Nước là thành phần rất cần thiết cho sự sống, chưa từng phát hiện sự tồn tại của nó trên bề mặt của bất kì hành tinh nào khác. | 174 The Core boundary and can investigators better resolve this interaction with seismic-wave studies Although it is clear that the inner core is anisotropic the cause of this anisotropy remains problematic. Another area about which scientists know little is the rate at which the inner core is crystallizing and how it crystallizes. Is crystallization episodic resulting in sudden bursts of heat loss or is it uniform and gradual This could be important in understanding mantle-plume events which may be triggered by sudden losses of core heat. Although investigators are beginning to understand the geodynamo in more detail to make significant progress on this question three-dimensional simulations are needed which will require significant time on high-speed computers at great expense. So unlike our understanding of the crust and mantle which have been significantly enhanced in the last decade the information highway for the core is just beginning to open. Further Reading Buffett B. A. 2000. Earth s core and the geodynamo. Science 288 2007-2012. Dehant V. Creager K. C. Karato S. and Zatman S. 2003. Earth s Core Dynamics Structure Rotation. American Geophysical Union Washington D. C. Geodynamic Series Vol. 31. Jacobs J. A. 1992. Deep Interior of the Earth. Chapman Hall London 167 pp. Merrill R. T. McElhinney M. W. and McFadden P L. 1996. The Magnetic Field of the Earth. Academic Press New York 531 pp. Newsome H. E. and Jones J. H. eds. 1990. Origin of the Earth. Oxford University Press Oxford UK 378 pp. Tromp J. 2001. Inner core anisotropy and rotation. Ann. Rev. Earth Planet. Sci. 29 47-69. The Atmosphere and Oceans 6 Introduction Not only in terms of plate tectonics is the Earth a unique planet in the solar system it also is the only planet with oceans and with an oxygen-bearing atmosphere capable of sustaining higher forms of life. How did such an atmosphere-ocean system arise and why only on the Earth Related questions are once formed how did the atmosphere and oceans
