The Surprising Ways Earth Could Survive an Asteroid Strike
It’s widely held that it was an asteroid that doomed the dinosaurs; a
hurtling hunk of space rock that, around 66 million years ago, crashed
into Earth and rewrote the ecosystems of an entire planet.
Today, an asteroid impact is still something we to some
extent “plan’ for… but what says that we would fare any better than
the dinosaurs did?
This is Unveiled, and today we’re uncovering the extraordinary ways
that Earth could survive an asteroid strike.
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Asteroid strikes actually already occur with surprising frequency.
The size of the asteroid is what determines how
much damage it can do, with smaller impacts sometimes passing by
unnoticed.
But asteroids big enough to strike Earth with the force of a
hydrogen bomb reportedly happen every couple hundred years, or so.
One of the last events of this kind was in Siberia, in 1908, where there
were thankfully less people directly affected… but swap the remoteness
of Siberia for a city housing millions, and it’s clear there’s
the potential for catastrophe!
It’s thought that a city could fall to an asteroid that’s around 100
meters across.
Meanwhile, a one-kilometre rock could pack enough force
to destroy a wider region, perhaps a mid-sized country; and a
ten-kilometre asteroid could cause planet-wide devastation.
It’s proposed that the K-T mass extinction that
killed the dinosaurs, triggering the rise of the mammals, was caused
by an asteroid ten-to-fifteen kilometres wide.
Today, we have the Torino Impact Hazard Scale to quantify potential Earth-impact
risks on a scale of one-to-ten.
It says that events scoring “ten” on the scale occur once
every 1000,000 years.
So, are we in any imminent danger of being hit by a “10”, right now?
Well, no…
But there have been various “scares”, like in 2002 when we
sighted an asteroid which was deemed to have a chance of colliding
with Earth in 2019.
It would’ve been big enough to cause a major disaster, but luckily, it missed.
And, while we do have astronomers all around the world scanning the skies for
threats, there have also been some that we’ve missed - like in 2013,
when the Chelyabinsk meteor crashed into Russia, sending out a
shockwave that shattered windows and injured around 1,500 people.
No one saw that coming, once again proving how dangerous asteroids can
be… and how vulnerable Earth can suddenly become!
But there’s no need to overly worry, because we do spot most of them,
and NASA even has an impact risk page on its website, where you can
check to see the status of the asteroids currently being monitored.
One of the top impact risks listed right now is the asteroid Bennu,
which it’s predicted could potentially strike in around 2175.
But, say a big one slipped through the net…
Say an Earth-ending rock was suddenly spotted at close approach to
our planet…
How could we survive it?
We can’t outright “stop” an asteroid because they’re traveling too
fast, clocking speeds up to 55,000 miles per hour…
But we can try to alter its trajectory, with just a tiny nudge
being enough to drastically change its path.
How do we do that?
One way is with vehicles known as gravity tractors.
Gravity tractors are massive, sprawling machines which work by inflicting
on the oncoming asteroid a gravitational influence of their own.
Over years or even decades, this influence is enough to push the asteroid toward
a different, non-Earth-bound course.
It’s a method of deflecting the rock without actually touching it.
The only downside… is that gravity tractors are
totally theoretical right now.
A great idea, but if we learnt of a near-future impact tomorrow, they probably
wouldn’t be a lot of help!
Another perhaps less impressive but arguably more doable approach
would be to slow the asteroid down.
In this way, we wouldn’t be altering the space rock’s course, but were
we to slow it sufficiently, it could miss Earth anyway - because we’d
be at a different place in our orbit by the time it arrived at a slightly
later point.
In this case, we’d more simply need something - another
massive, remote-controlled spaceship, perhaps - to
crash into it… hopefully causing the rock to falter.
Even better, we could try bombarding one side of the asteroid with multiple ships,
all at the same time.
On the plus side, it could work.
On the downside, it could be dangerous, it definitely would be expensive and, well, it
might not work!
But there might be other ways of slowing it down without destroying
billions of dollars’ worth of our own equipment.
We could try firing paintballs at it.
Yep, this really is one proposed way of stopping an
asteroid!
Put forward in 2012 by MIT’s Department of Aeronautics and
Astronautics graduate Sung Wook Paek, the plan is that by pelting the
rock with white paint which, crucially, reflects the most light, we
could - theoretically - cause it to experience more “solar radiation
pressure”… which is a force exerted by the photons given out by the
sun.
It perhaps sounds farfetched, but we have already seen satellites
of our own being pushed ever-so-slightly by this phenomenon over long
periods of time.
Therein lies the downside, though, because it’s
estimated that paintballing an asteroid away from us would take around
twenty years to achieve.
It’s more feasible than some of the other options, but only if we have the time to make
it work.
So, we’ve tried diverting it, slamming into it and painting it…
Next, we’ll remove some of its mass.
In theory, if we could chisel enough of an asteroid’s surface mass away, we could
again change its trajectory.
And for fans of this method, the instrument of choice is almost always
a laser!
Were we to build a laser strong enough to heat the rock so
that parts of it began to dissolve, then the escaping gas could work
against it in space, acting like a thruster, to edge it toward a
different destination.
It’s a technique officially called “Asteroid Laser Ablation”, and it’s an idea which
is already genuinely being considered by the likes of NASA.
Of all the asteroid-averting proposals, this one is arguably the most likely
to actually get developed.
But if gravity tractors, paint-guns, and even lasers don’t work, what
then?
Desperate times really would call for desperate measures… in the
shape of atom bombs.
Here’s where the world’s space agencies would
need to tap into their inner-Bruce-Willis, with suggestions that we
really could blast an asteroid out of the sky… though not quite as
they do in the movies!
One idea says that if we could detonate a large
enough bomb close enough to an asteroid, we could both burn off some
of its mass and alter its path in one explosive move.
It’s easily one of the more unpredictable methods, however,
with one particularly glaring downside being the possibility that
we’d be transforming the asteroid into one massive shotgun blast - shooting
dozens of smaller but still lethal bits of rock toward Earth,
striking various locations that might’ve even been safe otherwise.
It’s lucky, then, that there are more than a few options to try out beforehand.
Were we ever to discover an asteroid heading straight for our planet,
it’d represent arguably the biggest technological challenge humanity
had ever faced to try and in some way avoid impact.
We do have at least some ideas on what we’d try to do
next, but those are the surprising ways Earth could survive an asteroid
strike.
What do you think?
Is there anything we missed?
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