Why does the Earth spin?

Question

and has it been spinning at the same speed since the beginning?

Answer 1

Because it formed 4.5 billion years ago as a result of the coalescence (aggregation) of planetesimals that where in such close proximity as to collide with each other. The collisions imparted angular momentum to the newly formed proto-Earth. Since then our planet has been spinning. Initially once every 6.5 hours or so, now once every 24 hours or so.
This spinning phenomenon is observed in every celestial object, planets, stars, galaxies; they all rotate because their mechanism of formation is similar: from colliding particles.

Answer 2

Momentum keeps Earth spinnin' and it has slowed down. I don't know about the beginning.

Interestingly, Venus is spinning backwards(retrograde). Most planetary bodies (we've observed) spin the same way around as the Earth. Maybe Venus got smacked by a meteor.

Answer 3

The rotation of planet Earth is gradually slowing. For four and one half billion years, its entire lifetime, its rate of rotation has been gradually slowing. As the Earth loses its kinetic energy due to all forms of friction acting on it; tides, galactic space dust, solar wind, space weather, geomagnetic storms, etc., like any flywheel, it will slow down. (The space surrounding the planet is far from empty).

The length of time it takes the Earth, at the present time, to rotate once is 86,400.002 seconds compared to 86,400 seconds back in 1820. The rotation has slowed roughly only by 2 milliseconds since 1820. That seems like an insignificant amount of time BUT over the course of the planet's entire lifetime, it has had very profound effects on the geophysics of the planet.

Tracing these tiny milliseconds back for 4.5 billion years adds up to a very significant amount of time for a solar day. In fact Don Hamilton, the author of, "The Mind of Mankind", has determined that the day was 63,000 seconds shorter than the present 86,400 seconds it is today. This would put the Earth's rotation at about 6.5 hours per day/night cycle, when it was created, 4.5 billion years ago.

Answer 4

spin refers to the angular momentum intrinsic to a body which is generated by the motion of its center of mass about an external point.the spin angular momentum of a body is associated with the rotation of the body around its own center of mass.the spin of the Earth is associated with its daily rotation about the polar axis. On the other hand, the orbital angular momentum of the Earth is associated with its annual motion around the Sun.


It takes the Earth, on average, 23 hours, 56 minutes and 4.091 seconds (one sidereal day) to rotate around the axis that connects the north and the south poles. From Earth, the main apparent motion of celestial bodies in the sky (except that of meteors within the atmosphere and low-orbiting satellites) is to the west at a rate of 15 °/h = 15'/min, i.e., an apparent Sun or Moon diameter every two minutes.

In addition, the rotational velocity varies, in a phenomenon known as length of day variation.
The interior of the planet remains active, with a thick layer of convecting yet solid Earth mantle and an iron core that generates a magnetic field

Answer 5

Every object in the universe is in motion.

All objects rotate in some form or other.

Movement is the norm out there. You should ask, why would anything not spin.

Answer 6

the answer above me is pretty close to correct. But I would say it is because when things in the solar system form, anything like galaxies, solar systems, individual bodies, when they coallesce gravity pulls it all in you can think of a rotating I ce skater, when she pulls her arms in she spins faster, when gravity pulls it in it makes a spin, the more it pulls in the faster it spins.

Answer 7

tke999 is correct.The speed of earth's rotation about itself was six times greater when it was created.

Answer 8

Love makes the world go round.

Or is it Money?