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Comments of the Week #152: from NASA’s future to testing your scientific theories [Starts With A Bang]
“When you are joyous, look deep into your heart and you shall find it is only that which has given you sorrow that is giving you joy. When you are sorrowful look again in your heart, and you shall see that in truth you are weeping for that which has been your delight.” -Khalil Gibran
Another incredible week has gone by here at Starts With A Bang! If you didn’t get a chance to catch me in Jacksonville, don’t fear; I’ll be at MidSouthCon in Memphis, Tennessee in just a little over a week. Catch me there! Our Patreon campaign is really taking off, and with the new rewards commitments I have, there’s never been a better time to join. (And if we can hit the next rewards tier, I’ll be able to buy better equipment to help me produce them, which would be a tremendous help!) There has been a lot of fighting in the comment sections on a variety of posts, so I thought I’d remind everyone of a reason we all have to delight in this world: Maru. Who is still at it after all these years, this time with a hamster ball.
- What surprises might NASA’s future space telescopes discover? (for Ask Ethan),
- The first woman in space turns 80, and you’ve probably never heard of her (for Mostly Mute Monday),
- How Richard Feynman convinced the naysayers 60 years ago that gravitational waves are real (by Paul Halpern),
- The science has spoken: Pluto will never be a planet again,
- Proxima b and the worlds around TRAPPIST-1 might be habitable after all, and
- A 200 year old lesson: scientific predictions are worthless unless tested.
You’ve had your Maru fix, but now it’s time to chew on some of the meatiest morsels you’ve doled out on this edition of our comments of the week!
Image credit: Universe Review.
From Michael Mooney on traveling close to the speed of light: “Does special relativity actually claim that distance, between stars for instance, depends on the speed of a traveler between them… not just “apparent” distance, but actual astronomical distance?”
It depends on the distance and to whom. If you’re in the spacecraft and moving towards a star 4 light years away, but you’re doing it at 88% the speed of light, then yes: the star will be only 2 light years from you, and you will reach it in a little over two and a quarter years. That contraction is “real”. Now your spaceship, to an outside observer, will also appear contracted, as the ball in the above image appears. Is that contraction physically real? We don’t think so. Relativity is still challenging to wrap your head around, even more than 100 years after we’ve first discovered it.
A planetary nebula represents a phase of stellar evolution that the Sun should experience several billion years from now. When a star like the Sun uses up all of the hydrogen in its core, it expands into a red giant, with a radius that increases by tens to hundreds of times. In this phase, a star sheds most of its outer layers, eventually leaving behind a hot core that will soon contract to form a dense white dwarf star. A fast wind emanating from the hot core rams into the ejected atmosphere, pushes it outward, and creates the graceful, shell-like filamentary structures seen with optical telescopes. It also looks like an exploding brain. Image credit: NASA / CXC.
From Wow on comment moderation: “Ethan are you going to do anything about that…”
No. He has not violated my comment policy in any way. He has not threatened anyone; he has not link-spammed anyone; he has not promoted his own personal pet theory ad nauseum. He is also not the person you accuse him of being, which I strongly against anyone doing. You are allowed to comment anonymously/pseudonymously here, and he is, too. His actual name is John, but he is not the John you accuse him of being. Nor should you be accusing anyone of being someone in particular, as you would not like me to say whether someone was right or not if they guessed at who you are. And if you think that one or ten or a thousand extra clicks on this site makes a lick of difference in what I get paid, you are sorely mistaken as to how my contract works.
So no, I am not going to do anything about the comments of a commenter who’s abiding by all the rules here, who you (or I, or anyone) simply disagrees with.
The contributors to global warming, from the 2013 IPCC report.
From Denier on global warming: “There are kernels of truth in most of it. I’m swapping right side #3 with #4 just because I think it lines up with the left counters better.”
