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First Results From Deep Impact Mission

jdoire wrote to mention a Physicsweb piece revealing some of the first bits of data from the Deep Impact mission. From the article: "Based on data from the flyby spacecraft and the impactor, Michael O'Hearn of the University of Maryland and colleagues say that Tempel 1 belongs to the Jupiter family of comets, although its overall shape and surface features are quite different from the nuclei of the two other comets that have been studied in detail -- Wild 2 and Borelly. They also report that Tempel 1 consists largely of extremely fine particles that seem to be very loosely bound together: in other words, the comet is more like a pile of powder than a solid rock." Looks like the Electric Universe folks were a bit off.

48 of 189 comments (clear)

  1. Posted on Technocrat.Net by geomon · · Score: 2, Interesting

    "The Washington Post reports that the comet struck by the Deep Impact projectile had higher than expected concentrations of carbon. The July collision with Comet Tempel 1 produced a cloud of ice and other debris that was analyzed by an accompanying space craft. Although the composition of the comet appears to be frozen water, other analytes found in the debris stream include formaldehyde and cyanide. I guess the EPA should be notified."

    --
    "Rocky Rococo, at your cervix!"
    1. Re:Posted on Technocrat.Net by SimilarityEngine · · Score: 2, Informative

      From the article:

      ...Horst Uwe Keller of the Max Planck Institute for Solar System Research and co-workers used the Rosetta mission - which is on its way to another comet called Churyumov Gerasimenko - to survey the collision at from a distance of 80 million kilometres over a period of 17 days. Again they found that the relative amount of organic material being ejected increased following the impact...

      So, if such comets are life seeders, maybe we just increased the likelihood of life evolving elsewhere in our solar system in a few billion years :-) How does it feel to be potential parents to an alien species?

      --
      Those who can make you believe absurdities can make you commit atrocities. - Voltaire
    2. Re:Posted on Technocrat.Net by geomon · · Score: 4, Funny

      How does it feel to be potential parents to an alien species?

      Like a Scientologist?

      (rimshot!)

      --
      "Rocky Rococo, at your cervix!"
  2. Sorry by Saiyine · · Score: 3, Interesting


    If the're "loosely bound together" how is that there were an impact at all? Wouldn't the probe just sunk into the comet?

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    1. Re:Sorry by TripMaster+Monkey · · Score: 5, Informative


      The same way the Shuttle on reentry 'impacts' the atmosphere, or the way a suicie from the Golden gate Bridge 'impacts' the water.

      If you're moving fast enough, it's sure gonna feel like an impact.

      --
      ____

      ~ |rip/\/\aster /\/\onkey

    2. Re:Sorry by geomon · · Score: 2, Interesting

      I would agree that sounds like the case. However, my experience has been that snow packed loosely together into a projectile can hurt. I got pelted by nearly 100 snowballs as a freshman and one left a cut above my eye.

      No rocks or other debris was packed into the snow. It was a loose powder compressed by punk-assed kids - you guys know who you are. I'm still comin' for ya.

      --
      "Rocky Rococo, at your cervix!"
    3. Re:Sorry by Anonymous Coward · · Score: 2

      Think about a sandbox. It's not just "loosely bound" - it's not bound at all. However, I can gaurantee you you can still impact the sand in a sandbox.

    4. Re:Sorry by forkazoo · · Score: 4, Funny

      The comet becomes terribly afraid whenever anything is about to hit it. This natural "tensing up," it what allows us to study it effectively.

      Also, moving at many thousands of kilometers per second means that you can impact almost anything and cause an explosion. If the probe gently touched down, it might well have settled into the comet very ently.

    5. Re:Sorry by Anonymous Coward · · Score: 2, Informative

      "Loosely bound" relative to solid rock. Also, from the article, although the outer layers of the comet were composed of tiny particles (~1 micron - 100 micron in size), the density of the comet's nucleus was about 600 kg per cubic metre, so the probe was never going to sink too far...

    6. Re:Sorry by smooth+wombat · · Score: 5, Interesting

      When I saw the article (YESTERDAY!!) I thought about this also but came up with what I hope is a good analogy.

