# User Portlet

Jeff Bryant
Discussions
[![enter image description here][1]][2] **Full gallery:** https://www.flickr.com/photos/jeff-m-bryant/albums/72157686287351384 ---------- Here are [**some pictures**][3] of the aurora borealis I took last night from southwest Champaign...
![enter image description here][1] While investigating the TRAPPIST-1 exoplanet system in WL, I found this very cool looking mandala pattern that arises by connecting lines between the 7 planets in the system, and iterating time in discrete steps....
BTW, I should add that this meteor shower typically produces about 100 meteors per hour: In[5]:= Entity["MeteorShower", "Perseids"]["PeakZHR"] Out[5]= Quantity[1.0*10^2, 1/("Hours")] Although some predictions are claiming that...
The source doesn't specify a range of dates for which the results are valid, at least not in an obvious way. Often, additional references are given for some of the sub-computations. Its possible that if you do enough source spelunking, you might find...
Very nice! One minor improvement would be to use the following LightSource so that the Sun doesn't look like its being illuminated off to one side. Instead of "Natural", use: Lighting -> {{"Directional", White, ImageScaled[{0, 0, 1}]}} ...
I edited the code a bit to change the original Thickness directives with AbsoluteThickness which behaves better when large numbers of digits are involved.
Essentially, your premise is true for an object at infinity. The Sun is far enough away that this approximation nearly fits, but the Moon is close enough that there is a measureable parallax effect. Using simple trigonometry using the polar diameter...
For clarification, this visualization is for illustrative purposes, as mentioned in the first sentence. The function being plotted is not derived from any general relativity equations. Its a very similar surface to the one used on the Wikipedia page...
I'm a big fan of the book, "[The Martian][1]" and am very much looking forward to the movie, due in theaters on Oct. 2nd. I focused my pent-up excitement into exploring aspects of the story via the [Wolfram Language][2]. Using [Mathematica 10.2][3],...
Your comments are not entirely clear. The issue with supporting dates is a known recent problem dealing with how dates are exposed via EntityValue (used by StarData and PlanetaryMoonData under-the-hood). Its more general and doesn't affect the Alpha...