White and yellow daisy type flowers remind me of sunshine. The dark leaves could be space and the greenery earth. Strange how a picture of petals and leaves make me think if the universe.

We need light to live. Heat from the sun warms us enough to keep the planet temperate. Light allows plants to photosynthise and create Oxygen. Without sunlight we would just be a lump of rock and frozen gasses in the infinity of space.

But it goes further than that…. the first chemical that was present after the big bang, was Hydrogen. Atoms of hydrogen were pulled together by gravity to form stars. Stars are nuclear reactors, the more hydrogen they gather from surrounding clouds of gas, the heavier they get. Eventually nuclear fusion begins and the stars light up. Hydrogen atoms join together and create Helium….

After a while (a few billion years) the stars will have converted most of their Hydrogen to Helium, and further pressure changes that to heavier atoms, from Carbon, upwards in increasing atomic weight. Eventually the star is a cinder of Iron.

But once a star is mainly burning Iron atoms, it needs to use more energy to turn the Iron into heavier elements than the Iron can provide. The energy from it also helps keep the layers of material in the star supported, or expanded. The pressure of radiation and photons of light hold the layers of star plasma up.

Then the star uses up all its fuel . If it is small nothing much may happen and it just burns out. But if it is large enough the pressure from radiation and light is not enough to hold up against the force of gravity which is trying to make it collapse.

The inward pull of gravity can make all the atoms collapse inwards, making a neutron star. A tiny ball of it will weigh a massive amount.

But if the old star is heavy enough it continues to collapse, then the energy created by the collapse can cause the stars outer layers to explode outwards. This may be a Nova, or Supernova. Supernovae create a flash of light that can be as bright  as a whole galaxy.

If the star was even bigger it can collapse completely and create a black hole. In that case the gravity of the black hole will not allow matter or light that comes close to it to escape. There is a complete absence of light.

Funny what thinking about daisies can do to you.

Apologies to the physicists, chemists and biologists out there for my rambling explanation. I’m short on facts and figures but I do like to think about these things.

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