STAR LOOP PATTERN ILLUSION
Bruce L. Gary, Last Updated 2023.11.16

We must learn to be skeptical of patterns our eyes are prone to see. This was made forcefully clear to me when I chanced upon a star field that looked persuasively like a star loop, shown in the figure below:


Figure 1. 10.5 x 15.6 ' arc field, centered on RA Dec = 21:29:40 +45:07:22.

The next figure shows the pattern I "saw":


Figure 2. A loop pattern that my "lying eyes" saw.

I asked Saul Rappaport what could have caused it, and he was wary of it's physical reality, i.e., that the stars along the loop were actually related to each other (by a physical event).

To test this Saul sent me a listing of Gaia information for stars in this region and suggested I determine whether or not the stars in the loop were at the same distance.

I did this and in the next figure I show parallaxes for a few of the most prominent stars comprising the loop:


Figure 3. Parallaxes ["arc] for a few prominent loop stars. Notice that they're not the same.

The next figure shows how these parallaxes are spread out in a way that could be expected for unrelated stars: 


Figure 4. Histogram of parallaxes for ~400 stars in the loop region. The numbers at the top are at parallax values for 7 loop stars.

I conclude that since the loop stars are not at the same distance they are unrelated to each other and the loop pattern that they form is an "illusion" that occurs infrequently enough that after many views of star fields, as I have done, such an uncanny illusion will occasionally be encountered.

Return to Bruce Gary home page: http://brucegary.net/resume.html
____________________________________________________________________

This site opened 2023.11.16. Nothing on this web page is copyrighted.