Video Experimental Relacionado
Updated: May 7, 2026
09:44
Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System
Published on: June 5, 2014
El enfriamiento de la Tierra y la formación del núcleo después del impacto gigante
Bernard J Wood1, Alex N Halliday
1Department of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK. bwood@els.mq.edu.au
Nature
|October 28, 2005
Resumen
La Tierra La Tierra La Tierra La Tierra La Tierra
Área de la Ciencia:
- La geofísica es la geofísica.
- Ciencias planetarias Ciencias planetarias.
- La geoquímica es la geoquímica.
Sus antecedentes:
- Lord Kelvin estimó la edad de la Tierra en 24 millones de años basándose en el enfriamiento conductivo.
- El impacto gigante que formó la Luna alteró significativamente el estado térmico y la composición de la Tierra.
- Existen discrepancias entre los sistemas isotópicos U-Pb y Hf-W con respecto a las escalas de tiempo de acreción y segregación del núcleo de la Tierra.
Objetivo del estudio:
- Para explicar las diferentes escalas de tiempo derivadas de los sistemas isotópicos U-Pb y Hf-W.
- Para conciliar los primeros modelos de enfriamiento de la Tierra con la evidencia geológica e isotópica.
- Proponer un mecanismo para la segregación del núcleo en etapa tardía y su impacto en la edad de la Tierra.
Principales métodos:
- Análisis de sistemas isotópicos (U-Pb y Hf-W) para determinar escalas de tiempo.
- Modelado de los procesos de enfriamiento y segregación del núcleo de la Tierra.
- Investigando el papel de los impactos gigantes y la cristalización del manto.
Principales resultados:
- La escala de tiempo Hf-W refleja la formación del núcleo antes del impacto de formación de la Luna.
- La oxidación durante el impacto gigante condujo a la segregación tardía de un núcleo metálico rico en azufre.
- Esta segregación tardía, que ocurrió 30 +/- 10 millones de años después del impacto que formó la Luna, explica la datación U-Pb de la Tierra.
- La Tierra se enfrió en aproximadamente 4.000 K durante este período, alineándose con las estimaciones de enfriamiento de Kelvin.
Conclusiones:
- Un proceso de formación de núcleos en dos etapas concilia diferentes escalas de tiempo isotópicas.
- La oxidación y la segregación tardía de metales influyeron significativamente en la evolución térmica temprana de la Tierra.
- El modelo propuesto proporciona una comprensión más completa de la historia temprana de la Tierra y el enfriamiento.
Videos de Conceptos Relacionados
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
02:36Nuclear Power
Controlled nuclear fission reactions are used to generate electricity. Any nuclear reactor that produces power via the fission of uranium or plutonium by bombardment with neutrons has six components: nuclear fuel consisting of fissionable material, a nuclear moderator, a neutron source, control rods, reactor coolant, and a shield and containment system.
Nuclear Fuels
Nuclear fuel consists of a fissile isotope, such as uranium-235, which must be present in sufficient quantity to provide a...
Nuclear Fuels
Nuclear fuel consists of a fissile isotope, such as uranium-235, which must be present in sufficient quantity to provide a...
02:45Nuclear Fusion
The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
01:17Radiation: Applications
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...