> I wonder if the site will still be there on 1/1/2013 ?
> Regards, > Martin Brown
It'll be on the Wayback Machine. ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
Rich Webb wrote: > On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> > wrote:
>> On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >> <|||newspam...@nezumi.demon.co.uk> wrote:
>>>> In the long run one day the sun will go out, long before that >>>> it will burn earth and make it impossible to live there. >>> Shock horror!! The sun will run out in 4 or 5 billion years. I must >>> remember to cancel the newspapers. >> The gas density at the "surface" of a red giant is much less than the >> athmosperic pressure a few hundres kilometers out of the Earths >> atmosphere. So in practice Earth would rotate around the sun for quite >> a while "inside" the red giant "surface".
>> Remember that the average solar density is in the same order of >> magnitude as water and if the Sun would grow from current 750.000 km >> radius to 150 million kilometer radius to engulf the earth, so the >> average density would be 1/8,000,000 of the density of water or >> 1/10,000 of the density of air at ground level.
>> The problem is of course that the power output from our star will >> increase significantly before this.
>> In order to change the orbital parameters of our planet to navigate >> into a more comfortable orbits and hence radiation levels, some solar >> sails on the ground could be used. After all, there is 5E9 years to do >> the trick.
>> Using a huge number of 1x1 m movable reflectors should be enough .eg. >> with the reflectors acting as spring morning reflectors and spring >> evening and autumn morning acting as absorbers would slowly harness >> the radiation pressure to change the orbital orbit and slowly increase >> the semi-major axle of the Earth to something similar than the orbit >> of Mars.
> Rather a lot of bother. Simpler to just fire up the Sheewash drive.
Given that many red giants fluctuate, and none of them has a very long life--they're the stellar equivalent of the 90-year-old marrying a fashion model--it hardly seems worthwhile. What's a few million years anyway? ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
Jan Panteltje wrote: > On a sunny day (Thu, 29 Oct 2009 08:01:17 +0000) it happened Martin Brown > <|||newspam...@nezumi.demon.co.uk> wrote in <eZbGm.541$zr....@newsfe04.iad>:
>> Jan Panteltje wrote: >>> In the long run one day the sun will go out, long before that >>> it will burn earth and make it impossible to live there. >> Shock horror!! The sun will run out in 4 or 5 billion years. I must >> remember to cancel the newspapers.
> Well, you should cancel those anyways and read online. > Paper kills trees, and distributing stuff spreads viruses.
I only buy newspapers at weekends or on holiday. It is very hard to light a fire using online media or digital paper.
>>> You children's children, and further down the line >>> will be extremely grateful if they have the technology to leave >>> the solar system, and possibly the galaxy, before that. >> It is so far down the line that humans will be long gone and replaced by >> whatever we evolve into. Dinosaurs lasted about 200 million years before >> being out evolved to put things into perspective.
> That sounds a bit like denialism? Sure if we sit and do nothing we will go the dino's way. > I am not saying humanity will not, but we have the ability to use technology to spread > this life form, whatever it may look like in the long run, across the universe.
It is one of those jobs that is sufficiently difficult that the fastest way to get to the desired result is to wait until there is appropriate technology. The same rules of the game apply to anything that requires more than about 3 or 4 years continuous computation. It is faster to go to the beach for 2 years and then start from scratch using hardware that is twice as fast. Moores law is still holding up so far - though you may have to work at load spreading to get the full benefit.
> That may even be in a form we do not yet know, perhaps by shooting containers > with DNA and some other stuff to the stars, the 'plans' so to speak, and let nature > evolve, in millions of years, an other species like us, so seeding the universe. > Maybe that is how we came about anyways?
Perhaps. But with present technology we are not in the game.
>> You have been watching too much Bladerunner - we are never going to get >> out of the solar system with chemical rockets.
> I have never watched 'Bladerunner' that I know about.
It is a good 1980's scifi thriller film. DVD quality is poor. Ridley Scott produced it. Opening sequence based on Teesside steel furnaces. Music by Vangelis. Original had an inappropriate sentimental ending because of Hollywood suits. Directors cut(s) are a bit more hardline. Based on "Do Androids Dream of Electric Sheep".
>> The specific impulse just >> isn't there. Voyager the fastest man made objects ever has not yet >> reached the heliopause after more than thirty years and only another >> 40000 before it reaches the first star.
> Look I know all that stuff, there are other ways, now we will get Vasimir, > there is nuclear, even that Voyager is still working after all that time on a RTG.
It is doing very well indeed considering its design lifetime. Radio telescopes have become more sensitive and bigger too so we can still get a decent signal. I hope that is true when it reaches the heliopause.
> It is just the LEFTIST WEENINES anti nuclear politics that have stopped us from going > to other planets, > HAHAHAHAHAHAHA
Sending people even at solar minimum to Mars would be like signing their death warrant. At best they would have to be tended by robotic nurses on arrival and at worst they would not survive the journey.
>> The fantasy of the rich all moving to another planet and leaving the >> plebs on the rancid remains of the Earth is a right wing fantasy.
> Well, I was thinking everybody, rich or poor. > Maybe we will even be able to slingshot the whole planet to elsewhere, technology advances.
It takes a fair bit of energy to move the Earths orbit.
> Think about it, if 200 years ago, and what is that compared to how long humans have been around, > if your were to mention that *everybody* on earth would have a little box the size of a slice of bread, > and be able to talk and listen to anybody else, even far away, over the seas, you would have been locked > up, possibly burned as a witch by the church, declared insane. > And you should not mention the earth was round, it orbits the sun, and that people will be able to fly, > color paintings (TV) in each house would show a reality and phantasy better then any painter that ever existed, > magic (electric) lights would appear with the touch of a finger, or commanded by voice, > people would ride in carriages without horses at incredible speed, weapons would destroy whole cities at once... > the list is endless.
OTOH we are running out of new physics. That is a dangerous thing to say though - shortly after the last time someone announced that physics would be solved within the decade someone observed the radioactivity and the photoelectric effect. I cannot rule that out but any technology that facilitated the energies needed for interstellar travel would be very dangerous. A speck of dust at relativistic speed does a lot of damage.
> 200 YEARS. > And here you claim limits for the future? > You should really kick the old neural net into gear, its rusted...
Not at all. I made the comment about chemical rocket technology which is completely irrelevant to travelling to the stars.
>>>> There's a lot of vacuum out there. The Chinese are welcome to all they >>>> want. >>> It does not really matter who builds the bases, history shows >>> that empires come, and empires go. >>> We have the sum of all there achievements. >> Oh I expect a lot of hubris and hand wringing from the Americans after >> it happens. Much like they did after the launch of Sputnik.
> Sure, they may want to catch up, but the money printing presses could break down, and are made in China > how to order new ones ?
Phil Hobbs wrote: > Rich Webb wrote: >> On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >> wrote:
>>> On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>> <|||newspam...@nezumi.demon.co.uk> wrote:
>>>>> In the long run one day the sun will go out, long before that >>>>> it will burn earth and make it impossible to live there. >>>> Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>> remember to cancel the newspapers. >>> The gas density at the "surface" of a red giant is much less than the >>> athmosperic pressure a few hundres kilometers out of the Earths >>> atmosphere. So in practice Earth would rotate around the sun for quite >>> a while "inside" the red giant "surface". >>> Remember that the average solar density is in the same order of >>> magnitude as water and if the Sun would grow from current 750.000 km >>> radius to 150 million kilometer radius to engulf the earth, so the >>> average density would be 1/8,000,000 of the density of water or >>> 1/10,000 of the density of air at ground level.
The drag at orbital velocity would still be a problem and once the star surface came within the Roche limit of the Earth we would accrete matter from the solar atmosphere. Red giants shed a fair amount of gas in their old age. M57 is a canonical example.
>>> The problem is of course that the power output from our star will >>> increase significantly before this.
>>> In order to change the orbital parameters of our planet to navigate >>> into a more comfortable orbits and hence radiation levels, some solar >>> sails on the ground could be used. After all, there is 5E9 years to do >>> the trick.
>>> Using a huge number of 1x1 m movable reflectors should be enough .eg. >>> with the reflectors acting as spring morning reflectors and spring >>> evening and autumn morning acting as absorbers would slowly harness >>> the radiation pressure to change the orbital orbit and slowly increase >>> the semi-major axle of the Earth to something similar than the orbit >>> of Mars.
>> Rather a lot of bother. Simpler to just fire up the Sheewash drive.
> Given that many red giants fluctuate, and none of them has a very long > life--they're the stellar equivalent of the 90-year-old marrying a > fashion model--it hardly seems worthwhile. What's a few million years > anyway? ;)
They don't stay red giant for all that long but the core gets to live on as a white dwarf, neutron star or black hole according to the mass it has when the fuel runs out and it implodes under gravity.
I am reminded of a risque late 1970's lecture title by an expert on cataclysmic variable stars:
Can a degenerate white dwarf find lasting happiness in the arms of a red giant? The answer was no. It all ends in tears.
<alien8...@gmail.com> wrote: >On Oct 29, 7:28 am, Rich Webb <bbew...@mapson.nozirev.ten> wrote: >> On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >> wrote:
>> >On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >> ><|||newspam...@nezumi.demon.co.uk> wrote:
>> >>> In the long run one day the sun will go out, long before that >> >>> it will burn earth and make it impossible to live there.
>> >>Shock horror!! The sun will run out in 4 or 5 billion years. I must >> >>remember to cancel the newspapers.
>> >The gas density at the "surface" of a red giant is much less than the >> >athmosperic pressure a few hundres kilometers out of the Earths >> >atmosphere. So in practice Earth would rotate around the sun for quite >> >a while "inside" the red giant "surface".
>> >Remember that the average solar density is in the same order of >> >magnitude as water and if the Sun would grow from current 750.000 km >> >radius to 150 million kilometer radius to engulf the earth, so the >> >average density would be 1/8,000,000 of the density of water or >> >1/10,000 of the density of air at ground level.
>> >The problem is of course that the power output from our star will >> >increase significantly before this.
>> >In order to change the orbital parameters of our planet to navigate >> >into a more comfortable orbits and hence radiation levels, some solar >> >sails on the ground could be used. After all, there is 5E9 years to do >> >the trick.
>> >Using a huge number of 1x1 m movable reflectors should be enough .eg. >> >with the reflectors acting as spring morning reflectors and spring >> >evening and autumn morning acting as absorbers would slowly harness >> >the radiation pressure to change the orbital orbit and slowly increase >> >the semi-major axle of the Earth to something similar than the orbit >> >of Mars.
>> Rather a lot of bother. Simpler to just fire up the Sheewash drive.
> Too dependent on "special skills". Anybody can run a spindizzy.
Good point but can a city-sized drive be scaled up to push a planet around?
Have to root around in my dusty stacks -- haven't read "Cities" for <cough> a while.
