Space - a BBC TV Documentary

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Red Devil, Jul 31, 2001.

  1. Red Devil Born Again Athiest Registered Senior Member

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    Although previously posted elsewhere, it has been suggested that I start a new thread on this subject, so I reprint my previous post here.
    I dont pretend to understand physics or quantum thingies or relativity. I am neither a scientist nor an astronomer. However, I have just watched the second in the series of "Space", with Sam Neill, a BBC documentary, which I recommend to you all. As soon as you can, watch it - it is an eye opener to us amateurs on this fragile planet we call Earth. In this second programme (UK spelling!) Sam Neill explains how the Earth is like a ball in a giant game of luck! Not only does the Earth spin around the sun, which rotates about the galaxy, but the sun also rotates up and down - every 30 million years or so it passes through the densest part of the galaxy - and the dangers increases proportionately. If you like, you can describe the sun's galactical path as a corkscrew. The sun and our solar system last passed through this dense region one million years ago BUT, the dislodgement of the outer sphere of tons of debris which coats our system, takes a million years for it (as comets) to reach the inner system! Therefore, we can expect, within the next 200 years, according to an eminent scientist, something WILL hit the Earth! In the programme it was explained that we must be doing something NOW to try and achieve some sort of planetary defence system. Also explained in this second episode, the dinosaurs were wiped out during such a phase, and there have been at least 20 "civilisations" before that!! Should a comet the size of Schumaker-Levy 9 hit the earth - all life would have been wiped out. As we all saw in the 90s; the explosion on Jupiters surface (SL9) were actually bigger than the Earth. As it happens, and has happened since the solar system began, Jupiter has acted as a giant vacuum cleaner, sweeping up the comets of sufficient size, before they enter the inner solar system. But our luck, and it has been luck, will one day run out and Jupiter will miss one!! The Earth, when it was forming, was hit by a molten object the size of Mars; it nearly decimated the planet - but didn't! More luck! The resulting explosion released thousands of tons of rock as asteroids into the system - most of which Jupiter ate up. The remainder can be found in the asteroid belt. The moon was born of this titanic detonation. More luck - as the moon is instrumental in our existence and survival. The universe has thrown all it can at us in an effort to wipe us out, so far we have been lucky!! But in order to survive, our species has to learn, now, how to defend the planet from debris - or we will all perish. I look forward to the remainder of this programme with interest. It looks like we are riding a giant roulette wheel and pretty soon, something is going to throw the ball in! Should any of you get the chance to see this programme for yourselves - I thoroughly recommend it!

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    and looks upwards! Addendum: The dislocation of the debris from the outer sphere is caused by the passing of the solar system to the gravitational pull of a nearby star as we pass through the dense arm; it sucks the debris outwards, releases it, which then has the momentum to enter the solar system en route towards the sun.
     
    Last edited: Jul 31, 2001
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  3. wet1 Wanderer Registered Senior Member

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    This is quite different from the Planet X theory. To me it better accounts for the time span between events. Through several generations people have searched for the Planet X. No trace has ever been found. I had made a post concerning the Planet X theory and its speculation of what would be required for it to exist. Even to the point of quoting a news article that dealt with it. It would seem odd that with our better imageing, telescopes, and instruments, that we have found no physical trace to show such exists if it were indeed there. There should be something to be seen or some physical evidence besides thought experiments to show for results. If none can be found that suggests that we have not hit upon the answer yet. This does supply another way, another reason why we have not seen anything. Geologic evidence shows that something is happening on a regular basis so there should be some underlying cause, some event that we can point to and say this is the cause. So far that ability has escaped us. This may be one of the contributing factors leading to just such an ability. It does indeed give some pausable reason for the lack of discovery. NEO's are indeed a frightening event even when they are just near. That such has happened in the past shows that it is reasonable to believe that it will happen again in our future. I hope that it is in our far future and not as near as might be thought.
     
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  5. Biggles Custos morum Registered Senior Member

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    Last edited: Jul 31, 2001
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  7. wet1 Wanderer Registered Senior Member

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    A lot depends on how much warning we have and how large the NEO is. Also what it is composed of.

    I see you have the link refering to the UK's looking into setting up a task force to deal with NEO's. There is also an automated sky search being preformed on a regular basis in (I think) Arizona, which looks for NEO's and comets. One of the problems with determining orbits is that it requires several sightings to properly place the orbit of the body. A lot of them "get lost" in that the follow-ups are not preformed soon enough to relocate them.

    There are many studies that have been done on this problem. Some of the basic stuff, which I'm sure you already know, are that given sufficent warning it is possible to nudge the orbit so that the deflection misses the earth. This is probably the most desired outcome. A lot of bodies are dark in color and this makes spotting them hard. So not near the warning is given as it takes so long to spot them.

    The nearer the object, the less time you have to do something and the more force is required to do it. The last thing you want to do is to fragment it into a lot of smaller chucks. This gives the shotgun effect and if the chunks are spread out enough you have probably assured that some will certainly strike the earth.

    Softer materials present special problems in that anything used to move it may give you undesired results.

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    It has been some time since I studied this material.
     
    Last edited: Aug 1, 2001
  8. Red Devil Born Again Athiest Registered Senior Member

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    NEO's - options

    2 options were mentioned in this, the second programme of the series. (1) Hitting it with a nuke - but that creates thousands of smaller, possibly more lethal pieces, but hell, what a display! (2) Mounting rockets on the object to remove it from Earths locality. The second is possibly the "easier" option. What is cost compared with saving a whole damn planet!

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  9. Chagur .Seeker. Registered Senior Member

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    Whoa ...

    Red Devil Re.
    Old Mother Earth has been banged a few times before over the ages and survived. What we'd be saving, hopefully, is our asses and maybe a bunch of other species that we haven't succeeded in wiping out.
     
  10. Biggles Custos morum Registered Senior Member

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    OK, now they've produced a scale ..... now I'm scared!





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  11. wet1 Wanderer Registered Senior Member

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    The Torino Scale has been around for quite some time. It is a threat assessment tool to give those of the populace some idea of what damage is on a scale they understand. Not all are like those of the Sciforums where information and ideas stimulate and flow at a reasonably steady pace. This leaves the general populace in a stagnated position and all of a sudden out of the blue comes a rock headed for earth. So how do the information bringers relate the threat on a level to be understood? This is the purpose of the Torino Scale. Just like the Richter Scale it gives some idea of what to expect.
     
  12. Red Devil Born Again Athiest Registered Senior Member

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  13. wet1 Wanderer Registered Senior Member

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    Perhaps this would better illustrate for the readers...

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    The image will give some perspective on how large the Oort cloud is.

    As a side note, I used to particpate at this .com. I really got burned at the popup ads that would come up and run in the background while you were posting. After you left the scene then you to had to deal with them.

    After I found this site I had no reason to continue to post there.
     
    Last edited: Aug 2, 2001

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