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Heliotropism, a form of tropism, is the diurnal or seasonal motion of plant parts (flowers or leaves) in response to the direction of the Sun. The habit of some plants to move in the direction of the Sun, a form of tropism, was already known by the Ancient Greeks. They named one of those plants after that property Heliotropium, meaning "sun turn".
A rendering of the magnetic field lines of the magnetosphere of the Earth. In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. [1] [2] It is created by a celestial body with an active interior dynamo.
The interaction between solar wind and geomagnetic field eventually combine to result in the formation of an electrical current layer, which is called the magnetopause. This electric current layer confines the Earth's magnetic field. The region in which the magnetopause is enclosed in is known as the magnetosphere. [7]
In such a field, if an ion or electron enters perpendicular to the field lines, it can be shown to move in a circle (the field only needs to be constant in the region covering the circle). If q is the charge of the particle, m its mass, v its velocity and R g the radius of the circle ( "gyration radius" ), all one needs do is notice that the ...
The plasmasphere, or inner magnetosphere, is a region of the Earth's magnetosphere consisting of low-energy (cool) plasma. It is located above the ionosphere . The outer boundary of the plasmasphere is known as the plasmapause , which is defined by an order of magnitude drop in plasma density.
These rapid plant movements differ from the more common, but much slower "growth-movements" of plants, called tropisms. Tropisms encompass movements that lead to physical, permanent alterations of the plant while rapid plant movements are usually reversible or occur over a shorter span of time.
If the pressure from particles within the magnetosphere is neglected, it is possible to estimate the distance to the part of the magnetosphere that faces the Sun.The condition governing this position is that the dynamic ram pressure from the solar wind is equal to the magnetic pressure from the Earth's magnetic field: [note 1] (()) where and are the density and velocity of the solar wind, and ...
It has been argued that for plants that display foliar nyctinasty, it is a crucial mechanism for survival; however, most plants do not exhibit any nyctinastic movements. [1] Nyctinasty is found in a range of plant species and across xeric , mesic , and aquatic environments, suggesting that this singular behavior may serve a variety of ...