Dangerous Environment for Planetary Systems
Our solar system is located in a comparatively sparsely populated neighborhood. Systems in the center of our galaxy, on the other hand, are much more frequently exposed to encounters with other stars, which can have a devastating effect on the stability of the systems.
When astronomers estimate the potential habitability of an exoplanet, they usually first measure the distance to its parent star, because this gives information about the temperatures to be expected. If the planet is too close to the star, the radiation is too great and the planet too hot. Water, which is considered the ideal medium for the emergence of life, would evaporate under these circumstances.
On the other hand, if it were too far away, the water would freeze, and under either circumstance, life forms are unlikely to emerge. While this consideration provides a first indication of the possibility of life on a planet, the length of time it takes for life to emerge must also be taken into account. The climatic conditions on earth were stable enough for life forms to develop over a period of three to four billion years and also to adapt to warm and cold periods.