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Off Topic => Engineering => Topic started by: Stormbringer on September 07, 2005, 12:44:31 pm
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Largest Asteroid Might Contain More Fresh Water than Earth
By Bjorn Carey
SPACE.com Staff Writer
posted: 07 September 2005
01:15 pm ET
The largest known asteroid could contain more fresh water than Earth and looks like our planet in other ways, according to a new study that further blurs the line between planets and large space rocks.
Astronomers took 267 images of asteroid Ceres using the Hubble Space Telescope. From these images and subsequent computer simulations, they suggest Ceres may have a rocky inner core and a thin, dusty outer crust.
A team led by Peter Thomas of Cornell University said today that Ceres is nearly spherical, which suggests that gravity controls its shape. Also, the asteroid's wobbly rotation indicates that material is not evenly distributed throughout the inside.
These and other new clues, including Ceres' low density, point to an interior loaded with frozen water, the astronomers said.
The results are detailed in the Sept. 8 issue of the journal Nature.
Big and round
Ceres has long been considered one of the tens of thousands of asteroids that make up the asteroid belt between Mars and Jupiter. At 580 miles (930 km) in diameter – about the size of Texas – it's the largest asteroid in the belt, accounting for about 25 percent of the belt's total mass.
Astronomers had thought Ceres might never have been heated enough to create layers of material.
But computer models now suggest Ceres has a differentiated interior – dense material in the core and lighter stuff near the surface. Possible configurations include a mantle rich in water ice around a rocky core.
If this mantle is composed of at least 25 percent water, Ceres would have more fresh water than Earth, according to a statement released by the Space Telescope Science Institute, which operates Hubble for NASA and the European Space Agency.
"The most likely scenario from the knowledge we have on how other objects form, it probably has a rocky core and a mantle. That mantle is probably some watery, icy mix, with other dirt and constituents. That mantle could be as much as ¼ of the whole object," study coauthor Joel Parker of the Southwest Research Institute told SPACE.com. "Even though it's a small object compared to Earth, there could be a lot of water."
On Earth, fresh water makes up only a thin layer just a few miles deep in some places, less in others. The water layer proposed for Ceres, while smaller in circumference, is many miles thicker.
The total volume of water on Earth is about 1.4 billion cubic kilometers, around 41 million of which is fresh water. If Ceres' mantle accounts for 25 percent of the asteroid's mass, that would translate to an upper limit of 200 million cubic kilometers of water, Parker said.
Since all the nine "regular" planets have differentiated interiors, this new view of Ceres has some astronomers calling Ceres a "mini-planet," adding fuel to an ongoing debate over exactly what qualifies as a planet.
Embroyonic world
Other researchers recently announced the discovery of 2003 UB313, a round object in our solar system 1-1/2 times larger than Pluto and about three times further away from the Sun. But even an object of this size – at 2,100 miles in diameter roughly four times the size of Ceres – doesn't receive universal endorsement as being a planet.
One astronomer, Brian Marsden, who runs the Minor Planet Center where data on small bodies is collected, says that if Pluto is considered a planet, then any other round worlds should also be considered planets. Under this definition, which some other astronomers subscribe to, Ceres 2003 UB313 and a handful of other large objects would be named planets. The alternative, Marsden and others say, is to stop calling Pluto a planet.
Another explanation is that Ceres is a sort of 'baby' planet – an underdeveloped version of Earth and other rocky planets. Looked at this way, Ceres appears as other fledgling planets might have looked more than 4 billion years ago.
The leading theory for planet formation holds that small rocks collided, stuck and gradually grew. Depending on location and orbit, a developing world may or may not have encountered enough raw material to become as large as the four traditional rocky planets.
"Ceres is an embryonic planet," said observation team member Lucy McFadden of the Department of Astronomy at the University of Maryland. "Gravitational perturbations from Jupiter billions of years ago prevented Ceres from accreting more material to become a full-fledged planet."
In 2015 scientists will get a close up look at Ceres when the NASA Dawn mission orbits the asteroid. A closer look should provide more clues about the asteroid's composition.
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Does it have any magnetic field?
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Does it have any magnetic field?
Don't know but i understand Mars has a negligible one. Mars is still a planet. The true definition of Planets is quite in dispute.
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Oh, I wasn't wondering about its classification, I was wondering what's in it!
