Short summary: it's an entertaining but rather far fetched proposal in an arxiv preprint not published anywhere but mentioned in a Scientific American op ed. Implausible for many reasons including its spectrum which is not the shiny spectrum you'd expect from a solar sail but the red of tholins mixed with rock and metal as you'd expect from an asteroid / comet.

I am getting many people contacting me scared of this asteroid, which was proved to miss Earth back on 1st August 2002! Right now, it is coming from below Earth's orbit, but not directly towards us. We are circling the sun at the same time. It crosses Earth's orbit ahead of us. By the time we get to the place where our orbits cross, it is already high above our orbit and moving away. It will be closest on 13th January, but even then it is at a vast distance of 61 million kilometers away. We already knew this back on 29 July, 2002,

This is a rather fun idea by Peter Koch originally suggested in the Moon Miner's Manifest Classics - 1987-1988 (see page 31). It's not so likely in the early stages, because of the large amounts of water needed to construct it, but it may perhaps be of great value at a later stage, especially for bases that have a lot of traffic in and out. If the liquid is water, it has to be over sixty meters deep (62.3 meters), to equalize the pressure inside and outside the habitat. The depth can be much less, if it is a denser fluid. You then don't need any doors but can just dive through it and come out on the surface of the Moon.

The basic message of the IPCC report is that we need to act now before 2040, to avoid more expensive mitigation measures in the last 60 years of the century. The worst effects are for 2100. And that if we aim for 1.5°C, it is far better than 2 °C.

Just before the flyby of Pluto by New Horizons I wrote a speculative fun article about whether it could spot moonlets of Pluto’s moons. Can Moons Have Moons? Or Rings? Theoretically it seems possible that moonlets just possibly might be dynamically stable, there as with many of the moons of our solar system such as the more distant moons in the Saturn system.

Does this discovery of 'The Goblin make 'Planet 9' more likely? Yes I’d say so. It’s looking really strange. I’m beginning to be won around to the idea :). There is plenty of space for planets to exist beyond Neptune. No known big gas giants to get in their way. And - objects get far far fainter the further they are from the sun. It was hard to find, even though it was only 80 au from the Sun - at it's furhest it would be 2300 au away. They spotted it first in 2015 and it's taken since then to figure out its orbit.