On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being downgraded
from a 1 in 32 chance of hitting Earth (the 17th February estimate) to a
one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there
are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few of
them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
On Tue, 4 Mar 2025 22:59:44 +0000, TTman <kraken.sankey@gmail.com>
wrote:
On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being downgraded
from a 1 in 32 chance of hitting Earth (the 17th February estimate) to a >>> one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there
are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few of >>> them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
Silly suggestion. You'd have to plan your wars 30 years in advance,
and you couldn't sign a peace treaty with the thing a week away from
hitting earth.
We can launch a nuke in 20 minutes.
On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being
downgraded from a 1 in 32 chance of hitting Earth (the 17th February
estimate) to a one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there
are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few
of them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
Timing is everything in orbital dynamics.
The Earth is moving along it's orbit at 30km/s and the impactor is similar or possibly faster depending on its orbital parameters. IOW just a couple of minutes difference between a direct hit and a miss.
Its actually better than that since glancing impacts will skim off the upper atmosphere like a stone does off off a pond. And only iron or stone ones coming
in at relatively steep angles get to reach the ground. Many are loose aggregates of ice and pebbles that disintegrate on entry.
Earth also spins at 1000 mph at the equator which further complicates timing if
you want to hit an actual specific coordinate on the globe.
On 04/03/2025 22:59, TTman wrote:
On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being
downgraded from a 1 in 32 chance of hitting Earth (the 17th February
estimate) to a one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there
are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few
of them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
Timing is everything in orbital dynamics.
The Earth is moving along it's orbit at 30km/s and the impactor is
similar or possibly faster depending on its orbital parameters. IOW just
a couple of minutes difference between a direct hit and a miss.
Its actually better than that since glancing impacts will skim off the
upper atmosphere like a stone does off off a pond. And only iron or
stone ones coming in at relatively steep angles get to reach the ground.
Many are loose aggregates of ice and pebbles that disintegrate on entry.
On 5/03/2025 10:21 am, john larkin wrote:
On Tue, 4 Mar 2025 22:59:44 +0000, TTman <kraken.sankey@gmail.com>
wrote:
On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being downgraded >>>> from a 1 in 32 chance of hitting Earth (the 17th February estimate)
to a
one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there >>>> are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a
few of
them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
Silly suggestion. You'd have to plan your wars 30 years in advance,
and you couldn't sign a peace treaty with the thing a week away from
hitting earth.
You wouldn't have just one of them, and the trick would be to have a
bunch of them in orbits that could easily (and quickly) shifted from
earth grazing to earth impacting. You might mot be able to shift it back
into earth grazing in a week, but you could probably get it to hit the Pacific ocean rather than your enemy's territory.
We can launch a nuke in 20 minutes.
And everybody can see where it came from. Junk in the asteroid belt is anonymous, and an asteroid hitting the earth will vapourise anything
that might otherwise have been traceable back to you.
On 2025-03-05 05:28, Bill Sloman wrote:
On 5/03/2025 10:21 am, john larkin wrote:
On Tue, 4 Mar 2025 22:59:44 +0000, TTman <kraken.sankey@gmail.com>
wrote:
On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being downgraded >>>>> from a 1 in 32 chance of hitting Earth (the 17th February estimate)
to a
one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there >>>>> are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a
few of
them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would >>>>> upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
Silly suggestion. You'd have to plan your wars 30 years in advance,
and you couldn't sign a peace treaty with the thing a week away from
hitting earth.
You wouldn't have just one of them, and the trick would be to have a
bunch of them in orbits that could easily (and quickly) shifted from
earth grazing to earth impacting. You might mot be able to shift it back
into earth grazing in a week, but you could probably get it to hit the
Pacific ocean rather than your enemy's territory.
We can launch a nuke in 20 minutes.
And everybody can see where it came from. Junk in the asteroid belt is
anonymous, and an asteroid hitting the earth will vapourise anything
that might otherwise have been traceable back to you.
In The Expanse series of novels, asteroids are used as weapons, and it
took them months. Of course, you need the proper drive (which we don't
have). I'm not sure they calculated the hit place.
