What is gravity? What is zero gravity? Why earth has gravity and moon has zero gravity?
Matter is what one can touch and feel. Where there is more and more matter there is more and more gravity. From Newton to Einstein gravity is defined in many ways and the ultimate findings is positioning of the planets around Sun and positioning of the planets between themselves. Because of gravity thing around us are not flying up, hitting each other and creating chaos. just by existing, you are compelled to move through space – this is gravity. ( source: http://math.ucr.edu/home/baez/physics/Relativity/GR/gravity.html ). One can feel gravity. The simple example is when you accelerate the car you will pushed backwards. This is because the car seat exerts force on you.
Zero gravity on the other hand is the state or condition in which there is no apparent force of gravity acting on a body, either because the force is locally weak, or because both the body and its surroundings are freely and equally accelerating under the force.
Moon also have gravity but much less to what earth has. It is because of less matter on moon. Some planets like mars have more matter and have more gravity compared to earth.
- Mercury: 38% of Earth’s
- Venus: 91% of Earth’s
- Earth: 100% of Earth’s (9.81 meters/second2)
- Mars: 38% of Earth’s
- Jupiter: 254% of Earth’s
- Saturn: 108% of Earth’s
- Uranus: 91% of Earth’s
- Neptune: 119% of Earth’s
- Pluto: 8% of Earth’s
Micro gravity on the other hand is less gravity or feeling weightlessness as astronauts feel in space..
So far people on earth have travelled to moon and experienced the gravitational hazards. They had fun on moon and and faced problems too. Now NASA research center found out that zero gravity will affect brain. Let us see the details.
Zero gravity will affect brain is the recent observation at NASA.
Once the space travellers come back to base station, NASA researchers observed problems in them with balance and perceptual illusions because of of microgravity in space. They conducted tests on structures in the brain and found that the perceptual illusion is due to lack of gravity reference in space, Seidler, principal investigator and director of the University of Michigan’s Neuromotor Behaviour Laboratory. said “On Earth, your vestibular – or balance – system tells you how our head moves relative to gravity, but in space, the gravity reference is gone”. These observations concluded that the brain experiences difficulty in coordinating movement of the eyes and head.As there is no up and down in micro gravity environment the space travellers find it difficult to cope up with the movements for example, switching back and forth between right-side-up and upside down. In order to help space travellers to cope up with microgravity hazards like coordinating movements between eyes and head, identifying and working with instruments in space , a series of tests are conducted before going to space, in space while on space craft and after landing back to earth.These tests help space travellers in their future explorations to Mars and other planets Source NASA.