
An Asteroid Could Destroy the World Before Impact - longdefeat
https://lithub.com/how-an-asteroid-could-destroy-the-world-before-impact/
======
btilly
Mistake #1, the idea of a "risk corridor" applies to an object in a decaying
orbit. It will hit somewhere along the line of orbit. But for an object coming
from out of orbit, there is a center of where it is likely to hit, and then a
bell-shaped curve across the cross-section of the Earth for where it might.
Basically half the world is at risk, with some areas at higher risk than
others.

Mistake #2, objects that we find which could hit us get within range of our
rockets only a finite number of times. For a previously unknown large object
with a several year returning orbit, that finite number is likely to be 2 -
once when we found it and once when it comes back (at which point it is too
late). A more realistic version would be that it is on a long trajectory that
will hit Earth after 3-4 times. Which gives us a lot longer to prepare, and a
clear timing on when we want to try to hit it.

I won't comment on the cultural mistakes. Except to note that "We're going to
get hit but odds are good that it is over water and nobody gets hurt" might be
less panic inducing than the story claims.

~~~
T-A
> the idea of a "risk corridor" applies to an object in a decaying orbit. It
> will hit somewhere along the line of orbit

It also applies to asteroids, and is a standard concept used in these
scenarios. See e.g. the materials from the exercise at this year's Planetary
Defense Conference [1] (the story on LitHub is basically a variation on that
scenario, which also features an asteroid splitting in two during the
deflection attempt, a failure to use nukes, and a city destroyed by the
impact: New York).

> objects that we find which could hit us get within range of our rockets only
> a finite number of times

There are more and less viable launch dates, clustered in launch windows, but
the details vary depending on your vehicle and the orbit. JPL's NEO Deflection
App [2] has several illustrative examples which you can play with, and which
work pretty much as in the story.

[1]
[https://cneos.jpl.nasa.gov/pd/cs/pdc19/](https://cneos.jpl.nasa.gov/pd/cs/pdc19/)

[2] [https://cneos.jpl.nasa.gov/nda/](https://cneos.jpl.nasa.gov/nda/)

~~~
btilly
Huh, that is bizarre. How does this square with my understanding that the path
is off by something close to a normal distribution?

I guess that the big question mark is time. If we know the path of the
asteroid very precisely, and the path of the Earth very precisely, but we
don't know exactly when the asteroid goes down that path, it would result in
something like a risk corridor depending on where the asteroir was between
leading and trailing the Earth at the point of impact. I wouldn't (in fact
didn't) guess that.

Thank you for the references!

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lucb1e
I don't really understand the title. Before I call clickbait, how did this
destroy the world? Sure, house prices will fall in the predicted impact zone,
people will panic and create shortages of essentials in a much wider region,
and the worldwide economy is set back by a decade or two. But destroying the
world before impact? What?

~~~
jaysonelliot
It really is clickbait.

Nowhere in the article does it talk about "destroying the world." You'd
suppose they were referring to some kind of near-miss from a massive body
causing, I don't know, gravitational forces or something.

What it's actually saying is that there would be a lot of panic in the run-up
to an impact, so that even a relatively small event could cause oil prices to
spike and real estate values to drop in the impact area.

Hardly anything at all like the headline suggests.

~~~
jandrese
Worse than the possible destruction of life is the destruction of _money_.

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feral
Not a specialist, but I don't buy this.

In this story, they have a 6-year warning of an asteroid with 35% chance of
700megaton impact.

I just know that with that lead time, and with such an aligning mission,
humanity would be able to do amazing things.

The Apollo program was from JFKs speech in '61 to moon in '69, and that's
built on a '60s technological and social infrastructure. We have tons more
brainpower and tech now, globally.

This scenario would just be so politically aligning we'd be able to mobilize
massive resources to stop it in that timeframe; way more than 6 launches. I'd
be much more concerned about one they didn't see until 6 months out or
something.

~~~
arkades
At six years out, it’s unclear where the asteroid will strike. You think
Americans will throw their national budget behind doing “amazing things” for
the Caribbean?

~~~
tyingq
How localized would the effects of a 700 megaton impact be?

~~~
SEJeff
Horrible mental exercise...

As localized as a 700 megaton nuke (compared to the 13-18 kiloton nuke that
his Hiroshima). Reliable sources say that virtually everything within a 3 mile
radius from the impact was heavily damaged in Hiroshima and everything within
1.6km / ~1 mile radius was obliterated so you should be able to extrapolate
from that.

For comparison, the entire USA is ~3.797 million sq miles, so the equiv area
of 184.35 entire United States would be utterly obliterated.

    
    
        700000000 - 18000 = 699,982,000 sq miles of totally obliterated things
    
    

For comparison, the entirety of planet earth is 196.9 million sq miles, so the
equiv area of 10 planet earths would be heavily damaged.

    
    
        (700000000 - 18000) * 3 = 2,099,946,000 sq miles of heavily damaged things
    

Update: My math is totally wrong and people smarter than me explained it. Yay
for internet people!

