The pulling force that keeps all matter together is called gravity. As the matter increases so does the gravitational force. The amount of matter in something is measured by mass. When things are huge they exert more gravitational force. A very good example of gravitational force is the force exerted by Earth. When we walk the earth pulls us towards it and on the contrary we pull the earth towards us. However since the earth is massive we are not able to move it. The earths force is much higher and is powerful enough to make a person face down.
Gravity depends on the mass and also the distance. This is exactly why we still remain on the earth and are not pulled out into space by the sun which has a gravitational force that is many times more powerful than that of Earth.
All about Space-time and its fundamentals
Things start and happen in space. Time is considered to be when these things happen. It is necessary to combine these two elements to actually understand the universe.
Another fundamental is that though light travels at 299,792,458 meters per second and you are in motion one might perceive that time travels faster which is not the reality
The Anti-gravity wheel
A wheel of 19 kg is lifted overhead using just one hand while the wheel is spinning at a few thousand RPM. The wheel at this point felt as light as a feather and this was due to the Gyroscopic precession.
The object’s weight produces a torque and this is why the wheel feels light when spinning. The torque vector is seen to increase the angular momentum in the same direction of the torque. Now when there is no angular momentum at the start, the new momentum will cause it to swing in the direction of torque. Now if there was an angular momentum at the start then the direction will be changed towards the angular momentum that causes precession.
Time travel by Stephen Hawking
Stephen Hawking researches the actual requirements for the concept of travelling time. He has provided detailed instructions to build a time travelling machine. He says that the requirements are very simple because it one takes a worm hole, a rocket or a large hadron collider to build the machine.
The premise is rooted in Einstein’s theory of relativity and Hawking believes that since time moves faster in certain places one can use this to move and travel to the future however impossible to travel to the past.