* Solar Wind: The Sun constantly emits a stream of charged particles called the solar wind. This wind pushes on the dust and gas in a comet's coma (the fuzzy atmosphere around the comet's nucleus).
* Radiation Pressure: The Sun also emits light, and this light exerts a slight pressure on the comet's dust particles.
* Combined Effect: The combined forces of the solar wind and radiation pressure push the dust and gas particles away from the Sun, forming the comet's tail.
The tail doesn't point towards Earth because Earth's gravity doesn't have a significant impact on the tail's direction. The Sun's influence is much stronger.
Important Note: There can be a *secondary tail* pointing away from the Sun and slightly towards Earth. This is caused by the interaction of the comet's tail with Earth's magnetic field. However, this tail is usually much fainter and less noticeable than the main tail.