> Jan Panteltje wrote: > > On a sunny day (Wed, 28 Oct 2009 14:47:21 -0700) it happened John Larkin > > <jjlar...@highNOTlandTHIStechnologyPART.com> wrote in > > <fpehe5thmhutmkihd7rj39v78ie0arf...@4ax.com>:
> >> Apollo accomplished nothing, and the Space Station carried on that > >> tradition decades after Vietnam. People are finally waking up to the > >> fact that putting people into space is expensive, dangerous, and > >> useless.
> > Look at the bigger picture, from a humanity point of view. > > Apollo was indeed a big step for mankind, first time > > anyone left the planet.
> Agreed. It was stunningly well done and an important milestone.
> > In the long run one day the sun will go out, long before that > > it will burn earth and make it impossible to live there.
> Shock horror!! The sun will run out in 4 or 5 billion years. I must > remember to cancel the newspapers.
> > You children's children, and further down the line > > will be extremely grateful if they have the technology to leave > > the solar system, and possibly the galaxy, before that.
> It is so far down the line that humans will be long gone and replaced by > whatever we evolve into. Dinosaurs lasted about 200 million years before > being out evolved to put things into perspective.
Dinosuars weren't out-evolved - they just didn't put enough money into their asteroid-watch program, and were collateral damage when a decent- sized asteroid got around to hitting the earth. That particular global extinction does seem to be the only one that has been caused by an asteroid impact, while global warming seems to have been a factor in several of the others.
WangoTango wrote: > In article <YLnGm.97$CK...@newsfe12.iad>, > |||newspam...@nezumi.demon.co.uk says... >> I only buy newspapers at weekends or on holiday. It is very hard to >> light a fire using online media or digital paper.
> Then what is the Amazon 'Kindle" good for? > Sounds like it is perfect for the job!
Just driving a nail through the lithium battery should do the trick.
>>On Oct 29, 7:28 am, Rich Webb <bbew...@mapson.nozirev.ten> wrote: >>> On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >>> wrote:
>>> >On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>> ><|||newspam...@nezumi.demon.co.uk> wrote:
>>> >>> In the long run one day the sun will go out, long before that >>> >>> it will burn earth and make it impossible to live there.
>>> >>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>> >>remember to cancel the newspapers.
>>> >The gas density at the "surface" of a red giant is much less than the >>> >athmosperic pressure a few hundres kilometers out of the Earths >>> >atmosphere. So in practice Earth would rotate around the sun for quite >>> >a while "inside" the red giant "surface".
>>> >Remember that the average solar density is in the same order of >>> >magnitude as water and if the Sun would grow from current 750.000 km >>> >radius to 150 million kilometer radius to engulf the earth, so the >>> >average density would be 1/8,000,000 of the density of water or >>> >1/10,000 of the density of air at ground level.
>>> >The problem is of course that the power output from our star will >>> >increase significantly before this.
>>> >In order to change the orbital parameters of our planet to navigate >>> >into a more comfortable orbits and hence radiation levels, some solar >>> >sails on the ground could be used. After all, there is 5E9 years to do >>> >the trick.
>>> >Using a huge number of 1x1 m movable reflectors should be enough .eg. >>> >with the reflectors acting as spring morning reflectors and spring >>> >evening and autumn morning acting as absorbers would slowly harness >>> >the radiation pressure to change the orbital orbit and slowly increase >>> >the semi-major axle of the Earth to something similar than the orbit >>> >of Mars.
>>> Rather a lot of bother. Simpler to just fire up the Sheewash drive.
>> Too dependent on "special skills". Anybody can run a spindizzy.
>Good point but can a city-sized drive be scaled up to push a planet >around?
They did it in the book "Cities in Flight". The City Fathers concept in that book is interesting as well. Though Mayor Amalfi turned out to have gotten pretty old.
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >wrote:
>>On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >><|||newspam...@nezumi.demon.co.uk> wrote:
>>>> In the long run one day the sun will go out, long before that >>>> it will burn earth and make it impossible to live there.
>>>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>remember to cancel the newspapers.
>>The gas density at the "surface" of a red giant is much less than the >>athmosperic pressure a few hundres kilometers out of the Earths >>atmosphere. So in practice Earth would rotate around the sun for quite >>a while "inside" the red giant "surface".
>>Remember that the average solar density is in the same order of >>magnitude as water and if the Sun would grow from current 750.000 km >>radius to 150 million kilometer radius to engulf the earth, so the >>average density would be 1/8,000,000 of the density of water or >>1/10,000 of the density of air at ground level.
>>The problem is of course that the power output from our star will >>increase significantly before this.
>>In order to change the orbital parameters of our planet to navigate >>into a more comfortable orbits and hence radiation levels, some solar >>sails on the ground could be used. After all, there is 5E9 years to do >>the trick.
>>Using a huge number of 1x1 m movable reflectors should be enough .eg. >>with the reflectors acting as spring morning reflectors and spring >>evening and autumn morning acting as absorbers would slowly harness >>the radiation pressure to change the orbital orbit and slowly increase >>the semi-major axle of the Earth to something similar than the orbit >>of Mars.
>>Paul
>There's lots of angular momentum in the asteroid belt. It takes >careful aiming but nearly no energy to nudge an asteroid into a >hyperbolic fly-by of Earth and steal most of its momentum. The math >has been done and it would work. Again, we'd have a long time to do it >and there are lots of asteroids.
>John
I do suspect that the asteroid(s) would become notable (navigation) hazard(s) as a byproduct.
JosephKK wrote: > On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin > <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>> There's lots of angular momentum in the asteroid belt. It takes >> careful aiming but nearly no energy to nudge an asteroid into a >> hyperbolic fly-by of Earth and steal most of its momentum. The math >> has been done and it would work. Again, we'd have a long time to do it >> and there are lots of asteroids.
>> John
> I do suspect that the asteroid(s) would become notable (navigation) > hazard(s) as a byproduct.
Not unless they got the deflection trajectory wrong. There is an Earth watch program to find and catalogue the orbital elements of all near Earth asteroids to check for future potential collisions. An asteroid of just a few km across would really spoil your day of it hit the Earth.
The objective would be to drop them in so that they slow the Earth down in its orbit and the asteroid exits the solar system on para/hyperbolic orbit taking some of our momentum with it. You wouldn't want to leave them in a bound elliptical orbit - that would be asking for trouble.
We would have to be pretty desperate to try this sort of measure. Imagine what the press would make of it given their response to QQ47 doomsday asteroid panic.
"JosephKK"<quiettechb...@yahoo.com> wrote: >On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >>wrote:
>>>On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>><|||newspam...@nezumi.demon.co.uk> wrote:
>>>>> In the long run one day the sun will go out, long before that >>>>> it will burn earth and make it impossible to live there.
>>>>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>>remember to cancel the newspapers.
>>>The gas density at the "surface" of a red giant is much less than the >>>athmosperic pressure a few hundres kilometers out of the Earths >>>atmosphere. So in practice Earth would rotate around the sun for quite >>>a while "inside" the red giant "surface".
>>>Remember that the average solar density is in the same order of >>>magnitude as water and if the Sun would grow from current 750.000 km >>>radius to 150 million kilometer radius to engulf the earth, so the >>>average density would be 1/8,000,000 of the density of water or >>>1/10,000 of the density of air at ground level.
>>>The problem is of course that the power output from our star will >>>increase significantly before this.
>>>In order to change the orbital parameters of our planet to navigate >>>into a more comfortable orbits and hence radiation levels, some solar >>>sails on the ground could be used. After all, there is 5E9 years to do >>>the trick.
>>>Using a huge number of 1x1 m movable reflectors should be enough .eg. >>>with the reflectors acting as spring morning reflectors and spring >>>evening and autumn morning acting as absorbers would slowly harness >>>the radiation pressure to change the orbital orbit and slowly increase >>>the semi-major axle of the Earth to something similar than the orbit >>>of Mars.
>>>Paul
>>There's lots of angular momentum in the asteroid belt. It takes >>careful aiming but nearly no energy to nudge an asteroid into a >>hyperbolic fly-by of Earth and steal most of its momentum. The math >>has been done and it would work. Again, we'd have a long time to do it >>and there are lots of asteroids.
>>John
>I do suspect that the asteroid(s) would become notable (navigation) >hazard(s) as a byproduct.
Mathematics is often more useful than suspicions. It would be easy to design a hyperbolic path that would steal most of the angular momentum of an asteroid. What happens to an object 90e6 miles from the sun that has nearly no angular momentum?
NASA has long used ultra-precise hyperbolic flyby trajectories to boost spacecraft into deep-space paths, farther out than we could easily accomplish with direct rocket thrust. Orbital momentum transfer is already a useful tool.
<|||newspam...@nezumi.demon.co.uk> wrote: >JosephKK wrote: >> On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>> There's lots of angular momentum in the asteroid belt. It takes >>> careful aiming but nearly no energy to nudge an asteroid into a >>> hyperbolic fly-by of Earth and steal most of its momentum. The math >>> has been done and it would work. Again, we'd have a long time to do it >>> and there are lots of asteroids.
>>> John
>> I do suspect that the asteroid(s) would become notable (navigation) >> hazard(s) as a byproduct.
>Not unless they got the deflection trajectory wrong. There is an Earth >watch program to find and catalogue the orbital elements of all near >Earth asteroids to check for future potential collisions. An asteroid of >just a few km across would really spoil your day of it hit the Earth.
>The objective would be to drop them in so that they slow the Earth down >in its orbit and the asteroid exits the solar system on para/hyperbolic >orbit taking some of our momentum with it.
"Suggestions are being taken for a good name for this asteroid. "
How about "Obamaturd" ?:-)
...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 |
Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!"
John Larkin wrote: > On Thu, 05 Nov 2009 08:29:05 +0000, Martin Brown > <|||newspam...@nezumi.demon.co.uk> wrote:
>> JosephKK wrote: >>> On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>> There's lots of angular momentum in the asteroid belt. It takes >>>> careful aiming but nearly no energy to nudge an asteroid into a >>>> hyperbolic fly-by of Earth and steal most of its momentum. The math >>>> has been done and it would work. Again, we'd have a long time to do it >>>> and there are lots of asteroids.
>>>> John >>> I do suspect that the asteroid(s) would become notable (navigation) >>> hazard(s) as a byproduct. >> Not unless they got the deflection trajectory wrong. There is an Earth >> watch program to find and catalogue the orbital elements of all near >> Earth asteroids to check for future potential collisions. An asteroid of >> just a few km across would really spoil your day of it hit the Earth.
>> The objective would be to drop them in so that they slow the Earth down >> in its orbit and the asteroid exits the solar system on para/hyperbolic >> orbit taking some of our momentum with it.
> Or drop them into the sun.
Paradoxically it takes a lot more energy to drop something into the sun starting from our orbital velocity than it does to send it out to infinity. Probes bound for Mercury need very big rockets!
<|||newspam...@nezumi.demon.co.uk> wrote: >John Larkin wrote: >> On Thu, 05 Nov 2009 08:29:05 +0000, Martin Brown >> <|||newspam...@nezumi.demon.co.uk> wrote:
>>> JosephKK wrote: >>>> On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>> There's lots of angular momentum in the asteroid belt. It takes >>>>> careful aiming but nearly no energy to nudge an asteroid into a >>>>> hyperbolic fly-by of Earth and steal most of its momentum. The math >>>>> has been done and it would work. Again, we'd have a long time to do it >>>>> and there are lots of asteroids.
>>>>> John >>>> I do suspect that the asteroid(s) would become notable (navigation) >>>> hazard(s) as a byproduct. >>> Not unless they got the deflection trajectory wrong. There is an Earth >>> watch program to find and catalogue the orbital elements of all near >>> Earth asteroids to check for future potential collisions. An asteroid of >>> just a few km across would really spoil your day of it hit the Earth.
>There is a *much* cooler one with an orbit that is like a long sausage >bent around the Earth's orbit. And this newer one I found while looking >for it.
>>> The objective would be to drop them in so that they slow the Earth down >>> in its orbit and the asteroid exits the solar system on para/hyperbolic >>> orbit taking some of our momentum with it.
>> Or drop them into the sun.
>Paradoxically it takes a lot more energy to drop something into the sun >starting from our orbital velocity than it does to send it out to >infinity. Probes bound for Mercury need very big rockets!
>Regards, >Martin Brown
But our goal is to steal all the angular momentum that we can. Ideally we'd leave the asteroid nearly motionless after we suck it dry, and let it drop directly into the sun. Splat!
That would be Cruithne. It's orbit looks weird indeed, from an earth-centered perspective.
However, the asteroid simply orbits the sun in an elliptical orbit that happens to have a period very close to one year. It looks much simpler that way.
Apparently it *does* exchange momentum with the earth from time to time, so that over a period of several hundred years, it is locked to the earth's orbit around the sun. The lock-in transient hasn't died out yet, it would seem.
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 05 Nov 2009 15:07:07 +0000, Martin Brown ><|||newspam...@nezumi.demon.co.uk> wrote:
>>John Larkin wrote: >>> On Thu, 05 Nov 2009 08:29:05 +0000, Martin Brown >>> <|||newspam...@nezumi.demon.co.uk> wrote:
>>>> JosephKK wrote: >>>>> On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>>> There's lots of angular momentum in the asteroid belt. It takes >>>>>> careful aiming but nearly no energy to nudge an asteroid into a >>>>>> hyperbolic fly-by of Earth and steal most of its momentum. The math >>>>>> has been done and it would work. Again, we'd have a long time to do it >>>>>> and there are lots of asteroids.
>>>>>> John >>>>> I do suspect that the asteroid(s) would become notable (navigation) >>>>> hazard(s) as a byproduct. >>>> Not unless they got the deflection trajectory wrong. There is an Earth >>>> watch program to find and catalogue the orbital elements of all near >>>> Earth asteroids to check for future potential collisions. An asteroid of >>>> just a few km across would really spoil your day of it hit the Earth.
>>There is a *much* cooler one with an orbit that is like a long sausage >>bent around the Earth's orbit. And this newer one I found while looking >>for it.
>>>> The objective would be to drop them in so that they slow the Earth down >>>> in its orbit and the asteroid exits the solar system on para/hyperbolic >>>> orbit taking some of our momentum with it.
>>> Or drop them into the sun.
>>Paradoxically it takes a lot more energy to drop something into the sun >>starting from our orbital velocity than it does to send it out to >>infinity. Probes bound for Mercury need very big rockets!
>>Regards, >>Martin Brown
>But our goal is to steal all the angular momentum that we can. Ideally >we'd leave the asteroid nearly motionless after we suck it dry, and >let it drop directly into the sun. Splat!
>John
Using the Al Gore Rules of Physics ;-)
...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 |
Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!"
>That would be Cruithne. It's orbit looks weird indeed, from >an earth-centered perspective.
>However, the asteroid simply orbits the sun in an elliptical >orbit that happens to have a period very close to one year. >It looks much simpler that way.
>Apparently it *does* exchange momentum with the earth from time >to time, so that over a period of several hundred years, it is >locked to the earth's orbit around the sun. The lock-in transient >hasn't died out yet, it would seem.
>Jeroen Belleman
It apparently alternates sign on the momentum transfer, so long-term it averages to about zero.
>>On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >>>wrote:
>>>>On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>>><|||newspam...@nezumi.demon.co.uk> wrote:
>>>>>> In the long run one day the sun will go out, long before that >>>>>> it will burn earth and make it impossible to live there.
>>>>>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>>>remember to cancel the newspapers.
>>>>The gas density at the "surface" of a red giant is much less than the >>>>athmosperic pressure a few hundres kilometers out of the Earths >>>>atmosphere. So in practice Earth would rotate around the sun for quite >>>>a while "inside" the red giant "surface".
>>>>Remember that the average solar density is in the same order of >>>>magnitude as water and if the Sun would grow from current 750.000 km >>>>radius to 150 million kilometer radius to engulf the earth, so the >>>>average density would be 1/8,000,000 of the density of water or >>>>1/10,000 of the density of air at ground level.
>>>>The problem is of course that the power output from our star will >>>>increase significantly before this.
>>>>In order to change the orbital parameters of our planet to navigate >>>>into a more comfortable orbits and hence radiation levels, some solar >>>>sails on the ground could be used. After all, there is 5E9 years to do >>>>the trick.
>>>>Using a huge number of 1x1 m movable reflectors should be enough .eg. >>>>with the reflectors acting as spring morning reflectors and spring >>>>evening and autumn morning acting as absorbers would slowly harness >>>>the radiation pressure to change the orbital orbit and slowly increase >>>>the semi-major axle of the Earth to something similar than the orbit >>>>of Mars.
>>>>Paul
>>>There's lots of angular momentum in the asteroid belt. It takes >>>careful aiming but nearly no energy to nudge an asteroid into a >>>hyperbolic fly-by of Earth and steal most of its momentum. The math >>>has been done and it would work. Again, we'd have a long time to do it >>>and there are lots of asteroids.
>>>John
>>I do suspect that the asteroid(s) would become notable (navigation) >>hazard(s) as a byproduct.
>Mathematics is often more useful than suspicions. It would be easy to >design a hyperbolic path that would steal most of the angular momentum >of an asteroid. What happens to an object 90e6 miles from the sun that >has nearly no angular momentum?
>NASA has long used ultra-precise hyperbolic flyby trajectories to >boost spacecraft into deep-space paths, farther out than we could >easily accomplish with direct rocket thrust. Orbital momentum transfer >is already a useful tool.
Part of the problem is that you need is not precisely zero WRT the sun, but that you need something that is on the order of 1E-40 of its previous momentum about the sun. Otherwise it misses and becomes a problem again, of course this assumes that "dropping" that much mass (many megatons to several gigatons) into the sun will not have unwanted effects. A better plan may be to impact Mercury or Venus instead, much smaller targets, but far less to drop that much mass into.
"JosephKK"<quiettechb...@yahoo.com> wrote: >On Thu, 05 Nov 2009 06:27:43 -0800, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>On Wed, 04 Nov 2009 21:23:38 -0800, >>"JosephKK"<quiettechb...@yahoo.com> wrote:
>>>On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >>>>wrote:
>>>>>On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>>>><|||newspam...@nezumi.demon.co.uk> wrote:
>>>>>>> In the long run one day the sun will go out, long before that >>>>>>> it will burn earth and make it impossible to live there.
>>>>>>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>>>>remember to cancel the newspapers.
>>>>>The gas density at the "surface" of a red giant is much less than the >>>>>athmosperic pressure a few hundres kilometers out of the Earths >>>>>atmosphere. So in practice Earth would rotate around the sun for quite >>>>>a while "inside" the red giant "surface".
>>>>>Remember that the average solar density is in the same order of >>>>>magnitude as water and if the Sun would grow from current 750.000 km >>>>>radius to 150 million kilometer radius to engulf the earth, so the >>>>>average density would be 1/8,000,000 of the density of water or >>>>>1/10,000 of the density of air at ground level.
>>>>>The problem is of course that the power output from our star will >>>>>increase significantly before this.
>>>>>In order to change the orbital parameters of our planet to navigate >>>>>into a more comfortable orbits and hence radiation levels, some solar >>>>>sails on the ground could be used. After all, there is 5E9 years to do >>>>>the trick.
>>>>>Using a huge number of 1x1 m movable reflectors should be enough .eg. >>>>>with the reflectors acting as spring morning reflectors and spring >>>>>evening and autumn morning acting as absorbers would slowly harness >>>>>the radiation pressure to change the orbital orbit and slowly increase >>>>>the semi-major axle of the Earth to something similar than the orbit >>>>>of Mars.
>>>>>Paul
>>>>There's lots of angular momentum in the asteroid belt. It takes >>>>careful aiming but nearly no energy to nudge an asteroid into a >>>>hyperbolic fly-by of Earth and steal most of its momentum. The math >>>>has been done and it would work. Again, we'd have a long time to do it >>>>and there are lots of asteroids.
>>>>John
>>>I do suspect that the asteroid(s) would become notable (navigation) >>>hazard(s) as a byproduct.
>>Mathematics is often more useful than suspicions. It would be easy to >>design a hyperbolic path that would steal most of the angular momentum >>of an asteroid. What happens to an object 90e6 miles from the sun that >>has nearly no angular momentum?
>>NASA has long used ultra-precise hyperbolic flyby trajectories to >>boost spacecraft into deep-space paths, farther out than we could >>easily accomplish with direct rocket thrust. Orbital momentum transfer >>is already a useful tool.
>Part of the problem is that you need is not precisely zero WRT the >sun, but that you need something that is on the order of 1E-40 of its >previous momentum about the sun. Otherwise it misses and becomes a >problem again, of course this assumes that "dropping" that much mass >(many megatons to several gigatons) into the sun will not have >unwanted effects. A better plan may be to impact Mercury or Venus >instead, much smaller targets, but far less to drop that much mass >into.
Mercury and Venus are easier to hit than the sun? Wow, you learn something every day here on usenet.
>>On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >>>wrote:
>>>>On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>>><|||newspam...@nezumi.demon.co.uk> wrote:
>>>>>> In the long run one day the sun will go out, long before that >>>>>> it will burn earth and make it impossible to live there.
>>>>>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>>>remember to cancel the newspapers.
>>>>The gas density at the "surface" of a red giant is much less than the >>>>athmosperic pressure a few hundres kilometers out of the Earths >>>>atmosphere. So in practice Earth would rotate around the sun for quite >>>>a while "inside" the red giant "surface".
>>>>Remember that the average solar density is in the same order of >>>>magnitude as water and if the Sun would grow from current 750.000 km >>>>radius to 150 million kilometer radius to engulf the earth, so the >>>>average density would be 1/8,000,000 of the density of water or >>>>1/10,000 of the density of air at ground level.
>>>>The problem is of course that the power output from our star will >>>>increase significantly before this.
>>>>In order to change the orbital parameters of our planet to navigate >>>>into a more comfortable orbits and hence radiation levels, some solar >>>>sails on the ground could be used. After all, there is 5E9 years to do >>>>the trick.
>>>>Using a huge number of 1x1 m movable reflectors should be enough .eg. >>>>with the reflectors acting as spring morning reflectors and spring >>>>evening and autumn morning acting as absorbers would slowly harness >>>>the radiation pressure to change the orbital orbit and slowly increase >>>>the semi-major axle of the Earth to something similar than the orbit >>>>of Mars.
>>>>Paul
>>>There's lots of angular momentum in the asteroid belt. It takes >>>careful aiming but nearly no energy to nudge an asteroid into a >>>hyperbolic fly-by of Earth and steal most of its momentum. The math >>>has been done and it would work. Again, we'd have a long time to do it >>>and there are lots of asteroids.
>>>John
>>I do suspect that the asteroid(s) would become notable (navigation) >>hazard(s) as a byproduct.
>Mathematics is often more useful than suspicions. It would be easy to >design a hyperbolic path that would steal most of the angular momentum >of an asteroid. What happens to an object 90e6 miles from the sun that >has nearly no angular momentum?
>NASA has long used ultra-precise hyperbolic flyby trajectories to >boost spacecraft into deep-space paths, farther out than we could >easily accomplish with direct rocket thrust. Orbital momentum transfer >is already a useful tool.
>John
Momentum transfer is a useful tool to be sure, but there is a big difference between managing 5 tons at 1E-8 accuracy and managing 1E6 tons to 1E-14 accuracy. Say about a billion times the impulse required? How much would it take to loft a billion times the impulse available to voyager after Mars flyby?
"JosephKK"<quiettechb...@yahoo.com> wrote: >On Thu, 05 Nov 2009 06:27:43 -0800, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>On Wed, 04 Nov 2009 21:23:38 -0800, >>"JosephKK"<quiettechb...@yahoo.com> wrote:
>>>On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >>>>wrote:
>>>>>On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>>>><|||newspam...@nezumi.demon.co.uk> wrote:
>>>>>>> In the long run one day the sun will go out, long before that >>>>>>> it will burn earth and make it impossible to live there.
>>>>>>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>>>>remember to cancel the newspapers.
>>>>>The gas density at the "surface" of a red giant is much less than the >>>>>athmosperic pressure a few hundres kilometers out of the Earths >>>>>atmosphere. So in practice Earth would rotate around the sun for quite >>>>>a while "inside" the red giant "surface".
>>>>>Remember that the average solar density is in the same order of >>>>>magnitude as water and if the Sun would grow from current 750.000 km >>>>>radius to 150 million kilometer radius to engulf the earth, so the >>>>>average density would be 1/8,000,000 of the density of water or >>>>>1/10,000 of the density of air at ground level.
>>>>>The problem is of course that the power output from our star will >>>>>increase significantly before this.
>>>>>In order to change the orbital parameters of our planet to navigate >>>>>into a more comfortable orbits and hence radiation levels, some solar >>>>>sails on the ground could be used. After all, there is 5E9 years to do >>>>>the trick.
>>>>>Using a huge number of 1x1 m movable reflectors should be enough .eg. >>>>>with the reflectors acting as spring morning reflectors and spring >>>>>evening and autumn morning acting as absorbers would slowly harness >>>>>the radiation pressure to change the orbital orbit and slowly increase >>>>>the semi-major axle of the Earth to something similar than the orbit >>>>>of Mars.
>>>>>Paul
>>>>There's lots of angular momentum in the asteroid belt. It takes >>>>careful aiming but nearly no energy to nudge an asteroid into a >>>>hyperbolic fly-by of Earth and steal most of its momentum. The math >>>>has been done and it would work. Again, we'd have a long time to do it >>>>and there are lots of asteroids.
>>>>John
>>>I do suspect that the asteroid(s) would become notable (navigation) >>>hazard(s) as a byproduct.
>>Mathematics is often more useful than suspicions. It would be easy to >>design a hyperbolic path that would steal most of the angular momentum >>of an asteroid. What happens to an object 90e6 miles from the sun that >>has nearly no angular momentum?
>>NASA has long used ultra-precise hyperbolic flyby trajectories to >>boost spacecraft into deep-space paths, farther out than we could >>easily accomplish with direct rocket thrust. Orbital momentum transfer >>is already a useful tool.
>>John
>Momentum transfer is a useful tool to be sure, but there is a big >difference between managing 5 tons at 1E-8 accuracy and managing 1E6 >tons to 1E-14 accuracy. Say about a billion times the impulse >required? How much would it take to loft a billion times the impulse >available to voyager after Mars flyby?
The sun is about a degree wide as seen from earth. That's a pretty big target. Voyager 2 slingshotted Jupiter, then Saturn, then Uranus, then Neptune. A quad slingshot requires much higher precision than a simple dump into the sun. A few hundred million years from now, technology should be up to it.
The impulse is available almost for free, from other asteroids in the asteroid belt. Just slingshot them.
>>On Thu, 05 Nov 2009 06:27:43 -0800, John Larkin >><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>On Wed, 04 Nov 2009 21:23:38 -0800, >>>"JosephKK"<quiettechb...@yahoo.com> wrote:
>>>>On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >>>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>>>On Thu, 29 Oct 2009 15:50:43 +0200, Paul Keinanen <keina...@sci.fi> >>>>>wrote:
>>>>>>On Thu, 29 Oct 2009 08:01:17 +0000, Martin Brown >>>>>><|||newspam...@nezumi.demon.co.uk> wrote:
>>>>>>>> In the long run one day the sun will go out, long before that >>>>>>>> it will burn earth and make it impossible to live there.
>>>>>>>Shock horror!! The sun will run out in 4 or 5 billion years. I must >>>>>>>remember to cancel the newspapers.
>>>>>>The gas density at the "surface" of a red giant is much less than the >>>>>>athmosperic pressure a few hundres kilometers out of the Earths >>>>>>atmosphere. So in practice Earth would rotate around the sun for quite >>>>>>a while "inside" the red giant "surface".
>>>>>>Remember that the average solar density is in the same order of >>>>>>magnitude as water and if the Sun would grow from current 750.000 km >>>>>>radius to 150 million kilometer radius to engulf the earth, so the >>>>>>average density would be 1/8,000,000 of the density of water or >>>>>>1/10,000 of the density of air at ground level.
>>>>>>The problem is of course that the power output from our star will >>>>>>increase significantly before this.
>>>>>>In order to change the orbital parameters of our planet to navigate >>>>>>into a more comfortable orbits and hence radiation levels, some solar >>>>>>sails on the ground could be used. After all, there is 5E9 years to do >>>>>>the trick.
>>>>>>Using a huge number of 1x1 m movable reflectors should be enough .eg. >>>>>>with the reflectors acting as spring morning reflectors and spring >>>>>>evening and autumn morning acting as absorbers would slowly harness >>>>>>the radiation pressure to change the orbital orbit and slowly increase >>>>>>the semi-major axle of the Earth to something similar than the orbit >>>>>>of Mars.
>>>>>>Paul
>>>>>There's lots of angular momentum in the asteroid belt. It takes >>>>>careful aiming but nearly no energy to nudge an asteroid into a >>>>>hyperbolic fly-by of Earth and steal most of its momentum. The math >>>>>has been done and it would work. Again, we'd have a long time to do it >>>>>and there are lots of asteroids.
>>>>>John
>>>>I do suspect that the asteroid(s) would become notable (navigation) >>>>hazard(s) as a byproduct.
>>>Mathematics is often more useful than suspicions. It would be easy to >>>design a hyperbolic path that would steal most of the angular momentum >>>of an asteroid. What happens to an object 90e6 miles from the sun that >>>has nearly no angular momentum?
>>>NASA has long used ultra-precise hyperbolic flyby trajectories to >>>boost spacecraft into deep-space paths, farther out than we could >>>easily accomplish with direct rocket thrust. Orbital momentum transfer >>>is already a useful tool.
>>>John
>>Momentum transfer is a useful tool to be sure, but there is a big >>difference between managing 5 tons at 1E-8 accuracy and managing 1E6 >>tons to 1E-14 accuracy. Say about a billion times the impulse >>required? How much would it take to loft a billion times the impulse >>available to voyager after Mars flyby?
>The sun is about a degree wide as seen from earth. That's a pretty big >target. Voyager 2 slingshotted Jupiter, then Saturn, then Uranus, then >Neptune. A quad slingshot requires much higher precision than a simple >dump into the sun. A few hundred million years from now, technology >should be up to it.
The sun is an easy target. Cancelling the delta-V of an orbiting body isn't so easy. Do the second and the first is a done deal. The only way to do it, in fact.
JosephKK wrote: > On Thu, 05 Nov 2009 06:27:43 -0800, John Larkin > <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>> On Wed, 04 Nov 2009 21:23:38 -0800, >> "JosephKK"<quiettechb...@yahoo.com> wrote:
>>> On Thu, 29 Oct 2009 08:20:14 -0700, John Larkin >>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>>>> There's lots of angular momentum in the asteroid belt. It takes >>>> careful aiming but nearly no energy to nudge an asteroid into a >>>> hyperbolic fly-by of Earth and steal most of its momentum. The math >>>> has been done and it would work. Again, we'd have a long time to do it >>>> and there are lots of asteroids.
>>>> John >>> I do suspect that the asteroid(s) would become notable (navigation) >>> hazard(s) as a byproduct. >> Mathematics is often more useful than suspicions. It would be easy to >> design a hyperbolic path that would steal most of the angular momentum >> of an asteroid. What happens to an object 90e6 miles from the sun that >> has nearly no angular momentum?
It is still easier to fling them out of the solar system entirely. And there is a *lot* more of it to aim for.
>> NASA has long used ultra-precise hyperbolic flyby trajectories to >> boost spacecraft into deep-space paths, farther out than we could >> easily accomplish with direct rocket thrust. Orbital momentum transfer >> is already a useful tool.
Although we tend to use one of the gas giants. Much more bang per buck.
> Part of the problem is that you need is not precisely zero WRT the > sun, but that you need something that is on the order of 1E-40 of its > previous momentum about the sun. Otherwise it misses and becomes a > problem again, of course this assumes that "dropping" that much mass > (many megatons to several gigatons) into the sun will not have > unwanted effects. A better plan may be to impact Mercury or Venus > instead, much smaller targets, but far less to drop that much mass > into.
Comets do crash into the sun and/or get very close indeed. SOHO data is released in realtime precisely so that keen amateurs can use software to search for them as professionals are not really that interested in them. 1600 comets found so far in 13 years operation. That is more than any other comet detection system and it is a byproduct of the solar coronagraph. Even have their own website.
BTW the sun would barely notice if the Earth hit it head on.
There are a handful of old observations from noted comet seekers of comets that were brilliant one night setting just after the sun and never seen again (respected observers). They were generally not believed. These days SOHO shows the ones that go in but do not come out.
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