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Comments of the Week #135: from an infinite Universe to Supermoons [Starts With A Bang]

Sunday, November 13, 2016 12:49
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(Before It's News)

“For me, insanity is super sanity. The normal is psychotic. Normal means lack of imagination, lack of creativity.” -Jean Dubuffet

It’s been a week unlike any other I’ve seen since I started Starts With A Bang! all those years ago. There are a lot of people looking for a lot of explanations — some are excited, many are terrified, most are disappointed — about the direction the USA and the world are headed. I might not have the answers, but perhaps taking a look at the Universe will help put some things in perspective. Have a look back at what we’ve discussed and thought about this past week:

And keep in mind some of the things we’re looking forward to. There’s a new Starts With A Bang podcast coming out later this month; at the end of this week I’ll be at Orycon 38 (come see me there!); it’s crunch time as I’m working hard to finish my new book, Treknology; and I’m looking forward to the big, bright full perigee Moon that’s imminent. The world is still here, and we’re still lucky enough to be a part of it. Now, let’s jump on into our comments of the week!

Happy Halloween 2016, from Ethan to the world!

Happy Halloween 2016, from Ethan to the world!

From eric on Halloween costumes: “Though I bow to your dedication in signing autographs for fans, and if I was in the northwest, I would be one of them. I must also say I admire your dedication to a costume theme. Frankly, I always either choose – or modify – costumes so as to allow easy movement and beer holding.”

Wearing this year’s costume meant that I was unable to walk as normal: no using my hip joints or moving my thighs. Sometimes, you have to suffer for your art. It takes a very unique type of vanity to do what I do, I suppose.

The X-ray (pink) and overall matter (blue) maps of various colliding galaxy clusters show a clear separation between normal matter and dark matter. Image credit: X-ray: NASA/CXC/Ecole Polytechnique Federale de Lausanne, Switzerland/D.Harvey & NASA/CXC/Durham Univ/R.Massey; Optical & Lensing Map: NASA, ESA, D. Harvey (Ecole Polytechnique Federale de Lausanne, Switzerland) and R. Massey (Durham University, UK).

The X-ray (pink) and overall matter (blue) maps of various colliding galaxy clusters show a clear separation between normal matter and dark matter. Image credit: X-ray: NASA/CXC/Ecole Polytechnique Federale de Lausanne, Switzerland/D.Harvey & NASA/CXC/Durham Univ/R.Massey; Optical & Lensing Map: NASA, ESA, D. Harvey (Ecole Polytechnique Federale de Lausanne, Switzerland) and R. Massey (Durham University, UK).

From Anonymous Coward on dark matter vs. MOND: “Supporters of modified gravity frequently accuse supporters of dark matter metaphorically “adding more epicycles” to make their theories work. But then I take a look at the TeVeS version of the Einstein field equation and their tortured explanations of the Bullet Cluster and other phenomena that are touted as strong evidence for dark matter and have to wonder who has added more epicycles to make their theory work.”

There’s nothing wrong with the idea of modifying gravity. The problem is that by modifying the laws of gravity, you have to make a consistent modification that works on all scales: terrestrial, planetary, stellar, galactic, cluster and cosmological scales. That’s why dark matter is so successful:

  • It’s too diffuse to affect stellar scales and below.
  • It’s appropriately dense to affect cluster and cosmological scales in line with what we observe.
  • And the right amount of matter is there to affect galactic scales as we observe them, but arguments over the distribution persist.

For modified gravity, the story is different.

Xkcd's comic on Astrophysics. Image credit: Randall Munro of xkcd, via http://www.xkcd.com/1758/.

Xkcd’s comic on Astrophysics. Image credit: Randall Munro of xkcd, via http://www.xkcd.com/1758/.

You can make a simple modification to explain galactic rotation curves without screwing up the Solar System, but you can’t get the large scales without adding something that looks very much like dark matter on top of that. Everyone who’s tried has failed, and there have been hundreds of attempts over many decades. The problem with epicycles — and why the Copernican revolution took so long — is that they worked. On larger-than-galaxy-scales, modifying gravity doesn’t.

Screenshot from my Forbes page, showing the source of my incredulity.

Screenshot from my Forbes page, showing the source of my incredulity.

From Sinisa Lazarek on Forbes’ new html5 player: “sadly the side-effect of having a more solid player is that you can set auto-play within it and the end user has no choice.”

That is correct. And I disapprove, on my own website, nonetheless.

Artist’s logarithmic scale conception of the observable universe. Image credit: Wikipedia user Pablo Carlos Budassi.