First off, kudos to you on reading the undark piece I linked to. I didn’t even think to line up the two narratives side-by-side in a point-counterpoint fashion, and it may be more interesting to do so, as you did. It’s interesting to me that you find public opinion and actions designed to sway public opinion just as valid — or perhaps even more valid — than what the actual science says. You claim quite frequently that “the models have failed to make accurate predictions” so I went and looked up the first predictions I could find.
The most seminal paper in climate change history? Perhaps!
Turns out there’s a paper going all the way back to 1967 that asked this question: Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity, by Syukuro Manabe and Richard T. Wetherald. It’s now 50 years old. And as professor Steve Sherwood says,
Its results are still valid today. Often when I’ve think I’ve done a new bit of work, I found that it had already been included in this paper.
One of the largest uncertainties around — climate sensitivity and water vapor feedback — was first quantified and addressed in this paper. There isn’t a definitive solution, but many plausible ones that all fall within a particular range. By averaging that range, we can arrive at a “best guess” prediction. That’s how the modern IPCC arrives at their results, and it’s incredibly robust.
Of course, the big sticking point is “what do we do about it,” and the status quo answer seems to be, “burn all the fuel and let the climate change, unfettered by environmental conservation efforts.” But I can’t help myself in being dissatisfied with the status quo in this regard. I love the natural world too much. Perhaps your retort will be that you love economic success and (what you define as) freedom too much, and that’s our fundamental impasse here?
A sample of telescopes (operating as of February 2013) operating at wavelengths across the electromagnetic spectrum. Observatories are placed above or below the portion of the EM spectrum that their primary instrument(s) observe. Image credit: Observatory images from NASA, ESA (Herschel and Planck), Lavochkin Association (Specktr-R), HESS Collaboration (HESS), Salt Foundation (SALT), Rick Peterson/WMKO (Keck), Germini Observatory/AURA (Gemini), CARMA team (CARMA), and NRAO/AUI (Greenbank and VLA); background image from NASA).
From John on the future discoveries from NASA’s new observatories: “With science extending and enhancing human senses, humanity’s perception of itself and its relationship to the natural world can, and with luck will improve.”
To me, the best part of this is that given our understanding of light, gravity, nature and the electromagnetic spectrum, we can make our own luck. We can extend and enhance and go well beyond our senses and our perceptions. Our minds, rooted in the full suite of scientific knowledge and with the full suite of scientific data, can help us understand the natural world in a superior fashion to any humans that have ever come before. Thousands and thousands of living scientists understand gravitation and quantum theory better than Einstein or Feynman ever did in their lifetimes, and we continue to do better with each new discovery.
To look inward, however, and perceive ourselves and our relationship to the natural world, is a journey that it’s up to each of us to take as individuals. Science will only take you so far in that one.
Valentina Tereshkova, just prior to her launch aboard Vostok 6 in 1963. Image credit: Science Source/Photo Researchers, Inc.
From dean on Valentina Tereshkova: “I remember learning about her in a high school world history course, but I had forgotten that she made 48 orbits.
I suspect the Soviet Union was ahead of the United States in allowing women into their space program not because they were more knowledgeable about the ability of women in general, but because they had a history of women demonstrating their strength from the roles women played in their military during WWII.”
The 48 orbits thing is actually the easiest thing to explain. In low-Earth orbit, you need to continuously move at the right velocity to maintain your orbit, or you’ll either crash into the planet, fly off into deep space, or require a tremendous (i.e., unrealistic) amount of fuel in order to consistently stay in orbit. The equilibrium speed you need to reach, dependent on your altitude, means you make a complete orbit every 90 to 100 minutes, depending on your orbital parameters, which translates to 15-to-18 orbits per day. The earliest cosmonauts and astronauts orbited at the same speeds and rates that the ISS does today. For 3 days in space, 48 orbits was really the only realistic number for Tereshkova.
Why did it turn out this way? The best I can tell you is that Korolyov (sometimes Korolev, according to Wikipedia) was both incredibly competent and had incredible vision for a space program. If he hadn’t unexpectedly died in 1966, there are many who speculate that the Soviets would have won the ultimate prize of the space race — humans on the Moon — instead of the Americans. Alas, we will never know.
