Asteroids aren't the only thing we have to fear

Growing up in the 1970s and 80s, I remember "sandwich board men" walking around London, prophesying, "The End is Nigh." I was reminded of this the other day while watching a spy drama called The Game set in 1972. It was portrayed as an especially intense time during the Cold War, when the British were wrought with anxiety over the threat of a Soviet nuclear strike and the island's possible annihilation.

Forty years later, the Cold War's over, Britain's still in business (and clinging onto Trident, its form of nuclear deterrent), and I'm left wondering, "So how soon is nigh?"

Some would say it may be as soon as Tuesday, March 8.

Asteroid 2013 TX68

It happens quite a lot, but perhaps not as close as this: NASA estimates that on March 8, Asteroid 2013 TX68 will fly by Earth at a distance of about 3 million miles (5 million kilometers). That's a lunar distance of 13 LD.

"There is still a chance that it could pass closer, but certainly no closer than 15,000 miles (24,000 kilometers) above Earth's surface," says NASA.

That's a fairly big window of opportunity, and the closest - 24,000 kilometers - is pretty, pretty, pretty close. If Asteroid 2013 TX68 comes that close, it'll be dancing with orbiting satellites.

The good news is, NASA does not expect 2013 TX68 to impact Earth over the next century.

So why should I worry?

Well, it's up to you, obviously. But asteroids have wiped out life before. They regularly perform a flyby - as do other celestial objects. Some, becoming meteorites, impact Earth.

Asteroids are balls of ice and rock which leave home, often from somewhere in the Kuiper belt or between Mars and Jupiter, to come and orbit our sun. About once a year an asteroid the size of a car enters Earth's atmosphere and burns up before hitting the surface.

Asteroid 2013 TX68 is between 23 and 52 meters in diameter, which is small compared to some. This week, another near-Earth object one called 2007 DM41, which is also doing a flyby, is estimated to be 120 meters in diameter - but will be farther away. Then there's 2001 PL9, boasting a diameter of between 770 meters and 1.7 kilometers, on March 9… but that "close approach" will be at 77.6 LD. Bags of space.

But asteroids are a threat. We still believe an asteroid about 10 kilometers wide wiped out the dinosaurs. Not in one fell swoop, but it's thought that it caused their demise by first unleashing a global firestorm, then, with all the dust that created, the Earth experienced a mega cooling, possibly followed by a mega overheating, that few things could survive.

More recently, an asteroid hit Earth in 1908, causing devastation in Siberia. And in 1989, an asteroid passed through Earth's orbit. We missed each other by just six hours.

And what are the chances?

Hard to say. But if you're in need of entertainment, watch Stephen Petranek's 2002 TED Talk "10 ways the world could end." Asteroids are his number one. He quotes research by Dr Clark Chapman of the Southwest Research Institute, which suggests we have a 1 in 20,000 chance of being hit by an asteroid - the same as a passenger airplane crash.

Petranek's other top threats include:

10. We lose the will to live

9. Aliens invade

8. Ecosystem collapse

7. Particle accelerator mishap

6. Biopesticide disaster

5. Earth's magnetic fields reverse

4. Giant solar flares

3. Global epidemic

2. Rogue black hole

There are others Petranek missed or omitted. One example: the threat of a supervolcano unleashing an almighty cloud of ash over the planet so as to create the same effect that helped wipe out the dinosaurs.

Contagion: pandemic and pandemonium

Anthrax? Forget it. If anything, the past few years have shown diseases such as Ebola pose a greater threat to our survival as a species than doomsday predictions of terrorist acts involving biological warfare. We've known about Ebola for years, and yet we lack sufficient defenses. Why? Is it because of apathy, low commercial incentive, or incompetence?

Neil Gardner (@outsider63) responded to our Twitter poll with the following comment:

".@dw_scitech You failed to add my preferred choice: Stupidity. The biggest threat to human civilisation."

Neil, you may have a point.

So how about artificial intelligence (AI)?

This is the idea that robots will take over the world and kill all humans, presumably? Let's call it a fear.

Coupled with things like Moore's Law, which predicted computing power would increase at exponential rates, and Raymond Kurzweil's theorizing about an era of "technological singularity" - a time when we humans no longer comprehend our own progress - we've worked ourselves up into quite a state, haven't we? Some say the age of singularity has already begun to rear its head. Later this week, we'll see just how powerful artificial intelligence has become when AlphaGo (a computer) plays Lee Sedol (a human) in a five-game Go match. Some expect AlphaGo to win.

Science fiction has supped at the altar of artificial intelligence for decades - in novels such as John Brunner's "The Shockwave Rider" or William Gibson's "Neuromancer," or films such as Alex Garland's "Ex Machina." They paint real images, with lashings of fear.

There is every possibility this fear is just as much a figment of our imagination as those actual works of fiction. Despite the reams of academic analysis of the subject, who can say, with any certainty, whether robots will seize power and kill us? After all, aren't we humans the ones driving this development? If we fear it so much, why don't we just stop it?

At the same time, we are developing the ability to use our brains to control robotics. So rather than our dying out at the hands of evil robots, there's every chance we will see a fusion of humans and robots. Which could be pretty kinky, don't you think?