Ok, it is fiction, but calculated fiction.
On Wed, 5 Mar 2025 10:02:17 +0000, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:
On 04/03/2025 22:59, TTman wrote:
On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being
downgraded from a 1 in 32 chance of hitting Earth (the 17th February
estimate) to a one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there >>>> are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few
of them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
Timing is everything in orbital dynamics.
The Earth is moving along it's orbit at 30km/s and the impactor is
similar or possibly faster depending on its orbital parameters. IOW just
a couple of minutes difference between a direct hit and a miss.
Or milliseconds.
Its actually better than that since glancing impacts will skim off the
upper atmosphere like a stone does off off a pond. And only iron or
stone ones coming in at relatively steep angles get to reach the ground.
Many are loose aggregates of ice and pebbles that disintegrate on entry.
Drones are more sensible weapons.
Silly suggestion. You'd have to plan your wars 30 years in advance,
and you couldn't sign a peace treaty with the thing a week away from
hitting earth.
You wouldn't have just one of them, and the trick would be to have a
bunch of them in orbits that could easily (and quickly) shifted from
earth grazing to earth impacting. You might mot be able to shift it back
into earth grazing in a week, but you could probably get it to hit the >Pacific ocean rather than your enemy's territory.
We can launch a nuke in 20 minutes.
And everybody can see where it came from. Junk in the asteroid belt is >anonymous, and an asteroid hitting the earth will vapourise anything
that might otherwise have been traceable back to you.
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
Silly suggestion. You'd have to plan your wars 30 years in advance,
and you couldn't sign a peace treaty with the thing a week away from
hitting earth.
You wouldn't have just one of them, and the trick would be to have a
bunch of them in orbits that could easily (and quickly) shifted from
earth grazing to earth impacting. You might mot be able to shift it back
into earth grazing in a week, but you could probably get it to hit the
Pacific ocean rather than your enemy's territory.
We can launch a nuke in 20 minutes.
And everybody can see where it came from. Junk in the asteroid belt is
anonymous, and an asteroid hitting the earth will vapourise anything
that might otherwise have been traceable back to you.
If you're planning to maintain anonymity and convincing deniability
(as your final statement suggests) then you aren't really in a position
to use the asteroid as a bargaining chip in a war, are you?
You can't contact your enemy's leader and say "Well, an asteroid that
we have absolutely nothing to do with, and have no power over, is
going to smash your capital city in a few weeks... unless you make
peace with us. Then, we promise to pray to the Flying Spaghetti
Monster to divert it to a place where it will only kill a lot of fish
and cause tsnuamis that flood numerous uninvolved nations. That
won't be our fault since we have no control over it."
In addition to that... if you really want a bunch of them moved into Earth-grazing orbits, it'll require a truly huge industrial effort to
loft the necessary number of "engines" to divert them into those
orbits (e.g. by gravity-tug effect, ablative lasers, etc.).
Do you really expect that any nation can do such a thing, and not have it detected and traced back to the nation in question? Outer space is
a lot more "visible" than something like the Manhattan Project was.
A counter to this sort of gambit would be for the targeted nation
to make it clear that their own retaliatory counter-force (ICBMs, atomic-tipped cruise missiles, etc.) has been put into a deadman
switch of sorts, and will be launched if the asteroid strikes.
It'd be just another round of "Mutually Assured Destruction", without
a bunch of the existing safeguards (two-man firing rule, the ability
to hit a destruct switch up until the last moment, etc.) to stave off Armageddon.
That's not to say that somebody military won't propose it... but
I doubt that it will fly.
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
In addition to that... if you really want a bunch of them moved into
Earth-grazing orbits, it'll require a truly huge industrial effort to
loft the necessary number of "engines" to divert them into those
orbits (e.g. by gravity-tug effect, ablative lasers, etc.).
I haven't done the calculations - but then again neither have you.
My guess is that sort of ion drives that you'd use wouldn't be all that
big, and you'd power them with solar cells. They'd need to keep pushing
for quite a while. The first stage would be to stop the asteroid
tumbling and get it spinning on an axis that more or less pointed at the
sun so that the solar cells could stay illuminated for most of the time.
You might have ship up more reaction mass from time to time. Using theasteroid mass as your reaction mass might be practicable, but it
would be an additional complication.
Do you really expect that any nation can do such a thing, and not have it
detected and traced back to the nation in question? Outer space is
a lot more "visible" than something like the Manhattan Project was.
But there is a lot of it, and most of the action would be happening a
long way away from the earth - more than 93 million miles, on average.
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
...
In addition to that... if you really want a bunch of them moved into
Earth-grazing orbits, it'll require a truly huge industrial effort to
loft the necessary number of "engines" to divert them into those
orbits (e.g. by gravity-tug effect, ablative lasers, etc.).
I haven't done the calculations - but then again neither have you.
My guess is that sort of ion drives that you'd use wouldn't be all
that big, and you'd power them with solar cells. They'd need to keep
pushing for quite a while. The first stage would be to stop the
asteroid tumbling and get it spinning on an axis that more or less
pointed at the sun so that the solar cells could stay illuminated for
most of the time.
You might have ship up more reaction mass from time to time. Using
theasteroid mass as your reaction mass might be practicable, but it
would be an additional complication.
Do you really expect that any nation can do such a thing, and not
have it
detected and traced back to the nation in question? Outer space is
a lot more "visible" than something like the Manhattan Project was.
But there is a lot of it, and most of the action would be happening a
long way away from the earth - more than 93 million miles, on average.
Russell's teapot :-p :-)
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
...
Do you really expect that any nation can do such a thing, and not
have it
detected and traced back to the nation in question? Outer space is
a lot more "visible" than something like the Manhattan Project was.
But there is a lot of it, and most of the action would be happening a
long way away from the earth - more than 93 million miles, on average.
Russell's teapot :-p :-)
Not exactly. My claim was simply that observation would be difficult -
not impossible - in the same way that it isn't impossible to intercept
an intercontinetal ballasitc missile in mid-flight, but that the
practical difficulties mean that nobody is trying to do it.
Reagan's "Star Wars" proposal pretended that it was practical.
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
...
Do you really expect that any nation can do such a thing, and not
have it
detected and traced back to the nation in question? Outer space is >>>>> a lot more "visible" than something like the Manhattan Project was.
But there is a lot of it, and most of the action would be happening
a long way away from the earth - more than 93 million miles, on
average.
Russell's teapot :-p :-)
Not exactly. My claim was simply that observation would be difficult -
not impossible - in the same way that it isn't impossible to intercept
an intercontinetal ballasitc missile in mid-flight, but that the
practical difficulties mean that nobody is trying to do it.
Reagan's "Star Wars" proposal pretended that it was practical.
The thing is, it is impossible to prove that there are no objects out
there in an intercept orbit with earth.
If you find one, you have proved it exists, but you can not prove the negative.
On Wed, 5 Mar 2025 10:02:17 +0000, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:
On 04/03/2025 22:59, TTman wrote:
On 04/03/2025 02:02, Bill Sloman wrote:
The latest New Scientist talks about asteroid 2024 YR4 being
downgraded from a 1 in 32 chance of hitting Earth (the 17th February
estimate) to a one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there >>>> are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few
of them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Excellent suggestion.! Needs some clever maths calcs though...
Timing is everything in orbital dynamics.
The Earth is moving along it's orbit at 30km/s and the impactor is
similar or possibly faster depending on its orbital parameters. IOW just
a couple of minutes difference between a direct hit and a miss.
Or milliseconds.
Its actually better than that since glancing impacts will skim off the
upper atmosphere like a stone does off off a pond. And only iron or
stone ones coming in at relatively steep angles get to reach the ground.
Many are loose aggregates of ice and pebbles that disintegrate on entry.
Drones are more sensible weapons.
The latest New Scientist talks about asteroid 2024 YR4 being downgraded
from a 1 in 32 chance of hitting Earth (the 17th February estimate) to a
one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there
are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few of
them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
...
Do you really expect that any nation can do such a thing, and notBut there is a lot of it, and most of the action would be happening
have it
detected and traced back to the nation in question? Outer space is >>>>>> a lot more "visible" than something like the Manhattan Project was. >>>>>
a long way away from the earth - more than 93 million miles, on
average.
Russell's teapot :-p :-)
Not exactly. My claim was simply that observation would be difficult
- not impossible - in the same way that it isn't impossible to
intercept an intercontinetal ballasitc missile in mid-flight, but
that the practical difficulties mean that nobody is trying to do it.
Reagan's "Star Wars" proposal pretended that it was practical.
The thing is, it is impossible to prove that there are no objects out
there in an intercept orbit with earth.
If you find one, you have proved it exists, but you can not prove the
negative.
And you'd be mad to try. Meteorites hit the earth every day, so there
are clearly lots of small objects out there with intercept orbits with
earth.
Larger objects hit the planet and make it down to the surface less
often, and the frequency drops off with size. A really big one killed
off the dinosaurs about 65 million years ago.
In this particular case you couldn't prove the negative because there
isloads of evidence to the contrary. People like Trump do make that kind
of assertion from time to time, and some people do seem to take them seriously, but that's all about influencing the hopelessly gullible.
On 2025-03-06 17:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
...
Do you really expect that any nation can do such a thing, and not >>>>>>> have itBut there is a lot of it, and most of the action would be
detected and traced back to the nation in question? Outer space is >>>>>>> a lot more "visible" than something like the Manhattan Project was. >>>>>>
happening a long way away from the earth - more than 93 million
miles, on average.
Russell's teapot :-p :-)
Not exactly. My claim was simply that observation would be difficult
- not impossible - in the same way that it isn't impossible to
intercept an intercontinetal ballasitc missile in mid-flight, but
that the practical difficulties mean that nobody is trying to do it.
Reagan's "Star Wars" proposal pretended that it was practical.
The thing is, it is impossible to prove that there are no objects out
there in an intercept orbit with earth.
If you find one, you have proved it exists, but you can not prove the
negative.
And you'd be mad to try. Meteorites hit the earth every day, so there
are clearly lots of small objects out there with intercept orbits with
earth.
Obviously I refer to objects of a dangerous size.
On Tue, 4 Mar 2025 13:02:09 +1100, Bill Sloman <bill.sloman@ieee.org>
wrote:
The latest New Scientist talks about asteroid 2024 YR4 being downgraded >>from a 1 in 32 chance of hitting Earth (the 17th February estimate) to a
one in 25,000 chance on the 24th February.
It's some where between 40 and 90 metres in diameter. Presumably there
are more smaller asteroids (which will be harder to see).
Eventually some military clown is going to get the idea finding a few of
them and sending up stick-on ion drives, so that the earth-grazing
orbits can be shifted into earth-impacting orbits.
A couple of them hitting Russian occupied-areas of the Ukraine would
upset Putin no end.
Isn't Russian-occupied Ukraine already a mined wasteland?
You think Putin gives a damn?
Throwing rocks? It may come to that, if the conflict goes on
long enough without aid. Look at Gaza.
Aid that is already withdrawn isn't a threat or bargaining
chip, it's simple betrayal.
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
...
Do you really expect that any nation can do such a thing, and notBut there is a lot of it, and most of the action would be happening
have it
detected and traced back to the nation in question? Outer space is >>>>>> a lot more "visible" than something like the Manhattan Project was. >>>>>
a long way away from the earth - more than 93 million miles, on
average.
Russell's teapot :-p :-)
Not exactly. My claim was simply that observation would be difficult
- not impossible - in the same way that it isn't impossible to
intercept an intercontinetal ballasitc missile in mid-flight, but
that the practical difficulties mean that nobody is trying to do it.
Reagan's "Star Wars" proposal pretended that it was practical.
The thing is, it is impossible to prove that there are no objects out
there in an intercept orbit with earth.
If you find one, you have proved it exists, but you can not prove the
negative.
And you'd be mad to try. Meteorites hit the earth every day, so there
are clearly lots of small objects out there with intercept orbits with
earth.
Larger objects hit the planet and make it down to the surface less
often, and the frequency drops off with size. A really big one killed
off the dinosaurs about 65 million years ago.
On 10/03/2025 11:52 pm, Carlos E.R. wrote:
On 2025-03-06 17:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
...
Do you really expect that any nation can do such a thing, andBut there is a lot of it, and most of the action would be
not have it
detected and traced back to the nation in question? Outer space is >>>>>>>> a lot more "visible" than something like the Manhattan Project was. >>>>>>>
happening a long way away from the earth - more than 93 million
miles, on average.
Russell's teapot :-p :-)
Not exactly. My claim was simply that observation would be
difficult - not impossible - in the same way that it isn't
impossible to intercept an intercontinetal ballasitc missile in
mid-flight, but that the practical difficulties mean that nobody is
trying to do it.
Reagan's "Star Wars" proposal pretended that it was practical.
The thing is, it is impossible to prove that there are no objects
out there in an intercept orbit with earth.
If you find one, you have proved it exists, but you can not prove
the negative.
And you'd be mad to try. Meteorites hit the earth every day, so there
are clearly lots of small objects out there with intercept orbits
with earth.
Obviously I refer to objects of a dangerous size.
And that means that you don't know what you are talking about.
There's a whole distribution of space junk up there. The bigger they
are, the more damage they can do when they hit the surface of the earth.
The historical record - in terms of meteor craters big enough to have survived for a few million years - demonstrates that big earth grazing asteroids are pretty rare. I imagine that somebody has worked out what
the distribution is, at least roughly.
https://www.researchgate.net/ publication/278734323_The_Compositional_Structure_of_the_Asteroid_Belt/ figures?lo=1
There doesn't seem to be any reason to imagine that the distribution
isn't smooth and monotonic.
A really small meteor - one only just big enough to make it the surface
of the earth - could still kill you if it hit your head.
https://en.wikipedia.org/wiki/Tunguska_event
may have killed three people, but it did knock down a lot of trees.
It seems to have been a stony asteroid, rather than a lump of nickel-
iron, and seems to have come apart at an altitude of of between five and
ten kilometres.
On 06/03/2025 16:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
There is a limit to haw far into the future we can predict theThat insight has been formalised as a claim that the planets' orbits are chaotic over longer time scales, in such a way that the whole Solar
trajectory of a comet or asteroid. It depends how well the orbit has
been determined and how close it gets to any of the other big solar
system bodies. Jupiter serves as a cosmic hoover by slingshot effect
putting things into orbits that typically intersect with it or get flung
much further out. Shoemaker Levy 9 famously suffer that fate
On 2025-03-10 15:28, Bill Sloman wrote:
On 10/03/2025 11:52 pm, Carlos E.R. wrote:
On 2025-03-06 17:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
Obviously I refer to objects of a dangerous size.
And that means that you don't know what you are talking about.
There's a whole distribution of space junk up there. The bigger they
are, the more damage they can do when they hit the surface of the earth.
The historical record - in terms of meteor craters big enough to have
survived for a few million years - demonstrates that big earth grazing
asteroids are pretty rare. I imagine that somebody has worked out what
the distribution is, at least roughly.
There is evidence of dangerous "objects" hitting the earth and causing destruction in the "historic" age.
Example: https://en.wikipedia.org/wiki/Tunguska_event
We were just fortunate that it hit a non populated area, otherwise it
could have destroyed a city. The explosion was between 3 and 50 megatons.
https://www.researchgate.net/
publication/278734323_The_Compositional_Structure_of_the_Asteroid_Belt/ figures?lo=1
There doesn't seem to be any reason to imagine that the distribution
isn't smooth and monotonic.
