A giant gun is assembled in record time. The army thinks we have already defeated the Martians, but they do like the idea of firing a warning shot back again, so they cooperate fully. Within six months, a missile packed with explosives is on its way to the red planet.
The distance is immense. For three months we watch its progress through a specially designed telescope.
Then, to our horror, just as it finally approached its goal, missiles appear from Mars and shoot it down!
Our weapons don't stand a chance! And we have shown ourselves to be aggressive, so the Martians are certain to attack us now! What were we thinking???