He realized (意识到) that there must be some unseen force (力量) pulling the apple towards the ground. He called the force "gravity (地球引力)".Newton then started to watch other things carefully. He learned that the Moon circles the Earth and that planets (行星) go around the Sun. He...
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The summer solstice marks the official start of astronomical summer and the longest day of the year. It occurs when one of Earth's poles is tilted toward the sun at its most extreme angle, and due to Earth's tilt, this happens twice a year. In the Northern Hemisphere, the summer solsti...
Using the lunar calendar, it falls on the 15th day of the eighth lunar month. Eating moon cakes is a must during this celebration. Both in spring and fall, Neo-Druids visit Stonehenge to watch the equinox sunrise to give thanks for the harvest and prepare for the coming winter. The ...
How long does it take to get to the moon? Distance to Mars: How far away is the Red Planet? Mars is the fourth planet from the sun, and the second closest to Earth (Venus is the closest). But the distance between Earth and Mars is constantly changing as they orbit the sun. In...
During the evening and night, the earth becomes colder, but our air temperature might be slightly higher. When the humidity is close to 100 percent, water molecules, called vapor, begin to collect droplets and fog is formed. Spring, summer and early fall mornings are usually the time fog is...
. That's because the days start to get longer as Earth moves from thewinterseason tospringandsummer, with the longest day of the year on the summer solstice. During the summer season in each hemisphere, Earth, which revolves around its axis at an angle, is tilted directly toward the sun...
Similarly, the ISS and its inhabitants fall towards the Earth at the same rate. What ensues is akin to two objects gradually rising in an unleashed lift racing down its shaft. Deprived of any underlying surface to rest on, an object feels weightless. In fact, our weight is nothing but the...
Cloud seeding adds more of those particles to the air. Aircraft fly through existing clouds and inject the tiny particles, like silver iodide, with the goal of creating more water or ice droplets. In any cloud, once enough droplets merge, they become heavy and fall to the Earth as rain or...
The underlying theory is that the lunar cycle affects plant growth; that just as the moon’s gravitational pull causes tides to rise and fall, so it also affects moisture in the soil. This effect is believed to be strongest during its waxing phase, the two weeks between a new and a full...