⑴ 關於宇宙或太空的英語文章
為什麼引力在太空和在地球上一樣?
Why Is Gravity in Space Not the Same as Earth?
Every object in the universe pulls on every other object. This is called gravitation, or gravity. But the strength of that pull-- of gravity --depends on two things.
First, it depends on how much matter a body contains. A body (object) that has a lot of matter has a lot of gravitation. A body that has very little matter has very little gravitation. For example, the earth has more matter than the moon, so the earth』s pull or gravitation is stronger than the moon』s.
Secondly, the strength of gravitation depends on the distance between the bodies. It is strong between bodies close together. It is weak between bodies far apart.
Now let』s take a human being on earth. The earth has more matter than the human being, so its gravitation pulls him to the earth. But the earth behaves as if all its matter were at its center.The strength of gravity at any place, therefore, depends on the distance from the earth』s center.
The strength of gravity at the seashore is greater than at the top of a mountain. Now, suppose a human being goes some distance up into the air, away from the earth. The pull of the earth』s gravity will be even weaker.
When people go out into space, they are away from the earth』s gravitational field. There is no pull. They are in a condition of weightlessness. And this is why, in rockets and space capsules, weightless astronauts and objects float about in the air.
為什麼引力在太空和在地球上一樣?
宇宙中的每一個物體都將另一物體拽向自身。這叫引力。但那個拉力(引力)的強度取決於兩個因素。
首先，它取決於一個天體所含物質的多少。一個天體（物體）所含的物質多，它的引力就大。一個天體所含的物質很少，它的引力也很小。比如，地球比月球含的物質多，所以地球的拉力或引力就比月球大。
其次，引力的強度還取決於天體之間的距離。天體之間靠得越近引力就越強，相反，天體之間隔得越遠引力就越弱。
現在以地球上的一個人為例。地球比此人所含的物質多，所以它的引力把他牢牢地吸住。但地球的行為方式好像是，它所有的物質都集中在它並局的中心。因此，任何方位引力的強弱都取決於它同地心之間的距離。
海邊的引力就比山頂的引力要大賀則。現在，假設一個人離開地球，升到空中一段距絕拍讓離。地球對這個人的引力就會更弱些。
當人們進入太空，他們就離開了地球的引力場，那就沒有引力了，他們就處於失重狀態。這就是為什麼在火箭和宇宙飛船里，失重的宇航員和物體會在空中漂浮。
⑵ 急…！！！關於太空space的簡介！要英文的！！
This article is about the idea of space. For the space beyond Earth's atmosphere (as in astronomy and spaceships), see outer space. For all other uses, see space (disambiguation).
The idea of space has been of interest for philosophers and scientists for much of human history. The term is used somewhat differently in different fields of study, hence it is difficult to provide an uncontroversial and clear definition outside of specific defined contexts. Disagreement also exists on whether space itself can be measured or is part of the measuring system. (See Space in philosophy.) Science considers space to be a fundamental quantity (a quantity which can not be defined via other quantities because other quantities — like force and energy — are already defined via space). Thus an operational definition is used in which the procere of measurement of space intervals (distances) and the units of measurement are defined.
In philosophy
Space has a range of definitions:
* One view of space is that it is part of the fundamental structure of the universe, a set of dimensions in which objects are separated and located, have size and shape, and through which they can move.
* A contrasting view is that space is part of a fundamental abstract mathematical conceptual framework (together with time and number) within which we compare and quantify the distance between objects, their sizes, their shapes, and their speeds. In this view, space does not refer to any kind of entity that is a "container" that objects "move through".
These opposing views are relevant also to definitions of time. Space is typically described as having three dimensions, see Three-dimensional space and that three numbers are needed to specify the size of any object and/or its location with respect to another location. Modern physics does not treat space and time as independent dimensions, but treats both as features of space-time – a conception that challenges intuitive notions of distance and time.
An issue of philosophical debate is whether space is an ontological entity itself, or simply a conceptual framework humans need to think (and talk) about the world. Another way to frame this is to ask, "Can space itself be measured, or is space part of the measurement system?" The same debate applies also to time, and an important formulation in both areas was given by Immanuel Kant.
In his Critique of Pure Reason, Kant described space as an a priori intuition that (together with another a priori intuition, time) allows us to comprehend sensual experience. Kant referred to such intuitions as noumena and as things in themselves. In Kant's view, neither space nor time are conceived of as substances, but rather both are elements of a systematic framework we use to structure our experience. Spatial measurements are used to quantify how far apart objects are, and temporal measurements are used to quantify how far apart events occur. However, these measurements are applied by our minds to categorize what we sense and are not an inherent part of the thing in itself.
