Saturday, February 17, 2018

"The random walk of cars and their collision probabilities with planets"

Initial conditions - very important. Just ask grandmother.*
From the Physics arXive at Cornell:

Astrophysics > Earth and Planetary Astrophysics

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.
Comments: 5 pages, 4 figures, to be submitted to MNRAS, comments welcome
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1802.04718 [astro-ph.EP]
(or arXiv:1802.04718v1 [astro-ph.EP] for this version)

Download page

*Grand mother was last sighted/cited in Feb. 6's "Mr. Macho Market Man Says: "Parachute? We Don' Need No Stinkin' Parachute"":
Grandmother would say something like "If the initial condition given is 'The sky is falling', your course of action would be to short sky, try the eggplant"
The long version, also re: trajectories, 2013's:

The Future Price Trajectory of Copper and Aluminum and the Implications for Oil
In Which Our Hero Explains the Importance of Recent Events and Their Impact on the Cost of Day-to-Day Living
...For me it was how to approach the profit possibilities; much in the same way Grandmother would quiz: "Your initial conditions are 'The sky is falling, the sky is falling', what is your course of action?" to which I'd reply "I'm this many: ||||, four" and she'd say, "No silly, your course of action is 'Short sky'"