~~~
TheOtherHobbes
Yield isn't linear. It's a cube root relationship.

The difference between 100MT, 10MT and 1MT is hardly insignificant, but it's
smaller than many people realise.

FWIW a ballpark estimate says 700MT would have a 1 psi overpressure radius -
which would break windows but not buildings - of less than 100km.

It would be a huge bang and the noise would circle the world a few times. But
if it landed on land, the total obliteration region would be smaller than a
state. And the explosion itself wouldn't be extinction-level - although the
winter that followed it would cause some severe problems.

Tambora, which is the biggest explosion in modern records, was estimated
around 33GT, and the blast effects from that were very, very, very bad, but
still relatively localised.

Chicxulub has been estimated as at least 20 _billion_ Hiroshimas - and perhaps
as much as four times that. That set fire to most of a hemisphere. And it
still wasn't a complete obliteration/sterilisation event.

~~~
SEJeff
> Chicxulub has been estimated as at least 20 billion Hiroshimas - and perhaps
> as much as four times that. That set fire to most of a hemisphere. And it
> still wasn't a complete obliteration/sterilisation event.

Unless you were a dinosaur living at the time :)

Thanks for the cluebat, I've put an update on my post to note the math is all
bollocks.

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module0000
I'm ready. An asteroid is an alright way to go out for me, everything else
seems lackluster by comparison. This would be an acceptable early-ending to my
normally schedule programming of marching endlessly behind the other humans
towards oblivion.

In all seriousness, what can be done about this sort of thing(mitigating it)?
Opinions(albeit ones from the internet) range from spacecrafts intercepting
and mounting thrusters to divert the object's course, or planting nuclear
bombs, and other "fantastic" sounding solutions. Is there anything to be done
other than expect the unexpected?

~~~
magduf
It's very easy to avoid asteroid impacts. You do lots of observation, so that
you can tell _decades_ in advance, that the asteroid is an imminent threat.
Then you build spacecraft which intercept it, and use some type of engines
(probably ion engines) to slightly change its orbit. You don't need extremely
powerful ones, you just need them to operate for a long time. A very small
orbital change will result in it completely avoiding the Earth decades later.

The key, of course, is being prepared well ahead of time, and looking for
these things. We're doing a terrible job of these.

If you're a stupid species like the dinosaurs and don't bother to prepare for
these things decades in advance, then there's nothing to be done; just let it
happen.

~~~
craftyguy
Eh, that all assumes the object has a relatively short orbital period around
the Sun. None of that would work for an object with a very long orbital
period, which would have a very high velocity in the inner solar system and
likely would not be observed until it was already on its way here. Then there
are objects which are not in orbit around the Sun, with even higher
velocities.

~~~
magduf
>and likely would not be observed until it was already on its way here.

That's my whole point: if we were more serious about this, we'd have orbital
observation platforms looking for all these objects and keeping track of them
all, so that we _aren 't_ surprised by anything short of another asteroid from
totally outside the solar system like that one a couple years ago.

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carapace
Only about 150 years ago the idea of rocks coming out of the sky was
ridiculous, fringe, crazy-person talk.

We laugh at the flat-earthers, but I think you can estimate how sane an
Earthling is by its attitude towards meteor defense.

My point is most of us are "flat-earthers" after a fashion. Most people don't
really internalize physics and the structure of the Universe[1], but when you
do, you have these moments where your mind resolves the inconsistencies in
your worldview and it expands and these mind-blowing vistas spread out before
you.

One thing you realize is that the sky is fucking terrifying.

The world includes gigantic explosions that happen literally out of the blue
for no real reason other than there are falling rocks in the sky and gravity.

[1] If we did, solar power would have taken off the moment someone thought of
it. The Sun is _awesome_.

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gojomo
Fun story, but one quibble: with a week's warning, Pasadena, Texas could
manage an efficient & orderly evacuation. The region has a high level of
cooperativeness in the face of imminent common threats.

~~~
post_break
Living about 15 minutes away from Pasadena, if it needed to be evacuated it
would take months. There's a meme of evacuating Katy any time it rains because
the people there tried during a hurricane and ended up staying locked in grid
lock for days. Now imagine that same scenario with the entire city of Houston
trying to evacuate. Most people would not be able to escape in a week.

~~~
rhino369
Part of the issue with Hurricanes is that they hit a huge area. If you just
need to evacuate a single city, it would be a lot easier. Especially with the
added urgency of an asteroid. Hurricanes happen all the time and usually, it's
not the end of the world.

