How Charts Can Be Confusing Or Misleading -- September 19, 2016

Be sure to note the y-axis in these two graphs, taken from Richard Zeits' article over at SeekingAlpha today:

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Emmy Ratings Flirt With All-Time Low Audience

Link here. It doesn't help when the event becomes a political fundraiser for Hillary Clinton, though I doubt that had much effect on overall viewership.

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A Note For The Granddaughters

Astrophysics 101 In The Year 2020
The Nine Numbers of the Cosmos
Michael Rowan-Robinson
c. 1999
DDS 523.1 ROW 

This is kind of cool. I won't finish this note today; the reason will become obvious.

Michael Rowan-Robinson's The Nine Numbers of the Cosmos was published in 1999. Rowan-Robinson focused on nine numbers which he thought were "the major aspects our knowledge of the observable universe. [He was] only trying to characterize what we know about the large-scale universe. Even if all the quantities discussed in this book were known with immense precision, we would still not be able to predict the details of how stars and planets form, how life arises, or what is in your fridge."

In the last chapter the author then summarizes his estimates for each of the nine numbers and tries to predict how accurately they will be known in 2015. It will be interesting to see how close he came.

Today, just the nine numbers and his predictions. At a later day, I will see how close he came.

1. The density of baryonic matter (_b): 0.03 ± 0.006, a 20% accuracy
2. The anisotropy of the universe, ΔT/T: 1 part in 100,000, to n accuracy of 25%
3. The Hubble constant, H₀: 65 km s⁻¹ Mpc⁻¹, with an uncertainty of 12%
4. The age of the universe, t0: 12 billion years with a total uncertainty of 2 billion years either way, a 20% reduction from the value of 15 billion years which was believed only a few years ago
5. The temperature of the microwave background, T0: 2.728 degrees Kelvin to an accuracy of 0.1%
6. The density of cold dark matter, (_cdm): enormous uncertainty; currently in the range of 0 - 0.97; currently favored values are in the range of 0.2 - 0.4, and values lower than 0.1 seem unlikely; in 2015, the author says we should  know _cdm and _tot  to an accuracy of 1%
7. The tilt, the string tension, or the density of hot dark matter, _cdm: currently believed to be about 0.2. The recent discovery of muon neutrino oscillations tells us the value is greater than or equal to about 0.001
8. The cosmological constant, Λ: currently another largely unknown number, lying anywhere in the range of 0. to 0.7
9. The star formation history of the universe, Q, the ratio of the age of the universe to the exponential timescale; currently, the value is in the range of 3 - 6; the author expects that by 2015, we will know this function to an accuracy of 20%

Our granddaughters will likely be able to "skip" years of uncertainty with regard to these values, and begin Physics 101 in college -- their freshman year -- with very accurate numbers for these constants, allowing them to move more quickly in physics than my colleagues were able.

Over the course of the next few days, I will post current values for these nine numbers of the cosmos and see how far we've come in 15 years.