Updated in November 2014
A small celebrity in the scientific community since the 80s, the hypothetical Nemesis is just as famous among the non-specialists, at least after the publication of Richard Muller’s book. Since then a series of articles have been then written about the subject and, in 2011, astronomers had finally the opportunity to investigate more seriously its existence by going infrared.
Nemesis, aka The Death Star. What‘s so infamous about this space object to have it nicknamed in such an unflattering way? And yet, instead of the cruel sister of the Greek Goddess of Justice, this ghost star should have been called the Fist of God or Beware you Earthlings, if the theory is right. According to Dr. Muller, Nemesis is responsible of many of the big planetary catastrophes – from the sudden death of the dinosaurs to the Tunguska impact (no, not of the subprime crisis.) Exactly how, it’s another story: is it due to its own motion? Has been ejected from the galactic core at some point (yes, it happens sometimes)? Unclear. According to its supporters, however, Nemesis does affect the trajectory of the Oort Cloud’s comets and “slingshot” them towards the solar system. A few crash to Earth wreaking havoc. Or something like that.
(Credit: NASA)
Appealing (or scaring) this idea may have been, until a few months ago a chorus of denials surrounded the Death Star. The first argument against it actually makes a lot of sense: if such an object exists and is located…wherever it’s supposed to be, it wouldn’t be able to remain there very long. Given the attraction of other stars and passing objects, its orbit would be extremely unstable, and, being a relatively small star, it would most likely be captured by others. Bye bye Sun, then.
Moreover there are no proofs of regular impacts on the Earth’s surface to support the disaster theory; and, by using the Bayesian analysis’s approach, some researchers have heavily chastised this human-biased pattern detection in the paleontologists’ claims of cyclical extinctions. Extinctions by asteroids, maybe so, but 27 million year cycles remain to be seen, and they don’t seem very likely either by looking at fossils (For more, see this. This one is also interesting for more scientific analysis). Eventually, with yet no direct observations whatsoever, Nemesis looked very much on its path to join Nibiru (also called Planet X , with a rich story on its own) in the graveyard of non-existing astral bodies, only good for conspiracy theories and paranormal activities.
But humans are a stubborn species. And, as usual, absence of proof is not proof of absence. The idea itself of a far relative of our main star is enticing. So the quest, in a minor tone, kept going. Also because, statistically speaking, the likelihood of having a twin is high. Binary stars are quite common in our galaxy (a brief look at some of the well-known main stars of famous constellations easily supports this point) so a sister star somewhere in space is less far-fetched than it may seem. And some of the star couples or triplets are far away one from another. Thus the fact that efforts to locate our twin have been unsuccessful doesn’t mean a great deal by itself, especially if the star in question is a red, or worse, a brown dwarf. It’s this last aspect that reopened the star hunt.
(Credit: NASA)
In a recent infrared chase a certain amount (an impressive 173) of brown dwarfs have been located, far more numerous than previously believed. One of them may well be Nemesis, after all.
Enters Sedna. Discovered by Michael Brown at Caltech in 2006 – an interesting story in its own right – it has reinforced claims of Nemesis’ existence. “Sedna simply shouldn’t be there”, Brown has allegedly said many times. The trans-Neptunian planet’s position can only been explained by the gravitational pull of another body.
There is more. Compiling data collected over two years, astronomers from Penn State University have located this year what it looks like the Sun’s nearest star (6.5 LY), apart from Alpha and Proxima Centaury (4.3 LY) and Barnard’s Star (6 LY). Unsurprisingly, a binary brown dwarf, with the rather unsexy name of WISE 1049-5319.
A body of evidence for Nemesis then? Not really.
Luhman himself has excluded WISE 1049-5319 could actually be the infamous Death Star; its movement on the sky is just too fast for what we should expect in that case.
SEDNA (Credit:NASA)
And for what concerns Sedna, it’s important to notice that Brown has never officially supported Nemesis. In his own view, Sedna’s puzzling orbit is rather due to the gravitational pull of transient stars passing near the Solar System. Considering the planet’s unusual long and elliptical orbit – around 12 K years and up to 975 AU, the average Earth-Sun distance – this may well be the case.
So far – science. What about fiction, speculative or not? Unsurprisingly, rogue stars enjoy, and since a while, certain popularity in literature.
The first one worth mentioning is obviously the 1897 H.G Wells’ short story The Star, in which a rogue star almost destroys Earth. A few inconsistencies in its mathematical foundations don’t spoil its charm – sci-fi has not to be hard in order to be enjoyable. (You may want to have a go at it). But Nemesis is not – the one portrayed by Wells is not the Sun’s twin.
In Rogue Star (1969), Pohl and Williamson describe instead the unlikely love between a god-like, sentient celestial body and a human girl (gosh…. I will write about this trilogy one day or another. I did like it, it’s just that last twist left me with hangover!) A nemesis of a different kind indeed. The book with the same title but published a few years later (1998) by Michael Flynn is somehow more classical sci-fi (even though the main character Mariesa somehow puzzles me) and portraits Earth-threatening asteroids. Another Rogue Star, this time by Murray Leinster, and included in the collection Twists in Time (1960) is closer to H.G. Wells scenario.
The doomsday’s plot is a favourite in the genre, and I will avoid here mentioning the other rogue, outer space objects menacing humanity, be them planets as in Leiber’s The Wanderer, or the comet of Lucifer’s Hammer (simply love this one!) Too many, even if some made excellent stories.
And what for Nemesis itself – do we have at least one named this way? Yes, we actually do, and funny enough, its fate turns out just the same way than in real life – or sort of. In Asimov’s Nemesis, one of his last books written in 1989, a star called Nemesis is threatening to destabilise the gravity in the Solar System with dire consequences. But the fictional red star was, again, no companion for the Sun, just (another) transient celestial body. Apparently, sci-fi writers still needs time to pick up the “real” – if we can call it this way – Nemesis as subject for a story.
Controversy over its existence continues, with rather undeterred ufologists and cosmophobia-prone individuals clinging to it like creeper plants. Even the 2012 Mayan Apocalypse has been conveniently delayed for some decades – time enough for the Death Star to do some nasty work in our system. Take your pick.
In the meantime, WISE, the NASA’s Wide-field Infrared Survey Explorer, reactivated in August 2013 for an exploratory three-year mission on asteroid threat, will keep sniffing around and hopefully locate comets and moving objects that present a potential danger to Earthlings. One day it may well stumble on Nemesis, for the good and bad of it.
Update, November 2014: Nemesis is for now remaining undetected, but candidates for a (giant) Planet X beyond Pluto are multiplying. Apparently, there might be two of them, lurking in the depth of the Kuiper Belt. I have not to add here that Planet X has been rife with conspiracy theories on its own. I am going to write a post on it soon, but for the moment have a look at this one.