How long would it take to reach planet 9?

Some researchers believe that a hypothetical Planet 9 could be discovered in just a few years. If so, how long would it take for humans to send probes to this world?

An elusive planet

Planet 9 is a hypothetical world believed to exist on the edge of the Solar System, far beyond Neptune. The first ones clues to its existence were discovered by observing the behavior of several trans-Neptunian objects that appeared to be affected by the gravity of a massive, yet unidentified celestial body. These objects indeed appeared follow irregular trajectoriesas if a much larger planet was influencing them with its gravitational force. According to calculations and simulations, Planet 9 is assumed to be a giant planet, probably gaseous or frozen type with an estimated mass between five and ten times that of Earth. She would have a very elliptical and elongated orbitwhich would make it out of sync with the orbits of other known planets in our Solar System. Naturally, the search for this hypothetical world has mobilized several teams of researchers and astronomers around the world. Despite numerous attempts to observe it directly using ground-based and space-based telescopes, it remains elusive. Technological advances, including improved observation instruments such as the Vera C. Rubin Observatory, scheduled for 2025, could nevertheless provide additional data to confirm or deny its existence.

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A long trip

Once detected, provided it is one day, the interest in sending a probe to this distant planet will of course be inevitable. A question then arises: how long would it take to reach it if we find it? In 2022, researchers tried to answer itAccording to their estimates, a probe similar to NASA’s Voyager probes could put between 45 and 75 years old to cover the assumed average distance of 400 astronomical units to this planet. As a reminder, one astronomical unit is equivalent to the distance from the Earth to the Sun, or approximately 150 million kilometers. Thus, 400 AU represents approximately 60 billion kilometers. However, recent revisions suggest that the true distance may be closer to 500 to 550 astronomical units. Comparatively, Voyager 1, the most distant spacecraft from Earth, is currently about 163 AU away after 46 years of mission. This indicates that to reach Planet 9 in the same time frame, a probe would have to travel much faster than Voyager 1. Advanced technologies such as light sailswhich could potentially reduce the travel time to just seven years, are notably being considered for the future, although their development would still require several decades. As you can see, the discovery and exploration of Planet 9 would represent a major scientific challenge that would be very difficult to meet for the generations concerned.