Solar-System | Simple solar system experiment

Author of the tutorial here. I'm glad you enjoyed it!

This is a good question. I'm not an expert on astronomy or mathematics, but I'll do my best to answer.

Setting Speed Via Custom Property

The first thing to know is that the rotation speed is controlled by the --rotation-speed custom property. We'll be updating that value from distance * randomInt(40, 70) to a more accurate value. Right now this is set in milliseconds.

So we need to determine what value to set that custom property to.

Non-scientific caveats

I'm going to be taking a couple short-cuts in my math here:

• Kepler's law has complex math to account for the fact that most orbits are elliptical (not circular). My tutorial is using circular orbits, which makes the match simpler. (For an additional challenge you could try switching to elliptical orbits)
• Obviously real-life orbits are too slow for us to observe, so we'll need to speed them up, but make them more realistic in relation to eachother.

Determining a more accurate speed

With those caveats in mind, let's find a formula we can use. I found this helpful article which describes how to calculate circular orbital speeds: https://www.nagwa.com/en/explainers/142168516704/

Here's a JS approximation of the formula they outline in the article:

Add a size parameter with the planet.size value and use it in your component.

const SolarSystem = () => { ...

You are pretty close. To get all the different types out of your data object you could use Object.keys then replace data in your loop with data[type].

Instead of add you need to use appendChild to add elements into another DOM node.

If the spring boot application has no enforcement of security, what is to prevent someone from bypassing the Apigee API gateway and calling it directly?

If you have successfully managed to secure the spring boot application so that only the API gateway can communicate with it (via mutual TLS connection, IP allow listing, etc), you might be able to forego any enforement at the service level, but I would recommend doing some authorization checks in the service itself.

The way that scmutils handles the integration is interesting. The state derivative function works with a local tuple as described in SICM, but the integrator wants to work with a function that takes an array of floats as input and produces an array of equal size as output. To do this, scmutils takes the initial state data and replaces the values in it with symbols and passes this to your derivative. This produces symbolic output, which can be used to prepare a function with the right signature for the integrator. (I can describe this process in greater detail if you would like).

Your problem is in Cartesian coordinates, however, and the resulting symbolic expression is hairy. You can see this process in action by creating your own symbolic state and passing it to the derivative function, and simplifying the output (by passing the result through pe (print expression)):