Richard Feynman, at approximately the age he was during the 1957 conference. Image credit: Caltech.
From Anonymous coward on Feynman and gravitational waves: “The article doesn’t seem to mention the curious detail that Feynman had, to express his disdain for the state of gravitational physics, insisted on registering under a pseudonym (”Mr. Smith”) when he attended that conference.”
I didn’t know that detail either, and perhaps it may even be novel to Paul as well. Having heard many, many stories about people who knew Feynman personally, the only thing that surprises me about that story is the pseudonymous method employed about expressing his disdain. Feynman was both one to feel disdain frequently at a great number of targets, and to rarely censor himself from expressing such disdain. He had a touch of the egomania, but he never had the insecurity that plagued his contemporaries like Gell-Mann, whom I met once and was still, decades and a Nobel Prize of his own later, still bathing in it.
TRAPPIST-1 system compared to the solar system; all seven planets of TRAPPIST-1 could fit inside the orbit of Mercury. Note that at least the inner six worlds of TRAPPIST-1 are all locked to the star. Image credit: NASA / JPL-Caltech.
From Wow on planethood and definitions: “The clincher really is the quote you started with there. The problem for the geophysical definition was it was OK as long as you could look close enough to determine the composition roughly and determine the size in enough detail to SEE it is round.”
The geophysical definition doesn’t require a teleporter/transporter either, no more than the IAU one does. Because we understand gravitation so well, simply measuring a planet’s mass is a good enough proxy for knowing whether it’s in hydrostatic equilibrium. Hit about 10^21 kg, more or less, and you’ll be in hydrostatic equilibrium. Vesta, under most arguments, falls just short; Makemake, similarly, makes it in.
The geophysical definition is a purely intrinsic definition, however, and that’s what I don’t like about it. You can learn a lot about a world by standing above it and looking down: at the atmosphere, surface and interior. I’d argue that you can know almost half the things there are to know about it that way. The rest? Its temperature, its orbital properties, its proximity to other objects, etc., are all extrinsic. And to me — like most astronomers — that’s what’s required to define its planethood. Otherwise, there’s nothing special about being a planet in the way that Earth is a planet, and that’s scientifically less useful to me.
Of course, that’s scientifically more useful to planetary scientists, and that’s where the current argument comes from.
This artist’s impression shows the view just above the surface of one of the planets in the TRAPPIST-1 system, which may contain liquid water on the surface if the atmospheric conditions are right. Image credit: ESO/M. Kornmesser/spaceengine.org.
From Dunc on how to solve the dilemma: “Here’s a radical suggestion: we should abandon the entire concept of “planets”. There are lots of different types of objects orbiting around out there, and you can categorise them into different groupings depending on which characteristics you’re particularly interested in, but trying to reify this distinction between “planets” and “non-planets” looks increasingly arbitrary and meaningless. Does the Earth really have more in common with Jupiter than it does with Pluto, or even it’s own Moon? Well, in some ways it does, and in other ways it doesn’t…”
This is probably fair. My proposal is that we allow everyone to call objects what they will. Dwarf planets, ice planets, minor planets, rogue planets, orphan planets, ejected planets, former planets, etc. It’s all fine. But give the 8 in our Solar System — and the ones meeting the needed criteria in other Solar Systems — a name denoting how they are special. Major planets, classical planets, astronomical planets, or you can go with my (tongue-in-cheek) suggestion: actual planets.
Pluto’s atmosphere, as imaged by New Horizons when it flew into the distant world’s eclipse shadow. Image credit: NASA / JHUAPL / New Horizons / LORRI.
From Melvin Whartnaby on a different opinion: “Sorry, I just don’t buy it! Not just me, but all of my friends and family know that Pluto is a planet. Our teachers told us. We say it in books.”
