Being a lover of teh stars, and of heavenly bodies in general, I"m quite
interested in the concept of asteroids hitting the earth in the furture. I
saw teh mini-seires and the geographic special. The latter states that large
asteroids have hit earth in the past and will inevitably hit in the furture.
There are many earth-crossing asteroids that have been discovered, but it is
those that have yet to be discovered that we must worry about most. If we are
in the path of a gigantic space-rock, what can we do to stop it? And what can
we do to preserve human life in the aftermath?

99 responses total.

I seem to remember some treaty about detonating nuclear devices in space. 
I suppose we might collectively agree to break the treaty if we had time. 
This would only work for smaller rocks.  Small enough to pulverize/vaporize.
The blast wouldn't impart enough momentum to divert a big rock unless we
caught it way early.  (er that's what I figure anyway).

would the science fw please link this?

The "big ones" are only 6 km or so in diameter. An H-bomb makes that big a
splash. It would be tricky, but if the proper nudge were made at the
proper time and distance, the asteroid might be made to miss us. Might.
But is this really a threat? We've made it "OK so far" for several million
years.  The last major asteroid impact/extinction event was the K-T one,
wasn't it?  65Ma bp? I think we have more serious threats to concern
ourselves about for the next few centuries. We *know* that there will be
lots of problems due to human population growth, resource depletion,
global warming,, etc. 

There is no posslble way to "*know*" that about the future.
Doomsayers have been predicting cataclysm for centuries
and have always been wrong.
We're still here.

yet what harm is there in determining reasonable preparations for a
realistically possible scenario?

one thing i remember from the TDC special was the idea of a near surface burst
causing the heated side of the rock to propel it sideways out of our path.
what is the comparative potential of applying the same tactic directly in the
path of the rock to slow it just enough to cause the timing of its
intersection with earth's obit to be delayed sufficiently to miss?

There is a "best point" at which to sock it - all determinable from orbital
mechanics (even, *Newtonian* orbital mechanics). 

I wasn't predicting a cataclysm, klg. I was identifying sources of
future problems, and everyone agrees (except you, apparently) that those
are sources of future problems. Incidentally, we are not *all* here, contrary
to your assertion - many people have died because of excess population and
resource depletion already. Global warming will take a while.

I have read that some scientists believe there is a 1 in a thousand 
chance that a young child alive today will be witness at some time in 
his/her lifetime to an asteroid collision with earth.  When such 
collision occurs, there will be massive geoclimatic shifts, ensuing 
environmental upheaval and many people will starve.  

Recently, material in the floorbeds of the Atlantic ocean, was 
discovered that is claimed to be scientific verification of the asteroid 
collision that caused the equivalent of a nuclear winter and caused the 
dinosaurs to become extinct.  Nature is usually cyclical.  What has 
happened once is usually going to happen again.

Maybe we know now what is going to cause Armageddon.  Sobering thought.

if this planet is going to play celestial billiards, i would prefer
that we were teh cue ball. <g>.

I only hope these fears arent used to revive support for the Star Wars missile
defense system.  We have betterthings to spend money on than weapons systems
to blow theoretical asteroids out of thesky.

you have, obviously, never been a physical target, have you?

I have to agree with Richard.  How aoften have asteroids hit the earth with
devastating effects?  Is it worth spending tons of money on?  I don't think
so.

Only has to happen once in your life time to ruin your whole species.

It's happened quite regularly throughout the life of this planet.  Happened
in about 1912 in Russia.  knocked over about 50 square miles of trees.  People
might think it sucked if all of New Jersey just went away.  Then again, maybe
they'd like that.

The frequency of impactors is inversely prortional to the about -2.5 power
of their size. We will see millions like the 1912 meteorite for every K-T
asteroid. One must keep in mind that all human history - the whole
Plesitocene, which includes a lot more than human history - is but a tiny
blink in the age of the earth. 

re #11: So, you're willing to spend billions on a system that probably won't
work in the extremely unlikely event that something will happen?  

sounds like reagan's sda...

sdi, but i digress
  
there is no *immediate* problem, or the hubble & etc. would have
given some sort of alert.
  
however, that being said, there is a reasonable apprehension of the
planet earth playing pool with other celestial bodies.
  
no 'crash' program is even considered, rather a planet-wide buildup
for what is inevitable.

