All stars form from dust. In nebulae, dust gathers together into clumps, which collide and cling together to form an ever larger proto star. At this stage, the future star has no energy, it’s just a ball of ice and rock. Something happens as the proto star gets larger. At a certain point, the size of the star gets large enough that gravity begins to compress the center. As the star gathers itself from the surrounding cloud of dust, the pressure inside builds until the star lights. The light is actually atoms inside the star being crushed into energy.
In normal matter like iron, the atoms are fairly far apart. Matter is a surprising loose conglomeration of atoms. An atom is 99%… nothing. If we could blow up an atom’s nucleus to the size of a tennis ball, the electrons would orbit somewhere out by Jupiter. This is important to a star because it’s in the business of crowding atoms together until their electrons interfere with their neighboring atoms. As the star’s mass and gravity increase, the atoms at the center are forced closer together. As they “rub” together, they heat up until they start to break down, creating new elements and energy that expands. That’s the delicate balance that keeps a star together. Gravity wants to crush the star, fusion wants to blow it apart. These two forces keep the star in balance until hydrogen, a star’s fuel, runs out. That’s when gravity finally wins and crushes the star. A star’s death can take several forms, depending on its size.
It’s the balance inside a star that I was thinking about today. Energy escapes the gravity well of a star, but the matter being carried along with it gets pulled back into the center by gravity. There’s a metaphor for the way the Universe works in that balance.
We’ve wondered about the boundaries of the Universe since our first inklings of how big it really is. Red Shift tells us that galaxies are moving away from each other, accelerating outwards in all directions. Imagine that the Universe has a central gravity well like a star. It would be a black hole of immense proportions. Gravity tries to pull all the galaxies into that black hole, while an analog of fusion pushes them outwards. Galaxies are the atoms of the Universe in this model. Energy escapes from the Universe as energy escapes from a star.
Here’s where it gets even more speculative. Forces in the Universe are categorized as the “Weak force” (gravity) and the “Strong force” (Magnetism). Instead of just emitting energy like a star, the Universe could be emitting gravity. That would solve the problem of why gravity is so much weaker than magnetism… Gravity is emitted by the Universe, while the magnetism remains inside the Universe’s “corona”. If we someday discover a massive black hole out there somewhere, and determine that it lies at the “center” of the Universe, then we can ditch string theory and develop a new unifying theory of physics.
Just a thought.