“It all had a beginning in the original cosmic explosion, whatever that was, and it’ll all have an end when all the stars run down.” -Isaac Asimov, The Last Question
Each week brings new challenges, new questions, new topics and new things to think about here at Starts With A Bang! For those of you looking for something awesome to do later this month, come to Seattle, Washington’s May 24th event: Astronomy On Tap, at Peddler Brewing Company, where I’ll be speaking! Beyond that, I just received my first look at the layout of the inside of my upcoming book, Treknology, and it’s going to be amazing; I’m super proud of what we’re putting together. Can’t wait to show it to you all! In the meantime, here’s what we’ve covered in this past week:
- Why can’t I see Mercury without a telescope? (for Ask Ethan),
- What’s the largest galaxy in the Universe? (for Mostly Mute Monday),
- There’s no science behind denying climate change,
- There is sound in space, thanks to gravitational waves,
- No, mysterious signals from space are not dark matter, and
- When will the first star go dark?
So with all of that amazing science, what did you find interesting enough to comment about? What were your questions and follow-ups? Let’s find out on our comments of the week!
From Elle H.C. on the point of simulations: “…my point is that simulations will give us deeper insights and a better understanding of what we have measured.”
You have to recognize that theory drives simulations. You have a set of equations that are sensitive to initial conditions, and some system that cannot be completely solved analytically. So you program a simulation to run, and you allow various parameters to vary. That is how you get an insight into how well your best models, via simulation, match your observation. They can, occasionally, reveal details that are otherwise unexplained. But it’s only in cases where simulations predict something odd, as in counterintuitive, unexpected or not-yet-measured, that they drive discovery. They can help discern nuanced differences between theory and observations, and help uncover cracks in our understanding. But simulations are only a tool in the toolkit; there is nothing fundamental or special about them over any other theoretical tool.
From Michael Mooney on his idea of the real world: “I am very clear on the epistemology of how science verifies its investigation of the real world.
Yes, there is one, and it doesn’t give a damn how you measure it!”
That you are using the phrase “the real world” implies that some frame of reference is preferred, and somehow “more real” than any other. This is demonstrably false. Your philosophy is overly restrictive, and science will not be constrained by ideological arguments. There is data; there is theory; there are laws; there are measurements and observations. Your assertions are tantamount to nothing more than an arbitrary choice, and the physics bears this out. You don’t have to like it (you pretty clearly don’t), and you don’t even have to agree (but you are wrong if you don’t), but your philosophical arguments will change no physicist’s mind. As well they shouldn’t.
And one last follow up from the same: “I’ll just wait for Ethan’s reply, if he cares to address his obvious contradiction. I am not intimidated by relativity’s true believers who tolerate no criticism and want to ban all critics.”
When I respond to commenters — like you — what I attempt to do is understand their line of thinking, and respond to comments in a way I believe will be illuminating and informative. I try; I don’t always succeed. I try not to get frustrated, I try not to take anything personally, I try to assume the best intentions. When I first responded to you, I thought it was important to address the ladder/pole-in-a-barn paradox, and to state that an external observer’s motion does not change any internal properties about a stationary object to a stationary observer. When you called for more information and explanations, I tried to give a deeper, more nuanced explanation of what was happening. If you see a contradiction, you are missing the point of what I am doing here.
The internet shows that you have been banned by many physics and relativity forums for anything ranging from spamming them to name-calling and other unwanted behavior. No one is banning you here or talking about banning you here. But do not conflate “allowing you to post” with the idea that “anything you say has any sort of validity.” Your philosophy needs to be consistent with what observations and measurements dictate, or it has no utility when applied to this Universe. Physics concerns ourselves with this Universe. Your philosophical criticisms have no physical foundation, and until they do, I am happy to let the other commenters on this forum take it from here.
From Ragtag media on scientific vs. political ideology and debate: “LOL.. I Know You Are But What Am I?”
Whenever a politician says, “don’t do this thing,” my first instinct is now to look at their side, whatever that side is, and to ask, “how long have they been doing the thing they’re accusing the other side of beginning to do?” When someone says “don’t politicize science,” the real question, to me, is “how long have the people saying that been politicizing the very science they’re referring to?” From the science of addiction to the dangers (and non-dangers) of marijuana to climate science, basic science education and more, the answers are all for far longer than they’ve been saying “don’t politicize science.” It’s only when the actual science begins to threaten their racket that they start saying that. Try that perspective and see what you notice.
From Sinisa Lazarek on the problem of scale: “One problem with ourselves is that from earliest childhood even through to higher education… all the renderings we see of our solar system are HIGHLY inaccurate.”
Humans are generally very, very bad at perceiving or visualizing scales even two orders of magnitude away from what we’re directly viewing. We might be able to understand the size of the planets relative to one another; we might be able to understand the distances from one planet to the next relative to one another. But ask us to compare the size of the Earth and Sun to the Earth-Sun distance? Our brains just aren’t well-equipped to handle that. Accurate renderings, by the way, do exist, but that doesn’t really help us get “a feel” for it. As with anything, if you want to get better at it yourself, you need to practice. Since most of us don’t become specialized physicists or astronomers, working with and thinking about this stuff all the time, most of us don’t get there.
From Ciaran on seeing Mercury: “I got my first proper view of Mercury in the Canary islands in December 2015 having had the high-latitude problem for my whole life before that. I had to check Google Sky to be sure of what it was, it looked bright enough and high enough in the sky to be Venus.
I’m pretty sure I saw it between two houses in the Western twilight once before but it wasn’t very impressive!”
The above image you see comes from 55 degrees North Latitude, but it comes very close to the equinox, not either solstice. Apparently, the equinoxes are when the Sun descends most closely to vertical anywhere in the world, and when Mercury is at maximum elongation within plus-or-minus a few days of the equinox, it’s possible to see it very close to the horizon. For high-latitude observers, the August 21st eclipse is your next best bet, but I’ll be sure to look for clear eastern horizons just before sunrise approaching the autumnal equinox this year and clear western horizons after sunset just before the spring equinox next year. It’s not a great maximum elongation, but it’s the next best shot!
From Jonathan on the comparison of the Milky Way with IC 1101: “I make the volume of IC1011 on the order of 10^20 ly^3 […] The Milky Way’s volume is on the order of 10^13 ly^3. But there are only about 1000 times more stars in IC1011… what gives, are these giant ellipticals especially sparse?”
A disk galaxy is generally very dense because it only achieves a large extent in two dimensions. The Milky Way’s diameter is about 100,000 light years. The thickness of the Milky Way’s disk? About 2-6% of that, depending on your distance from the galactic center. So that’s one large contributing factor to the difference between spirals and ellipticals. But there are other differences: ellipticals are older than spirals, ellipticals have little-to-no gas in them, ellipticals are not presently forming stars. The largest difference, though? It’s all about orbits and gravity. Think about our Solar System for a small-scale example. Think about where the planets, asteroids, and Kuiper belt object are. Then think about the Oort cloud.
Elliptical galaxies are more like the Oort cloud; spiral galaxies are more like the Kuiper belt (and interior). We observe molecular clouds in the outskirts of spiral galaxies (including our own) that extend well beyond the thin disk of the galaxy, including in all three dimensions. In spirals, that’s not where the stars are. In ellipticals, those clouds have either formed stars, been stripped or been ejected, and so there are stars there throughout them. The inner regions of spirals and ellipticals are comparable in densities, but the outer regions are where ellipticals are significantly richer in stars.
From lloyd on arguing convincingly: “One of the things I think is probably most valuable that I can teach students is how to evaluate for yourself who is arguing honestly and who isn’t. Who is actually responding to objections and pointing out why they’re misleading, and acknowledging where their own case is weak and needs to be strengthened–versus who is simply stating and restating the same points over and again, packaged to provide maximum misdirection. You can’t win an argument with these people. But what you can do is attempt to innoculate young people against dishonest argument tactics so they are well-equipped to ignore those who don’t deserve to be taken seriously.”
You are doing some excellent work; at least, I agree with this goal completely. It’s important to consider the merits of each argument as it comes up, but not to fall victim to believing in discredited/debunked arguments, and to be able to tell the difference. Most of us cannot, except in our own fields of expertise. (And sometimes, not even then!) Our minds are designed to take the path of least resistance to an answer, and that often means we reinforce our prior beliefs and discount evidence to the contrary. The more deeply-held our beliefs are, the harder it is for us to overcome our internal biases.
From Anonymous Coward on what motivates climate inaction: “Perhaps the short-term profits obtained from the continued use of fossil fuels are worth more than the prospect of a future earth that is too warm to permit agriculture as we do it today. These people denying the science of global warming ought to just fess up and declare that their value system values short-term profits more than it is worried about the consequences of the extraction of those profits.”
Some do; most don’t. Short-term profits are, if I understand correctly, what publicly-traded corporations are legally bound to their shareholders to maximize, so these values are actually enshrined into law. Perhaps those on the forum better versed in law than I am can tell me about the legality and the consequences of that.
From eric on the utility of investing in alternative energy regardless of the climate: “It would seem to me that even without the climate change debate, R&D investment in other energy sources would be very valuable. After all, a more efficient battery or power line or solar panel is still useful, regardless of whether the Earth is warming or not.”