Artist’s logarithmic scale conception of the observable universe. Image credit: Wikipedia user Pablo Carlos Budassi.

From Naked Bunny with a Whip on the end of inflation: “If eternal inflation is true, then is there any vantage point in our spacetime where we could see the inflation continuing to happen around it?”

If inflation didn’t end everywhere at once, but only everywhere within a certain pocket at once, there would be a tiny chance that we would have been “born” within a region of space that was causally connected to the edge of where inflation didn’t end. Let’s assume that inflation went on for just 1 femtosecond: 10^-15 seconds. The size of the “inflated” Universe, assuming it started from a Planck-sized region, would today be ~e^100000000000000000000 times the size of what our observable Universe is today. So there’s approximately a 1-in-e^(10^20) chance that we’d exist at such a vantage point.

We didn’t win that lottery.

The fluctuations in the CMB give rise to the Universe's structure as it exists today. Image credit: NASA / WMAP Science Team.

The fluctuations in the CMB give rise to the Universe’s structure as it exists today. Image credit: NASA / WMAP Science Team.

From Tom T. on the size and age of the Universe: “Pardon my simple-minded comprehension, but: in the Forbes version of this post, you say “The nearest galaxy, some 2.5 million light years away, appears to us as it was 2.5 million years ago, because the light requires that much time to journey to our eyes from when it was emitted.” That would seem to mean that when we observe the far reaches of the observable universe, 46 billion light years away, we are observing it as it existed 46 billion years ago. Yet the Big Bang is said to have occurred only 13.8 billion years ago.”

I don’t think I’m ever going to be able to write an article where I say anything about distances and ages of the Universe without having to explain how this is possible. I write a piece explaining exactly this every six months or so, but no one ever googles it. But I can’t be mad that new people are reading my articles and asking this legitimate question for the first time, so let’s help you out!

An illustration of how redshifts work in the expanding Universe. Image credit: Larry McNish of RASC Calgary Center, via http://calgary.rasc.ca/redshift.htm.

An illustration of how redshifts work in the expanding Universe. Image credit: Larry McNish of RASC Calgary Center, via http://calgary.rasc.ca/redshift.htm.

There are a number of effects all happening at once: stuff is everywhere, light goes at c, stars and galaxies move, and the Universe is expanding. You can read my latest explanation, which ought to satisfy you, here.

Where the red Xs are, inflation comes to an end and we get a Big Bang, but there are more regions where inflation continues onwards (no X) than where it ends, and hence we get ongoing, unrelated Big Bangs. Image credit: E. Siegel.

Where the red Xs are, inflation comes to an end and we get a Big Bang, but there are more regions where inflation continues onwards (no X) than where it ends, and hence we get ongoing, unrelated Big Bangs. Image credit: E. Siegel.

From Omega Centauri on eternal inflation and infinity: “If we accept eternal inflation, even if the grand-universe (as opposed to our puny big bang universe) started a finite period of time ago, isn’t it effectively infinite, as its going to keep growing at an almost inconceivable exponential rate forever?”

It goes to infinity as time goes to infinity. But that is not the same as saying it is infinite. Indeed, many things go to infinity as time goes to infinity. Some, even, go to infinity more quickly than an inflating Universe does. And if you can’t conceive of it, try comparing a factorial to an exponential! By time you get to a few dozen (or a few hundred, or thousand) e-foldings, you’ll see what I mean.

Image credit: E. Siegel, of the GUT baryogenesis scenario.

Image credit: E. Siegel, of the GUT baryogenesis scenario.

From Michael Kelsey on inflation, baryogenesis and CP-violation: “Inflation (the expansion of quantum fluctuations to cosmological sizes) happens at energies comparable to the Planck scale (~10^19 GeV).
Baryogenesis and CP violation are processes that happen way down at Standard Model -ish energies, long after inflation, ~1000 GeV or so down below 1 GeV.
Above those energies, even if CP violating processes occur, the particles and photons are still in chemical equilibrium, so you can’t sustain an asymmetry.”

I’d like to clarify this a little bit, because I think it could get dangerous otherwise. We have some information about inflation and the scale at which it occurs, thanks to the fluctuations in the CMB. We know there’s an upper limit to the reheating temperature, which can be used as a proxy for the inflationary scale (although the reheating temperature could be lower). That limit is ~ 5 x 10^16 GeV, or more than a factor of 100 below the Planck energy.

We know of some CP-violation, but not enough to explain the baryogenesis we get in the Universe. There must be more than what the Standard Model alone gives us.

