Let's see, what is the K of 1000-ft asteroid. Assuming typical potato-shape with the average diameter 1000 ft (=about 0.3 km), its volume is about piD^3/6 = 1.4x10^7 m^3. If it is rocky asteroid (typical density D=3 g/cm^3), than its mass is about 4.2 x 10^10 kg, if iron-nickel (D=8 g/cm^3) then 1.1x10^11 kg.

Typical velocities of fly-by Earth asteroids are in 20-60 km/sec range. Let's take average 40 km/sec. Then the kinetic energy of 1000-ft rocky asteroid K =mv^2/2 is about 3.4x10^19 J and of the iron one - about 9x10^19 Joules.

How much is it anyway?

1 kiloton of TNT releases about 4x10^12 J, so average 20-KT atomic bomb (like Hiroshima one) releases about 8x10^13 J, and largest ever tested H bomb (russian 50-MT one) releases about 2x10^17 Joules.

Usually small 1 MT H bomb makes 1.2-mile diameter fireball, kills and levels practically everything within 8 mile diameter circle and makes major damages and lethally burns unprotected victims within 20 mile circle.

Asteroid impact of similar energy usually makes damages within factor 2-3 less radius than bomb, because it releases most energy underground.

Now, our rocky asteroid releases energy equivalent to about 8 Gigaton of TNT, which is about 0.4 millions Hiroshima bombs or 8 thousands small 1-Megaton H bombs, or about 160 large 50-MT H bombs.

Such amount of H bombs would produce fireball of about 40-mile diameter, levels and kills everything within 250 miles circle and makess essential damage within 700 mile circle.

Our Rock asteroid would make similar damages within 2-3 times smaller circle, and the iron one - within about 2 times more, killing everything within about 200 miles and essentially damaging everything within 600 miles.

This is indeed comparable to a small country.

