Not too long ago (May 17, 2020), various tabloids such as the UK’s Daily Star ran stories that claimed “NASA scientists detect parallel universe ‘next to ours’ where time runs backwards“. It was all over the place. Except … if you hit pause, you would soon realise that all you really had were various tabloids such as the New York Post and the Express all simply quoting each other as a “reliable” source.
What was actually going on was not “evidence” of a parallel universe, nor was it “evidence” of time running backwards. All they had done was to grab an actual observation of something odd, and then spun it all the way to Narnia and beyond.
Would a tabloid simply make stuff up without fact checking?
Well yes, that is perhaps akin to asking if Bears are Catholic or if the Pope … well, you know the rest.
To answer it, simply pick any tabloid and then read the Wikipedia page that describes it. Take for example the Daily Star Wikipedia page. There we find multiple examples of them simply generating fiction and promoting it as factual news.
What is the real backstory
To be wholly fair, the actual fault perhaps rests with New Scientist publishing a rather lurid headline that reads “We may have spotted a parallel universe going backwards in time” on April 8, 2020. Alas, the tabloids ran with the headline without really understanding what was actually going on.
It all basically boils down to these scientific papers …
- A research paper from the ANtarctic Impulsive Transient Antenna (ANITA). This is a balloon-based experiment that found “upward-pointing cosmic ray-like-events.”
- A what-if research paper published in response; one of many. This one is of immediate interest because it mulls over the thought that the ANITA results could provide evidence for a “CPT symmetric universe,” where time would run backwards from the Big Bang and where antimatter would dominate. This is the alpha source for the “parallel universe” claims.
- A research paper published in The Astrophysical Journal from the IceCube Neutrino Observatory explaining that they could not explain the ANITA observation and so suggested that we need to consider alternative explanations. (IceCube actually detected nothing, we will come to that further down)
The only solid empirical data was an observation concerning Neutrinos that nobody could explain. The rest was speculation.
What did Ibrahim Safa, the guy who made the original ANITA observation, think of the tabloid stories when they came out?
Basically this …
So what is really going on here?
The actual ANITA detection event was in 2016 … four years ago. They detected Neutrinos that appeared to be coming up out of the ground and rising upwards rather that coming down from the sky.
Scientific Interpretation: This observation of “upward-pointing cosmic ray-like-events.” is odd, we don’t know why it is happening.
Tabloid Interpretation: Grabs some of the wild what-if speculation and declares that this is “evidence” of a parallel universe where time flows backwards (Hint: No, it is not)
The IceCube Neutrino Observatory gets involved
OK, let’s briefly dig into the third paper I mentioned.
One idea is that what was detected might have actually passed right through the planet. The IceCure Neutrino (located in the Antarctic) attempted to look for an intense Neutrino source that might be responsible for something like this.
Did they find one?
Nope, in their press release last Jan they explain their results …
The collaboration found that these neutrinos could not have come from an intense point source.
OK, so no solution. They also added this within that same press release …
Other explanations for the anomalous signals—possibly involving exotic physics—need to be considered.
Do we have a solution?
Sometimes we might have something that we simply can’t explain, and might never be able to explain.
Then again, sometimes somebody might actually come up with a reasonable answer.
On April 24, 2020, just a couple of weeks ago, this research paper emerged …
Reflections on the anomalous ANITA events: the Antarctic subsurface as a possible explanation
In this paper, we study subsurface reflection, which can occur without phase inversion, in the context of the two anomalous up-going events reported by ANITA. It is found that subsurface layers and firn density inversions may plausibly account for the events, while ice fabric layers and wind ablation crusts could also play a role. This hypothesis can be tested with radar surveying of the Antarctic region in the vicinity of the anomalous ANITA events. Future experiments should not use phase inversion as a sole criterion to discriminate between down-going and up-going events, unless the subsurface reflection properties are well understood.
In other words, the actual hypothesis here is something very simple.
The anomalies are not from neutrinos, but are merely unflipped reflections of the ultra-high-energy cosmic rays that arrive from space — miss the top layer ice — then enter the ground, striking deep, compacted snow known as firn.
“We think sub-surface firn is the culprit, firn is something between snow and glacial ice. It’s compacted snow that’s not quite dense enough to be ice. So, you can have density inversions, with ranges where you go from high density back to low density, and those crucial sorts of interfaces where this reflection can happen and could explain these events.”
Ian Shoemaker, one of the papers co-authors, isn’t railing ANITA.
“Whatever ANITA has found, it is very interesting, but it may not be a Nobel prize-winning particle physics discovery.” But he’s not discounting that the so-called anomalies have no scientific merit. “ANITA still could have discovered something interesting about glaciology instead of particle physics, it could be ANITA discovered some unusual small glacial lakes.”
“When cosmic rays, or neutrinos, go through ice at very high energies, they scatter on materials inside the ice, on protons and electrons, and they can make a burst of radio, a big nice radio signal that scientists can see. The problem is that these signals have the radio pulse characteristic of a neutrino, but are appear to be traversing vastly more than is possible given known physics. Ordinary neutrinos just don’t so this. But cosmic rays at these energies are common occurrences and have been seen by many, many experiments.”
Is this the end game
Nope. That last paper is currently a working hypothesis. It can be tested. Radar surveying of the Antarctic region in the vicinity of the anomalous ANITA events can be used to check for firn. If it is there, then this looks like a good simple explanation. If not, then the mystery still prevails.
So far there have been something akin to 40 papers offering wildly different answers that strive to explain the observation. Many mulled over some truly weird and wonderful stuff .. “dark matter”, the long sought-after “fourth” neutrino known as the sterile neutrino, an entirely unknown frontier of particle and/or astrophysics physics, etc…
Yet here we now have something far simpler. Not yet confirmed, but very viable and testable.
We might indeed desire and crave for the truly unknown and strange, but often the simplest solution is most likely to be the correct one.
Your homework for today is to google Occam’s razor