Follow the reluctant adventures in the life of a Welsh astrophysicist sent around the world for some reason, wherein I photograph potatoes and destroy galaxies in the name of science. And don't forget about my website, www.rhysy.net



Saturday, 4 April 2015

Things That Look Like Other Things

Some potatoes look like asteroids, others look like cartoon dog bones. Some galaxies look like the Loch Ness Monster. And one comet nucleus looks a lot like a rubber duck. If there's any cosmic significance to an asteroid looking like a potato or a comet looking like a rubber duck, I should very much like to know what that is.


Which is why, when I see a meme like this one...

... there can be only one response.


It's just not even wrong. Even making the comparison is pointless. If you're of the opinion that this is harmless trivia, scroll to the end. Otherwise keep reading.

The Universe is quite a big place, and contains quite a lot of things. That some of them look like other things is as significant as the correlation between cheese consumption and the number of people who die by becoming tangled in their bedsheets. It's called a coincidence, people. When you have (literally) astronomically large numbers of objects, you're gonna get a few of those.

From the wonderful spurious correlations.
Let's look at each of the three comparisons in the meme, just because why not.


1) BRAIN CELL vs UNIVERSE !



I was not able to find the source of the image of the brain cell in the meme. I'm not a biologist, but since an image search for "brain cell" reveals hundreds of very similar images, I'm going to assume the image is accurate.

I already knew, however, exactly where the "Universe" image came from - the Millennium Simulation. The clue is in the name. This isn't an image of the real Universe at all, it's a simulation. And in some ways it's a very simple simulation, since the only physics involved was gravity. No gas, no stars, no complicated fluid effects, no magnetic fields. Just gravity. That's all that's needed to produce something that, for some amount of time, looks a bit like a brain cell.

Here's what the real Universe looks like... well, as close as is reasonable, at any rate (as I describe in great detail here) :


The simulation image only shows particles of dark matter. Make no mistake, the sheer number of particles (more than ten billion !) makes this an incredibly powerful simulation if you know how to use it. And it does look a lot like the observable Universe if you only count the positions of galaxies, and don't look at the details like actual images of said Universe.

That the simulation was visualised in such a way that it looks a bit like a brain cell is just not interesting  - it was an arbitrary choice by the scientists to (quite correctly) make a nice image for public outreach, and show the details they were interested in as clearly as possible. That simulation was produced by only modelling gravity. And you know what - that simulation did not become conscious or do anything remotely mystical. It couldn't, because at the end of the day a bunch of simulated particles that have no property except mass can't do a lot except fall together in an interesting way.

That one component of the Universe might look a bit like a brain cell for some short (on cosmic scales) amount of time ? Big bloody deal.


2) BIRTH OF A CELL vs DEATH OF A STAR

But... but... but they don't even look the same !!!


I mean, seriously. Come on people. The cell image shows two uniform-ish spheres pulling apart. The second shows two truncated shells with bright rings at the edges and a big bright thing in the middle. Even without knowing any of the details, they look completely different ! Seriously, who looks at this and thinks, "these two completely different looking things look like the same thing" ? Aaarrrgh.

The only, marginal and completely superficial resemblance is that there are round things in both images. The only conclusion one can draw from this is that round things exist. Bubbles exist. Footballs exist. Various fruits exist. Water drops exist. Planets exist. And various parts of the anatomy exist.


Many years ago I showed the above image of the Eta Carinae nebula (associated with the death throes of a massive star) to a less-nerdy friend. Since were were both about 15 at the time, his response was inevitably "testicles in space !". Does that mean anything ? God, I hope not.

Stars are round. When they die, they sometimes produce large round structures. Who'd have thunk it.

What's really ironic about the meme is that the supernova image is actually an artists impression. So even when you compare the splitting of a cell to an idealised view of an exploding star, you find they don't look anything like each other. Amazing ! Here's what it actually looks like :


There are also quite a lot of supernovae that look even less like cell division than this one. Ironically one of those is used in the very next image.


3) EYE vs NEBULA



Lord have mercy. Not only does this fine image of the Crab Nebula make the point that star death doesn't always look like a dividing cell, but with yet more irony there are plenty of nebulae that look a lot more like the overall structure of an eye than this one. But presumably, the intention here is to compare the filamentary structure of the iris with the filaments in the nebula.

As I have made great efforts to point out, the Universe looks completely different in different wavelengths, and no particular wavelength of light is any more real than the visible light we can see with our eyes. Here's the Crab Nebula at infra-red wavelengths, as seen by NASA's Spitzer Space Telescope :


So much for filaments. But OK, there are filaments at some wavelengths. The iris, however, has a size which is controlled by muscles to vary how much light needs to be let in. So if you look again at the iris image, you'll see that the strands near to the pupil are all straight, completely unlike anything seen in the Crab Nebula. Worse, the iris is thin, whereas nebula are complex three-dimensional structures. And, as with the brain-universe, simulations of supernovae can reproduce some of the observed structures quite well based entirely on known physics, which is again completely different to the processes which create an eye.


Conclusion



Come on people. Please stop. The Universe contains hundreds of billions of galaxy filled with hundreds of billions of stars each and who-the-frak knows how many nebulae and planets and asteroids. That some of them have, at best, a marginal and temporary resemblance to everyday objects is the very definition of coincidence. Unless you think there's also a mystical significance between the apparent resemblance of a galaxy to the Loch Ness monster, or a potato to an asteroid, or a comet to a rubber ducky, this doesn't mean a darn thing. Aaargh.

The human brain has an amazing pattern-recognition ability which is genuinely very useful in astronomy. I would go so far as to say that if you can't see a pattern, there probably isn't one, and if things don't look the same, they're probably not the same. Your brain can detect stripy tigers in dark forests, which helped your ancestors avoid getting eaten. But many of them probably also saw tigers that weren't there, which didn't matter very much. So when you do see things that look like other things, you've got to be much more careful about deciding whether the resemblance is significant, merely a coincidence, or just an outright illusion.


EDIT : Of course, if all you took from the meme was, "these things look nice, and these other things look nice too", then all is well. You probably shouldn't have bothered reading this. But many people do see a deeper meaning here; presumably visual pattern recognition is not a discrete, separate part of the brain. Moreover, that the comparison is about birth, awareness and death, and is so contrived that in two cases it had to use non-real images, is very strong evidence that that was the wilful intent of the creator. At the very least, it's tough to see anyone creating this meme without being aware of how people would react.

Stupid people aren't dangerous; stupid people who spread their stupidity around are a problem.

4 comments:

  1. Great post. I had many of the same thoughts about the OP. You did a better and more thorough job than I could have. I would add that the cell birth (division) and brain cell images probably used florescent dies /markers to high-lite certain structures in the cell. The objects would look very different with out human intervention. May the universe smile down upon you. http://www.spacetelescope.org/static/archives/images/screen/potw1506a.jpg

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    1. Great point ! I know little of medical imaging, but I'm sure you're right.
      Love the Great Galactic Smiley. :)

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    2. Colour is something I decided to omit for sake of brevity. Of course, even I know the brain isn't a bright glowing red and as you point out, the cell image isn't true colour (if such a thing exists). The Millennium Simulation image has colours which are, of course, completely arbitrary. The artist's impression of the supernovae has colours which are chosen to look nice.

      Only the eye is a simple photograph that is close to what the human eye itself would actually see. Astrophotography (i.e. the Crab Nebula) is more complicated and though the colours may be representative (things that look redder would be redder), they are likely highly exaggerated to show the structures more clearly.

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  2. But, the potato and the asteroid? Aha!

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