If it does have a magnetic field the inner material is most likely not to be water.
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Not according to the scientists in that article: "These and other new clues, including Ceres' low density, point to an interior loaded with frozen water, the astronomers said." ;)
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Step 1/ Travel to Ceres (could send Robots)
Step 2/ Set up magnetic catapault
Step 3/ Lob snowballs at Mars using trajectories designed to move Ceries towards Mars as well.
(It wouldn't matter if a snowball took 5 or 6 long orbits to get there)
Step 4/ Continue terraforming Mars with other methods at the same time
Step 5/ Mine Ceres for other resources while digging up the snowballs.
Step 6/ Move to Mars.
Note: Snowballs would be of a size determined to burn up without hitting the ground.
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7 Gravitational attraction causes impact.
8 Mars breaks up
9 BIG meteor ends life in Sol System
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7 Gravitational attraction causes impact.
8 Mars breaks up
9 BIG meteor ends life in Sol System
Note to self: Don't let Dracho near the navigation systems.
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Terraforming Mars? I honestly can't see it... apart from Russia, we can't even get our arses in gear to build a viable orbital Space Program, much less visit Mars and certainly not turn it into Earth 2... It's time NASA received some serious funding...
On the point about water on Ceres, beyond about 4 times further away from the Sun than Earth, water will not evaporate off into Space (Hence the formation of the ice giants), so it is possible there could be ice on this asteroid, since it is (I beleive) about 4 a.m.u. from the Sun...
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Terraforming Mars? I honestly can't see it... apart from Russia, we can't even get our arses in gear to build a viable orbital Space Program, much less visit Mars and certainly not turn it into Earth 2...
Today no. Tomorrow? But tomorrow won't come if people are not working towards it. No one backed Goddard, the Germans copied him and had the V1 and V2 while the allies were going WTF? Goddard wanted to build a lunar probe (pre WWII) but was told it was "impossible". It became possible once Russia decided to take the high ground and orbited sputnik. National prestige made the U.S. target doing better than "the Commies".
It's time NASA received some serious funding...
Actually I would like to see NASA told that they are a space research organization and have them trimmed back. No commercial launches. Operations beyond GEO only. At this point NASA is too large and has too much inertia. It also has in the past helped influence laws being passed to keep commercial rocket companies out of business. Losing a shuttle then another has weakened their influence which has allowed the commercial developments that are occurring. One of those laws was so poorly crafted that hobbiests could not legally launch toy rockets without governmental permissions. That was changed quickly when a model rocket engine company included the forms with each engine and drowned them in paperwork. :) NASA influence helped kill a number of startups in the 1980s. They couldn't use NASA or military launch facilities and couldn't build their own.
Get the LEO-GEO stuff into commercial hands. Move the space station into its own operation which should be told - replace the shuttle. There are at least 1/2 a dozen good candidates.
Why have activities in space heated up? Two reasons in my opinion. 1/ The Chinese putting a man in orbit renews competition as many Americans fear China. 2/ The X-Prize gave an immediate way to make back some of your money by winning the prize even if your project became a commercial failure.
If these commercial ventures result in affordable orbital trips (notice I say trips not missions) then deep space becomes much easier too. The first step is the big one.
NASA set the stage now they need to step aside and let the actors put on the play. Later when NASA has blazed the path to Mars, the Moon and the asteroids it will be once more time to tell them look further out, that is where you belong.
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7 Gravitational attraction causes impact.
8 Mars breaks up
9 BIG meteor ends life in Sol System
Note to self: Don't let Dracho near the navigation systems.
Install SFC on his navigational computer, tell him it's a real space traffic controller app, and let him slam as many ships into asteroids as he pleases! Get the modelers to help you get 21st century looking ships in it first. And hide the weapons controls.
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7 Gravitational attraction causes impact.
8 Mars breaks up
9 BIG meteor ends life in Sol System
Note to self: Don't let Dracho near the navigation systems.
"Hey Ya'll, Somebody Hold My beer and watch this!"
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Does it have any magnetic field?
Highly unlikely. Planetary megnaetic fields are produced by circulation and movement of molten iron in the core of a planet which acts like a giant magnetic dynamo. Mars is no longer geologically active and its molten core has cooled, thus it has no longer has a significant magnetic field.
