More about “Nothing” : Some Notes from the Book
- If an atom is 99.9999999999999% empty space, what does that tell you about the universe? It is mostly Nothing.. Matter Wise.
- “Atoms as huge voids may be true as concerns the particles within them, but that is only half the story: their inner space is filled with electric and magnetic force fields, so powerful that they would stop you in an instant if you tried to enter. It is these forces that give solidity to matter, even while its atoms are supposedly ‘empty’. The fields within atoms are over a thousand times greater than we can achieve in macroscopic technology, though they are restricted to atomic dimensions “(Close, Frank (). Nothing : A Very Short Introduction. Oxford, , GBR: OUP Oxford, 2009. p 28.)
- Does this remind you of s’akti, or sacI?
Magnetic Field :
- “Electric charges in motion give rise to magnetic forces whose effects can spread over vast distances as in the case of the magnetic field of the Earth. The molten metal core of our planet swirls as we rotate, the heat disrupting its atoms so that their electrons flow freely. The resulting electric currents make the Earth into a huge magnet with north and south poles, and with magnetic arms that stretch out into space. Far stronger than the Earth’s gravity, its magnetic field will deflect a small compass needle.” (Close, Frank (). Nothing : A Very Short Introduction. Oxford, , GBR: OUP Oxford, 2009. p 35.)
Gravitational Field :
- “Gravity is the most familiar force but it is actually rather feeble: it is easy to pick up an apple, defeating the gravitational pull of the entire planet. Our muscular strength comes from the much more powerful electrical forces, which give us shape and form. However, the attractions and repulsions from positive and negative charges within matter annul one another, whereas the gravitational attraction from each and every atom in a large body adds up. Gravity rules once an object is larger than about 500 km in diameter.
- The basic idea is that there is a kind of tension existing in otherwise ‘empty’ space that manifests itself by producing forces on objects that happen to be in the vicinity.
- This means that we could contemplate a region of space devoid of all material bodies but it would not be empty if there were even just one more body elsewhere in the universe: the gravitational field from that remote body would fill all of the otherwise ‘empty’ region. (Even that single body might not be required. According to Einstein’s theory of general relativity, energy in all its forms creates gravitational fields)”. (Close, Frank (). Nothing : A Very Short Introduction. Oxford, , GBR: OUP Oxford, 2009).
ElectroMagnetic Waves :
“The speed that water waves travel depends on the distance between successive peaks and troughs (the wavelength); in contrast all electromagnetic waves travel at the same speed – the speed of light. This is always true, whether you are travelling towards or away from the source. This sounds paradoxical: were you travelling away from the light source at nearly light speed yourself, you would expect that the light would only slowly overtake you; however, it rushes past at light speed itself. This bizarre phenomenon would lead Einstein to his radical new theory of space and time, special relativity
- Gravitational fields are also capable of giving waves, at least in theory. So what are these gravitational waves ‘in’? According to theory they are ripples in space-time itself.” (Close, Frank (). Nothing : A Very Short Introduction. Oxford, , GBR: OUP Oxford, 2009)
- “Newton envisaged some absolute space and time – a metaphorical grid of invisible measuring rods defining up– down, left– right, and front– behind: the three dimensions of space. Bodies that are at rest or in ‘uniform motion’ (i.e. not accelerating) relative to this moved according to his laws of motion. This grid formed the mental construct of what is known as an ‘inertial frame” (Close, Frank (). Nothing : A Very Short Introduction. Oxford, , GBR: OUP Oxford, 2009).
A planet moving in a circle around the Sun is not an inertial frame.. there is a centripetal force that is making it change its direction and hence its velocity every second.. even if its speed remains the same.
- “As we are trapped in the Earth’s gravitational field, subject to its gravitational force, we are not in an inertial frame even when at rest on the Earth’s surface. To make matters worse, we are orbiting the Sun subject to its gravitational whim. In practice the idea of an inertial frame is illusory. Yet in some ‘common sense’ manner we intuitively understand it as an approximation to an ideal, which for practical purposes enables precise computations and predictions to be made.” (Close, Frank (). Nothing : A Very Short Introduction. Oxford, , GBR: OUP Oxford, 2009).
Notes Compiled by Satya Sarada Kandula : All Rights For Sourced Material Vest With the Source