A really small meteor - one only just big enough to make it the
surface of the earth - could still kill you if it hit your head.
https://en.wikipedia.org/wiki/Tunguska_event
may have killed three people, but it did knock down a lot of trees.
It seems to have been a stony asteroid, rather than a lump of nickel-
iron, and seems to have come apart at an altitude of of between five
and ten kilometres.
On 11/03/2025 11:43 pm, Carlos E.R. wrote:
On 2025-03-10 15:28, Bill Sloman wrote:
The historical record - in terms of meteor craters big enough to have
survived for a few million years - demonstrates that big earth
grazing asteroids are pretty rare. I imagine that somebody has worked
out what the distribution is, at least roughly.
There is evidence of dangerous "objects" hitting the earth and causing
destruction in the "historic" age.
Example: https://en.wikipedia.org/wiki/Tunguska_event
We were just fortunate that it hit a non populated area, otherwise it
could have destroyed a city. The explosion was between 3 and 50 megatons.
You really are a twit. If you had bothered to read all the way through
my post, you would have found exactly the same url (so it shows up twice
in your post, which is a touch comical).
And the object didn't explode - it just came apart. Lots of very fast
moving, very hot rocks rocks (it does seem to have a stony asteroid,
which is presumably why it didn't make all the way down to the ground)
would have produced a huge shock wave, so it might as well have
exploded, but calling it an explosion implies that the energy emerged suddenly, rather than just coupling into the atmosphere when the air got dense enough to have a significant interaction with the fast moving rock.
On 11/03/2025 11:43 pm, Carlos E.R. wrote:
On 2025-03-10 15:28, Bill Sloman wrote:
On 10/03/2025 11:52 pm, Carlos E.R. wrote:
On 2025-03-06 17:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
<snip>
Obviously I refer to objects of a dangerous size.
And that means that you don't know what you are talking about.
There's a whole distribution of space junk up there. The bigger they
are, the more damage they can do when they hit the surface of the earth. >>>
The historical record - in terms of meteor craters big enough to have
survived for a few million years - demonstrates that big earth
grazing asteroids are pretty rare. I imagine that somebody has worked
out what the distribution is, at least roughly.
There is evidence of dangerous "objects" hitting the earth and causing
destruction in the "historic" age.
Example: https://en.wikipedia.org/wiki/Tunguska_event
We were just fortunate that it hit a non populated area, otherwise it
could have destroyed a city. The explosion was between 3 and 50 megatons.
You really are a twit. If you had bothered to read all the way through
my post, you would have found exactly the same url (so it shows up twice
in your post, which is a touch comical).
On 11/03/2025 9:18 pm, Martin Brown wrote:
On 06/03/2025 16:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
<snip>
There is a limit to haw far into the future we can predict theThat insight has been formalised as a claim that the planets' orbits are chaotic over longer time scales, in such a way that the whole Solar
trajectory of a comet or asteroid. It depends how well the orbit has
been determined and how close it gets to any of the other big solar
system bodies. Jupiter serves as a cosmic hoover by slingshot effect
putting things into orbits that typically intersect with it or get
flung much further out. Shoemaker Levy 9 famously suffer that fate
System possesses a Lyapunov time in the range of 2~230 million years.
https://en.wikipedia.org/wiki/Stability_of_the_Solar_System
On 11/03/2025 13:34, Bill Sloman wrote:
On 11/03/2025 9:18 pm, Martin Brown wrote:
On 06/03/2025 16:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
<snip>
There is a limit to haw far into the future we can predict theThat insight has been formalised as a claim that the planets' orbits
trajectory of a comet or asteroid. It depends how well the orbit has
been determined and how close it gets to any of the other big solar
system bodies. Jupiter serves as a cosmic hoover by slingshot effect
putting things into orbits that typically intersect with it or get
flung much further out. Shoemaker Levy 9 famously suffer that fate
are chaotic over longer time scales, in such a way that the whole
Solar System possesses a Lyapunov time in the range of 2~230 million
years.
https://en.wikipedia.org/wiki/Stability_of_the_Solar_System
I think Ovenden's conjecture is probably more likely to be true in the
sense that although we can't exactly predict things we can put quite
good bounds on how far out of kilter things can actually get chaos wise
in the solar system (barring a close encounter with a passing star or
other seriously massive object shaking things up).