      If you have ever been to the beach or played in a really deep sandbox, you know that the top layer of sand moves about easily. You can dig your toes in without any effort. The sand is loosely bound together.

      However, if you drop a bucket (or anything else) onto the sand, that object will only sink in a small bit. Why? Other than the fact that there isn't much force behind dropping whatever onto the surface of the sand the sand itself compresses slightly from the impact.

      'But Deep Impact was the size of a washing machine and travelling at a bajillion miles an hour when it hit. You can't compare that to dropping a bucket on the beach!' I hear you say.

      Actually, you can compare the two. If you take the size of a bucket compared to the size of the beach, there is a huge difference. Even if you were to take a replica of Deep Impact and fire directly onto the beach at a speed approximating the impact speed on the comet I can guarantee you would get a similar result.

      The impact would produce a nice big explosion of particles and the copper impactor would probably disintegrate. However, the beach would still be there albeit with a nice big hole in it.

      Hope this long-winded explanation helps.

      --
      We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
    7. Re:Sorry by dosle · · Score: 2, Funny

      This all goes back to the saying "Why don't you go pound sand.".


      *returns to punching fine particles*

    8. Re:Sorry by StrawberryFrog · · Score: 2, Informative

      The lower layers of an object will not compact in a zero-gravity environment.

      --

      My Karma: ran over your Dogma
      StrawberryFrog

    9. Re:Sorry by elliotCarte · · Score: 4, Informative

      ...how is that there were an impact at all? Wouldn't the probe just sunk into the comet?

      I'm guessing that what you're really asking is why any debris was thrown from the surface of the comet instead of the impactor just uneventfully sinking into the surface. Think of it like this: If you take a bowl and fill it with talc powder or flour (a very loosely bound together substance) and shoot a projectile into it with a slingshot, would it just sink in without producing any debris (a small puff of powder or flour)? Add to this the fact that there's far less gravity holding the comet together than there is holding the powder down/together (in the bowl). Does that visualization help?

      It's an easy experiment. Try it. I might suggest a coffe can instead of a bowl though so that 1. you don't break the bowl and 2. you minimize the risk of the projectile flying back up and hitting you or someone/something else. Also use plenty of powder or flour as to slow the projectile enough that it can't hit the bottom and bounce back up and of course you want to wear safety glasses. Alternatively you could just view the images sent back from the mission (included in TFA) and trust that it's not all just a hoax.

      --
      If you can't just be yourself, then be more like me, ok?
    10. Re:Sorry by StrawberryFrog · · Score: 3, Informative

      Correct, but the point remains: the comet was described as having the consitency of a snowdift.

      On the surface of earth, the bottom of a snowdrift compacts under the weight of snow on top of it. On a comet (i.e. a small body in a large orbital path around the sun) the same effect does not apply, and the snowdrift could be as loose as the top inch all the way through.

      --

      My Karma: ran over your Dogma
      StrawberryFrog

    11. Re:Sorry by LurkerXXX · · Score: 4, Informative
      But there is this little thing called inertia...

      You've got many many metric tons of snowdrift, floating through space.

      You ram a refridgerator size probe REAL fast into one side of it.

      The 'snow' right where the fridge hits is going to move inward, but the many many metric tons of snow on the other side of it is going to want to stay right where they are (a body at rest tends to stay at rest). The movement inward of the snow under the probe's impact against all that 'resting mass' will cause the compression of the 'snow' in that area.

    12. Re:Sorry by daeley · · Score: 4, Funny

      it might well have settled into the comet very ently.

      Harrrooomm! Harruummmmm! My, but you are a hasty comet. Very hasty, indeed. Harrooooooomm!

      --
      I watched C-beams glitter in the dark near the Tannhauser gate.
  3. Skip the middlemen by Anonymous Coward · · Score: 5, Informative


    and their advertising application masquerading as a "website"

    http://www.nasa.gov/mission_pages/deepimpact/media /spitzer-di-090705.html

  4. A big powdery comet? Precious! by deft · · Score: 4, Funny

    Well dang, if that's all it is, c'mon in for a landing buddy. Man, we had you comets all wrong.

    Won't be a planet killer...more like a planet tickler...cute little fella.

    --

    There's nothing Intelligent about Intelligent Design.
    1. Re:A big powdery comet? Precious! by CubicleView · · Score: 2, Funny

      Thanks alot, I bet one'll hit us now *blasted desk is covered in plastic veneer, runs off to find a real piece of wood to touch*

    2. Re:A big powdery comet? Precious! by hobbesx · · Score: 3, Funny
      Thanks alot, I'll bet one'll hit us now...


      Worry not! I believe one of GW's proposals for the mission to Mars involves an orbital sifter array.

      --
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  5. Mining by SumDog · · Score: 5, Interesting

    I think its cool that we are all ready at the point where we can crash probes into comets and examine them. I wonder how long it will be until we can actually pull a comet into earth orbit and mine it for resources.

    1. Re:Mining by lobsterGun · · Score: 3, Interesting

      Based on the information revealed today, it might not ever be practical to move a comet into Earth's orbit.

      If the COMET was a big ball of rock it would just be a matter of attaching to it and then pushing it where it needs to go. But with the comet being in essence a big pile of sand, it would be much more difficult to move around with our current technology. (I'm basing this on the idea that as soon as we start pushing it, it will start coming apart)

    2. Re:Mining by Rorschach1 · · Score: 2, Insightful

      We can visit and study mountains, too. Moving them is another matter.

      Besides, it's asteroids you want to mine for minerals, not comets.

  6. Re:Powder... by thc69 · · Score: 5, Informative
    --
    Procrastination -- because good things come to those who wait.
  7. Mirror of first bits by paz5 · · Score: 5, Funny

    10101110

  8. Question by Dutchmaan · · Score: 4, Interesting

    Does this mean that using an significantly large explosive device is almost a feasible scenario for specific types of comets.

    I mean, I can understand not using that approach for something make of rock and ice, but with fine particles one would think that sufficient force would break it apart like a cue ball.

    Obiviously this is just fuzzy thinking, but does anyone have any scientific input to why this would or would not be an emergency solution to be put on the table for this specfic type of comet?

    1. Re:Question by Anonymous Coward · · Score: 4, Interesting

      My instinct here is that trying to detonate a comet is not a great solution no matter the composition.

      You do not have quite the same threat of calving (i.e. splitting into two big chunks instead of one big chunk), but there is the possibility that either a) the explosion would just shove it (the beach/sand analogy above is good), or b) that you would face a sandblasting from billions of tiny particles.

      That might not seem so bad - hey, no impact crater! But the simultaneous atmospheric entry of that much material can generate so much heat as to start mass fires on the ground below (this is a normal side effect of debris reentry in a lot of impact models).

    2. Re:Question by Doc+Ri · · Score: 3, Interesting

      I think that it is relatively losely bound does not mean it is something like a cloud. If it were like that you would not have to worry about a collision in the first place. (As usual, depending on the energy -- with sufficient energy a 'dust cloud' can also kill you.)

      When you shoot a projectile at such a comet, parts if of it can become more compactified. (This is actually one scenario proposed for the formation of small yet compact objects in space.) It would be very hard to predict what exactly would happen in such a collision. You could end up with some dangerous debris heading towards your home planet.

      Another problem is that very likely not all the comets have exactly the same composition. As long as you do not know, you can not predict the outcome of the blow-it-up mission. And it takes some time to find out...

      --
      617B3B7F7E7C7D7F00EOF
  9. Re:Powder... by CubicleView · · Score: 2, Informative

    As I understand it a spongy asteroid will absorb much more force than a harder one of similar mass. Trying to break a sponge for example is far less fun than trying to break some silly figurine. I'm also guessing that the powder itself wouldn't be able to explode like (or at least to the same extent as) it would in an oxygen rich environment.

