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How long will one year last after malicious space aliens sabotage solar system?

The aliens arrived and constructed a spherical forced field around the sun of radius equal to one astronomic unit r=1au.

Then they also changed orbital parameters of Earth (orbital speed, initial position, etc) to make the Earth bounce off from the force field elastically and without friction on the outside, in such a fashion that orbit of Earth resembles now six petal flower like this

http://www.enchantedlearning.com/graphicorganizers...

The whole six petal flower is inscribed into a circle of radius R = 2au.

6 Answers

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  • ?
    Lv 5
    1 decade ago
    Favorite Answer

    The petals satisfy the Kepler equation

    r = p/(1- e cos θ),

    r is the distance to the Sun, and θ=0 in the aphelion, r = 2R. Petals strike the force field at r = R where θ=± π/6 (then each petal takes 1/6 of the circle). From these conditions we can find e and the semi-major axis a = p/(1-e^2).

    The rotation period in the gravitational field scales as a^(3/2). The period of a complete elliptic orbit (including part r<R) is T_complete = (a/R)^3/2 [years]. We should multiply the result on 6 and take into account the elliptic orbits are not complete. The fraction τ of T_complete, which is spent at r>R, is proportional to the fraction of the ellipse area swept by this part of the trajectory,

    τ = ∫ r^2 d θ / [π p^2/( 1-e^2)^(3/2)]=

    (1/π) { 2 arctan [ √[(1+e)/(1-e)] tan(θ/2)]

    + e √(1-e^2) sinθ /(1-e cos θ) }.

    Substituting numbers, we get

    e = 2/(4-√3)=0.88, a = 2(4-√3)/(6-√3) = 1.06 R,

    6 T_complete = 6.57 [years], τ = 0.54.

    The new year will last

    6 T_complete*τ = 3.54 [years] = 42.5 [months].

    EDIT. By mistake, I substututed π/12 instead of π/6 in the formula for τ. Substituting π/6 gives τ=0.8 and

    6 T_complete*τ = 5.3 [years] = 63 [months].

    Now, it's close to Remo's answer.

  • Anonymous
    4 years ago

    Eris, the main important dwarf planet universal, replaced into chanced on in an ongoing survey at Palomar Observatory's Samuel Oschin telescope by using astronomers Mike Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz (Yale college). We formally stated the call on 6 September 2006, and it replaced into popular and introduced on 13 September 2006.

  • 1 decade ago

    I agree with Zo Maar in part (ie., nature of the ellipse) but disagree regarding his final answer.

    The earth's orbit will be divided into six section of 60 degrees (π/3) each. The orbit will consist of 6 interlocking partial ellipse. We don't have to worry about the angle they are incident on the new force field because given their shared focus, they will reflect at the same angle they are incident.

    The max distance of the ellipses from the sun is 2au.

    We can also compute in terms r in terms of a

    r = earth's orbital radius

    ε = eccentricity

    a = semi-major axis.

    r = 1 au.

    2r + (1- ε)a = 2a

    r = a(1 + ε)

    The intersection between the partial ellipses and earth's radius occur at the radius.

    Apply the angle formula:

    r = a(1- ε^2)/(1± ε cosθ)

    θ = π/6

    In the case the denominator will be (1- ε cosθ)

    a (1 + ε) = a(1- ε^2)/(1 - ε cosθ)

    (1 + ε )(1 - ε cosθ) = 2(1 - ε^2)

    1 +(1 - cosθ)ε - cosθ ε^2 = 2 - 2 ε^2

    (2 - cosθ) ε^2 +(1- cosθ) ε - 1 = 0

    ε = ((cosθ -1)+/- √(1-2cosθ + cos^2θ + 8 - 4cosθ)) / 2(2 – cosθ)

    ε = ((cosθ -1)+/- √(9- 6cosθ + cos^2θ ) / 2(2 – cosθ)

    ε = ((cosθ -1)+/- (3- cosθ )) / 2(2 – cosθ)

    ε = 1/(2-cosθ) or (cosθ -2)/(2 – cosθ)

    ε = 1/(2-cosθ) =~ .8819

    Given the circumstance, ε = 1/(2-cosθ) should be the correct answer .

    a = 2r/( ε +1)

    a = 2r/(1/(2-cosθ) +1)

    a = r 2(2- cosθ)/ (3 -cosθ) =~ 1.0628 r

    b = a √(1- ε ^2)

    b = 2r √((1- ε)/((1+ ε)) =~ .5010 r …. purrrrfect

    Now the fun part. Apply Kepler's laws of area.

    Period of ellipse = 1 year * (1.0628)^3/2

    P ~= 1.0957 years

    Since I s..k. at finding areas of ellipses, we are going to turn our ellipse into a circle. There will be no loss of information. Here is a drawing on how: http://i278.photobucket.com/albums/kk114/Remo_Avir...

    Center of Ellipse (from focus, ie. sun) = a ε

    Ce= 2r ε /( ε +1)

    =~ .937218279

    Intersection of Ellipse and earth's present orbit

    Ie= √3 /2 r

    Let x = Ce – Ie

    x =~ .071193

    Area of Circle cut off by projection of intersection to axis.

    Ac= π a^2 – acos(x/a) a^2 – x√(a^2 – x^2)

    Ac =~ 1.77417 r^2

    Area of Triangle formed between Focus (sun) and intersection of ellipse with earth's orbit.

    At = √3/2 r * a/b * .5r

    At = √3 /2 r 1/√(1-ε^2) * .5r

    At = .918496 r^2

    Time between bounces

    T = P* (At +Ac)/π a^2

    T = ~ P * (.7588)

    T = ~ .83142 years

    Total time = T*6

    Tt = 4.9885 years.

    Dang Aliens

    *********** Edit 1*******

    I made an error in Ac, above. It should be:

    Ac= π a^2 – acos(x/a) a^2 + x√(a^2 – x^2)

    or

    Ac = acos(-x/a) a^2 + x√(a^2 – x^2)

    either way gets you

    Ac =~ 1.9248 r^2

    T=.8017 * 1.0957 yr = .8784 yr

    Tt = 5.27 yrs

    Zo Maar and I are in accord.

    [Pity poor Kepler before the invention of caculus -- he would have labored on and on like I have just done. Isaac Newton made the world much easier to solve as Zo Maar just showed. ;-)]

  • Anonymous
    1 decade ago

    wow...

    1 word... BLONDE!

    sorry i will be no help whatsoever!

    im going with 3 months ... just coz i like the number 3! :)

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  • Anonymous
    1 decade ago

    Who gives a ****

  • Anonymous
    1 decade ago

    damn i knew they would find us one day....

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