It is inconceivable that something as big as a jetliner could disappear from the face of the Earth just like that.
It is even more inconceivable that a Boeing 777 could vanish in a modern world where everyone and everything is digitally connected, where surveillance is the norm and the US National Security Agency has the technology to track everyone all the time.
Or is it really?
Since the disappearance of Malaysia Airlines flight MH370 and the international search effort that ensued, we have come to learn that the world is not as small as we had thought. Things can still get lost.
But in a world of Foursquare and social media, such a vacuum cannot simply be accepted. There has got to be something weird and out of the ordinary happening, right?
The clairvoyant theory
With Occam's Razor discarded, people in general began seeing all kinds of signs and portents, even in something as unconnected to the disappearance as a 2012 Pitbull-Shakira song, Get It Started. The lyrics No Ali/No freezer/But for now, off to Malaysia were perceived to have been prophetic, seeing as "Mr Ali" was the nickname given by the British media to one of the Iranian passengers with a fake passport.
The 9/11 theory
Two Middle Eastern passengers with fake travel documents onboard MH370 certainly got Islamophobic and racist conclusions going - not least the cart going beyond the horse with the idea that the plane was hijacked, landed in Pakistan, and the Taliban were loading bombs onto it to be flown into Israel for a 9/11-type attack.
This is no thanks to retired US Air Force Lt Gen Thomas McInerney who brought up the whole Pakistan theory on the American TV show Hannity.
The Lignet website, run by former US intelligence personnel, had this to say: "Israel is taking the possibility of a terrorist attack seriously by mobilising air defences and giving extra scrutiny to approaching civilian aircraft, according to the Times of Israel ... a Boeing 777 requires a lengthy, 7,500-foot runway, and Pakistan has many of them ..."
And McInerney chimed in: "When the US Navy quits their search, their ship search, they must know something in the Indian Ocean. When the Israeli defence forces, when they increase their defence alert, they must know something."
And media mogul Rupert Murdoch also had his say on Twitter with tweets on "jihadists", "Muslim extremist threat", "northern Pakistan" and "Bin Laden" to fuel a world already on edge.
The cloaking device theory
American TV and radio host Glenn Beck highlighted that there were 20 employees of Texas-based Freescale Semiconductor on board. It seemed that there was a cloaking device involved, one created by the company and coveted by China. Things were starting to take on a techno-thriller angle.
But then the theory came from "citizen news website" Beforeitsnews, which ran the piece with a reference to a Fox News report on stealth technology to give it some credence.
And some of Beforeitsnews' top articles include Michelle Obama is a man and Aliens are hiding in the Vatican.
The fearsome weapon theory
But more ominous is another "news" website called Natural News which stated that there is something even more sinister going on.
"The frightening part about all this is not that we will find the debris of Flight 370; but rather that we won't," Mike Adams wrote on Natural News.
"If we never find the debris, it means some entirely new, mysterious and powerful force is at work on our planet which can pluck airplanes out of the sky without leaving behind even a shred of evidence. If there does exist a weapon with such capabilities, whoever controls it already has the ability to dominate all of Earth's nations with a fearsome military weapon of unimaginable power."
'The pilot did it' theory
If these tabloid-style websites were peddling far-fetched conspiracies, other respectable publications offered their more palatable theories or speculations.
The Wall Street Journal first reported that counter-terrorism officials in the United States were investigating whether the plane was "intentionally diverted" and "with the intention of using it later for another purpose."
The New York Times also reported US officials as saying the flight-path diversion was "most likely programmed by someone in the plane's cockpit who was knowledgeable about airplane systems."
This comes as investigations are underway on the flight crew, most notably pilot Capt Zaharie Ahmad Shah who was found to have a flight simulator in his home.
While this fuels further speculation, especially when five airports found on the simulator included those in Sri Lanka and southern India, Acting Transport Minister Datuk Seri Hishamuddin Hussein stated that "the passengers, cabin crew and pilots remain innocent until proven otherwise."
The fanatic theory
Tenuous links have been made of Capt Zaharie with the Opposition, largely due to a photograph of the pilot wearing a "Democracy is dead" T-shirt.
Foreign publications such as the UK's Daily Mail irresponsibly dubbed the flight captain a "fanatical" missing airliner pilot.
A slight twist came recently with a theory put forth by Canadian pilot Chris Goodfellow, which was picked up and published by Wired magazine. Goodfellow stated that the plane had probably caught fire and Capt Zaharie was only doing the right thing, diverting the plane back towards Langkawi to try and land it there.
The hero theory
Although Goodfellow's take on the missing plane has since been negated by others, owing to the zig-zagging course that the plane took and his insistence that everyone on board had passed out due to smoke, his "startlingly simple theory" has one thing others have not - it puts the pilot and his crew in a positive light.
Goodfellow wrote: "It serves no purpose to malign pilots who well may have been in a struggle to save this aircraft from a fire or other serious mechanical issues. Capt Zaharie Ahmad Shah was a hero struggling with an impossible situation trying to get that plane to Langkawi."