So how do we get baryogenesis in sufficient amounts? There are some scenarios that occur at electroweak scales, where the Higgs symmetry breaks, or right around there. These include electroweak baryogenesis and the Affleck-Dine scenario. But there are also GUT-baryogenesis and leptogenesis scenarios, which occur at energies of ~10^14 GeV and up. (Leptogenesis then converts the initial lepton asymmetry to a baryon asymmetry through sphaleron interactions, which occur in the Standard Model.) What Michael said is true in the most commonly explored scenarios, but there are others that are just as viable.

The numbers of planets discovered by Kepler sorted by their size distribution, as of May 2016, when the largest haul of new exoplanets was released. Super-Earth/mini-Neptune worlds are by far the most common. Image credit: NASA Ames / W. Stenzel.

The numbers of planets discovered by Kepler sorted by their size distribution, as of May 2016, when the largest haul of new exoplanets was released. Super-Earth/mini-Neptune worlds are by far the most common. Image credit: NASA Ames / W. Stenzel.

From Omega Centauri on planetary types and masses: “So somewhere around two earth masses, a rocky planet becomes a magnet for gases, instead of just condensed matter (dust through planetoids). Now I presume this a largely a sequential process -accumulate rocky material, and then start accumulating large amounts of Hydrogen and Helium as well. Is there much scope for a rocky planet above roughly M=2, to be able to keep accumulating rocky material and rejecting gas? What if it were really hot? Could a large late impact cause the gas envelope to be lost? Could the accretion disk lose the gas, but still retain for an interesting length of time the rock and dust?”

First off, the “two Earth mass” threshold is an average. There will be some planets of slightly lower mass that are gassy, and others with slightly higher masses that are rocky. But that’s where the threshold occurs, with a ± 0.6 Earth masses thrown in there.

But the sequential assumption isn’t necessarily a good one. Earth itself likely had a H/He envelope early on, but just couldn’t hold onto it. Sunlight excites a light atom/molecule to a specific speed, and if that speed has a decent likelihood of exceeding the planet’s escape velocity, away it goes. This process is fast compared to the age of a Solar System, and so by time Earth was about 2% of its current age, the envelope was gone. But you don’t accumulate it after you make a core; you accumulate everything at once, and what you see today is an artifact of what survives.

Total voter turnout as of November 9th.

Total voter turnout as of November 9th.

From dean on polling: “The difficulty in today’s world is the changing modes of communication: there is still no good way to adapt traditional sampling methods to account for the huge numbers of people who don’t have a fixed location or phone number, and the weighting measures usually used to account for under-represented groups haven’t been adequately updated.”

Apparently, polling is good for informing what people who you actually poll have told you as answers to the poll questions. That doesn’t necessarily mean they’re going to vote the way they indicated, they’re going to vote at all, or they’re going to vote in proportion to the demographics you’ve surveyed. 69% of eligible voters for 2016 were white, for example, but over 70% of actual voters were white. A change of a little over 1% can result in a huge swing, especially in an electoral-based system like ours.

Truman holding up a copy of the infamous Chicago Daily Tribune after the 1948 election. Image credit: flickr user A Meyers 91 of the Frank Cancellare original, via https://www.flickr.com/photos/85635025@N04/12894913705 under cc-by-2.0.

Truman holding up a copy of the infamous Chicago Daily Tribune after the 1948 election. Image credit: flickr user A Meyers 91 of the Frank Cancellare original, via https://www.flickr.com/photos/85635025@N04/12894913705 under cc-by-2.0.

From Wow on a reason to vote: “There wasn’t a reason for voting, except for the reactionaries on the right who see their entire worldview collapse, and whose vote was the only one ever courted by the USA’s “left”.”

I remember being in 6th grade, and voting for our class’s president. Someone nominated, as a joke, an extremely unpopular and awkward kid for class president. The vast majority of the class was delighted that such a subversive, in-your-face refutation of what voting for president was supposed to be option was on the table that he won in a landslide. In college, my junior year, the same thing happened: we elected a graduating senior as our student government president for the next year, who ran under the name “Evil Dave” on a platform of “reparation for the people of the lake.”

Sometimes, people overwhelmingly want to shake the system up, and give the metaphorical finger to business-as-usual. Even if they themselves become collateral damage.

The final pre-election predictions from Larry Sabato / University of Virginia Center for Politics. Image credit: screenshot from 270towin at http://www.270towin.com/maps/crystal-ball-electoral-college-ratings.

The final pre-election predictions from Larry Sabato / University of Virginia Center for Politics. Image credit: screenshot from 270towin at http://www.270towin.com/maps/crystal-ball-electoral-college-ratings.

