After some image analysis, triangulation, and other calculations, the search began in earnest around the Kati Thanda-Lake Eyre area - the lowest natural point in Australia - on December 29. An unmanned drone and a manned light aircraft were used to guide DFN team members, Phil Bland and Robert Howie from Curtin University, to the correct spot, with the assistance of a local search party.

Three days into the search, they found it: a 1.7-kg (3.7-lb) rock embedded in thick salt lake mud, some 42 cm (16.5 inches) below the surface. If the researchers had been a few days later, heavy rains would've washed away the rock for good.

According to its discoverers, the meteorite fragment is a chondrite or stony meteorite that they estimate to be more than 4.5 billion years old - not a bad innings when you consider that Earth itself has been around for about that amount of time. "It was an amazing team effort - we got there by the skin of our teeth," said Bland.

Not only is it an exciting geological discovery that should eventually teach us more about the origins of the Universe, it's a huge boost for the founders of the Desert Fireball Network scheme. "This meteorite is of special significance as the camera observations used to calculate the fall positions have also enabled the solar system orbit of the meteorite to be calculated, giving important contextual information for future study," added Bland. "It demonstrates beyond doubt that this giant machine that we've built really works."

The researchers believe the rock came from somewhere between Mars and Jupiter, and now the serious work of studying the object can begin. "The fact we have managed to retrieve the meteorite at all is remarkable," said Bland's colleague, Jonathan Paxman. "Our people worked around the clock to reduce the data, enabling rapid recovery of something that would have been lost if we'd gotten there any later."

http://www.sciencealert.com/australian- ... than-earth

[Rod_Cloutier]

in 120 to 150 years, problems with the climate will make this long shot look like child's play

We have a window of opportunity now, while we still have NASA and other viable space programs to do something about this. If the economy/ civilization collapses over the next 120-150 years, then we won't have options of mitigating this.

Short term vs. long term thinking involved. Should we mitigate now while we have capacities, or delay action and take the chance that we won't have space technologies in 120-150 years when mitigation might actually be needed?