NASA rang in the New Year yesterday with a historic flyby of the farthest, and quite possibly the oldest, cosmic body ever explored by humankind -- a tiny, distant world called Ultima Thule -- in the hopes of learning more about how planets took shape. "Go New Horizons!" said lead scientist Alan Stern as a crowd including kids dressed in space costumes blew party horns and cheered at the Johns Hopkins Applied Physics Laboratory in Maryland to mark the moment at 12:33 am (0533 GMT) when the New Horizons spacecraft aimed its cameras at the space rock four billion miles (6.4 billion kilometers) away in a dark and frigid region of space known as the Kuiper Belt.

Offering scientists the first up-close look at an ancient building block of planets, the flyby took place about a billion miles beyond Pluto, which was until now the most faraway world ever visited up close by a spacecraft.

Real-time video of the actual flyby was impossible, since it takes more than six hours for a signal sent from Earth to reach the spaceship, and another six hours for the response to arrive.

The first signal back to Earth should come about 10 hours after the flyby, around 9:45 am (1445 GMT), letting NASA know if New Horizons survived the risky, high-speed encounter.

Hurtling through space at a speed of 32,000 miles per hour, the spacecraft aimed to make its closest approach within 2,200 miles of the surface of Ultima Thule. "This is a night none of us are going to forget," said Queen guitarist Brian May -- who also holds an advanced degree in astrophysics -- and who recorded a solo track to honor the spacecraft and its spirit of exploration.

Stern said Ultima Thule is unique because it is a relic from the early days of the solar system and could provide answers about the origins of other planets.