| Topic: |
Science > Physics |
| User: |
"George" |
| Date: |
09 Sep 2005 06:13:14 AM |
| Object: |
How to calculate total deflection |
hi,
Say for example, a comet is deflected 1mm from its natural path how
much deflection would occur till it starts it return journey, actually
it came to my mind after i read about a probe colliding with comet few
months back, definitely NASA must have thought about it , but they
could only figure it out for natural orbit(what it will have if it does
not collide with other objects in between),
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| User: "Sam Wormley" |
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| Title: Re: How to calculate total deflection |
09 Sep 2005 08:35:08 AM |
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George wrote:
hi,
Say for example, a comet is deflected 1mm from its natural path how
much deflection would occur till it starts it return journey, actually
it came to my mind after i read about a probe colliding with comet few
months back, definitely NASA must have thought about it , but they
could only figure it out for natural orbit(what it will have if it does
not collide with other objects in between),
A mathematician would also have to know things like orbital elements,
mass, etc., otherwise one millimeter means diddley squat.
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| User: "PD" |
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| Title: Re: How to calculate total deflection |
09 Sep 2005 12:26:24 PM |
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George wrote:
hi,
Say for example, a comet is deflected 1mm from its natural path how
much deflection would occur till it starts it return journey, actually
it came to my mind after i read about a probe colliding with comet few
months back, definitely NASA must have thought about it , but they
could only figure it out for natural orbit(what it will have if it does
not collide with other objects in between),
I think you perhaps want to describe the deflection not in terms of
distance but in terms of angle. Think in terms of a baseball instead.
If a bee hit a baseball right after leaving the pitcher's hand and
deflected it by 1 mm, it would be only 1 mm off its original path by
the time it hit the plate. But if it were deflected by a degree, then
it would be off by 18 inches by the time it crossed the plate!
PD
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| User: "Randy Poe" |
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| Title: Re: How to calculate total deflection |
09 Sep 2005 10:23:47 AM |
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George wrote:
hi,
Say for example, a comet is deflected 1mm from its natural path how
much deflection would occur till it starts it return journey, actually
it came to my mind after i read about a probe colliding with comet few
months back, definitely NASA must have thought about it , but they
could only figure it out for natural orbit(what it will have if it does
not collide with other objects in between),
Unanswerable, as has been pointed out. Too much missing info.
First let's talk about something moving in a straight line,
not in an orbit. Let's say instead that your cause a change
of direction of 10^-5 degrees (1.75E-7 radians).
If that comet was heading directly toward you and I make this
change when it is 1000 km away, then I will change the impact
point by 17.5 cm. Not enough to do you any good.
If I make this change when it is 55.8 million km away (the
distance to Mars at closest approach), then I would change
the impact point by 9.7 km, which might change a hit to a
miss.
To do the actual calculation you want, you need to know
what the change in VELOCITY vector (size and direction)
is, and the position of the comet relative to the sun at
that time. The change of direction is going to be many
of orders of magnitude below 10^-5 degrees.
- Randy
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| User: "" |
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| Title: Re: How to calculate total deflection |
09 Sep 2005 06:44:09 AM |
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Good Grief. the deflection was miniscule. If you knew any astronomy
you'd realize how much space there is out there and that the mass ratio
of impactor to main body was insignificant.
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| User: "the softrat" |
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| Title: Re: How to calculate total deflection |
09 Sep 2005 11:17:23 AM |
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On Fri, 09 Sep 2005 11:13:14 GMT, "George" <georgekinley@hotmail.com>
wrote:
hi,
Say for example, a comet is deflected 1mm from its natural path how
much deflection would occur till it starts it return journey, actually
it came to my mind after i read about a probe colliding with comet few
months back, definitely NASA must have thought about it , but they
could only figure it out for natural orbit(what it will have if it does
not collide with other objects in between),
Nop.e The theory provides for known irregular motion. The orbit just
is not a pure ellipse, and may not be a closed figure, that's all.
They (NASA) can determine the new orbit as precisely as they desire.
the softrat
Sometimes I get so tired of the taste of my own toes.
mailto:softrat@pobox.com
--
"Let's jump off that bridge when we come to it." -- Allan
Lamport (deceased), former mayor of Toronto.
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