Posts

Showing posts from 2018

Throwback Solstice Thursday - Venus Transit Collage

Image
Back in June of 2012, I went with my family to Hawaii where we watched the Transit of Venus. I have since been developing my collage skills - so, without further ado, I present the Venus Transit Collage:


1,000 Teslas, 200 years

Image
In my previous post, I simulated my best available information on the SpaceX Tesla roadster. In this post, I investigate a range of possible futures for the Tesla. I started with JPL's HORIZONS ephemeris. It turns out that it can evaluate probabilistic orbits; here are its predictions for close planetary encounters by the Tesla given the current uncertainties in its position:


          Date (TDB)      Body   CA Dist  MinDist  MaxDist   Vrel  TCA3Sg  Nsigs  P_i/p
  ----------------------  -----  -------  -------  -------  ------ ------ ------ -------
  A.D. 2020 Oct 07.26668  Mars   .049589  .047961  .052381   8.153  92.21 1.57E5 .000000
  A.D. 2035 Apr 22.36925  Mars   .014376  .003802  .055862   8.199 601.42 10658. .000000
  A.D. 2047 Jan 11.95105  Earth  .031798  .022547  .040258   4.488 5203.0 24104. .000000
  A.D. 2067 Apr 15.90602  Mars   .043165  .004269  .090230   7.193 3779.8 12481. .000000
  A.D. 2085 Jan 01.97974  Earth  .083090  .007954  .163620   6.224 13899. 32807. .000000
 …

Initial Evaluation of SpaceX / Tesla Orbital Stability

Image
Executive summary: its orbit is not very stable.

On February 6, 2018, SpaceX performed its test launch of its new Falcon Heavy rocket. It was a very successful launch. As most people know, the payload was Elon Musk's 2008 Tesla Roadster. After orbiting the Earth for a few hours, the upper stage lit up again and sent the Tesla on a Solar orbit:

Musk has famously tweeted that the Tesla will be orbiting for "a billion years." This is extremely unlikely. In fact, it will likely crash into the Sun, or a planet (most likely Earth but perhaps Venus), or be ejected from the Solar System.

To try to characterize this, I went to NASA's JPL Horizons web page to get current Cartesian elements for the Tesla (these are vectors of position and velocity). These are the elements as of today, February 10, 2018:

2458159.500000000 = A.D. 2018-Feb-10 00:00:00.0000 TDB
 X =-7.690802173107607E-01 Y = 6.236475652855626E-01 Z =-1.393643118679943E-03
 VX=-1.252512462814835E-02 VY=-1.488196764720…

Total Lunar Eclipse - Jan 31, 2018

Image
This morning was a Total Lunar Eclipse. Despite the moon setting during totality, I decided to take a sequence. Here is a collage of photos taken roughly every 10 minutes (I say roughly, since I was dodging clouds the whole time). Taken from the sidewalk in front of our house:



 Here is an animated GIF of the sequence:


And here is a parting shot of the moon in eclipse setting over Arthur's Rock and The Big A: