Asteriods

[squidbones]

What can be gained from visting an asteroid? What is there to mine, can their orbits be changed, ect?

 

[scottb50]

Do Squids have bones? Actually no. I have no idea what is in an asteroid and until someone goes there it's all speculation. <div class="Discussion_UserSignature"> </div>

 

[squidbones]

Don't they think that there's all sorts of minerals that don't exist on earth on Asteroids? maybe it's all Sci-fi and their just balls of dust and rock. And the Name is a combination of two of my old nicknames.

 

[arobie]

The asteroid Eros is worth oh...15.84 <b>trillion</b> dollars. It contains potassium, magnesium, aluminum, silicon, oxygen, and iron...well atleast that is what has been observed so far by the NEAR Shoemaker spacecraft.<br /><br />That was just an example, a sample of the asteroids for you to give you an idea of value.<br /><br />Asteroids contain anything you would need. Other than the materials listed above, asteroids can contain nickel, gold, platinum, water (providing something to drink or can be turned into rocket fuel, hydrogen and oxygen), carbon, calcium, and potassium...just to name a few.<br /><br />Their orbits can be changed, but it would be cheaper and easier to leave them where they are. We go to them instead of bringing them to us.<br /><br />Eros

 

[scottb50]

By the time fragments reach the surface all but the most substantial pieces have vaporized. How much could you determine if you had an Earth rock found on Mars? Like trying to prove life on Mars from a Mars rock recovered in Antartica?<br /><br />Until someone goes there and sees it we will never know. Robots can do just so much.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[scottb50]

If we know the composition of asteroids so well we should also know the composition of Mars and comets. Why waste the time and money on the MER's or send a penetrator to a comet if we already know all the answers?<br /><br />Perhaps there are asteroids that completely burnup in the atmosphere and nobody has seen one of those. Or the high metal meteor debris was part of the core of an asteroid not the main makeup of the original object. <br /><br />As I recall we have only seen one asteroid upclose, but I guess thats more than enough to close the book and move on to the next task. <div class="Discussion_UserSignature"> </div>

 

[najab]

><i>If we know the composition of asteroids so well we should also know the composition of Mars and comets.</i><p>That's got to be one of the most rediculous statements I have ever heard from a 'sensible' member of the board. What on Earth - or in space - does the composition of comets have to do with asteroids?</p>

 

[scottb50]

>What on Earth - or in space - does the composition of comets have to do with asteroids?<br /><br />Everything, they were formed in the same way, just like the planets and moons. Unfortunately the area they formed in didn't have enough bits of matter to amass into planets or moons, just smaller bodies. Or debris, if you want to get technical. <br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[najab]

><i>Everything, they were formed in the same way, just like the planets and moons.</i><p>And I suppose the fact that comets are 90% ice and asteroids are 99% rock doesn't really factor into the equation? Sorry Scott, tigerbitten is right, you're comparing islands to icebergs.</p>

 

[scottb50]

If an asteriod has been forced into a highly elliptical orbit around the Sun it would accumulate water, gasses and dust as it traveled outbound and cooled. As it returns the accumulated gasses and dust burn off as it nears the Sun and its temperature increases. The outbound leg repeats the process. Like a wet tennis ball rolling across dirt.<br /><br />If you look at the size of the outer planets there is still a lot of gasses in that part of the Solar System that didn't, or hasn't been swept up by the gas giants, as a comet passes through the region in its orbit it attracts any mass that comes close enough.<br /><br />Icebergs are all ice and nothing like a comet. I would think a substantial mass would be needed to put a comet into a different orbit, if it was just a snowball that much force would destroy it, not move it. The actual core of a comet must be more substantial.<br /><br />The mechanics work the same for everything, the available mass determines the makeup of a specific body, everything is built by accumulating more and more mass. <br /><br />Just like the shepard moons in Saturns rings, as long as there is available mass they grow bigger and bigger over time. As they get more massive they orbit closer to the planet and either find more material and keep growing or get trapped in a gap between rings and maintain a stable orbit. The same sequence happened with the Solar Systems formation. <div class="Discussion_UserSignature"> </div>

 

[najab]

<blockquote><font class="small">In reply to:</font><hr /><p>If an asteriod has been forced into a highly elliptical orbit around the Sun it would accumulate water, gasses and dust as it traveled outbound and cooled. As it returns the accumulated gasses and dust burn off as it nears the Sun and its temperature increases. The outbound leg repeats the process. Like a wet tennis ball rolling across dirt.<p><hr /></p></p></blockquote>You don't <b>really</b> believe this is how comets are formed, do you?

 

[mrmorris]

<font color="yellow">"You don't really believe..."</font><br /><br />I'm sure he's just kidding. Everyone knows that Comet's made of 1.2% Sodium dichloro-s-triazinetrione dihydrate and 98% inactive ingredients. And it comes in three great varieties: Disinfectant Cleanser With Bleach, Lemon Fresh Disinfectant Cleanser With Bleach, and Oxygenated Soft Powder Cleanser. All three make short work of tough stains even on your home’s most delicate surfaces. <br /><br /><br /><img src="/images/icons/smile.gif" />

 

[najab]

Oh yeah. Right. My bad.

 

[spacester]

Looks like a good time to post a copy-and-paste from a post I made here years ago. No guarantee all the links still work. The original question was about the average size of an asteroid.<br />***<br />The "Average Size"? We don't know, because we can only see the big ones if we get real lucky. Plus, for most of the ones we can see, we only guess at the size, based on the albedo (brightness) All the evidence indicates that the quantity goes up as the size goes down.<br /><br />Here's one estimate as of Nov 1996: (source: click on the "analyze" link below)<br />(1) more than 1500 larger than 1 kilometer<br />(2) more than 100,000 larger than 100 meters<br />(3) more than 100,000,000 larger than 10 meters<br />But I believe these estimates have been revised downward recently.<br /><br />That's the short answer. But I'm rather obsessed with asteroids, so I've gotta give you the long answer <img src="/images/icons/laugh.gif" /> (Remember we're talking about Near Earth Asteroids, not the Asteroid belt beyond Mars)<br /><br />The list provided by harmonicaman's first link is an excellent summary of the big ones we've spotted so far. It's unlikely that we've missed any as big as tens of kilometers, with the *significant exception* of ones orbiting entirely within Earth's orbit. You see, these will never show up in the night sky. They're called Arjunas, and there's every reason to believe there are thousands of them, counting the small ones.<br /><br />The thing is, Astronomers are mostly concerned with the orbits and spin of asteroids (when they're concerned with asteroids at all). They don't care as much about the composition, and because it's difficult to measure their size, the measurement is not commonly done.<br /><br />Here's my understanding of how we measure these properties:<br /><br />Orbits: Professional and sophisticated amateur astronomers are constantly hunting. NEAs are easies <div class="Discussion_UserSignature"> </div>

 

[scottb50]

You don't really believe this is how comets are formed, do you?><br /><br />Sure I do. If comets lost a percentage of their mass everytime they rounded the Sun they would have finite lifetimes and their orbits would change as they got lighter, outbound the accumulation of matter would have the opposite effect. A lot of comets have pretty accurate predictability, some having been recorded for thousands of years, indicating they replenish their resources on a consistant basis. If they got lighter on every pass wouldn't their orbit change, which would change their arrival?<br /><br />Comets are the same thing that developed into Planets and Moons or stayed asteroids or dust, or clouds of Hydrogen, Mass. It all depends on how much mass is in a particular ring of the Star, which depends on how much energy there was in the Black Hole that started it all by sucking up all the mass around it and exploding when it got so massive it couldn't take anymore.<br /><br />Most of the moons of the outer Planets, obviously didn't develop where they are, Titan, Io, even Pluto, they formed in rings closer to the Sun and were bumped out of their orbits to be captured, or not captured by the gas giants as they came by.<br /><br />Cosmic pool. An equal and opposite reaction. <br /> <div class="Discussion_UserSignature"> </div>

 

[najab]

><i>If comets lost a percentage of their mass everytime they rounded the Sun they would have finite lifetimes...</i><p>But they <b>do</b> have finite lifetimes! We have <b>observed</b> short period comets that 'burn out' after a few passes. The longer period comets last longer (a) because they their passes are infrequent and (b) because of the shape of their orbit, they zoom-zoom through the inner solar system quite quickly (velocity is highest at perihelion) - by the time they are warmed sufficently to start out-gassing, they are much closer to the Sun and so they spend less time outgassing.<p>><i> If they got lighter on every pass wouldn't their orbit change, which would change their arrival?</i><p>Remember, if the central body is very much more massive than the satellite (comet in this case), then the mass of the satellite has <b>no effect</b> on the shape of the orbit. A gnat and an battleship follow exactly the same orbit if they started at the same point with the same velocity.<p>In practice, the solar wind would exert a force that would affect the lighter body more than the heavier one, but given that even small comets are thousands of tonnes, we can ignore this effect.</p></p></p></p>

 

[scottb50]

We have observed short period comets that 'burn out' after a few passes.....<br /><br />Or hasn't found much matter in it's particular orbit. That doesn't mean the core doesn't stay in it's orbit, just like an asteroid, or maybe a big asteroid that didn't make it as a moon.<br /><br />Every speck of dust or gas being struck changes an objects velocity somewhat. An asteroid like Kingman changed the Earths orbit, somewhat, the bigger the collision the more change. <div class="Discussion_UserSignature"> </div>

 

[najab]

So far we (humans) have sent 4 probes out into the outer Solar System - Pioneer's 10 and 11 and Voyagers 1 and 2. It's pretty amazing that none of them have passed through any clouds of gas and water, given that your theory would require them to be quite abuntant.