From Denier on the polls vs. the results: “Late Night shows are heavily staffed by liberals, as are op-ed pages, and news rooms. Those men and women weren’t reading the data as a scientist would. They sought out the data that reinforced their view and reported it. Blaming the data is just scapegoating for a false narrative.
Ironically the pervasive narrative of a Hillary landslide combined with footage of loooooong lines at polling places likely depressed her vote. Why stand in a line for hours when it is unnecessary? In becoming partisan participants to further what they viewed as the ‘correct’ path forward, the media at large helped it to not happen.”

There were plenty of non-partisan or even pro-republican partisan sources (like RealClearPolitics) that had Hillary winning and Trump losing. (RCP, by the way, correctly called 49 of 50 states; the one they goofed had enough electoral votes to flip the election from Trump to Clinton.) Regardless, I think the overwhelming point-of-view is that Hillary lost not because so much of America was pro-Trump, but because so few people came out to vote for her. Few people were enthusiastic about her; her major campaign message was that she wasn’t Trump; she lost badly among working-class Americans (even among union workers); and she got about 10 million fewer votes than Obama did in 2008.

There’s a lot of blame to go around if you were pro-Hillary, but it’s pretty obvious just from the results that even if she had won, she was a looooong way from a landslide against arguably the most unqualified presidential candidate of all-time.

The star in the great Andromeda Nebula that changed our view of the Universe forever, as imaged first by Edwin Hubble in 1923 and then by the Hubble Space Telescope nearly 90 years later. Image credit: NASA, ESA and Z. Levay (STScI) (for the illustration); NASA, ESA and the Hubble Heritage Team (STScI/AURA) (for the image).

The star in the great Andromeda Nebula that changed our view of the Universe forever, as imaged first by Edwin Hubble in 1923 and then by the Hubble Space Telescope nearly 90 years later. Image credit: NASA, ESA and Z. Levay (STScI) (for the illustration); NASA, ESA and the Hubble Heritage Team (STScI/AURA) (for the image).

From CFT on science and influential moneyed interests: “No, Ethan,
Much like prostitutes (or economists) scientists flatter themselves and those that pay them. You keep pounding the self delusional drum of ‘noble science’ pristine and above the political fray, when you know it’s bullshit. Scientists are just people with many objectives and agendas that quite frequently are in conflict with their own presumed objectivity, questionable ethics, vacant morality, and are often more concerned with getting published than doing work that is actually reproducible.”

This is 100% untrue in physics and astronomy, and — in my experience — is a completely unsubstantiated accusation in most scientific fields. This includes chemistry, biology, geology, atmospheric sciences and any of the physical or life sciences. There is not a lot of money there; there are a great many “excellent”-rated proposals that go unfunded. Your charge of widespread scientific corruption is baseless, and you know it or you would have provided the non-existent evidence.

The beauty of science is that it is reproducible, and that if you follow a researcher’s methodologies, you should be able to obtain the same results. It isn’t perfect and many of those who engage in it are flawed, but it’s by far the best method we have of gaining knowledge about the world. I’ll take our scientific knowledge over any other attempted methods at knowledge every time.

The word Supermoon came into popular use in 2011, where three Supermoons in a row graced the night sky. Shown here is the central one, observed over Munich, Germany. Image credit: Kai Schreiber of flickr, under cc-by-2.0.

The word Supermoon came into popular use in 2011, where three Supermoons in a row graced the night sky. Shown here is the central one, observed over Munich, Germany. Image credit: Kai Schreiber of flickr, under cc-by-2.0.

And finally, from Julian Frost on the full (Super) Moon happening tomorrow: “Thank You Ethan. That was quite fascinating, particularly about women’s menstrual cycles not following the moon. A few years ago, I read a post by one of your Sciblings (I forget who) which mentioned that the belief that mental illness was correlated with full moons (hence lunacy) was actually incorrect, and the mentally ill were no more likely to have an episode during the full moon than any other time.”

I don’t remember that piece (and I couldn’t find it with Google), but old legends and myths die hard in today’s world. It isn’t just about the Moon, either; it seems to be about women in general. There are a great many who believe that cohabiting women’s periods will sync up over time, although they only do in the sense that two different frequencies will see their peaks move closer together, align, and then drift apart.

Two different frequencies will see their

Two different frequencies will see their “peaks” align over time, but only for a brief moment before they drift apart again. Image credit: Pearson / Prentice Hall, 2005.

It’s my great hope that the scientific truth on all matters will win out. It may never become common knowledge, but perhaps it isn’t to much to hope that it will someday be valued by the overwhelming majority as the go-to source for useful, reliable and robust knowledge. I’ll keep fighting the good fight no matter what!

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