Voronwë the Faithful wrote:
Though I still think that Pluto should be promoted back to being a planet and we should go back to talking about Planet X.
It would actually become Planet XI, as promoting Pluto would mean promoting Eris as well. But yes, it was convenient when Planet X was actually Planet X.
Primula Baggins wrote:
It's very, very, very far away—if the closest it gets to the sun is 200 times farther from the sun than we are, that's 18.6 billion miles. The farthest point from the sun would be well over 100 billion miles out. And its "year" is 15,000 of our years, so it hasn't been at its nearest point to the sun in all of recorded human history.
And it's dark out there! Planets don't glow, so we can only see it by reflected light from the sun, which is very dim at that distance—at closest approach, less than a ten-thousandth as bright as sunlight on Earth. At the farthest range of its orbit, the sun's irradiance is less than a billionth what it is here. So it will be a tricky challenge to spot it.
This will be particularly true if it's dark (assuming it exists). Most of the distant objects that we've found are fairly reflective. Pluto is beige (something that we now know thanks to New Horizons
!), Eris seems to be nearly white, and Sedna is red like Mars. If Planet 9 is an ice giant and is a darker blue than Neptune, it will be very hard to find.
ETA: And we've observed a black gas giant
in transit across its star in another solar system, so it's not impossible.
Primula Baggins wrote:
This is pretty exciting stuff. And Túrin, your summary was very clear and concise. Have you considered blogging (or do you already)? With your book coming out, it would be a good way to connect with readers and build your "platform," which seems to be required these days. You have a big accumulation of worthy posts on this board that would let you get a good start without the need to focus on it daily.
I have considered it (and I've been a blogger in the past). I've found two issues, though - one is that my last site got hacked and taken down, so I'd need to sort out security, and the other is that most successful blogs I know and/or follow have a particular theme (and hence a readership) and I'm not sure what mine would be. My interests jump all over the place.