Falcon Heavy lifts off, NOW!

Fora ASTRO-FORUM GENEREL ASTRONOMI Falcon Heavy lifts off, NOW!

Dette emne indeholder 2 svar, har 2 stemmer og blev senest opdateret af Bjarne 14/02/2018 12:47.

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  • #316266

    nvc
    Participant

    Det er nu, live! Mvh. Niels

    http://www.spacex.com/webcast

    #316346
    Bjarne
    Bjarne
    Moderator

    Elons Musks første påstand om, at bilen med “Starman” når næsten ud til Ceres var forkert. Den når lidt uden for Mars’ bane. Hans anden påstand om, at den vil befinde sig i denne bane i flere hundrede millioner år, viser sig også at være forkert. Baner af denne form og i denne afstand fra Solen perturberes af Jupiter, så de enten slynges ud af Solsystemet eller ender med af falde ind i Solen. Det sidste hjælpes godt på vej af termisk emission (varmestråling), hvis massen er så lille som i dette tilfælde.

    ‘Starman’ puts Earth in the rearview mirror

    STORY WRITTEN FOR CBS NEWS

     

    #316425
    Bjarne
    Bjarne
    Moderator

    The random walk of cars and their collision probabilities with planets

    On February 6th, 2018 SpaceX launched a Tesla Roadster on a Mars crossing orbit. We perform N-body simulations to determine the fate of the object over the next several million years, under the relevant perturbations acting on the orbit. The orbital evolution is initially dominated by close encounters with the Earth. The first close encounter with the Earth will occur in 2091. The repeated encounters lead to a random walk that eventually causes close encounters with other terrestrial planets and the Sun. Long-term integrations become highly sensitive to the initial conditions after several such close encounters. By running a large ensemble of simulations with slightly perturbed initial conditions, we estimate the probability of a collision with Earth and Venus over the next one million years to be 6% and 2.5%, respectively. We estimate the dynamical lifetime of the Tesla to be a few tens of millions of years.

     

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