Jellymatter

A NASA research satellite is spinning out of control and is due to crash-land today.  The satellite, which weighs 20,000 tonnes and could easily be mistaken for a small moon, is expected to explode in a deadly fireball of fiery death, engulfing an area of at least 500 square kilometers.  Its malfunctioning weapon systems were designed to target cities, and NASA expects it to obliterate one with an expected population of just over two million.  Unfortunately, because of the battle station’s unpredictable trajectory, they won’t know which population centre is doomed until about two hours before it hits, leaving precious little time to evacuate the area.  A NASA spokesperson was unavailable for comment on why a research satellite needs to be so big, how such a gigantic object was launched into Earth’s orbit, or why its trajectory is biased towards built-up areas.  However, they did release an estimate that your personal probability of being one of the millions who perish in this impending disaster is 1 in 3200…

…or at least, that’s what I was able to deduce from a news report on (Australian) telly the other day, which quoted the 1 on 3200 figure and then ran a whole segment on how much more likely you are to be hit by this satellite than to be struck by lightning, win the lottery, etc.

Of course, in reality, the 1 in 3200 figure is the probability of the debris from the falling spacecraft hitting some person, somewhere in the world, i.e. there’s a 3199 in 3200 chance that it will just plop into the ocean or crash in some unpopulated area and not hit anyone at all.  Since there are seven billion people in the world, your chance of being the one person who does get hit is 1 in 22 trillion.  You’re more likely to win the lottery and get struck by lightning than you are to be struck by debris from this particular piece of falling space hardware.  All of which was completely obvious to me the moment the news anchor quoted the figure – with just a tiny bit of thought it should have been obvious to them as well.