Since the beginning of the space age, many observations sharply contradict the theories of a gravity-dominated Cosmos, yet recent observations have created even larger holes in those theories. Now it is impossible to cover these holes with any theoretical solution, such as the so-called red giants.
According to the consensus model, a star becomes a red giant in the later part of its life. In this stage, most of the fuel powering nuclear fusion in the core of the star is exhausted. As a result of this deficiency, “gravitational collapse” is induced. In other words, the star would collapse on itself due to a lack of light pressure which is pushing out against the force of gravity.
When this self-collapse takes place, it heats up a shell of hydrogen that surrounds the core. That heat would be sufficient to reignite fusion reaction, causing the star to become bigger as a result of increased light pressure and this process would make the star 1 000-10 000 times more luminous.
However, almost 60% of red giants exhibit variations in their luminosity. The difference in brightness happens over a period of several months to a few years. The Long Secondary Period (LSP), which involves the changing brightness of the star over a longer timescale, remains a mystery. All proposed explanations of this mysterious variability fail to agree with the data of recent observations.