The effects of gravity There are some people who fear that when they are outside, if they don't keep a good grip on the ground, they will end up flying into space. They don't really have to worry about this, because gravity generally prevents this from happening. The fact is that no one is really sure what causes gravity, but the effects have been studied by many physicists and astronomers. Three of the most obvious effects of gravity are things falling, weight, and the moon and planets staying in their orbits. Things fall. People have generally come to accept that if you let go of your precious textbook while walking in a mud puddle, the book will invariably end up in the puddle and thus be stripped of all value and even readability. gravitational attraction between things of great mass, such as the Earth, and things of low mass, such as a book. The only problem with this relatively simple explanation is that no one really knows why this is the case. What people have understood so far is that gravity is a force, and a force is anything that changes an object's state of rest or motion. In the absence of external forces, the momentum of a system remains constant. This means that if there were no gravity, when you let go of the textbook, it would remain stationary in the air. If a force acts on a body, the body accelerates in the direction of the force. In the example of the force of gravity, small things like textbooks are pulled downward, towards the center of the great mass of the Earth, and not upward, although some people think this can happen. Torgerson 2Isaac Newton was the first to conceive of weight as the gravitational attraction between a body and the Earth. The force that results from the Earth's gravitational pull on bodies on its surface is what we call weight. Science has chosen to measure the mass of objects in units that are more or less equivalent to the weight of those objects on Earth. For example, if a textbook weighs four pounds on Earth, it would have a mass of four pounds on an orbiting spaceship. The textbook would be "weightless" because it is not affected by the gravitational attraction of the Earth, but, even in space, to push the