I have read that different nations have their own version of truth about Hiroshima and Nagasaki bombings during World War-II in their history books.
Is this true?
What have you read in your history class?

Its been 70 years since that incident.
Hiroshima was bombed on August 6 and Nagasaki was bombed on August 9, 1945.

AFAIK:

1. US wanted to force Japan to surrender and avoid heavy casaulties while invading Japan home islands (likely they've also saved numerous casaulties among Japaneese people which would be better for them as they intented on occupying Japan after the war).
2. They also wanted to impress/scare Stalin.
3. Nagasaki bombing had some 'aditional scientific test value' for US as the bomb was composed of different material than the one droped on Hiroshima.

i've read that us government wanted to destroy all evidence and avoid capturing by japan of an usaf alien-hybrid super ufo space ship that crushed there some hours before. thats why they nuked hiroshima

Mostly correct as far as I understand it, with the exception of the first point. Japan had effectively already surrendered and the U.S. had refused the surrender. There was not going to be any fighting for Japan.

As to point three, I can't speak to the composition of the bombs but I do know that there was a feeling that more than one had to be successfully detonated so it couldn't be considered a "fluke." As in, the Soviets couldn't ever think "Sure, they got one to go, but who is to say they have more, or could even do it again?" So the U.S. sought to resolve all doubt.

They only mentioned it in passing when I was in school. I learned more about it from Hadashi no Gen :


https://www.youtube.com/watch?v=ZTJaxdRGjMY

According to a survey around 60% of American thinks it was right decision.


Also I never saw any reference about these A-bombs in any of WWII games.
May be because it would give rise to controversy.

As I recall, a faction within the Japanese gov't was in talks with U.S. about surrender, but they balked at it being unconditional surrender.

Relevant: Hiroshima survivor Keiji Nakazawa's manga series about the bombing, Barefoot Gen, is being Kickstarted for distribution to American schools and libraries.

On topic: I'm used to the classic American story about the nuclear attacks, and how necessary and "sanitary" they supposedly were. To us it seems like everything was basically vaporized. (That really isn't what happened, as Nakazawa's many comics about the event make clear.) There's a general lack of handwringing about nuking Japan among Americans, and even the more progressive types tend to ignore the whole business these days.

According to The Onion Nagasaki was bombed "...just for the hell of it..." and that "The second bomb would have just sat around anyway."

That's not correct as you've phrased it. Allegedly there was a translation error that resulted in the bomb being dropped on Nagasaki. There was no attempt by the Japanese to surrender prior to the bomb being dropped on Hiroshima.

The point is that the US had not refused a surrender prior to dropping that first bomb, it was the second bomb where there was likely an attempt by the Japanese to surrender. Considering the Kamikaze missions there was ample reason to believe that it would have been a blood bath if there had been an invasion. Well above and beyond the loss of life in those cities that resulted, Not just for the Allies coming in, but for the Japanese as well.

What people often times fail to realize when the discussion about this comes up, is that the Japanese themselves inflicted a similar level of damage to Chinese cities, just rather than having a nuke to do it with, it was tons of munitions, some of which, is probably still lying there waiting to be found.

Little Boy was Uranium based, while Fat Man used Plutonium. The U.S. had to decide which technology they wanted to pursue in the future, hence the speculations that Nagasaki was rather a test than a mandatory military action.

Pretty much just and not much else.

The Pacific War is barely a footnote in school in Poland- we have so much of our own history with World War II to go through there isn't much time to talk about other theatres of war. What little I know about it (at least the list of more important events- Doolittle Raid, Battle of the Coral Sea, Midway, Iwo Jima) comes from games, movies, and reading I did on my own.

Cables to Moscow (which might indicate the larger issue here) indicating surrender would it occur if "unconditional" were dropped came from the Foreign Minister himself. The Emperor had already worked to undermine the military bureaucracy and stated surrender must occur under the Allies' terms (prior to the dropping of the bomb). Incidently, when surrender did occur it was under the implicit condition that the Emperor would be retained (largely to continue his work of removing the established military order internally - which he did a damn fine job of - I can't think of a single modern postwar occupation that went more smoothly - giving all due accord to our troops, officers and officials as well).

The inference being, Japan was done fighting. The nightmare scenario as far as the U.S. was concerned was that Japan would surrender to the Soviets (which almost / could have occurred?) or that the Soviets would push further into East Asia under the pretext of moving against Japan. NOT that we would have to fight our way through the Japanese isles.

In true military / interservice rivalry, the Army was desperate to invade and the Navy wanted nothing more than to bombard. While the nascent Air Force was eager to continue firebombing the hell out of Japan. They all wanted the glory of picking at the corpse. In the end, the decision was made with larger political ramifications in mind.

I'm not surprised. In China I ran into too many people who think of Hitler as that nice man with a mustache. They don't talk at all about the European theater of WWII, primarily because there's a lot that was directly related to them.

Thank you I had forgotten (perhaps never even known?) that!

It was terrible. If it weren't for the scale of it, the greater tragedy would be that it goes almost forgotten. I think we, so many years later often forget the sheer horror that was World War II. We have almost a romantic notion of it but the level of atrocity on all sides was mind boggling.