Then it depends on the size of the rock but of course the bigger the rock the farther out it will be seen. It would be an interesting experiment to say the least.

What would? Just watching it hit or trying to deflect it? :)

Both; I do know "The Great Satan" will have the upper hand in this . So you see this is a political problem as much as a scientific one. There are so many variables it is all supposition.

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But let's now look at a smaller asteroid strike with 12 months warning, which might take out a USA State, a European country, or the UK. Which nevertheless would still be a disaster of world changing proportions. [list]A. Could the USA evacuate 38 million from California or 26 million from Texas - maybe

The rock most likely will hit an ocean. I live in the New York City/Newark statistical area but I'm 940 feet above sea level miles away. How big is the wave going to be? People love to live by coast lines and they won't move. "Super Storm Sandy" devastated the Jersey Shore but no one moved; they just rebuilt with bigger dunes. With enough time a 1,000 foot dune could be constructed. The Ocean floor has enough sand close by.

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I make that over 70 billion tons of sand needing to be excavated and placed.

The dunes would only have to protect the big cities the Army Corps of Engineers does it all of the time to fight normal erroneous and they keep up. The funny thing is the rich who live along the shore fight it tooth and nail because it ruins their view.

I'm sure the world will come to our aid in doing this (eye role).

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I really do suggest that we try to leave politics out of this if we can.

The event that I have discussed so far is the worst case scenario of the "Big One", a large enough asteroid impact to wipe out a whole continent. The obvious questions must be

1. Would an impact that big alter the Earth's orbit around the sun?
2. Would it alter the Earth's rotation, which gives us a 24h day?
3. Would it alter the axial tilt of the Earth which gives us the seasons?
4. How about the "wobble" that moves the magnetic North Pole?

Even for those who survived an impact (by virtue of where they happened to be on the earth at the time) they would by no means be guaranteed to survive in the long term.

Many people would think that after an impact of that magnitude, you could just write the Earth off anyway.

The logistics are impossible. After Hurricane Katrina in New Orleans there was a complete breakdown of civility as people had to fight for their lives on their own and it got ugly quickly.

I agree.

But let's now look at a smaller asteroid strike with 12 months warning, which might take out a USA State, a European country, or the UK. Which nevertheless would still be a disaster of world changing proportions.

A. Could the USA evacuate 38 million from California or 26 million from Texas - maybe
B. Could Europe evacuate Germany with 82 million, or France with 66 million - maybe
C. Could they evacuate the UK with 63 million - maybe

Would they even try to do it? You tell me.

This is the kind of event that I was referring to. It will still be much cheaper to build a means of preventing such a disaster than trying to recover from one after doing nothing more than watching and warning. If we are lucky, in a sense, a smaller rock will hit in a mildly populated area killing only a few thousand people. Such an event would surely wake up world governments and spur a properly funded space program with the goal of building a space rock defence system.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

If we are lucky, in a sense, a smaller rock will hit in a mildly populated area killing only a few thousand people. Such an event would surely wake up world governments and spur a properly funded space program with the goal of building a space rock defence system.

Russia had three hits since 1908; the 1908 hit was the biggest in recorded history and at most it was only 600 feet across. The one last year injures a thousand; Big meteorite strikes in Russia — again! The world is aware it could happen but governments have other agendas; especially the one that has been hit three times. Sorry but it's difficult to not get political when one considers the reality of the situation.

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Considering the time available from detecting a space rock to being able to do anything with it. Taking into consideration the Rosetta mission to Comet Churyumov–Gerasimenko, what do you propose for a defense system.

Rosetta launched in March 2004, planned meeting May 2014, Rosetta power point presentation (pdf)

Considering the time available from detecting a space rock to being able to do anything with it.

The time to impact gets longer the bigger the boom. Does anyone know how far out, for the size, an object can be detected. If that is known it would make our hypothetical saving the planet easier.

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Some interesting figures:







Sorry, I can't find the source of the graphics.

But you've all seen the recoil when tanks fire shells,

Rockets don't have recoil. When I was in the Army I got to fire the "Recoilless Rifle" and the Bazooka which were deadly accurate tank killers. Both were actually rockets. Just don't stand behind them while they are being fired.

That last NEO probably weighed more that 5 thousand tons and traveling in excess of 25,000 mph so had a lot of kinetic energy.

How much energy would you need to push it off course for Earth if it was 7 days way?

Or if you wanted to destroy it so that the pieces would either miss or burn up in the atmosphere, how big would the bomb have to be?

But you've all seen the recoil when tanks fire shells,

Rockets don't have recoil.

The LAW anti tank weapon didn't recoil because the gas didn't push on anything, it was a tube. Perhaps the launch platform lets the gas escape instead of pushing on it as in an earth based launch.

What if we had 50 or 100 years notice? A little over 100 years ago the only flight was by balloon now the sky is no limit. In 100 years it would be much easier and most likely cheaper to accomplish. It better be as that would be one big rock.

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What if we had 50 or 100 years notice?

Are you trying to be actually serious?

I would suggest to you that is extremely unlikely in the extreme, that we could detect an asteroid with any accuracy that MIGHT hit the earth as far ahead as 50 or maybe 100 years time.

Well I asked how far out and how big an asteroid would have to be to be spotted. A chart was posted that went up to 100 years and up to 6 miles across. If you have better information I'll listen.

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I would suggest to you that is extremely unlikely in the extreme, that we could detect an asteroid with any accuracy that MIGHT hit the earth as far ahead as 50 or maybe 100 years time.

We can.

For example: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=6344%20P-L;orb=1;cov=0;log=0;cad=1#cad

Click and enjoy: http://neo.jpl.nasa.gov/orbits/

I found a similar chart here (p. 66).

And I found the original chart!

Edit - the data linked to in the last post was made in 2005. Is there an update?

It's from 2013-Aug-05 12:15:53.

I found a similar chart here (p. 66).

That is from The International Academy of Astronautics a non governmental organization. They have been around a long time but they can only suggest they cannot do. So they are not doing any looking and the charts are for information only.
Here we go right from the horses mouth. The farthest one out they have seen may impact between 2185-2196. So now the question is how far out can they be sure, very very sure, of an impact?

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Armageddon time

NASA is planning to send astronauts to an asteroid in the 2020s, and preparations are already being made.

http://www.nasa.gov/content/nasa-astronauts-go-underwater-to-test-tools-for-a-mission-to-an-asteroid/index.html#.U3KOyiga3z8

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NASA is planning to send astronauts to an asteroid in the 2020s, and preparations are already being made.

I see they won't have to use a trampoline, they will have the Orion spacecraft.

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NASA is planning to send astronauts to an asteroid in the 2020s, and preparations are already being made.

I see they won't have to use a trampoline, they will have the Orion spacecraft.

The EFT-1 is set to launch on Dec 4th 2014.

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rOZZ
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After looking at the NASA list of objects that MIGHT strike the Earth it is quite apparent that even with provable science the uncertainty factor makes it imposable to say not only where but if one will hit. Science is exact only if all uncertainties are eliminated. Specials interests don't hype asteroids strikes because they can't hustle a buck doing so.

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only if all uncertainties are eliminated

There you said it. Science would not be Science if uncertainties predominated. Science has a wide spectrum of branches though in human language.

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rOZZ
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