## That’s not mass, it’s area. Poor science means bad reporting.

It will come from space, be as massive as half a football field, have the explosive power to decimate hundreds of square miles of land and will hurtle perilously close to Earth.

I cringed when I read this paragraph in a QMI story published in the London Free Press recently, titled “Rock of Ages: Killer Asteroid Likely to Pass in 2013.” So many mistakes in so few words. But it might be a great start for a Roger Corman B-flick script.

Of course, “it” will come from space: “it” is an asteroid. Asteroids, says Wikipedia, are, “…a class of small Solar System bodies in orbit around the Sun.” So it’s pretty obvious an asteroid can’t come from your basement, from the North Pole or from Ottawa.

“As massive as half a football field,” the writer declares. How massive is a football field? It isn’t massive at all. It has area, which is a measurement of its size in two dimensions, not mass. Mass, as Wikipedia says, has nothing to do with size: “In everyday usage, mass is often referred to as weight… In scientific use, however, the term weight refers to a different, yet related, property of matter. Weight is the gravitational force acting on a given body.”

Let’s get more technical, so we can be exact in our definition of mass: “…inertial mass, can be defined as a quantitative measure of an object’s resistance to the change of its speed.” An asteroid moving at an estimated 8.2 km/second certainly has inertial mass.

[pullquote]So many mistakes in so few words. But it might be a great start for a Roger Corman B-flick script.[/pullquote]Massive is an adjective that refers to mass, of course. So tell me, Terry Davidson, how you can measure the mass of a football field? What does a football field weigh? And is that an America, Canadian or Australian football field – because they are different sizes. The asteroid in question is estimated to be about 46m (150 feet) wide. But that doesn’t say anything about its mass which is also related to its density and speed.

Explosive power? Not really. Asteroids are not explosive, although impacts create explosions.

An explosion happens when the kinetic energy of the asteroid is converted to other forms of energy on impact. Until that moment, an asteroid does not have “explosive power,” just kinetic energy. Sometimes asteroids explode in the atmosphere as this one did over Indonesia, in 2009. But that’s a combination of rapid heat expansion, pressure and kinetic energy, not because the asteroid was “explosive.”

Decimate hundreds of square miles? Does the writer mean it will destroy every tenth square mile? The origin of decimate is Latin, and refers to a practice in the Roman Army of killing every tenth soldier as a form of punishment. Common usage means to “kill, destroy, or remove a large percentage or part of (something),” and “drastically reduce the strength or effectiveness of (something).” Decimate does not mean destroy everything.

It is called 2012-DA14, an asteroid that NASA scientists have been watching closely in anticipation of Feb. 15, 2013, when the mammoth piece of solid space rock will soar past the Earth a mere 24,000 kms from the planet’s surface. It will be passing even lower than the altitude at which many man-made satellites orbit.

Man-made. Bit of an anachronism, that term. I’m pretty sure there were also women working on some of those parts. I would have preferred “artificial” as a neutral adjective over the sexist “man-made.”

Mammoth? Compared to what? To a football field? It’s certainly bigger than the house Dorothy dropped on the Wicked Witch of the West, but compared to Ceres or Vesta? At 45-46m (150 feet), on the cosmic scale, it’s a pebble. It’s a fraction of the size of Asteroid 2005 YU55, which will whiz by Earth on November 8, about 319,000 kms away.

In fact 2012-DA14 is eerily similar to an asteroid that destroyed hundreds of square miles of forest in remote Siberia a little over a century ago.

In fact”? Since nothing has ever been found of the Tunguska meteorite, and certainly no sample has ever been taken of 2012-DA14, how can they be compared? Where are the “facts” about either? Many scientists believe the Tunguska event was caused by a chunk of comet, or even a micro black hole, not an asteroid. No one even knows the size of the rock that caused Tunguska, although there are educated guesses. We can only guess at any possible similarities; not state facts.

Eerily? What’s eerie about similarities between pieces of material? Eerily means, “…inspiring inexplicable fear, dread, or uneasiness; strange and frightening; suggestive of the supernatural; mysterious.” What is supernatural about a natural piece of space rock? Why would some physical similarity – size is the only property that can be estimated for both – instill dread or fear? Is it a haunted asteroid? Being “haunted” requires imaginary creatures called ghosts, not science.

The rock that exploded over Siberia, did so at an estimated 5–10 kilometres (3–6 mi) above the Earth’s surface, and likely on an impact trajectory. Asteroid 2012-DA14 will pass us by at 2,400 to 4,800 times that distance, and will not be aimed at the planet’s surface. These two are as “eerily similar” as the distance from my home to my town hall – about a mile – is similar to the distance from my home to Vancouver (about 3,500 miles).