Schopenhauer, in the preface to his On the Will in Nature, stated that "space is the condition of the possibility of juxtaposition." This is in accordance with Kant's understanding of space as a form in the mind of an observing subject.
Similar philosophical questions concerning space include: Is space absolute or purely relational? Does space have one correct geometry, or is the geometry of space just a convention? Historical positions in these debates have been taken by Isaac Newton (space is absolute), Gottfried Leibniz (space is relational), and Henri Poincaré (spatial geometry is a convention). Two important thought-experiments connected with these questions are: Newton's bucket argument and Poincaré's sphere-world.
In physics
Space is one of the few fundamental quantities in physics, meaning that it cannot be defined via other quantities because there is nothing more fundamental known at present. Thus, similar to the definition of other fundamental quantities (like time and mass), space is defined via measurement. Currently, the standard space interval, called a standard meter or simply meter, is defined as the distance traveled by light in a vacuum ring a time interval of exactly 1/299,792,458 of a second. This definition coupled with present definition of the second is based on the special theory of relativity, that our space-time is a Minkowski space.
Before Einstein's work on relativistic physics, time and space were viewed as independent dimensions. Einstein's discoveries have shown that e to relativity of motion our space and time can be mathematically combined into one symmetric object — space-time. (Distances in space or in time separately are not invariant versus Lorentz coordinate transformations, but distances in Minkowski space-time are — which justifies the name).
However, time and space dimensions should not be viewed as exactly equivalent in Minkowski space-time. One can freely move in space but not in time. Thus, time and space coordinates are treated differently both in special relativity (where time is sometimes considered an imaginary coordinate) and in general relativity (where different signs are assigned to time and space components of spacetime metric).
Spatial measurement
The measurement of physical space has long been important. Geometry, the name given to the branch of mathematics which measures spatial relations, was popularised by the ancient Greeks, although earlier societies had developed measuring systems. The International System of Units, (SI), is now the most common system of units used in the measuring of space, and is almost universally used within science.
Geography is the branch of science concerned with identifying and describing the Earth, utilising spatial awareness to try and understand why things exist in specific locations. Cartography is the mapping of spaces to allow better navigation, for visualisation purposes and to act as a locational device. Geostatistics apply statistical concepts to collected spatial data in order to create an estimate for unobserved phenomena. Astronomy is the science involved with the observation, explanation and measuring of objects in outer space.
In geography
Geographical space is called land, and has a relation to ownership (in which space is seen as property). While some cultures assert the rights of the indivial in terms of ownership, other cultures will identify with a communal approach to land ownership, while still other cultures such as Australian Aboriginals, rather than asserting ownership rights to land, invert the relationship and consider that they are in fact owned by the land. Spatial planning is a method of regulating the use of space at land-level, with decisions made at regional, national and international levels. Space can also impact on human and cultural behaviour, being an important factor in architecture, where it will impact on the design of buildings and structures, and on farming.
Ownership of space is not restricted to land. Ownership of airspace and of waters is decided internationally. Other forms of ownership have been recently asserted to other spaces — for example to the radio bands of the electromagnetic spectrum or to cyberspace.
Public space is a term used to define areas of land is collectively owned by the community, and managed in their name by delegated authorities. Such spaces are open to all, while private property is the land owned by an indivial or company, for their own use and pleasure.
Abstract space is a term used in geography to refer to a hypothetical space characterized by complete homogeneity. When modeling activity or behavior, it is a conceptual tool used to limit extraneous variables such as terrain.
In psychology
The way in which space is perceived is an area which psychologists first began to study in the middle of the 19th century, and it is now thought by those concerned with such studies to be a distinct branch within psychology. Psychologists analysing the perception of space are concerned with how recognition of an object's physical appearance or its interactions are perceived.
Other, more specialised topics studied include amodal perception and object permanence. The perception of surroundings is important e to its necessary relevance to survival, especially with regards to hunting and self preservation.
Phobias include:
* Agoraphobia is a fear of open spaces.
* Astrophobia is a fear of celestial space.
* Claustrophobia is a fear of enclosed spaces.
* Kenophobia is a fear of empty spaces.
In anatomy
In anatomy, a space (or spatium) is an area of the human body with certain borders consisting of anatomic structures, e.g. the axillary space.