How inevitable?  Let's have some numbers.

I think the chances of it happening in my lifetime are pretty much nil.
As a matter of fact, I am so sure of that I am willing to bet my life on it
by doing nothing. 

We should have an "Asteroid Fund" where people can voluntarily donate money
to save the human race. I am quite content to be thrown back into the stone
age if it happens (and if I am still alive). It will also answer an
age-old question: Will those who have the money now still have it if 
everyone started from ground zero? :-)

This item has been linked from Agora 87 to Intro 147.
Type "join agora" at the Ok: prompt for discussion of
falling stars, rising stars, movie stars, and other topics
of general interest.

How inevitable? Oh, I'd say the chance of a person being killed by a 
small meteorite is much greater than the chance of death by a nearby impact,
in any given year. That's because there are so many more small meteorite
impacts than big ones. There are some million times as many 6 cm meteorites
hitting the earth as 6 meter meteorites (and 6 kilometer ones, which do global
damage, are some .0000000001 as frequent as 6 meter ones). Everyone has a
vastly greater chance of being injured by a falling tree, or falling off their
chair. 

Extending Rane's logic just a little further, it should be straightforward
to come up with an easy answer to this question.  Is the increase in life
expectancy per dollar spent greater or less than the increase gained with
some alternative expenditure, such as immunization programs or highway
safety construction?  To value an asteroid protection program you just
have to multiply a very large number (of deaths) times a very small number
(the probability).  I've no idea what the answer is, but I gather that
most people who've done the calculation have concluded that it *might* be
worth it, with some future technology that would be less expensive or more
certain than what is currently available. 

There's one more little question in the cost-benefit calculation,
though--an interesting one:  Does "civilization" have some value itself? 
Or is the cost of the end of the world just equal to the sum of the costs
of losing each life in it?  Of course, if *God* places some value on it
all, then God should pay for the asteroid prevention. 

Agora 87 <-> Science 19

There is not only a cost-benefit calculation, but a temporal one. Everyone
on earth will be dead (a thousand generations or more) before the next major
impact (with a high probability). 

There are 70 some earth orbit crossing asteroids known at the present time.
Thousands more could be out there that we haven't seen yet.  Teh Hubble isn't
used to track any of these, it is done by amatuer scientists, the same ones
that catch most of the comets.

This sounds like a bad Oliver Stone conspiracy-theory movie.

The human race has *FAR* more serious problems facing it than the evil
asteroids in outer space. There are too many better places to spend
trillions of dollars than on a system to protect the earth from the
asteroids. 

There were few mammals in existence and primates were still tens of
millions of years in the future when the last major extinction occurred.
All the recent earth orbit crossing asteroids have missed by millions of miles
(the earth is only 8,000 miles in diameter, a very small target). Humans and
civilization developed with no one getting paranoid about this. I say, sure,
keep looking, but don't invest anything until it is known what to invest for.
Even if we prepared for something, it is just as likely to be the wrong thing.

        Yeah... Spinoff Technologies are just a waste of time & money.

        I'm sure it won't be important for a looong time..

        Of course, species extinction, as pointed out above somewhere,
        has the nasty habit of _really_ ruining yer day, let alone yer
        plans for the weekend..

For once I agree with pfv (taking his first two sentences as sarcasm).
Pushing the technological envelope to reach a well-defined goal can be
worthwhile for its own sake.

