Is the earth expanding?

Question

is the earth expanding? is that what accounts for sea floor spreading?

Answer 1

The Earth isn't expanding, but as it spins, it becomes less spherical and more elliptical. And the plates move as all of this is happening. The movement of the plates is what causes the expansion of the sea floor.

Answer 2

No, the Earth is not expanding.  The tectonic Plates are moving across the mantle and, although they are spreading apart in some areas, one plate is subducting beneath another on the other side of the plate.  This means that the surface is being recycled, although it is happening very slowly.

"Divergent boundaries occur along spreading centers where plates are moving apart and new crust is created by magma pushing up from the mantle. Picture two giant conveyor belts, facing each other but slowly moving in opposite directions as they transport newly formed oceanic crust away from the ridge crest.

Perhaps the best known of the divergent boundaries is the Mid-Atlantic Ridge. This submerged mountain range, which extends from the Arctic Ocean to beyond the southern tip of Africa, is but one segment of the global mid-ocean ridge system that encircles the Earth. The rate of spreading along the Mid-Atlantic Ridge averages about 2.5 centimeters per year (cm/yr), or 25 km in a million years. This rate may seem slow by human standards, but because this process has been going on for millions of years, it has resulted in plate movement of thousands of kilometers. Seafloor spreading over the past 100 to 200 million years has caused the Atlantic Ocean to grow from a tiny inlet of water between the continents of Europe, Africa, and the Americas into the vast ocean that exists today.

The volcanic country of Iceland, which straddles the Mid-Atlantic Ridge, offers scientists a natural laboratory for studying on land the processes also occurring along the submerged parts of a spreading ridge. Iceland is splitting along the spreading center between the North American and Eurasian Plates, as North America moves westward relative to Eurasia.

The consequences of plate movement are easy to see around Krafla Volcano, in the northeastern part of Iceland. Here, existing ground cracks have widened and new ones appear every few months. From 1975 to 1984, numerous episodes of rifting (surface cracking) took place along the Krafla fissure zone. Some of these rifting events were accompanied by volcanic activity; the ground would gradually rise 1-2 m before abruptly dropping, signalling an impending eruption. Between 1975 and 1984, the displacements caused by rifting totalled about 7 m.

The size of the Earth has not changed significantly during the past 600 million years, and very likely not since shortly after its formation 4.6 billion years ago. The Earth's unchanging size implies that the crust must be destroyed at about the same rate as it is being created, as Harry Hess surmised. Such destruction (recycling) of crust takes place along convergent boundaries where plates are moving toward each other, and sometimes one plate sinks (is subducted) under another. The location where sinking of a plate occurs is called a subduction zone.

The type of convergence -- called by some a very slow "collision" -- that takes place between plates depends on the kind of lithosphere involved. Convergence can occur between an oceanic and a largely continental plate, or between two largely oceanic plates, or between two largely continental plates."

Answer 3

no, the earth isn't expanding. the sea floor water is spilling due to global warming, if you know what it is.  

Answer 4

the Earth is growing and expanding rapidly by external accretion ( meteorites, dust and solar energy ) and internal core expansion

The ocean floors appear to be re-generating themselves through volcanic activity along the different oceanic ridges.

Answer 5

No. Sea floor spreading is caused by thermal currents in the earth's upper mantle. New oceanic crust is generated at mid-oceanic ridges, but the new crust formed in this way is taken back down into the mantle along subduction zones. Therefore there is no need for the earth to expand to accomdate the new crust formed.  

Answer 6

the plates are moving. that explains the sea floor expanding.