Why can we not prove the existence of planet 9?
Astronomers and astro-physicists have for at least 70 years had good reason to believe in the existence of an extra planet in our solar system, beyond the furthest known planet. This is known as planet 9. But currently there is no definitive proof. It has not been detected. However, the eccentric movements of known dwarf planets and other objects way way out there are very good indications of something with a large gravitational field influencing this behaviour and thus the scientific opinion is that there is a substantial planet.
The nearest star to Earth, other than our Sun, is a distance of 4.2 light years away and we can not only detect but even discern some of the fundamental characteristics of its 7 planets. So, given that planet 9 is estimated to be one light week from Earth why can we not definitively detect it?
A light year is defined as the distance that light can travel in a year at its speed of 186,282 miles per second. Voyager One is the fastest space craft ever built, currently travelling at 38,000 miles per hour. At that speed it would take 70,000 years to reach the Proxima Centauri solar system.