  10. The real reason for the mission by Red+Flayer · · Score: 2, Funny

    "in other words, the comet is more like a pile of powder than a solid rock."

    NASA wants its Tang back.

    --
    "Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
  11. Its like a comet composed of garbage by MooseTick · · Score: 3, Funny

    I once saw a documentary about a comet that was made completely from garbage. It was nearly impossible to destroy because it was such a loose collection of items. This comet seems very similar.

  12. Re:Powder... by LnxAddct · · Score: 3, Informative

    The gravity and velocity of the comet i'm sure held it together. Your used to being on Earth, rules are a bit different when you leave the atmosphere. Matter tends to clump together, when that matter is in an orbit and moving at high velocities all together, it acts nearly as a solid. Despite that its a bunch of powder, you still calculate its center of gravity as though its solid. You are a bunch of cells but if I hit you, you don't fall apart. A bunch of powder moving in a direction will continue to move in that direction until acted upon by an outside force. The comet was big, the probe was small, the force not nearly large enough to knock it off oribt or to make the thing explode.
    Regards,
    Steve

  13. Audio version of the impact by Spy+der+Mann · · Score: 2, Funny

    -Impact in 3... 2... 1....
    *POOF*

  14. sounds like Bender.. by hamburger+lady · · Score: 2, Funny

    "10101110??? It's gibberish...(looks in mirror) 01110101!!! Ahhhhhhhh!!!!"

    --

    ---
    Is this the MPAA? Is this the RIAA? Is this the DMCA? I thought it was the USA!
  15. Fine powder? by Mr.Fork · · Score: 2, Funny

    Uh oh. Don't let the cosmetic companies in on our cosmic find. Heaven forbid Channel or Revlon market a powder puff from comet dust. I can see it now. The funded research/harvesting rocket Delta rocket lifts off with 'Maybe it's Maybelline' on the side sliding past the live web-cam tower broadcast is just wrong. Ugh - cosmic cosmetics.

    --
    Management is doing things right; leadership is doing the right things. - Peter F. Drucker
  16. They thought the moon by blair1q · · Score: 2, Interesting

    They thought to moon could be a big ball of loose powder, too.

    Neil Armstrong says he didn't know if they were going to land on the surface, or sink into it never to be seen again.

  17. Tunguska Comet Impact - 1908 by infonography · · Score: 4, Informative

    http://en.wikipedia.org/wiki/Tunguska_event

    There have been a wide range of theories about this, but a puffball comet explains a lot about what happened there. From Aliens;

    http://www.space.com/scienceastronomy/tunguska_eve nt_040812.html

    to Victorian Era Superweapons testing ala League of Extraordinary Gentlemen (the Comic book, not the movie). I have tried to find the site on Google Earth but have not been lucky.

    --
    Sorry about the writing. Robot fingers, you know? Cliff Steele in DOOM PATROL #23
    1. Re:Tunguska Comet Impact - 1908 by saider · · Score: 4, Informative


      Turn on the Lat/Lon grid and goto 6055' N 101.57' E

      --


      Remember, You are unique...just like everyone else.
    2. Re:Tunguska Comet Impact - 1908 by fbjon · · Score: 2, Informative

      You can't really find it in g-earth, since it didn't leave any big marks. There are some placemarks with an overlay map though. I found one in the community forums, and made some improvements: Tunguska Event in Google Earth.

      --
      True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
  18. Re:First results back from comet by twifosp · · Score: 3, Insightful
    We found out fast things hitting big things make big collisions. This is great science.

    We make dumb posts that over-simplify and generalize events. This is great commentary.

    If you don't have anything worthwhile to post, don't post at all. I know you're just a silly troll, but a lot science has been at the hest of speeding things up and mashing them together to create collisions. Ever heard of a particle accelerator?

  19. Re:Density question by Doc+Ri · · Score: 2, Informative

    Water's density is 1000 kg/m^3, so 600 kg/m^3 is pretty dense.

    --
    617B3B7F7E7C7D7F00EOF
  20. Unlikely they thought the moon was powder by John_Sauter · · Score: 4, Insightful
    They thought to moon could be a big ball of loose powder, too.

