Adam Hibberd
Around the middle of last year I read an article by Siraj and Loeb in which they analysed closely a database of bolides (which are meteor fireballs) maintained by NASA-JPL CNEOS (Center for Near Earth Object Studies).
In so doing they identified at least one bolide as having an interstellar origin (designated CNEOS 2014-01-08). Could it be interstellar? There is a great degree of scepticism in the field concerning such an attribution as I explain in my recent paper, here.
This stimulated me to take a look at this database myself to see what I could make of it, without ever having the intention of going into the depth of analysis conducted by Siraj and Loeb.
At this point, something occurred to me. 'Oumuamua, the first interstellar object ever discovered, came within only 0.16 au from Earth and missed us by a hair's breadth. Could there be a meteor listed in this CNEOS database which was ejected from 'Oumuamua and instead of flying past, intercepted Earth?
I discovered that if such a piece of 'Oumuamua was flung out, then the least ΔV to intercept Earth would necessitate an arrival on or around October 9th 2017, and this was the case for a wide range of possible ejection times.
I then put my little diversion to one side and returned to more pressing matters.
However you may have noticed a few weeks ago, Loeb's much-publicised exploits near Papua New Guinea, where he claimed to have discovered debris in the form of metallic spherules at the bottom of the ocean below the path followed by their proposed interstellar meteor in 2014.
This prompted me to look back at the research I had conducted into data from the CNEOS catalogue a year earlier, to see whether I could find anything new. To my surprise I unearthed something I had originally overlooked.
There was in fact a bolide over Bolivia, South America, observed by satellite on exactly the expected date of 9th October (which I shall dub henceforth CNEOS 2017-10-09). Was this object indeed from 'Oumuamua?
I make the case in the paper but it seems to me the likelihood is rather low.
You see because the ΔV (the velocity change) needed from 'Oumuamua was small, then it does not necessarily follow, ipso facto, that there would be an increased likelihood of it originating from 'Oumuamua. In fact, wouldn't it be just as likely any bolide originating from 'Oumuamua would have a higher initial ΔV?
The argument that a small ΔV from 'Oumuamua makes it more likely to be from 'Oumuamua, is very much suggestive that it was sent on its way intentionally, controlled in such a manner that the ΔV was a minimum to reach Earth.
For example one possible interpretation would be that the bolide was actually a probe sent from 'Oumuamua to intercept Earth, thus requiring a minimum fuel or energy (so minimum ΔV) to achieve this goal.
That seems rather unlikely to me, but there is another possibility. If this object came from a fragmentation event where the ejection velocities were relatively small, then that would mean that any object reaching Earth might necessarily have a small ΔV required from 'Oumuamua.
Whatever the case, it seems to me that the paper is rather speculative as it stands and is on a rather precarious foundation. What is needed is more analysis to establish whether other meteors (including micrometeoroids) might also have come from 'Oumuamua. That's work to do.
