Six tweets that rocked the world

Steve Dinneen
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Yesterday, Manchester United announced the retirement of Sir Alex Ferguson via Twitter. Whether it's carefully planned, widely anticipated announcements like this one or tweets from eye-witnesses to big news events, the micro-blogging site is the first port of call for the latest on any story. Here are some of the biggest news events broken by the site (compiled by Alex Dymoke).

ManUtd_PressOffice @ManUtd_PO
Sir Alex Ferguson retires. #thankyousiralex

Sir Alex Ferguson retires
One hour after this tweet, Alex Ferguson was mentioned more than 1.4m times. To put that into perspective, Margaret Thatcher’s death was mentioned 1m times in the four hours that followed.

Aja Dior @AjaDiorNavy
omgg , my aunt tiffany who work for whitney houston just found whitney houston dead in the tub . such ashame & sad :-(

Whitney Houston dies
Aja Dior, a relative of one of Whitney Houston’s entourage, broke news of the singer's death 42 minutes before The Associated Press. The tweet also corroborated later reports that her body was discovered in a bath tub.

Sohaib Athar @ReallyVirtual
helicopter hovering above Abbottabad at 1am (is a rare event). Go away helicopter – before I take out my giant swatter :-/

Osama Bin Laden SWAT team lands
He didn’t realise it at the time but Sohaib Athar was the first person to tweet about the mission to kill Osama Bin Laden. He later tweeted “Uh oh, now I’m the guy who liveblogged the Osama raid without knowing it.”

MarsPhoenix @MarsPhoenix
Are you ready to celebrate? Well, get ready: We have ICE!!!!! Yes, ICE, *WATER ICE* on Mars! Woot!!! Best day ever!!

Ice found on Mars
When its robot spacecraft Mars Phoenix Lander captured images of water ice, NASA eschewed the usual press conference and instead shared the news with this jubilant tweet.

Jim Hanrahan @highfours
I just watched a plane crash into the hudson river in manhattan

Plane crashes into Manhattan’s River Hudson
Jim Hanrahan broke the news that a plane had crashed in the Hudson fifteen minutes before any of the mainstream news outlets caught wind. Many of the images in the following day’s newspapers were twitpics captured at the scene.

Clarence House @ClarenceHouse
The Prince of Wales is delighted to announce the engagement of Prince William to Miss Catherine Middleton

Royal wedding announced
The engagement of Prince William to Kate Middleton was formally announced by Prince Charles’s office. However, this 132 character tweet from Clarence House (the Royal home in London) got there first.