Some Criticisms of the New Cosmos

March 9th, 2014

I watched the premiere of the new Neil de Grasse Tyson-hosted version of Cosmos tonight on Fox.

The goal was to update the science of Carl Sagan’s show — we have learned a lot in the last 30+years — and present it in as entertaining way as possible. Tyson says:

“The goal is to convey why science matters to the person, to our society, to us as shepherds of this planet. It involves presenting science in ways that connect to you, so Cosmos can influence you not only intellectually but emotionally, with a celebration of wonder and awe,” says Tyson. “Science should be part of everybody’s life. The prerequisite is not that you become a scientist. It’s that at the end of the series, you will embrace science and recognize its role in who and what you are.”

I strongly agree with those goals, and the show was for the most part visually striking and fun. While I had some concerns about the animated sequence showing Bruno’s execution for proposing a view of the universe that the Catholic Church did not agree with, the story was largely correct.

Where I want to criticize is in some scientific and technical details that the show just got wrong. I can forgive other kinds of errors, but this is really a show that needs to get these correct. If you see inaccuricies here, you can’t really trust anything, can you? This isn’t a professor answering a question off the cuff in public in realtime; this is an expensive, polished show with plenty of time and cause to be factually accurate.

Here are three points I thought were largely or totally wrong that need correction. I’ll take this opportunity for a teaching moment.

1. The graphics showing the asteroid belt, and the Kuiper belt, did not reflect reality. It showed a high density of large objects that would appear to crash into each other regularly. This is the same misconception that The Empire Strikes Back fell into. While there are systems of gravitationally bound asteroids (e.g., binaries, “rubble piles,” etc.), the general case is that you could fly a spacecraft through them a thousand times and not only not hit anything, you’d not be likely to even see anything. This was just an error and reinforces misconceptions.

2. Tyson referred to using night vision technology to see into the (thermal) infrared — cool objects in the universe. Wrong. While night vision does see slightly into the near-infrared (about 1 microns), it is primarily a light amplification technology. Thermal imagers are what we use to see cool dust, gas, and the coolest stars. Compare both technologies here.

3. Tyson, discussing the Big Bang, repeats a commonly held misconception that is wrong. He said that the entire universe came from a point smaller than an individual atom. If he’d used the modifier “observed” or “observable” in front of universe, I’d have given him a pass. But after making such a big deal about infinity earlier in the episode and bringing up the point of only part of the universe being observable, I can only call this a significant error. The reality is that if the universe is infinite today (and indications are that it is, and that is the adopted standard model), and therefore could never have been finite in size. Think about it. How do you change something from a finite size to an infinite size? The answer is that you don’t. A better way of thinking about the Big Bang was that the universe approached infinite density, but without approaching zero size.

So while I am pleased to see a show like Cosmos back on network TV in a good timeslot, I am worried that the quality control is lacking. I don’t know who gets input into the scripts and graphics, or who gets final say, but they’re not doing a good enough job in my opinion. If I were teaching astronomy 101 or cosmology this semester, I’d be discussing these points in my class — as well as assigning the show as homework.

P.S. Starlinks in the next day or two…


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