Scientists have now witnessed the formation of new planets. Does this evidence disprove the Big Bang theory?
Not at all. In fact, they could provide evidence that supports the Big Bang theory.
The Big Bang theory describes the origin and evolution of the universe. It begins with a singularity, where the entire universe existed at a single point. The universe then rapidly expanded, and continues to expand to this day.
After the initial inflation event, the universe began to cool, and about 300-500 million years later, the first stars, made almost entirely of hydrogen and helium, began to form. Many of these stars were incredibly massive, much more so than our sun. When they died, their supernovas seeded galaxies with atoms of heavier elements, the products of stellar fusion.
These atoms eventually collected into nebulas, which would collapse to form new stars and solar systems. Our sun for instance has elements inside of it that could not have been fused in its core. Heavier elements are also found in the planets, asteroids, and other bodies in our solar system. Therefore, our sun must be a second or third generation star, forming out of the exploded material of the stars that came before.
Since solar system formation is therefore an expected consequence of the Big Bang theory. We should expect to find new planets and stars forming out of the remains of previous stars.