Yeah lucky they dropped the bombs so not thousands of people would  lose their life..

....you're intentionally not getting the point it seems. -_-

A U.S invasion of Japan would've been more costly on both sides than the two atomic bombs dropped on them.

Like said before, they estimated a million lives would've been lost. How many of those do you think would've been civilians? Many more than were actually killed on the bombings. 

That is correct. Capitulation talks had been going on for quite a while. The key problem was the status of the japanese emperor (as actual "god" to the Japanese at that time).

I recently saw a documentary where they interviewed the guy that survived the Hiroshima bomb. Without any infrastruture left, he (amongst others) was immediately evacuated to a hospital in  ..... Nagasaki. Talk about bad luck..

what I ask you is how many AMERICAN CIVILIANS did the japanese kill? then compare that to the number of JAPANESE CIVILIANS americans killed with the bomb. to see who the was the biggest monster? Please understand I am under NO CIRCUMSTANCE trying to justify what the japanese did in pearl harbor because that was terrible too, but there is a huge difference here and if you think about it you may see it, the japanese attacked a military base. the military know that if there is war there is a chance that they may die and they are trained speacially for that. Instead who did america attack? the children who were in schools, moms that were cooking, people INNOCENT people doing regular things, now you may try to justify this and say that it was neccesary, but the tought of what was done and the consequences make me sick. Let me put it this way, if your watch on the news that someone got into a school a killed lets say 10 5 year old kids you would probably be repulsed by the idea but america did even worse. and to the people that think that 300,000 was nothing compared to the amounts of deaths in the war, is your life not a big deal? or you family´s life? every life is unique and irreplasible. just 1 person dead would be a terrible crime. Now if america had killed 300,00 japanese soldiers I wouldnt mind so much because as I said soldiers are trained for just that, but what they did cannot be forgotten. Now, were the japanse good? Hell no, they killed millions of chinese and tortured thousands too, and were just as bad if not worse than the nazis. I guess what I´m trying to say that everyone in war is a monsters too because war brings the worst in people. picture this. the USSR were the first to get to berlin and they saved many jews, but they were just as bad, they raped thousands of german women and killed many. Back to the topic I dont there is any justification to attack the innocent, the americans were just as bad as the others because they didnt attack the military but the innocent. and that is just unforgivable.

Now you may satinize my comments if you want

there were worse things that happened and the US warned people to leave the towns.

OK half a million.

War is a bad thing and about what would have happened if the A-bombs were never dropped we can now only speculate. People do ugly things in wars but there is a limit to everything. Mass murder is a crime, thats a fact.

As my war experience is quite fresh (Yugoslav Wars '91-'95) ill share few things with you. Every side did what they thought it was necessary. As a result of that was half a million people displaced, mine fields thruout Croatia and Bosnia (that are not yet cleared and every year several children still dies because of them), mass graves as a result of mass executions of war prisoners, Ovcara massacre,  Srebrenica genocide... just to mention a few. Every side did what they thought was necessary but that does not mean it was a right thing to do, or a good thing to do.

Everyone that thinks that A-Bombs were necessary evil should read "Sadako will leben by Karl Bruckner (eng The day of the bomb).

So I guess that justifies it then

Their is not really proof of it. Except that it would be more costly on USA side. 

Ofcourse, Terrorists warned USA civilians aswell still they stayed in USA.;..those people in the WTC towers asked for it X_X.

It's actually interesting what it brought forth, it made Japan the leader in the anti-atomic movement, but more interestingly Japan also made itself the only country that truly knows what Armageddon is. Little Boy and Fat Man is the indirect cause to story's like Nausicaä of the Valley of the Wind and Akira. It's why Armageddon story's are so common in Japan. It's also why a movie like Blade Runner has a Japanese setting. In a way September 6 - 08:15 has been a reset button for Japan. The new year zero if you will. From that point on Japan changed rapidly. Many then saw the atomic bombing as the point were Japan needed drastic change, of course also spurred by the American occupying the country for several years. But is was not only the American who thought Japan needed the change many Japanese themselves felt so.

On the subject itself, I think it was necessary evil, and yes it does exist. Even in Japan itself many see it that way. Not only did it end the War it also ended the Military Dictatorship. It's also the reason Japan doesn't really blame America, they don't point fingers at them. They just acknowledge nuclear weapons are horrible and should never be used again.