• response to that - quiet - January 9, 2002 - 20:22 UTC
  • this math is easy.. Asimov's .biography of James Joules - carefuluniverse - January 12, 2002 - 07:59 UTC
    • Asteroid Math, Asimov on Joules, repost exponents (html?) - carefuluniverse - January 12, 2002 - 08:01 UTC
      • IYou goofed saying "estimates vary " on TNT to Joules conversion - spazcon - January 12, 2002 - 08:42 UTC
      • Oops, left out a few words - carefuluniverse - February 27, 2002 - 19:02 UTC
    • apparently "sup" tags for exponents were stripped - carefuluniverse - January 12, 2002 - 08:14 UTC
• Yes, but - harvey1 - January 9, 2002 - 21:01 UTC
  • Better yet... - aurino - January 9, 2002 - 21:04 UTC
    • I too feel like peppering the list with inane comments - quiet - January 9, 2002 - 22:15 UTC
  • How can God prevent such catastrophe? - alexander - January 10, 2002 - 15:01 UTC
    • It's a matter of God's will - harvey1 - January 10, 2002 - 16:50 UTC
      • How does God realise his will if he find colliding rock? - alexander - January 10, 2002 - 17:06 UTC
        • Well - harvey1 - January 10, 2002 - 17:20 UTC
          • We have been hit before, ya know - stormcrow - January 10, 2002 - 17:43 UTC
            • Anthrocentric or anthropocentric? - harvey1 - January 10, 2002 - 18:15 UTC
              • Harvey, and what exactly is "God will"? - alexander - January 10, 2002 - 19:05 UTC
                • Think of it this way - harvey1 - January 10, 2002 - 20:15 UTC
                  • So, basicly He is a passive observer. - alexander - January 10, 2002 - 20:55 UTC
                    • You forgot about his active role - harvey1 - January 10, 2002 - 21:27 UTC
                      • The reason why it takes years - our brain is too weak. - alexander - January 10, 2002 - 22:02 UTC
                        • Not a suitable answer - harvey1 - January 10, 2002 - 23:07 UTC
                          • Pauli principle is a CONSEQUENCE too. - alexander - January 10, 2002 - 23:37 UTC
                          • Define God here... - stormcrow - January 11, 2002 - 04:16 UTC
                            • I actually did post definitions of God & you "commenteth'd not - quiet - January 11, 2002 - 19:33 UTC
                              • I must have missed it - stormcrow - January 11, 2002 - 23:24 UTC
                                • could take ten minutes ! -- Mike - carefuluniverse - January 12, 2002 - 03:13 UTC
                                  • Give me a little time to churn through this - stormcrow - January 12, 2002 - 05:09 UTC
                                    • Thank you. When will my pizza arrive? - carefuluniverse - January 13, 2002 - 17:38 UTC
                                      • Here you go - stormcrow - January 14, 2002 - 04:40 UTC
                                        • whoa - stormcrow - January 14, 2002 - 04:41 UTC
                                        • So, it's an IQ problem - quiet - January 14, 2002 - 07:07 UTC
                                          • Yes, probably - stormcrow - January 14, 2002 - 16:10 UTC
                                            • I know no reason to try harder to win your approval - occupant - January 14, 2002 - 19:20 UTC
                                              • I'm not demeaning you in any way - stormcrow - January 15, 2002 - 03:55 UTC
                                                • Why not...don't I deserve to be demeaned as much as anyone? - carefuluniverse - January 15, 2002 - 06:45 UTC
                                                  • Probably more so - stormcrow - January 15, 2002 - 17:13 UTC
                                                    • why more so? - occupant - January 15, 2002 - 18:17 UTC
                                                    • Mario, here is the definition (Anyway Mike does not have it). - alexander - January 15, 2002 - 20:01 UTC
                                                      • Isaac, Albert, Enrico, here is the definition (Alex is a ... : ) - occupant - January 15, 2002 - 21:56 UTC
                                                        • I did. It says "A supreme, or ultimate reality". Math, then. - alexander - January 20, 2002 - 22:46 UTC
                            • Reposting that - quiet - January 11, 2002 - 19:34 UTC
                          • More on the subject - harvey1 - January 11, 2002 - 06:16 UTC
                            • Three ways ways to explain. - alexander - January 11, 2002 - 20:02 UTC
                              • Thank you - stormcrow - January 11, 2002 - 23:25 UTC
                            • Mario, I'm afraid your missing the point - harvey1 - January 12, 2002 - 02:43 UTC
                              • No doubt I am - stormcrow - January 12, 2002 - 04:50 UTC
                                • Wow - carefuluniverse - January 12, 2002 - 06:22 UTC
                            • re: No doubt I am - harvey1 - January 12, 2002 - 16:09 UTC
                              • I'll specify - stormcrow - January 12, 2002 - 17:20 UTC
                        • You don't see the bigger picture - harvey1 - January 11, 2002 - 02:35 UTC
                          • Harvey, math governs it all, that is why. - alexander - January 11, 2002 - 20:29 UTC
                        • Doesn't work - harvey1 - January 11, 2002 - 20:52 UTC
                          • All forces and laws are related. - alexander - January 11, 2002 - 21:09 UTC
                      • Still won't work - harvey1 - January 11, 2002 - 21:54 UTC
                        • Harvey, try to understand simple things. - alexander - January 11, 2002 - 22:26 UTC
                      • Very simply - harvey1 - January 11, 2002 - 23:11 UTC
                    • No - harvey1 - January 10, 2002 - 22:55 UTC
                      • Oops! - harvey1 - January 10, 2002 - 22:56 UTC
            • Hmm. Let's See? - rggarfinkle - January 12, 2002 - 05:36 UTC
              • A serene travel through the topic - spazcon - January 12, 2002 - 20:54 UTC
          • what are "God's options" ? and our logical limits - quiet - January 10, 2002 - 17:58 UTC
            • Let me give you my view of the matter - harvey1 - January 10, 2002 - 18:29 UTC
              • I did read it... - quiet - January 10, 2002 - 22:30 UTC
                • Religion is another matter - harvey1 - January 10, 2002 - 23:12 UTC
          • Prayer was experimentally found absolutely ineffective. - alexander - January 10, 2002 - 18:32 UTC
            • The use of statistics doesn't work - harvey1 - January 10, 2002 - 19:29 UTC
            • Al's absolutely mistaken...this dogma ignores everything mental - quiet - January 10, 2002 - 19:41 UTC
              • This is not a belief (that all processes are a mathematical - alexander - January 10, 2002 - 20:42 UTC
                • So, what does math calculate I will say next? - quiet - January 10, 2002 - 22:19 UTC
                  • Quite simple math. - alexander - January 10, 2002 - 23:47 UTC
                    • I need not argue . . .self=evidently, that is not an answer - quiet - January 11, 2002 - 01:08 UTC
            • Placebos have been shown -- experimentally -- to be effective. - luis_hamburgh - January 10, 2002 - 23:53 UTC
              • Really? Why don't you try placibo for heart attack? - alexander - January 11, 2002 - 00:23 UTC
                • Or try math - quiet - January 11, 2002 - 07:02 UTC
                • Why do you argue against yourself so often? - luis_hamburgh - January 12, 2002 - 15:44 UTC
                  • Not 'oxymoron,' -- 'redundancy.' - luis_hamburgh - January 12, 2002 - 16:14 UTC
                    • A bit harsh - stormcrow - January 12, 2002 - 17:23 UTC
                  • Luis is also a musician....soars to achingly beautiful heights - spazcon - January 12, 2002 - 20:37 UTC
  • Math can estimate probability of the catastrophe. - alexander - January 10, 2002 - 16:55 UTC
    • Teacher says, "You, too, can do this math!" - quiet - January 10, 2002 - 18:19 UTC
• The period is 1321 days... - bruce - January 10, 2002 - 19:21 UTC
  • Bruce, Earth also moves (with 30 km/s). - alexander - January 10, 2002 - 21:36 UTC
    • Didn't I say orbital velocity? - bruce - January 10, 2002 - 22:07 UTC
  • No, I just want to point that it is relative v which counts here - alexander - January 11, 2002 - 00:40 UTC
    • I should have said... - bruce - January 12, 2002 - 04:29 UTC