This week’s TED Radio Hour tries to pinpoint what exactly makes a millennial a millennial. Growing up in a world marked by a new set of challenges and opportunities — the Internet, longer lifespans, an economic crisis — today’s twentysomethings have a vastly different perspective on and approach to life from previous generations. What makes this generation great? Will Generation Y change the world?

The show kicks off with Natalie Warne, the 18-year-old whose 2011 Talk at TEDxTeen encouraged young people to get involved with causes they care about. In her talk, Warne connects her personal story of fighting to save Ugandan children with a larger observation about her generation: This is one of the most enthusiastic and driven generations yet.

It’s a generation that chases its passions and deeply believes that it can change the world. Warne sees young involvement in social causes as an asset, rather than a setback: “I think at 18, everything was limitless and possible because I hadn’t been told otherwise yet.” No one, she reminds us, is too young to change the world.

Next up is Meg Jay, a psychologist who specializes in twentysomethings. Her talk from TED2013  explains why your twenties are a developmental sweetspot, perhaps the most critical period of adult development. As a therapist, she found that too many of her patients saw this age as a break, a time to relax and put off important decisions about careers and marriage until their thirties. Instead, she argues,  your twenties are the prime time to lay the groundwork for the rest of your life. “You’re deciding your life right now,” she says.

Following Jay is Charlie Hoehn, who spent his whole life doing what he was told, checking off the boxes to become a “Successful American.” But, as he shares at his 2011 talk at TEDxCMU, his plan didn’t quite pan out when he graduated in 2008, at the start of the worst economic recession in US history in 80 years. Rather than accept a menial and meaningless job, Hoehn instead decided to do Free Work — the work that he found meaningful, for free. This path eventually lead him to a paying job that he was passionate about, and he encourages others to try this route. “As long as there are problems to be solved, there will be work. Chase after the things that make you happy.”

As the trends manager at YouTube, Kevin Allocca’s job is to figure out why things become popular on the Internet. In his 2012 talk from TEDYouth, he discusses the dynamic of 21st-century celebrity, from the interactive fandom to the possibility that anyone can get into the limelight. Users can claim ownership over their own entertainment in unprecedented ways, making (and sharing) movies and music without any greenlighting involved.

This episode of the TED Radio Hour closes with Tavi Gevinson, who started a wildly popular fashion blog at age 11. In her 2012 talk from TEDxTeen, she discusses the challengies of growing up as a young girl in the 21st century, where she struggled to reconcile the many messages she received from the media about how to be a smart, pretty feminist who was interested in fashion and was just trying to navigate high school.

Teenage girls, she observed, are the subject of much media attention, but rarely have a platform to speak for themselves. In response, she launched Rookie Mag in 2011, at age 15, to create a space for teenage girls to voice their opinions and problems. She feels that her generation is in many ways defined by technology, because the Internet presents incredible opportunities to find communities and a place to fit in online.

The speakers in this episode offer different perspectives on what millennials might represent for the future of the United States. But one thing they all agree on is that millennials are a force to be reckoned with, and that, because of them, the world may never be the same.

Check out your local NPR schedule to find out when TED Radio Hour’s “The Next Greatest Generation” airs, or listen via the NPR website »

You can also head to iTunes, where the podcast is available now »

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