The event horizon is the boundary beyond which an event cannot affect or be observed by an observer. Information about an event, or light from it, reaches an observer at the speed of light. Therefore, if the source of the event is moving away from the observer faster than the speed of light, or if […]
The change in living things over long periods of time. Evolution is the change in inherited traits as a population of organisms passes through generations. Inherited traits encompass all levels of change, from changes in DNA sequences to life forms and social behaviors. The process of evolution has led to diversity at many levels. Not
Atomic nuclei are made up of protons and neutrons. When protons and neutrons combine to form an atomic nucleus, the ratio of protons to neutrons creates either a stable or unstable nucleus. An unstable nucleus gives off alpha particles (two protons and two neutrons), electrons, electromagnetic waves (gamma rays, X-rays, and neutrons), and changes into
What is radiation and how do we measure it? Read More »
La luz del Sol es la fuente de la vida. Reconocemos la importancia del Sol y trabajamos para entender cómo funciona, por qué cambia y cómo nos afectan estos cambios en la Tierra. Veamos algunas de las diferentes actividades del Sol Las manchas solares aparecen y desaparecen Cuando observamos la superficie del Sol, vemos unas
¿Qué hace el Sol? Read More »
Newton descubrió la gravitación universal observando cómo caÃa una manzana de un manzano. Probablemente hayas oÃdo la historia del descubrimiento de la gravedad universal por Newton y te hayas preguntado: “¿Qué es esta fuerza que hace caer las manzanas?” La gravedad es la suma de la gravedad universal y la fuerza centrÃfuga causada por la
La ingravidez no es la ausencia de gravedad Read More »
What is it? Swells are commonly known as surface gravity waves. These series of surface gravity waves are not pointed wind waves caused by neighboring local winds, but rounded waves caused by distant weather systems. Waves usually have a long wavelength, but this is dependent on the size, strength, and duration of the weather system
A sidereal month is the time it takes for the moon to change phases once. While the Moon revolves around the Earth, the Earth also revolves around the Sun, so after one sidereal month, the Earth is about 27° more orbited around the Sun. Therefore, for the moon to be in the same phase, the
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The interior of the United States consists of a vast, irregular lowland stretching from the Gulf of Mexico to the Canadian border and continuing into Alaska. Geographers interested in the development of the landscape divide these broad plains and gently rolling hills into three geomorphologic regions: the Atlantic and Gulf Coastal Plains, the Inland Lowlands
Geography and Natural Environment of the United States Read More »
The aurora borealis and the northern lights are two of the most spectacular weather phenomena in the Arctic. While Antarctica also has aurora borealis and white nights, the phenomenon is often thought of as unique to the Arctic because it is not possible to experience them except for researchers living there. Greenlandic natives use the
The Arctic dreams of auroras and midnights Read More »
Earthquake precursors are events that precede an earthquake, and are known to begin days, months, or even years before an earthquake occurs. Some of the known seismic precursors include animal behavior, changes in groundwater levels, certain radio waves, and seismic light, but it has not yet been scientifically proven that these events are directly related
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