        Hehehe.. Oops.. polygon agrees, and my sarcasm was almost
        unnoticable in the general pink noise! Wow ;-)

        Thanks, poly.. I was beginning to get the feeling I should
        go back to papyrus and save the world from itself with my
        measley paycheck, too! <chuckle>

Well, I agree too - I said, "sure, keep looking". Developing the technology
to detect errant asteroids at great distances, and deduce their orbits,
would be useful and would have lots of useful spinoffs. However building
big rockets now with atomic warheads when we have no idea at all what to aim
them at would be a waste of resources. S, I am finding fault with the proposed
technoogy, and suggesting there is a related useful one. But this would
not consume enormous resources, as it is sensing, scanning, data gathering,
etc, and not building pyramids.

        Well, the research would have to be World-Coordinated, since the
        cost/benefits are not national, and the effects would have to be
        such that one Nation with a Doomsday Beam would be a bit much to
        tolerate..

        The point remains: solving hunger, overpopulation and pollution 
        is completely moot when you go extinct the following week..

        And, you won't get the "leadtime" to solve the problem: it is 
        simply going to be a case of "Hello, in two weeks, you can kiss
        yer ass Goodbye, because a rock is inbound, big and fast. Have
        a Nice Day."

It shouldn't be hard to get several year's notice.

Sorry to cut in like this, but has anyone herd what "they" have said lately?
Well, they say that the two most logical ways the Earth will end is if 1) an
asteriod riceshes off the Earth cuasing it to spin faster and the continents
overlap each other, killing every one OR 2)the sun will start to die and get
so bright that it suddenly depleats the ozone, compleatly frying every one!

Of course, if they *did* discover an asteroid was headed this way, the
*last* thing they'd do is do a press release.  It'd be major panic.  No, the
government would sit on this one, particularly if they couldn't do anything
about it.  We wouldn't know until the sky turned red that anything was wrong.

        Nova's are sorta' hard to solve - except by sensibly gettin'
        the hell outta' Dodge!

        'Stroids are another matter, and yeah - at this point in space-
        time I'd fully expect governments to say nothing, let alone do
        nothing..

        Back to square one.. Force the UN to take it up and Force the
        nations of the world to co-operate? HAH!

how about a massive reflector/lens setup on earth, which by its nature would
be incapable of causing damage to anything on earth, which focuses an intense
beam onto a disyant asteroid, causing the heating/slowing effect...

responses?  feasibility?  component size requirements?

Heating, yes: slowing, no.

Re #33: the asteroid that caused the K-T extinction of some 75% of the
species in the world, 65,000,000 years ago, was only 6 km in diameter. An
asteroid that small will have no effect whatever on the rotation of the
earth. However it will blot out sunlight for months. The other option, the
sun becoming a red giant, is scheduled now for about four billion years
hence. We don't just fry - we evaporate. 

Keep in mind that an ateroid is not likely to destroy the earth.  That would
take a REALLY big asteroid, one that we would see coming for decades!  NO,
we are talking about the extinction of our species.  there is a difference.

If the K-T asteroid were to strike today (in the Yucatan), All life in North
America would be dead in less than an hour.  Well, maybe a dog here, a cat
there, rats, mice, small lizards, some fish, some protected woods or grassy
areas, and more than a few insrcts would survive.

But we, Our nation and our civilization would be gone.

Within several months, every other nation and civilization would be gone. 
With a lot of work and preperation, some humans might survive.  If they had
the good fotune to find a safe place to hide out, they could emerge several
years later to a world devoid of over 90% of all life.

How long would they be able to survive?  What differenc would it make to you
and me?

But the K-T asteroid willnot strike todayin the Yucutan.It will not strike
tomorrow.    There hasnt been such a collision in a million years.  So
whyworryaboutit?    Eventually we wil have thetechnology to see these things
coming well in advance and we willbe prepared.  But it isnt likely to occur
in our lifetimes or our grandchildren'slifetimes.  In fact, by the time such
a collision does occur, it may be so far into the future that we willhave
already destroyedourselves some otherkind of way.  The odds of anything
happening even in the remote future are so astronomical that it isnt worth
worrying about.

Besides, why worryabout asteroids when the sun maygo supernova first?

- Backtalk version 1.3.30 - Copyright 1996-2006, Jan Wolter and Steve Weiss