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That's what I was trying to get at, since it was mentioned that there may be much water in the interior.
However, no one knows what electrostatic and hence magnetic effects may occur due to the aggregate action of small effects from all the component particles of a large body of even dielectric material, which does have some polarizability, as with water.
Does it have any magnetic field?
Highly unlikely. Planetary megnaetic fields are produced by circulation and movement of molten iron in the core of a planet which acts like a giant magnetic dynamo. Mars is no longer geologically active and its molten core has cooled, thus it has no longer has a significant magnetic field.
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That's what I was trying to get at, since it was mentioned that there may be much water in the interior.
However, no one knows what electrostatic and hence magnetic effects may occur due to the aggregate action of small effects from all the component particles of a large body of even dielectric material, which does have some polarizability, as with water.
Does it have any magnetic field?
Highly unlikely. Planetary megnaetic fields are produced by circulation and movement of molten iron in the core of a planet which acts like a giant magnetic dynamo. Mars is no longer geologically active and its molten core has cooled, thus it has no longer has a significant magnetic field.
Well, a good well known example of such an object, is our very own Moon. While it too is no longer geologically active and creates no magnetic field of its own, it does have localised magnetic fields thought to be produced by iron compounds that have been deposited in the Moon's crust over time by collisions with meterors. If Ceres contains iron, then its possible that it may have a very weak local magnetic field in some areas, not unlike finding a magnet buried in the ground.
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That really isn't very much iron. I meant LOTS of water under Ceres' surface.
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Step 1/ Travel to Ceres (could send Robots)
Step 2/ Set up magnetic catapault
Step 3/ Lob snowballs at Mars using trajectories designed to move Ceries towards Mars as well.
(It wouldn't matter if a snowball took 5 or 6 long orbits to get there)
Step 4/ Continue terraforming Mars with other methods at the same time
Step 5/ Mine Ceres for other resources while digging up the snowballs.
Step 6/ Move to Mars.
Note: Snowballs would be of a size determined to burn up without hitting the ground.
Ya beat me to it! :) My first thoughts exactly. Or tow it into orbit around the moon and use it to colonise it first.
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The moon has enough water in the shadow of polar craters to fill the great lakes many times over. it is unnecessary to bring water from anywhere to the moon. same thing for Mars except ther is even more water. the only reasons to bring Ceres there is to populate the atmosphere with more oxygen and to use the other mass to increase the gravity. Ceres would otherwise be better off where it is to act as a way station to the outer solar system and for fueling mining operations in the belt. Of course i favor terraforming mars to include adding mass to increase the gravity or using the mass of asteroids, kuiper and Oort objects to construct a planet from scratch in the life zone of the sun. bombarding Mars with additional mass is problematic on ethical and scientific grounds by reason of anihilating any trace of exobiology if it exists and obliterating the geological record. building a planet from scratch though more difficult has none of those drawbacks.
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All Mars needs really is a little more greenhouse effect. Once the temperature rises high enough (and it doesnt need to go up by much) to get liquid water back on the surface (and hence rain bearing clouds in the atmosphere), the greenhouse effect will start to increase unlocking more and more frozen water in the surface. The atmosphere will thicken raising atmospheric pressure, and therefore with it the temperature. A lot of carbon dioxide is also likely to sublime to gas as well, further increasing the greenhouse effect. The real task will be getting oxygen back into the atmosphere which could be done longterm by introducing an ecosystem that can survive in the Martian modified environment.
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All Mars needs really is a little more greenhouse effect. Once the temperature rises high enough (and it doesnt need to go up by much) to get liquid water back on the surface (and hence rain bearing clouds in the atmosphere), the greenhouse effect will start to increase unlocking more and more frozen water in the surface. The atmosphere will thicken raising atmospheric pressure, and therefore with it the temperature. A lot of carbon dioxide is also likely to sublime to gas as well, further increasing the greenhouse effect. The real task will be getting oxygen back into the atmosphere which could be done longterm by introducing an ecosystem that can survive in the Martian modified environment.
Someone (I beleive it was death merchant) calculated it would take 16 million years for the atmospheric oxygen to escape the boundary of the gravity well due to Mars' weak gravity and radiation pressure let in due to mars' weak magnetic field. not enough is trapped in ice or oxidation despite mars' red color. it would need tremendous augmentation from cometary ice from the Oort cloud. Howevery 16 million years is many times the current life span of human history. It would suffice.
