alt="Cartoon of a person operating a flight simulator with a virtual reality headset. A greenish glowing cloud in front of their face shows what they see on the headset: the cockpit of a plane with galaxies outside the windows."

This cartoon is part of the DES Y3 #Darkbites social media series. It was drawn to illustrate a paper led by Joe DeRose, which describes simulations and simulated analyses used to validate the DES Y3 galaxy clustering and weak lensing analysis. The paper’s title is, “Dark Energy Survey Year 3 results: cosmology from combined galaxy clustering and lensing – validation on cosmological simulations” (arXiv:2105.13547).

The post’s associated text was:

Airplane pilots use flight simulators to train because it lets them plan routes and test techniques without the risks of flying a real plane. Similarly, before using real measurements to infer the properties of the Universe, we analyze simulated DES data.

These simulated analyses let us test-drive our calculations and code: we know what went into making the simulation, so we can check that we recover the right answer!

Here’s a link to the post. The twitter thread of the Y3 Darkbites posts begins here. The cartoons also being shared on the DES facebook and instagram pages.

Here’s a version of the illustration without the hashtag: alt="Same cartoon as above, but without the darkbites hashtag superimposed."