As the report states it to be a failed star, I would set the probabilities of such a passing to be similar to the last time a full-blown star came too close to our Sun. As stated in my “If” post:

“WISE and Spitzer, and all others capable, will need to track this bit of flotsam to chart it’s proper velocity, to be checked against that of the local neighborhood.”

1) hardly likely in our lifetime
2) not a damn thing we could do about it anyway

We’ve got a lot more to worry about from the occasional unassisted meteoroid or comet impact event.

They are not only not perfectly conceivable in our lifetime, but we might just be able to take some action to detect, avoid the strike or mitigate the effects.

As for Bowser’s paranoia, there’s still plenty for him to worry about, and us too. This is an election year.

Not to sound all mystical, but gravity binds all things. In cosmic billiards, the stars are pockets, and we live next to a cosmic sinkhole.

Close only counts in horseshoes and cosmic billiards. You don’t have to hit things in cosmic billiards to move them. How close would a mass 10 superjovian have to pass to Earth to perturb its orbit enough to tip the balance of climate change? Or swing it too far the other way into a permanent ice age? Forget getting flung into the cold interstellar night, even a tiny tweak to its orbit could render our planet uninhabitable.

I’ll give you credit for giving gravity a small pat on the head when you invoked the image of a hailstorm of comets. That’s not nothing. That’s a dinosaur killer waiting to happen. A superjovian passing through the solar system would break the table like god’s own cue ball.

Never thought I’d read myself saying this, but perhaps bowser’s right to be paranoid.

The close encounter with one of these dudes we’re most likely to have will probably be a near miss–one will fly through the Oort Cloud and shake a few comets loose to rain down on the inner solar system. It would take centuries to play out, and, assuming our current level of astronomical knowledge, we’d be well aware of what was going on. In fact, this isn’t even a new conspiracy theory, check out the “Nemesis” bogeyman that was circulating a few years ago.

And then things like this come along, out of our blue, never considered, and could be flooding the area. One big jostle from a galaxy or cloud could send it scooting our way. Now something 3 to 10 times the size of Jupiter is going to be hard to corral and control, would raise all kinds of hell if it got near us, let along transited the Solar System.

Maybe they should just stop looking, or reporting and let me go back to the quiet peace of my childhood where there was empty space out there with nothing lurking to clobber me when my back is turned.

Still, these observations are difficult to carry out, involve many risky assumptions, and have large uncertainties associated with them. Infrared astronomy is a very powerful tool, with many SETI applications: technology generates heat, and heat is detectable through IR.

Tip of the iceberg indeed…

If this is simply a rogue gas giant, roaming between the stars, then there may again be many, many others on similar voyages.

WISE and Spitzer, and all others capable, will need to track this bit of flotsam to chart it’s proper velocity, to be checked against that of the local neighborhood.

The RASC list for 2014 lists the 50 stars (and their stellar and planetary companions) known to lie within 5 parsecs (16.3 ly) of Earth. Of course, this list includes only objects, (faint stars and brown dwarfs) bright enough to be detectable in visual light–and it makes no claim to being complete. This new object, detectable only by using extraordinary technology due to its extreme cold, is nearer than all but three of the stars on the RASC catalogue: Sol, The Alpha Centauri triple system (4.24 ly) and Barnard’s Star (5.98 ly). See the movie I posted of Barnard’s in the thread on “proper motions”, below.

This dark and cold little visitor may indeed be an escaped gas giant planet from long ago and far away, or it may be a representative of a very common and highly numerous new class of object. We know the Mass Function for stars (the number of objects plotted against their mass) increases explosively for smaller masses, but the shape of the curve is poorly understood because faint brown dwarfs are difficult to detect and study unless they are relatively nearby. Those too cool to emit any visible light, like this one, are cloaked to our view. We can’t rule out they may be the most common objects in the Universe, far outnumbering stars or bound planets! They are, in spite of their numbers, collectively such a small fraction of the total mass of the galaxy that they give no gravitational clue to their numbers. For a while, it was thought that the galaxy’s “missing mass” could be explained by vast populations of these guys roaming around in space, but this possibility was ruled out for a variety of other reasons.

So what is this object? In appearance, something very similar to Jupiter or Saturn, a cold gas giant, but with no nearby star to illuminate it. At one time it might have glowed feebly with the leftover gravitational energy of its initial contraction from its primordial nebula. But that has long since radiated way.

The question remains, is this guy an outlier, a fluke, or is it just the first discovered of an extremely numerous stellar population we never even suspected existed? The more we learn about the Galaxy, the more complex and wonderful it seems to get.