Which way does Earth spin? What about the other planets?

Although we can't feel Earth spinning, the daily sunrise and sunset are reminders that our planet is in constant motion. But do we know which way Earth is spinning? And is it the same direction as the sun and the other planets circling it?

The answer is linked to the formation of the solar system some 4.6 billion years ago. 

It started with an enormous cloud of gas and dust that was so dense, it began collapsing down on itself, Joshua Pepper, a program scientist in NASA's Astrophysics division, told Live Science. The dense center became the sun, and planets formed in the surrounding swirl of gas.

The initial spin of this swirling cloud is still preserved today. When a rotating object shrinks, it speeds up. This is like when a figure skater pulls in their arms while twirling and they spin faster and faster, Pepper said. The sun is like the figure skater's center of gravity, and the planets and moons are like the skater's arms and legs. This is called angular momentum, and it's why the planets and sun are still spinning today. 

Related: Why do the planets in the solar system orbit on the same plane?

Therefore, astronomers might expect that all of the planets in the solar system would spin in the same direction as the sun.

"To look at the direction of the rotation, we always compare it to a reference direction," said Gongjie Li, an associate professor in the School of Physics at Georgia Tech. In the case of the solar system, that reference point is the sun, which spins counterclockwise, according to Space.com, a sister site of Live Science.