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This is very true. The martian gravity isnt strong enough to stop oxygen from leaking away into space, but as you say, this process will take millions of years. There is a lot of oxygen on Mars alaready, the problem is that it is all bound up in H20 and CO2. The oxygen in CO2 can be released by photosynthesis but this too would take 100s if not 1000s of years to create an Earth like atmosphere (maybe even millions).
Technology would have to provide oxygen replenishing in the short term. Hydrolysis of water perhaps in huge solar power stations, or sliding a chunk of ice comet through the martian atmosphere. Either way though, a sustainable ecosystem would need to be established to maintain the oxygen level, and aside from transplanting entire rain forests from the Earth (we cant even mainatin our own level of flora anyway), that process will still take a very long time, probably not in our lifetimes :-[
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This is very true. The martian gravity isnt strong enough to stop oxygen from leaking away into space, but as you say, this process will take millions of years. There is a lot of oxygen on Mars alaready, the problem is that it is all bound up in H20 and CO2. The oxygen in CO2 can be released by photosynthesis but this too would take 100s if not 1000s of years to create an Earth like atmosphere (maybe even millions).
Technology would have to provide oxygen replenishing in the short term. Hydrolysis of water perhaps in huge solar power stations, or sliding a chunk of ice comet through the martian atmosphere. Either way though, a sustainable ecosystem would need to be established to maintain the oxygen level, and aside from transplanting entire rain forests from the Earth (we cant even mainatin our own level of flora anyway), that process will still take a very long time, probably not in our lifetimes :-[
The primary oxygen replenishment on earth is actually the algae in the ocean. under the right circumstances in the presence of suspended iron its' already prodigious reproductive rate can be multiplied a thousand fold. this does not rest on nanotech or genetic tampering. such methods could provide other organisms or self replicating micro-machines to free the oxygen and even warm the soil. i do not think it must necessarily take thousands of year or even hundreds. admittedly the long estimate is more conservative and therefore more likely to be true but with effort the short estimates can be made true none-the-less.
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This would be very nice to see happen :)
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The moon has enough water in the shadow of polar craters to fill the great lakes many times over. it is unnecessary to bring water from anywhere to the moon. same thing for Mars except ther is even more water. the only reasons to bring Ceres there is to populate the atmosphere with more oxygen and to use the other mass to increase the gravity. Ceres would otherwise be better off where it is to act as a way station to the outer solar system and for fueling mining operations in the belt. Of course i favor terraforming mars to include adding mass to increase the gravity or using the mass of asteroids, kuiper and Oort objects to construct a planet from scratch in the life zone of the sun. bombarding Mars with additional mass is problematic on ethical and scientific grounds by reason of anihilating any trace of exobiology if it exists and obliterating the geological record. building a planet from scratch though more difficult has none of those drawbacks.
Storm did they actually find the water yet? I remember some satilite mission a few years back where they didn't find any in signifigant amounts.
They even crashed one into the craters, in hopes revealing some buried, at the bottom of a crater. and still not the amounts expected.
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The moon has enough water in the shadow of polar craters to fill the great lakes many times over. it is unnecessary to bring water from anywhere to the moon. same thing for Mars except ther is even more water. the only reasons to bring Ceres there is to populate the atmosphere with more oxygen and to use the other mass to increase the gravity. Ceres would otherwise be better off where it is to act as a way station to the outer solar system and for fueling mining operations in the belt. Of course i favor terraforming mars to include adding mass to increase the gravity or using the mass of asteroids, kuiper and Oort objects to construct a planet from scratch in the life zone of the sun. bombarding Mars with additional mass is problematic on ethical and scientific grounds by reason of anihilating any trace of exobiology if it exists and obliterating the geological record. building a planet from scratch though more difficult has none of those drawbacks.
Storm did they actually find the water yet? I remember some satilite mission a few years back where they didn't find any in signifigant amounts.
They even crashed one into the craters, in hopes revealing some buried, at the bottom of a crater. and still not the amounts expected.
If i recall correctly a eurpoean orbiter found significant amounts water ice in the polar craters even comparingthem to the volume of the great lakes. an american one had previously found hints but no conclusive evidence.