    Neil Armstrong says he didn't know if they were going to land on the surface, or sink into it never to be seen again.

    Hard to believe that Neil Armstrong was not familiar with Lunar Surveyor. See http://nssdc.gsfc.nasa.gov/planetary/lunar/surveyo r.html.
            John Sauter (J_Sauter@Empire.Net)

  21. Re:Formation of a City-Sized Crater? by CubicleView · · Score: 3, Informative

    The military is currently researching railgun technology. The shells said railgun will fire are inert and will not explode in the same manner as conventional shells. They'll simply strike the unfortunate target with such force that it'll basically explode. Nasa did the same thing, just with more mass and more velocity, no chemical reaction could explode with the same force obtained by striking a target in this manner.

  22. Re:Formation of a City-Sized Crater? by Blitzenn · · Score: 3, Insightful

    "Exactly what was in that impactor that could create a city-sized crater?"

    It is exactly the inordinate size of the crater that has caused them to beleive that the surface is like a 'pile of powder'. It wasn't that the impactor was so large or going so fast relative to the target, it was that the surface material reacted so violently in relation to the physical impact. That denotes that the surface material has little to no cohesive nature. What really makes that curious is why would it possibly stay together to begin with then? It is a relatively small body and should exhibit a very very small gravitation influence. Why would such material form a body that at least gives the illusion of cohesion in the abcense of the physics that we believe it takes create such a body?

  23. Answer: Kinetic energy by p3d0 · · Score: 2, Informative
    Exactly what was in that impactor that could create a city-sized crater?
    Kinetic energy. It's an amazing thing.
    --
    Patrick Doyle
    I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
  24. Re:Powder... by fbjon · · Score: 2, Funny

    That's no asteroid. That's one of those potatoes from Frontier: Elite II.

    --
    True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
  25. Re:Can someone help me? by phlegmofdiscontent · · Score: 3, Informative

    I can't think up a good answer beyond the usual origins of life or origins of the solar system stuff. It's not really practical for the layman, but it's interesting to scientists. I hold to the idea that the pursuit of knowledge in and of itself is a noble pursuit.
    On the other hand, I do hear quite often "why should I care?" from laymen. Well, turn back 100 years to the beginnings of quantum theory. "Why should I care how electrons behave around protons" or "Why should I care that uranium undergoes fission when bombarded by neutrons?" The first led to the development of the transistor and electronics and computers and just about everything technological in the past 50 years. The second led to the development of nuclear power (and weapons) and has also had a tremendous impact. By the same token "Why should I care what comets are made of?" may not have an answer now, but it might in the future. To withold funding from one scientific project may prevent some new discovery or technological advance. If all scientific endeavours were left to private industry, sure we'd make advances, but most private research is focused on the near term whereas public research is knowledge for knowledge's sake, and often produces advances and breakthroughs not seen in private research. In NASA's case, their investment in the 50's and 60's led to quite a few developments such as communication satellites and paved the way for businesses like Scaled Composites. That's at least worth something. I know I'm proselytizing a bit, but I think I have at least some of a point.

  26. Re:Can someone help me? by Ransak · · Score: 2, Insightful
    Aside from the obvious help something like this could be for helping turn away a Near Earth Object (check out this site for more info on NEOs), large portions of the technology used to develop these missions furthers other closer to home technologies. A few off the top of my head:

    Robotic missions furthers robotic tech for other industries. Bomb disposal anyone?

    Material science is furthered with every new probe, providing insights into stronger materials for planes/trains/automobiles back here at home. If you've bought a car in the last 25 years, you have benefited from the space program.

    New communication tech directly carries over to private industry. Without previous missions, there would be no DirectTV.

    In flight tech adjusted the Deep Impactor twice before colliding with the comet. That tech could easily be the precursor to an intelligent AI to land planes.

    These are just a few things off the top of my head. The great thing about programs like this is the untold tech that will be developed from this that we can't even guess at right now, and perhaps not for many years.

    --
    "Powers. I have them."