Piece of Newton's Apple Tree to Escape Gravity on Space Shuttle

A piece of the apple tree that helped British scientist Sir Isaac Newton explain the tug of Earth's gravity and laws of motion in the 17th century is about to escape that gravitational pull when it launches into space this week.

NASA astronaut Piers Sellers, who was born in England, is carrying the historic piece of wood into space for The Royal Society in the United Kingdom. It is packed with the rest of his space luggage for Friday's planned launch of the shuttle Atlantis toward the International Space Station.

"I am flying a chip of wood from Isaac Newton's apple tree. How about that?" Sellers told SPACE.com in an interview last week. "It's even got a little 17th century scrawl on it that says, 'I. Newton.' I don't know if he wrote it or someone else wrote it, but anyway, it's a very old piece of apple tree."

The tale of Newton and the apple tree is a storied one among space scientists. According to science lore, Newton watched an apple fall from its tree in his garden, which gave him the inspiration for what became his theory of gravity.

The original account appears in a 1752 biography of Newton by author William Stukeley, who describes a conversation he had with Newton that included the story.

Newton is a former president of the Royal Society, which is celebrating its 350th birthday this year. A portrait of Newton is also packed along with the apple tree shard among Sellers' official flight luggage.

"I?m pretty sure that Sir Isaac would have loved to see this, assuming he wasn?t space sick, as it would have proved his first law of motion to be correct," Sellers said in a statement.

Newton's first law of motion, one of three, states that an object at rest will stay at rest unless acted upon by an outside force. It also holds for an object in motion, which would stay in motion unless also confronted by an external force.

Newton's second law of motion describes the relationship between an object's force and its mass and acceleration, while the third law states that for every action there is an equal and opposite reaction.

Once it returns to Earth aboard Atlantis, the apple tree piece will be returned to the Royal Society to be displayed in an exhibit.

Sellers will carry a postcard portrait of Newton along with the apple tree piece during a planned 12-day mission to the International Space Station. Liftoff is set for 2:20 p.m. EDT (1820 GMT) Friday, May 14, from NASA's Kennedy Space Center in Florida.

The mission is set to be the last spaceflight of Atlantis and will deliver a new Russian science module to the space station, along with a ton of supplies and some spare parts. Three spacewalks are planned.

NASA intends to retire the shuttles by the end of the year. Two more shuttle flights remain after this one.

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