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the first probe an american one was known as the lunar prospector. here is an article: http://www.asi.org/adb/m/03/08/01/lunar-ice.html
I cannot find the second one on the european follow up. but Aricebo radio surveys later did not find evidence to back up the first two probes mentioned.
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Actually no, water has not been discovered on the Moon at all to date.
http://www.universetoday.com/am/publish/water_on_moon.html?2042005
But there are still high hopes for it.
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http://science.nasa.gov/headlines/y2005/14apr_moonwater.htm
"In 2008, NASA plans to send a new spacecraft to the Moon: the Lunar Reconnaissance Orbiter (LRO), bristling with advanced sensors that can sense water in at least four different ways. Scientists are hopeful that LRO can decide the question of Moon water once and for all."
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Thanks Tracy & Bear. :) :thumbsup: :thumbsup: I live for this stuff. :)
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IIRC from years and years ago, I read an piece on mars terraforming...the gist was slam a comet or two...preferably w/ high water content.
Seed said target w/ tailored lichen that is very high albedo and engineered to optimize O2 seeding. Bake in the sun for couple thousand years and there will be an athmosphere.
My prob w/ Mars Terraforming is simply that in the long run, as Sol is Main Sequence, Mars is not far enough away to be a nice place to set up shop when we go red giant. Titan looks like a good choice, though we would have to cut the umbilicus to the sun as the source of power.
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how hard would it be to jump-start Jupiter?
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how hard would it be to jump-start Jupiter?
I used to think Jupiter was on the brink of starhood due to reading too much science fiction and listening to too many science popularizers but the truth is Jupiter could swallow saturn, uranus and neptune and still not reach the requisite mass to become a star. :(
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how hard would it be to jump-start Jupiter?
I used to think Jupiter was on the brink of starhood due to reading too much science fiction and listening to too many science popularizers but the truth is Jupiter could swallow saturn, uranus and neptune and still not reach the requisite mass to become a star. :(
Jupiter is sometimes referred to as a failed star. The majority of star systems have multiple stars, our solar system is an exception rather than a typical example. Perhaps Jupiter came close to becoming our Sun's companion star. Jupiter radiates more heat energy than solar radiation falling on it, some people have theorised that while Jupiter is below the critical mass at which a star "switches on", some thermonuclear reactions maybe taking place at its core.
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how hard would it be to jump-start Jupiter?
I used to think Jupiter was on the brink of starhood due to reading too much science fiction and listening to too many science popularizers but the truth is Jupiter could swallow saturn, uranus and neptune and still not reach the requisite mass to become a star. :(
Jupiter is sometimes referred to as a failed star. The majority of star systems have multiple stars, our solar system is an exception rather than a typical example. Perhaps Jupiter came close to becoming our Sun's companion star. Jupiter radiates more heat energy than solar radiation falling on it, some people have theorised that while Jupiter is below the critical mass at which a star "switches on", some thermonuclear reactions maybe taking place at its core.
I beleive that that is now accepted as true: that there is intermitent fusion going on down in there.
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"My prob w/ Mars Terraforming is simply that in the long run, as Sol is Main Sequence, Mars is not far enough away to be a nice place to set up shop when we go red giant. Titan looks like a good choice, though we would have to cut the umbilicus to the sun as the source of power"
That far in the future,Thats assuming we survive the colision with the Andromededa Galaxy. :P
If we don't Kill ourselves off by then. :P
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If you believe the folks who claim to have discovered planets in other solar systems, Jupiter is actually a fairly small gas giant. Some have been found which are supposed to be several dozen times Jupiter's size & mass.
I say that with a grain of salt because nobody has acutally visually detected one yet, making them theoretical planets based on stellar wobble, which might have another cause.
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Thank you, Dracho.
People always scream when I say that. These " 'extrasolar' planets" have yet to be cirectly seen by anyone!
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Thank you, Dracho.
People always scream when I say that. These " 'extrasolar' planets" have yet to be cirectly seen by anyone!
They probably are planets, but we should know within a decade, as they are trying really, really hard to get a picture of one. No reason not to assume the galaxies aren't full of planets, but we need to actually see it to verify.
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Actually at least two have been seen (detected) directly if i recall correctly. and one of those was not a hot jupiter but a terrestrail around a pulsar. the other was a gas giant that had been ejected from it's star system and was wandering alone.