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Gravity is a force of attraction that exists between any two masses, any two bodies, any two particles. Gravity is not just the attraction between objects and the Earth. It is an attraction that exists between all objects, everywhere in the universe. Sir Isaac Newton (1642 -- 1727) discovered that a force is required to change the speed or ...
A cluster of stars, dust, and gas held together by gravity. GAMMA-RAYS Penetrating short wave electromagnetic radiation of very high frequency. GEOSYNCHRONOUS An orbit in which a satellite's rate of revolution matches the Earth's rate of rotation. This allows the satellite to stay over the same site on the Earth's surface at all times.
3. Activity: Explain that the sheet represents spacetime, the large object represents the Sun and the smaller object represents a planet. Have the students pull the edges of the sheet outward. Make sure the sheet is taut. Roll the lighter balls across the sheet. Note how they travel in a straight line. Place the heavy object in the center of ...
GRAVITY The invisible force between objects that makes objects attract each other. GRAVITATIONAL PULL The attraction that one object has for another object due to the invisible force of gravity. H HURRICANE A very, very strong windstorm where the wind blows in circles at more than 46 kilometers per hour. Heavy rains often come with the winds. I J K
如何评价Jai Wolf的歌曲《Gravity (feat. JMR)》？. 知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见解，找到自己的解答」为品牌使命。. 知乎凭借认真、专业、友善的社区氛围、独特的 ...
Dark matter is composed of particles that do not absorb, reflect, or emit light, so they cannot be detected by observing electromagnetic radiation. Dark matter is material that cannot be seen directly. We know that dark matter exists because of the effect it has on objects that we can observe directly. Scientists study dark matter by looking at ...
It is 9.5 trillion (9,500,000,000,000) kilometers. The size of a galaxy may be as little as a thousand light-years across or as much as a million light-years across. A galaxy contains stars, gas, and dust which are held together as a group by gravity. There may be millions, or even billions, of stars in one galaxy.
Galileo designed a variety of scientific instruments. Among them was the hydrostatic balance. This was an instrument used to find the specific gravity of objects by weighing them in water. Go to Imagine the Universe! (A site for ages 14 and up.) The StarChild site is a service of the High Energy Astrophysics Science Archive Research Center ...
What makes the Sun shine? Answer: The simple answer is that deep inside the core of the Sun, enough protons can collide into each other with enough speed that they stick together to form a helium nucleus and generate a tremendous amount of energy at the same time. This process is called nuclear fusion.
It is in the clouds of dust and gas that stars are born. As more and more of the gas (which is mostly hydrogen) is pulled together by gravity into a cloud, the cloud starts to spin. The gas atoms start to bump into each other faster and faster. This creates heat energy. The cloud gets hotter and hotter. Finally, it gets so hot within the cloud ...
