Today, FORBES announces its 2012 Most Powerful People on the planet, a ranking of 71 (representing the 7.1 billion people in the world) that spans continents, industries, number of people they influence and resources they control–including the dollars in their personal bank accounts. One of the most interesting juxtapositions is the range of ages. At 28, Facebook founder and billionaire Mark Zuckerberg (No. 25) is the the youngest on the list. King of Saudi Arabia Abdullah bin Addulaziz al Saud (No. 7) is the oldest at 88.

Developing and owning power on this level is mostly a middle-aged affair. The majority of people on the list are in their 50s (24) and 60s (22), with an overall average age of 60.

Then again, there are certain industries that embrace youth–and vice-versa. First and foremost is tech. Zuckerberg is joined by Google founders Larry Page and Sergey Brin, both 39 (both No. 20 on list) , as well as Elon Musk (No. 66), the 41-year-old entrepreneur behind PayPal and SpaceX; Robin Li (No. 64), 44, the cofounder and CEO of Chinese search engine giant Baidu; Reid Hoffman (No. 71), 45, the most connected VC in Silicon Valley and founder of LinkedIn; and Jeff Bezos (No. 27), CEO of Amazon.com. Notably, all are billionaires.

Youth can also be a driver of political ambition, as seen by five of the other youngest on the list. Kim Jong-un (No. 44), 29, took over as supreme leader of North Korea after his father’s death in 2011. David Cameron (No. 10), 46, is two years into office as prime minister of the U.K. Mexico just elected 46-year-old president Enrique Pena Nieto (No. 54). Earlier this year Dmitry Medvedev (No. 61) castled positions with Vladimir Putin (No. 3), now the former is prime minister and his mentor is back as president. Finally, Rostam Ghasemi (No. 57), 48, serves as both Iran’s oil minister and president of OPEC.

TechCrunch Conference - San Francisco, CAMark Zuckerberg, 28

CEO, Facebook

In May investors were giddy when the world’s biggest social media site went public: “How high will it go?” That was then. Facebook’s IPO was a debacle, and its stock remains far below the original $38 a share. Zuck’s personal fortune declined from $17.5 billion to less than $14 billion. But the man still pulls in impressive numbers: Facebook hit 1 billion monthly users in October.

Kim Jong UnKim Jong-Un, 29

Supreme Leader, North Korea

The youngest son of “Dear Leader” Kim Jong-Il took over leadership of the Hermit Kingdom after father’s December 2011 death, but some outside observers wonder if older uncle Jang Song-thaek is pulling his strings. In theory “Brilliant Comrade” Kim Jong-Un has absolute control over the 24 million citizens in his reclusive, rusting nuclear state; satellite photos reveal a newly constructed, half-kilometer-long message of praise carved into a hillside in Ryanggang Province.

Larry Page & Sergey BrinLarry Page & Sergey Brin, 39
Cofounders, Google

Page, the CEO, runs the company; Brin, now the director of special projects, says he spends more than half his time on Google Glass, the wearable ­computer due to hit the market in 2014. Together they’ve helped build the world’s most visited website–surpassing 1 billion visitors each month–and one of the world’s most valuable ­technology companies.

Elon Musk  Visits "Late Show With David Letterman"Elon Musk, 41

CEO, SpaceX, Tesla Motors

The billionaire entrepreneur behind PayPal and Tesla Motors is the most powerful man in space: His company SpaceX is a leader in the private space industry. Cash-strapped NASA has retired its Space Shuttle fleet and will use SpaceX vehicles to haul cargo to and from the International Space Station. With commercial business in space ready to boom, Musk stands to make out like a 19th-century railway tycoon.

Robin LiRobin Li, 44
Cofounder and CEO, Baidu

One of China’s richest, with a net worth of $7 billion, Li is the man behind his nation’s largest search engine.

Microsoft CEO Steve Ballmer & LinkedIn Executive Chairman Reid Hoffman Speak At The Churchill ClubReid Hoffman, 45
Venture capitalist

The world’s most powerful venture capitalist and the most-connected man in Silicon Valley can make or break a startup and shapes the future of tech. Hoffman cofounded LinkedIn, and its IPO made him a billionaire; he’s now a partner at VC firm Greylock Partners and a prominent angel investor in his own right.

Olympics & Paralympics Team GB - London 2012 ReceptionDavid Cameron, 46
British Prime Minister

Two years into office the Tory PM has gone from being called the second coming of Margaret Thatcher to standing in the shadow of Europe’s new Iron Lady, Angela Merkel.

Enrique Pe a Nieto Visits Sao PauloEnrique Pena Nieto, 46
President-elect of Mexico

Won election in July; just took office in December as leader of one of Latin America’s dominant powers.

Reception At Buckingham Palace For Heads Of State And Government Attending The Opening Ceremony Of The OlympicsDmitry Medvedev, 47
Russian Prime Minister

The junior member of Russia’s ruling duopoly swapped jobs with Putin and returned to the lower-profile PM gig. 2012 HIGHLIGHT: Facebook CEO Mark Zuckerberg put on a suit for a 20-minute meeting in Moscow with Medvedev in October.

Amazon Holds News ConferenceJeff Bezos, 48
Amazon CEO

Founder and chief of the biggest retailer on the Web, the biggest mover in the rapidly evolving publishing industry, and the biggest threat to companies like Netflix and Wal-Mart. Next Bezos is looking to disrupt feature film production and the database software business. 2012 HIGHLIGHT: In October the Kindle Fire was the number 2 bestselling tablet in the world, behind Apple’s iPad.

Rostam GhasemiRostam Ghasemi, 48

President, OPEC

Former commander in Iran’s Revolutionary Guard Corps serves as the country’s oil minister and as president of OPEC.