What is the use of military?

Military is necessary to keep the peace for a certain country. They dont develop the military to show off or to take over other countries but having military is a sign of peace.

And if at all there are some terror attacks,then military would be useful .

Totally pointless. If there was no military in ANY country, we wouldn't even need the UN forces since there would be no need to intervene. (considering there is still the police to handle crime etc). UN forces intervene in military conflicts so no other militaries and UN doesn't need to intervene in any conflict as there isn't any.

Also, UN is strictly defensive. That is they can't shoot unless they're shot at. They're mostly there to bring food, medicine and other such stuff.

So it wouldn't be altogether bad to concentrate all the militaries into one, but it wouldn't serve any purpose.

And as to answer 'the use of military' : the military is used to defend a country/values. However, some countries use it as a means to force a population to adhere to its point of view, its desires and beliefs. So depending who you go ask, the military is either offensive or defensive. I like to think of it more as something defensive but unfortunately, people nowadays use the military for just about anything.

Basically, if we stopped doing things through physical force, we'd have a lot less deaths on our hands...but since it is realistically impossibly to get rid of all militaries in the world, we might as well deal with it.

The purpose of the military is defense. In WWII the Germans were developing long range missiles and nuclear capability and the range was to reach NYC. The Japanese attacked our Navy fleet at Pearl Harbor. It was clear that the Axis was a direct threat to the U.S. Read Studs Terkel's "The Good War" to see the justification. Other wars like Korea and Vietnam were not so clear - there was not an obvious threat to the U.S., just a vague "domino theory". Nowadays often the U.S. military is not used so much to fight a conventional army, but to occupy space or "nation build". Often we want to create a democracy where they have no legacy of that type of government. The locals have mixed feelings. Can you trust a politician or policeman in Afghanistan? Whose side are they on? Often all the local factions unite against the "foreign invader". It happened with the British and the Soviets in Afghanistan.

Some countires are small enough like Sweden and Switzerland and Costa Rica to declare they won't have a military and are neutral. Works as long as nobody big decides to invade.

The U.N. is very ineffective. It would collapse without U.S. funding and support. It is a paper tiger. No American parent should have to send their child to war under a U.N. officer or banner. It does not work. If you are going to be in harms way as an American you need to be under a U.S. flag with U.S. command and control. An Egyptian U.N. commander just can't call the shots with U.S. troops.

What if everyone shared the wealth equally too, so no one starved?

It's communism, it doesn't work.

The same applies for this one military, in an ideological world it would work but in reality it wouldn't. Unless the earth was facing a outside invasion by aliens then the worlds militaries would never unite, if they would there wouldn't be much need for a military.

The UN is one of the most corrupt organizations on the planet. If you committed all of the worlds militaries into one organization, who would defend against it when it inevitably became despotic and turned on the people?

Basically, to defend America from foreign threats. Honestly, in my opinion, sending troops to other countries is a stupid idea, because we can barely help ourselves. However, it is necessary to have a form of defense IN CASE, someone decides to invade our asses.

SIMPLE,THE UNITED STATES FORCES ,NEVER SHOW THEIR POWER ,WHEN SIMPLE PLANES CRASH OVER NEW YORK.

BUT IS WEIRD,THE CIA AND THE FBI,KNOW THE NAMES OF THE BAD GUYS IN LESS THAN A DAY?.

A LOT OF PEOPLE DIE ,FOR THIS LIES..

Well...it wouldn't be particularity useful, nobody would be able to control it. and It would be a mess.

we are not a united planet therefore that idea is retarded.

theoretically, nothing!