Scientists practice for asteroid apocalypse

In seven years’ time, a space probe will crash into an asteroid in an attempt to change its path. It could stop us from being destroyed — but can we rely on scientists to save the world?

As the six-mile wide asteroid slammed into Earth, it released the energy of more than a billion Hiroshima bombs. It sent a huge ball of hot rock and vapour into space, which then fell back as super-heated particles. Powerful earthquakes rocked the world, the sun’s light was blocked out and wildfires raged. Sixty-five million years ago, the dinosaurs were doomed. One of history’s mass extinction events had begun.

A similarly-sized asteroid hits our planet roughly once every 20 million years, and several Hollywood blockbusters have explored our fear of destruction from the skies. Now the American space agency, Nasa, and their European counterparts have teamed up to do something about it. In October 2020, two spacecraft will take off to find out if they could prevent a collision.

The mission will meet Diddymoon, a 160m, egg-shaped asteroid, a year and a half later. The American ship will study it for a few months then fire a probe at it in an attempt to divert its path; the European craft will observe the impact from a safe distance. Diddymoon is not heading for Earth, but the mission may provide a blueprint for a response to such a threat to our existence.

None of the 872 known near-Earth objects larger than 1km are on course to hit us in the next few hundred years, but Nasa regularly discovers new asteroids and updates its research on those it is tracking. Earth is persistently bombarded from above. More than 100 tonnes of dust and sand-sized particles hit our atmosphere daily; small meteorites strike the surface about five to ten times per year; and near-misses from asteroids are fairly regular: this week, a 49m asteroid passed within 316,000 miles of us.

The mission is hoped to be the latest scientific advance to improve our chances of avoiding an apocalypse. Vaccination programmes could save us from a disease pandemic; green energy can reduce the impact of climate change; and while natural disasters remain unavoidable, improvements in predictive technology can help us prepare for them.

Others go further. The real threats to human existence are artificial intelligence, nuclear warfare and people mercilessly exploiting each other. In all three regards, science has made the destruction of the human race more possible, not less.

Deep Impact

We can be confident in science’s ability to save us, say some. It has always had an answer to humanity’s problems and when this mission is complete, we will even be able to avert danger from millions of miles away.

That’s complacent, say others; our knowledge of nature and physics is still so limited. Even medical advances which we now take for granted, for example, may soon be useless if bacteria develop resistance.

You Decide

  1. Is this mission a sensible use of time and resources?
  2. Will science prevent humans from becoming extinct?


  1. Create a logo for the mission.
  2. You are the head of a committee tasked with averting the apocalypse. Choose three threats to humankind and write a side of A4 on each, explaining how you would stop it from becoming reality.

Some People Say...

“Humans will cause their own apocalypse.”

What do you think?

Q & A

How likely am I to be hit by one of these space rocks?
Your chances are vanishingly small (about one in 250,000). You are more likely to die in an earthquake, tornado, flood, plane crash or car crash — although you are less likely to die from being struck by lightning.
Couldn’t I just survive the asteroid strike?
You’d have to be very well protected and have plenty of supplies, and then be able to start afresh once the climate had returned to relative normality. You’d have to consider how to get the basics you’d need: fresh water, food and shelter.
Where can I find out more about the skies above me?
Try the Royal Observatory or the Planetarium at Greenwich in south-east London, the astronomy museums in London and Bath or the Godlee observatory in Manchester.

Word Watch

Mass extinction events
There have been five periods in history when a large proportion of species have suddenly become extinct. The extinction 65 million years ago wiped out about three-quarters of species. The Great Dying, which took place 250 million years ago, was the worst in history, killing 96% of all species.
These rocks are mostly located between Mars and Jupiter and are not to be confused with comets, a mixture of ice and dust usually found on the edge of the solar system.
Hollywood blockbusters
Deep Impact and Armageddon were both released in 1998. But the fascination has extended further, as shown by the 1958 Italian film ‘The Day the Sky Exploded’.
These are small rocks which have broken off from asteroids or comets and hit the Earth’s surface. A similar rock which does not reach the surface is called a meteoroid. The light phenomenon seen when a meteoroid burns up is called a meteor.
In 2012, the closest asteroid flyby in history was recorded. A 45m-wide rock missed earth by 17,200 miles — passing within the orbits of many satellites.


PDF Download

Please click on "Print view" at the top of the page to see a print friendly version of the article.