His conjecture is pretty much that the big guys are locked in resonant orbital patterns that avoid each other as much as possible. It seems to
hold equally well for moons of planets as well as planets of suns.
It says nothing about whether or not they could contrive to say eject
Mars from the solar system entirely. What is known from composition of
the planets is that they didn't all form exactly where they are now.
On 2025-03-11 14:18, Bill Sloman wrote:
On 11/03/2025 11:43 pm, Carlos E.R. wrote:
On 2025-03-10 15:28, Bill Sloman wrote:
On 10/03/2025 11:52 pm, Carlos E.R. wrote:
On 2025-03-06 17:44, Bill Sloman wrote:
On 6/03/2025 10:54 pm, Carlos E.R. wrote:
On 2025-03-06 04:06, Bill Sloman wrote:
On 6/03/2025 1:45 pm, Carlos E.R. wrote:
On 2025-03-06 03:05, Bill Sloman wrote:
On 6/03/2025 8:28 am, Dave Platt wrote:
In article <vq8jtq$299g5$1@dont-email.me>,
Bill Sloman <bill.sloman@ieee.org> wrote:
<snip>
Obviously I refer to objects of a dangerous size.
And that means that you don't know what you are talking about.
There's a whole distribution of space junk up there. The bigger they
are, the more damage they can do when they hit the surface of the
earth.
The historical record - in terms of meteor craters big enough to
have survived for a few million years - demonstrates that big earth
grazing asteroids are pretty rare. I imagine that somebody has
worked out what the distribution is, at least roughly.
There is evidence of dangerous "objects" hitting the earth and
causing destruction in the "historic" age.
Example: https://en.wikipedia.org/wiki/Tunguska_event
We were just fortunate that it hit a non populated area, otherwise it
could have destroyed a city. The explosion was between 3 and 50
megatons.
You really are a twit. If you had bothered to read all the way through
my post, you would have found exactly the same url (so it shows up
twice in your post, which is a touch comical).
I did read it, later, and I decided to leave my text, as my reasoning is different than you
On 11/03/2025 13:18, Bill Sloman wrote:
On 11/03/2025 11:43 pm, Carlos E.R. wrote:
On 2025-03-10 15:28, Bill Sloman wrote:
The historical record - in terms of meteor craters big enough to
have survived for a few million years - demonstrates that big earth
grazing asteroids are pretty rare. I imagine that somebody has
worked out what the distribution is, at least roughly.
There is evidence of dangerous "objects" hitting the earth and
causing destruction in the "historic" age.
Example: https://en.wikipedia.org/wiki/Tunguska_event
We were just fortunate that it hit a non populated area, otherwise it
could have destroyed a city. The explosion was between 3 and 50
megatons.
You really are a twit. If you had bothered to read all the way through
my post, you would have found exactly the same url (so it shows up
twice in your post, which is a touch comical).
And the object didn't explode - it just came apart. Lots of very fast
moving, very hot rocks rocks (it does seem to have a stony asteroid,
which is presumably why it didn't make all the way down to the ground)
would have produced a huge shock wave, so it might as well have
exploded, but calling it an explosion implies that the energy emerged
suddenly, rather than just coupling into the atmosphere when the air
got dense enough to have a significant interaction with the fast
moving rock.
The exact dynamics for Tunguska are still a bit unclear but assuming it
was a typical rock ice composite material then it probably did to a very
good approximation explode once the hypersonic shockwave from impacting
the denser atmosphere exceeded the binding forces holding it together.
Most sources describe it as an explosion at about 6 miles altitude.
https://www.nasa.gov/history/115-years-ago-the-tunguska-asteroid-impact-event/
No pieces of it have ever been identified as reaching the ground.
It is assumed that most of it vapourised.
Finding meteorites is a lot easier in Antarctica than on Arctic tundra.
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