We turned to Paul Delaney, senior lecturer in astrophysics and astronomy at York University, to explain.
1) What is Planet 9?
“They’re speculating that a number of objects that are located in the outer solar system ... (have) got all the characteristics of being influenced by the existence of a much larger, more massive object, and they’ve now speculated that that object is about 10 times the mass of the Earth .. and they’re suggesting it could be (Planet 9).”
2) Why do we not know for sure?
“Haven’t seen it. In science, you’ve got to be able to say ‘You see that little point there? That’s it!’ And be able to define its various characteristics.
The gravitational influence of this object is what is giving rise to the orbital parameters of a number of objects in the outer solar system.
And while that is quite persuasive, it is certainly short of saying Planet Nine exists. Until we can actually literally take a photograph of it and at least confirm the existence of a point that is comparable in size to what they’re suggesting.”
3) If it is a gas giant, could we stand on it?
“Oh heck no. No, no, no. Definitely not. We’re not talking about any of the terrestrial planets. You can walk around on Pluto, that would be fine. But no, you’ll never be able to walk on the surface of Jupiter, Saturn, Uranus, and Neptune and if our speculation is correct, Planet Nine is similarly unobtainable as far as walking on the surface.”
4) How do we go looking for it?
“We’re talking about an object that is, give or take, 100 billion kilometres from the Sun. And it’s orbiting with a period of between 10,000 and 20,000 years. So it’s going to be faint, because it’s so far away, and it will move very slowly because of its distance from the Sun. So both of those attributes conspire to make it a big challenge from observational astronomers to find it.”
5) Could we physically reach it?
“Getting there physically with a probe with our current technology? You and I will not see that day, I’m sorry. We just don’t have the technology. We can’t get a spacecraft moving fast enough to get out there in a reasonable period of time and expect the spacecraft to still be fully functional.”
This artistic rendering provided by California Institute of Technology shows the distant view from Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. (R. Hurt/Infrared Processing and Analysis Center/Courtesy of California Institute of Technology via AP)
