If there was a hole through the earth would you be
stopped in the middle due to gravity or would you fall straight through?
Asked by: Kirk Herren, 10 years old
All objects are attracted to the centre of the Earth.
If the hole runs through the centre it will be rather like pulling a pendulum to one side and allowing it to settle, the pendulum oscillating back and forth. Thus you would fall in a straight line accelerating towards the centre then deccelerating away from the centre until you, almost reach the other side of the earth and your velocity is zero. Then you will be drawn back, accelerating and deccelerating again, to almost where you originally fell. Each journey
back and forth like the pendulum gets shorter and shorter until you settle stationery at the centre of the earth. This is due to the fact that there is air in the hole which provides friction or drag. Such motion is called Damped Harmonic Motion (if the hole was in vacuum then your would not settle at the centre but would continue to execute a full simple harmonic motion)
Holes not going through the centre have similar effects but you would fall in a curve and bump the side of the hole half way down, as the earth trys to attract you to its centre. You will again end up half way down the hole but stuck to the side which is closest to the
Answered by: Don Bird, Berkshire UK
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '