Major impact event on Jupiter

[Orionblamblam]

BLAM!

http://up-ship.com/blog/?p=3310

 

[bobbymike]

When Shoemaker - Levy happened I thought (pre-apologize to all the atheists and agnostics) to myself that God is telling us to get off our butts and not only prepare for a potential earth impact but get off the planet and spread humanity among the stars. The only way to absolutely ensure the future of mankind is to get off the Earth.

 

[sferrin]

You know the thing I find interesting is how most people kinda gloss over the fact that those same impacts on Earth would be catastrophic. And Jupiter has had two of them (that we know off) in just a couple decades.

 

[Ian33]

That single impact would of ended all life on earth - the damage would of been global, and with enough ferocity to strip our atmosphere right off the planet.

Shows how damn huge Jupiter is - after the multiple strike from Levy, it leaves you in no doubt what a fragile foothold we have on life. One thing though - it also makes me think that Jupiter is some kind of solar system hoover that saves us by sucking in comets et al with its huge gravity and magnetic fields...

 

[Abraham Gubler]

You know the thing I find interesting is how most people kinda gloss over the fact that those same impacts on Earth would be catastrophic. And Jupiter has had two of them (that we know off) in just a couple decades.

Jupiter is in a whole different league to Earth when it comes to attracting comets and asteroids. One of the reasons we get it so long between a major hit is that Jupiter is in our Solar System sucking up all the hits.

 

[bobbymike]

You know the thing I find interesting is how most people kinda gloss over the fact that those same impacts on Earth would be catastrophic. And Jupiter has had two of them (that we know off) in just a couple decades.

Jupiter is in a whole different league to Earth when it comes to attracting comets and asteroids. One of the reasons we get it so long between a major hit is that Jupiter is in our Solar System sucking up all the hits.

Maybe "Someone" put Jupiter there for this very reason to give us a chance to develop enough technologically to move off the fragile earth and populate the Galaxy. Everyone should read the book "The Millennial Project: Colonizing the Galaxy in Eight Easy Steps", by Marshall Savage.

 

[Orionblamblam]

[
Maybe "Someone" put Jupiter there...

It was Xenu!! I just know it!

 

[bobbymike]

I was thinking Vishnu or Shiva.

 

[Abraham Gubler]

Maybe "Someone" put Jupiter there for this very reason to give us a chance to develop enough technologically to move off the fragile earth and populate the Galaxy.

Without Jupiter its unlikely that life could evolve beyond the simplest forms on Earth. As the frequent bombarding of the planet would seriously disrupt the large numbers of generations needed to evolve from plankton to whale. So if you believe in the universe as it physically appears to be and also believe in some kind of supreme being that made it so then I guess you could conclude that the presence of Jupiter was one of the steps needed to create and sustain life on Earth.

Or you could believe that the presence of Jupiter through natural causes was just one of the many steps needed for life to evolve on Earth since the formation of our universe and why of all the billions and billions of stars only those billions of billions with high gravity planets to act as goalkeepers will be in a position to make possible the evolution of life. Another limitation on the possibility of sentient existence and why we haven't yet found anyone else in our end of the galaxy.

Or you could believe in a literal interpretation of whatever holy book takes your fancy and with the likely exception of Xenu and the Scientologists this means you must believe that this is all an elaborate fake.

 

[Orionblamblam]

Without Jupiter its unlikely that life could evolve beyond the simplest forms on Earth. As the frequent bombarding of the planet would seriously disrupt the large numbers of generations needed to evolve from plankton to whale.

A series of major impact events might wipe out a lot of critters, might even wipe out multicellular life, but even without Jupiter the inner solar system would have been pretty clean of the *big* impactors (hundreds of KM dia) by a billion or more years ago. So the worst that would happen woudl be that evolution would be *delayed.* Heck, who knows... without Jupiter, life on Earth could have evolved *faster* due to the more exciting environment... and the children of Earth might have colonized MGC 5679 a hundred million years ago.

 

[Rosdivan]

That single impact would of ended all life on earth - the damage would of been global, and with enough ferocity to strip our atmosphere right off the planet.

Doubtful. Aerial detonations on gas giants aren't quite comparable to impacts on Earth. It probably wasn't any larger than Shoemaker Levy 9, which was in fragments 1-2km in diameter when it impacted. Now, we've been hit by several asteroids half a dozen miles in diameter or more, and they've never managed to do anything of the sort, not even with the Permian-Triassic extinction event (impact theories of which involve asteroids up to 30 miles wide).

[quote author=bobbymike]
The only way to absolutely ensure the future of mankind is to get off the Earth.[/quote]

'Tis a pity that we have to deal with such minor issues as the complete inhabitability of the solar system, the necessity of a society and economy that would make communism seem downright pleasant, and that whole "unaffordable" issue.

 

[SOC]

Wow, you guys sure took this on some interesting tangents. ANYway, Jupiter is not quite shielding the Earth from impactors. Being a larger body, it does exert a greater pull on objects at a greater distance than the Earth does. But to claim that it is shielding the Earth is a little far-fetched. These things can come from any direction, and Jupiter would have to be close enough to the Earth for its gravitational field to take precedence to actually suck an impactor off on a different course. Random bits gallavanting through space are going to typically be drawn our way by the pull of the Sun. You need to get pretty close (in an astronomical sense) to have a planet's influence draw one of these things in and away from its natural course through the Sun's gravitational sphere of influence. This is why we have a Moon, and get buzzed by comets. The Moon is close enough to remain attracted to the Earth, but Comets don't come close enough to become perturbed into our atmosphere (or at least they aren't currently doing so at this exact moment). Inertia also plays into this, as do relative velocities and trajectories, but to go there would require a mental exertion I am not prepared for at 4AM, "rocket scientist" or no. Basically, Jupiter gets hosed because of its size.

Incidentially, I have determined what my "rocket science" education really is, while talking with some people this afternoon as our 2 year olds were chasing each other across the playground. It's a Party Degree. As in, it sounds great at a party, but is otherwise not currently so useful. Thought I'd share that bit of hilarity, being that it is 4AM and all. ;D

 

[bobbymike]

[quote author=bobbymike]
The only way to absolutely ensure the future of mankind is to get off the Earth.[/quote]

'Tis a pity that we have to deal with such minor issues as the complete inhabitability of the solar system, the necessity of a society and economy that would make communism seem downright pleasant, and that whole "unaffordable" issue.
[/quote]

That's what makes it interesting because it is so difficult. JFK - "We go to the Moon not because it is easy but because it is hard."

It stirs the creativity of mankind's soul and as one 40th anniversary of the Moon landing commentator said "If we waited for every social problem to be solved before we ventured out we would have never left the caves.

As for resources it is always about priorities not affordability. NASA's budget is around $19 billion the US federal budget is $3.6 trillion. I think it would be possible to spend a little more. In fact if we had ten years to get off the planet the US alone could easily spend a trillion/year. You want Buck Rogers you need the bucks (to paraphrase "The Right Stuff")

 

[Abraham Gubler]

Tis a pity that we have to deal with such minor issues as the complete inhabitability of the solar system, the necessity of a society and economy that would make communism seem downright pleasant, and that whole "unaffordable" issue.

The solar system is habitable. Its got free energy (sunlight) and lots of water... With a bit of work Mars and Venus could be converted to something like Earth with their own foibles of no Van Allen belt (Mars) and very long days (Venus).

As to the cost of getting a permanent, sustainable human settlement off Earth it would be no where near the kind of 40% of a deflated GDP that state capitalist economies (the Soviet Union was never a communist economy) can allocate. For one you don't need to lift everyone off Earth as humans are capable of reproduction from local resources. Secondly our current systems of space travel are hugely inefficient primarily because they are not built for mass scale. A hand built Bently costs a lot more than a mass produced Toyota Camray but they both can drive people along a highway in reasonable comfort and safety.

Apart from some kind of sense of biosphere survival (not just humans) expansion into outer space is muchly needed because human's don't do to well in stagnate societies. Growth brings out the best in us.

 

[sferrin]

Incidentially, I have determined what my "rocket science" education really is, while talking with some people this afternoon as our 2 year olds were chasing each other across the playground. It's a Party Degree. As in, it sounds great at a party, but is otherwise not currently so useful.

You can add "Game Developer" to that list.

 

[Hammer Birchgrove]

Tis a pity that we have to deal with such minor issues as the complete inhabitability of the solar system, the necessity of a society and economy that would make communism seem downright pleasant, and that whole "unaffordable" issue.

The solar system is habitable. Its got free energy (sunlight) and lots of water... With a bit of work Mars and Venus could be converted to something like Earth with their own foibles of no Van Allen belt (Mars) and very long days (Venus).

As to the cost of getting a permanent, sustainable human settlement off Earth it would be no where near the kind of 40% of a deflated GDP that state capitalist economies (the Soviet Union was never a communist economy) can allocate. For one you don't need to lift everyone off Earth as humans are capable of reproduction from local resources. Secondly our current systems of space travel are hugely inefficient primarily because they are not built for mass scale. A hand built Bently costs a lot more than a mass produced Toyota Camray but they both can drive people along a highway in reasonable comfort and safety.

Apart from some kind of sense of biosphere survival (not just humans) expansion into outer space is muchly needed because human's don't do to well in stagnate societies. Growth brings out the best in us.

Hopefully the costs will get payed by solar power station on the lunar surface or orbiting around the Earth, and by helium-3 mining.

 

[sferrin]

http://hubblesite.org/newscenter/archive/releases/2009/23/image/d/format/web_print/




I've thought of a use for the big Ares booster. We're all rubber-neckers at heart (even if some of us refuse to admit it), so I propose we send a family of probes to Jupiter outfitted with IMAX cameras and some high power radars for early warning and wait for the next crash. Sure they'd require power so we'd have to design some space capable nuclear reactors and so forth. Better yet, somebody blow the dust off the Big Dumb Booster/ Sea Dragon concept and ditch the Ares.

Just for giggles:

 

[bobbymike]

sferrin - I read about the Sea Dragon when you told me about the Aerojet 260" diameter solid rocket motor. Sea Dragon what an incredible rocket. Could someone really build a booster with 80 million lbs of thrust? Incredible.

 

[sferrin]

sferrin - I read about the Sea Dragon when you told me about the Aerojet 260" diameter solid rocket motor. Sea Dragon what an incredible rocket. Could someone really build a booster with 80 million lbs of thrust? Incredible.

There's a Boeing design mentioned in APR that would have used 14 of those 260" boosters or 10 372" diameter boosters around a central liquid core.

 

[Justo Miranda]

"The solar system is habitable. Its got free energy (sunlight) and lots of water... With a bit of work Mars and Venus could be converted to something like Earth with their own foibles of no Van Allen belt (Mars) and very long days (Venus)."


The main issue for the terraformation of Venus is the slow rotation of the planet. The long days, at such a short distance from the sun, produce excessive heating.
Although in a distant future we would have the technical means to increase the rotation speed, this would produce gigantic earthquakes.

In my opinion, the cheapest solution would be, at the current state of technology, is to surround the planet with a powder ring coming from an asteroid, that would decrease the amount of light received from the sun.

Spaceships should avoid it using polar orbits of entrance and exit.

The tectonic phenomena originated by the cooling of the planet crust are unavoidable, but might be regulated by slowly increasing the amount of powder in orbit.
How long would that process take? Does anybody dare to calculate an estimate?

 

[Orionblamblam]

The main issue for the terraformation of Venus is the slow rotation of the planet. The long days, at such a short distance from the sun, produce excessive heating.