The Democratic Republic of Congo, a near-failed state, managed to evacuate
300,000 people in three days from a Volcano. I'm pretty sure suburban Texas
can handle it.

~~~
magduf
I doubt it. DRC could do it because they can just get everyone to start
walking, and 300k people walking as a huge group isn't that hard to do. Texas
can't do it because everyone will try to load up their giant SUV and drive out
on roads never designed for that much traffic, and they'll be stuck in
gridlock where they'll die when the storm or asteroid hits.

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isostatic
In this scenarios it wouldn't destroy the world. A 50m asteroid hitting a
minor city in the western world (with time to evacuate for anyone with a
functioning braincell) is probably the best thing that could happen as far as
space defence goes.

~~~
magduf
We already had something a bit like this, several years ago when a small
asteroid exploded over Chelybinsk, Russia. 1000 people were injured.

Has humanity sat up and decided to take this threat seriously? Nope.

Most likely, this was a test from some aliens to see if we're smart enough to
avoid a much larger, extinction-level asteroid headed our way, and to try to
get us to prepare ourselves better without violating the Prime Directive too
badly. We failed.

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thowawaygbuk
Ridiculous to assume that US/NASA are only one with the capability,
EU/China/Japan/Russia/India/SpaceX could very well launch an interceptor and
ride the popularity. If anything I expect multiple independent efforts
competing to become the first one to take it out and saving humanity.

~~~
ChuckMcM
The cynic in me thinks Elon would first buy up all the property around the
impact zone for pennies through a bunch of shell companies, then send up a BFR
or FH with a W84 warhead (designed for a cruise missile so it would be
extremely light relative to the lift capacity), rig it with an impact
detonator that could be activated post liftoff, and then drive it into the
asteroid.

Save the day, collect the gratitude of a grateful nation, and then sell off
all the property at an obscene profit to make back all the costs.

~~~
godelski
I wouldn't take Armageddon as an instruction guide of how to safely get rid of
asteroids. In fact, detonating it would likely lead to a shotgun effect. Lots
of smaller pieces. Sure, these wouldn't do as much damage to a single city but
they could damage many cities and many objects in orbit. Beyond that you now
have to contend with the political ramifications of causing the destruction of
someone else's property.

Tldr: asteroid defense is quite hard. Currently we are not adequately equipped
to do so it safely.

~~~
ChuckMcM
Ok seriously, you read the article right? And its really just a summary of the
work of fiction that is coming out in book form, and in that fiction _the
people in the story all agree that using a nuclear weapon on the remaining
shard is their last and only option._ To be clear, I didn't write the book, I
was suggesting (what appears to be a way to cynical :-) a coda where a
billionaire with a penchant for making money in unconventional ways, exploits
the situation. He thus saves the world _according to what the book postulates
is the best strategy_ and he makes a ton of money.

That said, I agree with you, its stupid to blow up an incoming asteroid so
that it can basically shred all of the satellites in orbit and cause a Kessler
cascade and make it difficult if not impossible to put things in orbit for
decades. But in defense of my comment, you have to work within the confines of
the story, that is the rule of improv.

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mannewalis
[https://cneos.jpl.nasa.gov/pd/cs/ttx14/](https://cneos.jpl.nasa.gov/pd/cs/ttx14/)

~~~
ocdtrekkie
The part of the read where I realized it wasn't a real story I was reading was
where it became 35% chance to hit. And I was like, "I think I'd know if this
wasn't fictional".

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exabrial
Help me with the maths... current largest rocket we have is The Falcon Heavy,
correct? How much more capability would we need to hit something 3 years away
from impact with a Russian Tsar Bomba?

Let's assume we don't do multiple launches and orbit rendezvous.

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ssully
Has anyone read the full book this is an excerpt from? If the whole book is
like this it could be a fun read.

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post_break
The cynic in me believes we'd do absolutely nothing and just let it slam into
Pasadena after people who think it's a hoax fight with scientists.

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geogra4
Isn't this an allegory for global climate change?

~~~
mar77i
Sorry to break it to you, but last time I checked it wasn't climate if the
weather goes "BOOM!"

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mar77i
I'd find it funny if the US proved uncapable to hit the damn thing and Russia
just throws a makeshift deflection apparatus at it that basically makes use of
angular momentum for the task (Soyuz™ tech!) and just keeps burning itself to
death on the asteroid's surface. The result would be bipartisan gratitude to
Russia, while putting Rachel Mathews out of a job for good. The potential
hilarity of the future is literally endless, even without an asteroid on
collision course.

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swamp40
Fiction. Very realistic read, though.

