Lithosphere for silicate rocks, and formula_4 is the age of the given part of the lithosphere. The age is often equal to L/V, where L is the distance from the spreading centre of mid-oceanic ridge, and V is velocity of the lithospheric plate. Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years but after this becomes increasingly denser than asthenosphere. This is because the chemically differentiated oceanic crust is lighter than asthenosphere, but thermal contraction of the mantle lithosphere makes it more dense than the asthenosphere. The gravitational instability of mature oceanic lithosphere has the
The Earth Museum are like lamps lighted where we need them most, illuminating what is around them and the way we need to go. The fuel of those lamps is the imagination. Thank you, my Turkish readers and friends and fellow-writers, for keeping the light burning."" (Ursula K. Le Guin, January, 2018) The Earth Museum features Burak Albayrak as the editor, Tuðçe Nida Sevin as the coordinator and includes a preface by Bulent Akkoc. The collection comprises the following short stories: The Earth Museum The Earth Museum () is an anthology of 18 science-fiction stories by 18 Turkish sci-fi writers published in January