 

[scottb50]

It's pretty amazing that none of them have passed through any clouds of gas and water, given that your theory would require them to be quite abuntant......<br /><br />They've only made a one way trip. After billions of years in Solar orbit they would probably look a lot worse for the wear. Plus, the density of matter available changes as it is used up. A lot of them accumulated water and gasses not picked up by Planets and moons. <br /><br />I'm sure though, that they, the Pioneer's and Voyagers, have accumulated dust and probably a few nicks and scrapes, multiply that by a few billion orbit... <br /><br />Not quite abundant at all, more likely molecules are pretty well spread around and accumulate fairly slowly. Near the Sun a percentage of the total mass is lost. If the outbound orbit, adding mass doesn't keep up with expenditures the comet eventually uses up its accumulation and becomes, or returns to, an asteroid. In a highly elliptical orbit, which would mean it had to be pretty tough to handle the forces that put it there. Cosmic pool anyone?<br /><br />The biggest clue is moons such as ours and a lot of those in orbit around the gas giants. They formed in the same Solar area so it stands to reason they are similar in composition. The only difference being the amount of mass available. Moons like Mars has and some of the ones in the outer solar system are captured asteroids, or comets. <div class="Discussion_UserSignature"> </div>

 

[spacester]

<img src="/images/icons/rolleyes.gif" /> <div class="Discussion_UserSignature"> </div>

 

[propforce]

Hey how come a serious topic such as "how to design a rocket" don't get this type of attention and responses? <div class="Discussion_UserSignature"> </div>

 

[nexium]

What most everyone posted is about correct. We know the composition (sort of) of the surface of larger asteroids because of the spectum of the light reflected. Is light reflected by minerals one millimeter below the surface? Rarely. When is the surface the same material as a centimeter below the surface? When the surface has been recently sand blasted or was envolved in a major collision/rarely.<br /> When tiny asteroids pass though Earth's atmosphere, the dust is blown away, and the surface is ablated, so this is a good indication of the composition below the surface of tiny asteroids. Big meteorites are rare and typically have been contaminated by Earth for centuries or longer. Are tiny asteroids typical of larger ones? No, but they may be a close approximation. The dust samples analyzed by deep space probes may have some resemblence to what a 100 meter asteroid is made of. A small percentage of the moon dust brought back by the astronauts 36 years ago is pulverized asteroid, so we have some info, but not a lot.<br /> Likely we can double the consumption of elements extracted from asteroids, with only a small decrease in the market price, but most will be ten times cheaper before we achieve ten times consumption, even long term, adjusting for inflation. Neil

 

[mrmorris]

<font color="yellow">"Hey how come a serious topic ..."</font><br /><br />Probably for the same reason why I have about 70% of the posts in a serious topic like my Gemini 3x thread. In a thread that's either lighthearted or which contains obvious errors, it's much easier to fire off a quick post to either amuse or point out a problem. <br /><br />By contrast -- to post in the rocket design thread requires considerably more thought and/or research. Likewise, in the G-X3 thread, I've put enough research into the subject that it's hard for someone to post additions/corrections unless I happen to hit one of their special areas of interest ... or they do *more* research than I have already. I'd prefer to get more responses and input. On the other hand -- people apparently enjoy reading it, and I enjoy writing it -- so I'll continue with it. Likewise if you enjoy posting in the rocket design thread... then post. With a topic like that, people will read it, even if they don't contribute.

 

[scottb50]

You are just a cornucopia of misinformation.....<br /><br />To be more exact I meant they lose some off their outer gas, water and dust as they approach the Sun and get warm enough to start giving off gasses. The key word is some. Why is it so hard to imagine the outbound leg, being relatively warm, in relation to it's surroundings, the comet wouldn't attract matter that just happened to be along it's path.<br /><br /> Space is a vacuum, only in the sense there is no air, it's not empty, there's a lot of particals, molecules and simple Atoms floating around out their waiting to find something to react with. <br /><br />Draw a good orbit, that passes through the original disc of matter and a Comet lasts a long time, appearing over and over. Just look at how much gas existed in the orbits of the outer Planets for them to get so massive. What they didn't get the comets could snatch up as they past through. <br /><br />AFter hundreds to thousnad of years, they simply stop being comets......<br /><br />No they don't, they may have expended all their volatile components and don't form a tail, they don't mysteriously disapear. They remain in their orbit until they are disturbed. If they collide with another body then their Solar orbit would change, innner Solar system gravity could pull them apart and the become asteroids.<br /><br />All this tells me is matter can be in whatever orbit.<br /><br />A Some are tossed complelely out of the solar system, too. ...<br /><br />Has this ever been observed? The Sun is the only body big enough to do that and it would have to be a perfect shot to work. Not that it couldn't be done, just that it would take a lot of luck. <br /><br /> I think most matter generated by the Black Hole that became the Solar System has stayed within the Solar System, gravity over acceleration.<br /><br />Perhaps a lot of asteroids are Comets that burned of their outer layers. It's even conceivable that metallic meteors are Comet cores, just like the cores of the Planets. Ot <div class="Discussion_UserSignature"> </div>

 

[jatslo]

<font color="yellow">That's what has been observed. Read about comets, in detail, and then get back to us with some questions. Don't just guess, when the information is readily available on the net and in astronomical books.</font><br /><br />What? Don't listen to stevehw33, he has an attitude of a 2-year old. You're free to conduct yourself in any manner that does not conflict with "Terms of Service". And furthermore, stevehw33 isn't a good source of information.