From a Teenager in the Bronx to the World's Greatest Science Communicator: How Carl Sagan Changed Neil deGrasse Tyson's Life — and Millions of Young People

On December 20, 1975, a seventeen-year-old boy from the Bronx, New York, stepped off a bus into the snow-covered town of Ithaca. He had been invited by a scientist who, upon receiving his college application at Cornell University, had done something unusual: he wrote a personal letter to that young man, fascinated by the stars.

The scientist was Carl Sagan. The teenager was Neil deGrasse Tyson.

“He had been invited by a scientist who, upon receiving his college application at Cornell University, had done something unusual: he wrote a personal letter to that young man, fascinated by the stars.”

Sagan picked up Tyson at the bus stop, gave him a tour of his laboratory, walked him around campus, and signed one of his books with the dedication: "For Neil, a future astronomer." When the snow became too heavy for the return trip, Sagan offered his personal phone number: "If the bus can't leave, call my house. You can spend the night with us."

Tyson didn't stay at Cornell — he chose Harvard. But that encounter planted something far greater than a college enrollment. In his own words: "I already knew I wanted to become a scientist. But that afternoon, I learned from Carl the kind of person I wanted to become."

Today, Tyson is director of the Hayden Planetarium, hosted Cosmos: A Spacetime Odyssey (2014) — the direct successor to Sagan's 1980 series — and has become arguably the most recognized science communicator on the planet. But the most revealing aspect is what he does behind the scenes: he personally responds to every letter and email from young people asking about careers in astronomy.

"I have this duty," says Tyson. "To respond to students who are inquiring about the universe as a career path — in the way that Carl Sagan had responded to me."

The Carl Sagan Institute, founded at Cornell in 2015 under the direction of astrophysicist Lisa Kaltenegger, is today one of the most innovative research centers for extraterrestrial life. In 2024, a team from the institute — including an undergraduate student and two recent graduates — identified 45 potentially habitable rocky exoplanets using data from the Gaia satellite and NASA archives.

The institute also created the Nexus Scholars program, offering eight-week summer fellowships for undergraduate students to participate in real astrobiology research — exactly the kind of hands-on opportunity Sagan championed.

In November 2024, Ann Druyan — Sagan's widow and co-author of Cosmos — organized a public celebration at Cornell of what would have been the scientist's 90th birthday. The event brought together career researchers and students who never met Sagan personally but are walking paths he made possible.

Sagan used to say: "Every kid starts out as a natural-born scientist, and then we beat it out of them." His conviction was that the educator's role is not to answer questions — it is to protect the ability to ask them.

Tyson's story proves that a single act of intellectual generosity — a letter, an afternoon, a signed book — can trigger a chain reaction that inspires millions. And the young researchers at the Carl Sagan Institute today demonstrate that this chain continues to expand, thirty years after the passing of its spiritual founder.

In a world that often treats curiosity as a distraction, Sagan's message remains revolutionary: the unknown is not something to fear. It is the most beautiful invitation the universe offers us.