Actually, in many ways we could more easily colonize Venus *now* than we could Mars. We just wouldn't colonize the ground, but the sky above the sulfuric acid clouds. At about 60 km altitude, the atmospheric pressure drops to about that of sea level on Earth... and the temperature at that altitude is remarkably mild. The air is almost pure carbon dioxide. This opens the door to balloon-borne cities, with giant hydrogen filled balloons. Hydrogen would have vast lifting potential, about 50% more than on Earth, due to the density of CO2; and since CO2 and hydrogen are basically non-reactive, there be no risk of fire. The water/oxygen/hydrogen needs of the colonies would be met by dipping into the clouds below.

 

[Hammer Birchgrove]

The main issue for the terraformation of Venus is the slow rotation of the planet. The long days, at such a short distance from the sun, produce excessive heating.

Actually, in many ways we could more easily colonize Venus *now* than we could Mars. We just wouldn't colonize the ground, but the sky above the sulphuric acid clouds. At about 60 km altitude, the atmospheric pressure drops to about that of sea level on Earth... and the temperature at that altitude is remarkably mild. The air is almost pure carbon dioxide. This opens the door to balloon-borne cities, with giant hydrogen filled balloons. Hydrogen would have vast lifting potential, about 50% more than on Earth, due to the density of CO2; and since CO2 and hydrogen are basically non-reactive, there be no risk of fire. The water/oxygen/hydrogen needs of the colonies would be met by dipping into the clouds below.

Well that sounds far easier than, lets say, living under the ocean (as in some SF novels). We could live in those balloons/airships while algae converts the CO2 down under to O2.

Is there a way to get rid of the sulphuric acid?

 

[bobbymike]

sferrin - I read about the Sea Dragon when you told me about the Aerojet 260" diameter solid rocket motor. Sea Dragon what an incredible rocket. Could someone really build a booster with 80 million lbs of thrust? Incredible.

There's a Boeing design mentioned in APR that would have used 14 of those 260" boosters or 10 372" diameter boosters around a central liquid core.

sferrin - sorry to sound ignorant but what is APR? I would use just one 372" booster for an ICBM!! ;D

 

[Matej]

Probably it is Scott's Aerospace Projects Review.

 

[sferrin]

Probably it is Scott's Aerospace Projects Review.

Yep. And Bobbymike if you haven't seen it you're missing out.

http://www.up-ship.com/eAPR/index.htm

 

[bobbymike]

I am missing out no more, what a great site.

 

[Orionblamblam]

Is there a way to get rid of the sulphuric acid?

Numerous ways, all painfully slow from the current Presidential-administration timescale, but blisteringly fast on an evolutionary timescale. Gengineered critters that float in the clouds and gnaw on sulfuric acid, crapping out sulfur crystals that rain to the ground is one way. Another woudl be to process the sulfuric acid in an industrial way, and launch it into Venusian orbit. Make 0.5-meter diameter moons out of it, and slowly, slowly build a ring around the planet that would help shield it from the sun. If you can make dirt-cheap expendable rockets that use a sulfur-based solid fuel, overwrapped with a suflur-based plastic fiber, witha big chunk of sulfur payload in the nose, then you might really have something. A carbon/sulfur compound launched into Venus orbit would be best... solve two problems at once.

If you are willing to think really long term, then you can imagine moving, say, Europe from Jupiter orbit into Venusian orbit. Transfer the water from Europa to Venus; transfer the sulfur from Venus to Europa.

 

[Hammer Birchgrove]

Is there a way to get rid of the sulphuric acid?

Numerous ways, all painfully slow from the current Presidential-administration timescale, but blisteringly fast on an evolutionary timescale. Gengineered critters that float in the clouds and gnaw on sulfuric acid, crapping out sulfur crystals that rain to the ground is one way. Another woudl be to process the sulfuric acid in an industrial way, and launch it into Venusian orbit. Make 0.5-meter diameter moons out of it, and slowly, slowly build a ring around the planet that would help shield it from the sun. If you can make dirt-cheap expendable rockets that use a sulfur-based solid fuel, overwrapped with a suflur-based plastic fiber, witha big chunk of sulfur payload in the nose, then you might really have something. A carbon/sulfur compound launched into Venus orbit would be best... solve two problems at once.

If you are willing to think really long term, then you can imagine moving, say, Europe from Jupiter orbit into Venusian orbit. Transfer the water from Europa to Venus; transfer the sulfur from Venus to Europa.

Sounds neat. Thanks.

 

[pathology_doc]

Things like this are a very good reason for the US, UK, Russia and France to build many more new, reliable nuclear warheads; not to go scaling them back. President Obama, please take note. After all, do you really want to go begging and crawling to Iran or North Korea for the warheads you need to save the Earth?

If there is ever an extinction-level event, proponents of nuclear disarmament will, in humanity's twilight days, be lynched without mercy as traitors to their species.

 

[Hammer Birchgrove]

If there is ever an extinction-level event, proponents of nuclear disarmament will, in humanity's twilight days, be lynched without mercy as traitors to their species.

... and if there will be a WWIII, proponents for MAD and nukes in general will be lynched without mercy as traitors to their species. If there is any time to do any lynching.

Besides, how many times do you need to be able to kill all life on Earth? Isn't one time for each superpower enough (to provide deterrent)?

Sorry to digress, nothing personal.

 

[robunos]

The trouble is , 'off the shelf', military nukes won't work, see here :-

http://flux.aps.org/meetings/YR01/SHOCK01/abs/G310097.html

"n order to deflect asteroids or comets having a diameter over 1 kilometer, it will be necessary to use nuclear explosives.

Nuclear devices which deliver a large fraction of their total yield in the form of neutrons are considerably more effective for producing a velocity change in the target than devices which deliver x-rays or gamma rays.

Typical megaton-range nuclear weapons currently deployed are a three-stage design (fission-fusion-fission) which emit most of their energy in the form of x-rays.

Certain megaton-range nuclear weapons currently deployed are a two-stage design. These devices are often described as "tactical" or "clean" nuclear weapons. Because of the density of fusion fuel required to give an efficient burn, each neutron produced by the device experiences a large number of collisions before it is able to escape from the device. These collisions remove energy from the neutrons and cause most of the total device energy to be emitted as x-rays.

(High-yield devices developed for military purposes have been optimized for maximum yield or for maximum yield subject to some limit on total radioactive isotope emissions. Those devices which have been optimized for radiation, known as "neutron bombs", are in the kiloton range, not the megaton range.

If it is necessary to develop megaton-range nuclear explosives which have been optimized for total neutron energy output, then these devices should be developed while experienced bomb designers are still available.) "

Also here :-

http://pdf.aiaa.org/preview/CDReadyMPDC04_865/PV2004_1439.pdf

Is anyone able to get hold of this PDF?

Also this :-

"Nuclear weapons are an intriguing possibility, but have considerable political and technical obstacles. Would the rest of the world trust us to nuke an asteroid? Would we trust anyone else? And would the asteroid break into multiple asteroids, giving us more problems to solve?"

from http://blog.taragana.com/n/aerospace-engineer-thinks-up-way-of-deflecting-asteroids-29973/


Cheers,
Robin.

 

[bobbymike]

Maybe time for a nuclear power summit? All the major nuclear powers can come together to build a gigaton nuclear weapon mounted on a massive new booster, maybe rebuild Aerojet's 260" diameter rocket with its close to 6,000,000 lbs of thrust for just this purpose. And if they cannot agree the US will go it alone to save humanity while having the positive spin-off of reinvigorating the entire nuclear enterprise. Then we can build AMCISSBMs (Anti-meteor/comet Inter Solar System Ballistic Missiles) ;D

 

[robunos]

Sorry to dampen your enthusiasm, Bobbymike, but the idea is not to blow these things up, they're too big, but rather to nudge them gently into a new orbit.

This is why the special bombs are needed. The neutron flux from the device is absorbed by a patch of the asteroids' surface, which heats up and evaporates,
acting as a low pressure rocket, and pushes the asteroid into a different orbit.

Take the asteroid Apophis for example. It's estimated to be just under 300 metres across, and it's mass is estimated at 210 MILLION tonnes.
An impact with the earth would probably yield around 880-1480 Mt.

Now you've got to reduce that into pieces no larger than a few metres across, any larger, and you've just converted a solid slug into a shotgun round,
remember, the impactor that created Meteor Crater is estimated at about 50 metres across, and the impact energy at 200Mt.

What's needed is low megatonnage neutron bomb, detonated at some distance away, you don't want any blast damage at all, if possible.

cheers,
Robin.

 

[Orionblamblam]

This is why the special bombs are needed. The neutron flux from the device is absorbed by a patch of the asteroids' surface

Too complex and unreliable. Use evolved Orion pulse units. The absorbtion, vaporization and mechanical impulse created by a patch of asteroid after a neutron flux is highly dependant upon composition of the asteroid. Ice will respond diferently than carbon differently than iron differently than nickle diferently than silicon. But you give it a solid thumping of, say, vaporized tungsten (or, given time, vaporized asteroidal iron, carbon, nickle, ice...), spread out over the whole hemisphere of the asteroid, then it doesn't much matter what the composition is... it will still absorb much the same mechanical impulse.

A 25 kiloton pulse unit weighing 2540 pounds would impart a velocity increment of 44 feet per second to a 4000 ton Orion. The same pulse units would impart to a 210,000,000 ton asteoid a velocity increment of about 3 feet per hour. If you want to deflect it by, say, 6000 miles, then that means you have to hit it when it is 10,560,000 hours from impact, or about 1200 *years.* If you only have a year to save the world, then you need to nuke it 100 times, use a nuke 100 times as powerful and massive, or some combination. A 254,000 pound payload to deliver to an asteroid seems like a lot, but if you can get there early, most of the pulse unit mass can actually be scraped off the surface of the asteroid and thrown back at it.

 

[pathology_doc]

The other important thing, regardless of the nuke type you use (you may HAVE to use military-type warheads at a pinch if you have nothing else), is to catch the intruder early. That way for a given lateral shove X, producing an angular displacement Y, you get a greater miss distance Z.

With the X ray vs. neutron business, forgive my ignorance but wouldn't a thermal fireball big enough to obliterate a large city cause quite a "heating effect" in itself? I've always thought that the ideal thing to do is not to fire a missile at the intruder but to soft-land the nukes on it and detonate them on the surface for maximum effect.

 

[bobbymike]

How about a new ultimate WMD. Use Ares Vs to lift a couple of million pounds into orbit, send it around the moon in a gravitational slingshot and using thrusters strategically placed around the mass have it reenter the atmosphere at a place of your choosing. Or do it from a Moon base, the ultimate high ground. What do you think of my plan Mr. Powers?

 

[robunos]

Use evolved Orion pulse units

That was going to be my next thought! but wasn't able to calculate the size of unit required.
I can only assume the authors of the paper describing the neutron absorption technique are unfamiliar with, or unaware of,
orion pulse-unit technology...
Ideally what you need, is an Orion, standing off from the offending asteroid, and use it's propulsion system to fire pulse units at it,
but upside down, so the propellant, as you say, thumps the asteroid, not the pusher plate.

...soft-land the nukes on it and detonate them on the surface for maximum effect...

That risks disrupting the asteroid into fragments, as far as my understanding goes.
Also many of these asteroids are thought to be 'rubble piles', loosely held together by their mutual gravitation.
A surface or subsurface blast will probably cause them to just fall apart, only to coalesce again later.

And you're both right, like cancer, early detection is crucial.

cheers,
Robin.