All of these things are true, but none of those things count as “meaningful evidence.” In science, we require a much sterner standard. You will learn there’s an “appeal to authority” argument out there that’s a classic logical fallacy. What it really means is that it is a fallacy to appeal to a false authority. If you want a real authority to appeal to, try Alan Stern, the Planetary Society or any number of planetary scientists. (Some even work for NASA.) You’ll still be wrong, because you’ll still want to group Pluto in with the other 8 planets of the solar system, but at least you’ll be wrong for a less obviously bad reason.
Image credit: NOAA PMEL Vents Program.
From PJ on Earth-life life on the TRAPPIST-1 worlds: “You cannot say “not a chance”. If there are life forms existing around earths fumaroles, the probability is high for that existence around vents on another planet.”
This is exactly right, and is exactly the point that Adrian Lenardic (and many other scientists) make. You don’t know what conditions are present on these other worlds. Sure, the star they orbit might make for “too much radiation” if all the other conditions were like the ones we have on Earth, but who knows how shielding is different, how the atmosphere is different, how a magnetic dynamo is different, etc. All of these differences could lead to surface conditions that are very much Earth-like, despite any one of the remarkable and clear differences present.
That I can design conditions that would lead to very similar surfaces on these worlds doesn’t make them likely, but it means there’s a chance. And given that there are likely hundreds of billions of such chances in our galaxy alone — of Earth-sized planets around red dwarf stars — I would definitely not want to bet on “not a chance” with the current information we have.
Image credit: screenshot from the internet classic, https://www.youtube.com/watch?v=Ll-lia-FEIY.
From eric on navigating the comment jungle out there: “When I was a teen, I learned to choose my novels by author. When I graduated HS, I learned to choose my classes by professor. Now, I choose posts by handle.
And always remember, when browsing, the scroll wheel is your friend.”
This is the internet in its natural state: with comments turned on, moderated only lightly for spam and a very particular kind of trolling. To run a “comments of the week” requires curation and thoughtfulness. I am sure many, if not all, will disagree with my choices. Hopefully at least articles like this continue to be interesting. And if not, go watch that cat video again.
Image credit: Astrophysics Pro, via http://astrophysics.pro/experiments/photoelectric-effect/.
From Anonymous Coward on the wave nature of light: “And then just a little shy of a hundred years later, Albert Einstein comes along and shows how light actually does have particle-like properties too!”
Quantum mechanics gets weirder and weirder the more we learn about it. The fault is not with nature, but rather with our intuitions, and the unfamiliarity we have with the quantum rules that govern actual reality at a more fundamental, small-scale.
A theoretical prediction of what the wave-like pattern of light would look like around a spherical, opaque object. The bright spot in the middle was the absurdity that led many to discount the wave theory. Image credit: Robert Vanderbei.
And finally, from Michael Hutson on the Spot of Arago: “Re. the Arago Spot: this is why a simple occultation disc cannot be used for imaging exoplanets. Rather, a disk is used that has a special scalloped edge calculated to counteract the diffraction”
There are two ways to measure exoplanets accurately. You are correct: a simple disk would block out a large fraction of the light, but would create optical diffraction/interference patterns that would make direct planet imaging… difficult, if not impossible. You can, at best, get down to a contrast of 10^6-to-1, where you can image planets a million times fainter than the star they orbit. A better-designed coronagraph can get that down to about 10^8-to-1, where the scalloped edges help much more. But the best design of all is a free-flying starshade.
Image credit: Amy S. Lo et al. (2010), from the Starshade Technology Development Astro2010 Technology Development White Paper.
This gets a 10^10-to-1 ratio, allowing direct exoplanet imaging to a far better accuracy and resolution and sensitivity compared to any other means/method so far. The only problems are cost and navigation; the starshade would have to be physically moved many tens of thousands of kilometers from the telescope to get the appropriate alignment. Optics, even 330 years after Newton, is still a challenging pursuit.
Thanks for joining us this week, and looking forward to a fabulous week to come!
Source: http://scienceblogs.com/startswithabang/2017/03/12/comments-of-the-week-152-from-nasas-future-to-testing-your-scientific-theories/