It is arguable, from a long-term “best policy” point of view, that if you can have cleaner energy, more efficient energy, a more resilient energy grid, etc., that is the kind of improvement that everybody concerned with the general welfare of all citizens in the country (and the world) should be behind. But if there is a legal mandate to be more greatly concerned with something else… people will be.
From Denier (1 of 3) on global warming: “You should hold open the possibility that if you think one thing and the world thinks something else that it might not be the world that is wrong. It might be you who is deluding themselves.”
Surely you are not proposing that we now begin answering scientific questions through polling? There is a difference between “holding open the possibility” in the absence of evidence and “holding open the possibility” in the face of overwhelming evidence. The amount is how open I’ll hold the door, as it should be for us all.
From Denier (2 of 3) on the future of CO2: “Seeing as global CO2 emissions are currently flat, population growth is slowing and is set to reverse into population decline, technological advancement is still humming along, and every historical example shows roughly the same peak and decline curve, what do you think the future holds for global CO2 emissions?”
Global CO2 emissions are relatively flat. Population growth is more-or-less at an inflection point, set to plateau at around 11 billion at around the year 2100 (with some models predicting a slow decline afterwards and others not), and the large-population places where economic growth is occurring the most rapidly (e.g., China and India) are also seeing the greatest increase in per-capita CO2 emissions, in the face of technological advancement, I see global CO2 emissions remaining relatively constant, plus or minus maybe 20%, for the rest of the century so long as the current policies remain in place. Of course, that’s constant with respect to the last few years of CO2 emissions, which are the highest rates in history. Let’s take a look at the CO2 data!
You can see we’ve roughly plateaued at a global annual emission from fossil fuels of about 32 Gigatonnes of CO2 per year. If that continues from the present until the year 2100, how many parts-per-million of the atmosphere will CO2 be? Current atmospheric CO2 is a little over 3,000 Gigatonnes, so we are talking about almost adding the same amount of CO2 to the atmosphere as is already there. But don’t worry; the ocean absorbs a lot of the CO2, so we’ll probably only be somewhere in the 600s as far as ppm goes by 2100. Again, that’s my quantitative estimate, but that’s probably too conservative according to most climate scientists. What do you think?
And from Denier (3 of 3) on climate models: “While it may be true that you can cherry-pick specific models that are within error bars between cherry-picked years, I can more easily point to models that are not.
You are not pointing to models that aren’t within the data for cherry-picked years. You are pointing to bad data, plotted against successful models by someone who does not accept the very first point you agreed to, over and over, when you wrote this:
Question #1 – Is the Earth’s climate becoming warmer via a process that we can have influence on?
Alarmists answer the first question as ‘yes’. They answer it over, and over, and over with a ‘yes’. An avalanche of ‘yes’ is brought to bear on question #1.
Here is what the actual good data, from the actual satellites, shows:
I assume you will not make that same mistake again, and that you will be pleased to learn what the actual data says, just as you should be pleased that we got a visit from an actual climate scientist in the comments, who said:
First, current estimates of warming are well within the error bounds of 1980s predictions, even considering the rather rudimentary tools available to make those estimates at that time (see jonathon’s post (#15) for a spot-on rebuttal of your post). Remember, also, that those forecasts from the 1980s were made under the assumption that no transient or unforeseen things would happen in the system. Such things have happened, and some of them have effected the earth’s energy budget in ways that counteract some of the warming. Despite this, the forecasts are still within those error bounds. Second, there’s more to the AGW hypothesis than just temperature increases. A whole suite of changes to the global system are predicted, some of which can really only happen if enhanced greenhouse content is the reason for current temperature increases. Probably the most telling of these (and the one that seems to get discussed the least, among the denier community) are changes in the structure of upper atmospheric temperatures, which are a clear fingerprint of and enhanced greenhouse world.
The whole point that I’m trying to make is we must agree on the same facts as a starting point if we want to have a real discussion about climate policy. If you don’t want to have that discussion, or you want to exclude facts from that discussion, or you want to exclude voices from that discussion, then own it. But don’t pretend that made-up facts get to be on the same footing in an argument with factual facts.
From Carl on the Earth and the Sun: “From the post, “it would take 10^150 years for Earth to spiral into the Sun”.
With calculations this extreme, I wonder if the effects of expanding space (dark energy, “pushing” the Earth away from the Sun) were included. And if so, how do they compare in magnitude?”
This is a fun thing to consider, and a good thing to wonder about. Unfortunately, it doesn’t work because the effects of dark energy are a global effect, but they do not occur within a bound system. If you waited an arbitrarily long time, the expanding Universe would not affect the size of the local group (but gravity would), the Solar System (but gravity would), the size of an atom (but electromagnetism would) or anything else that’s already bound by a stronger force. Only if the Earth were gravitationally unbound from the Sun would dark energy play a role. It isn’t, and so it doesn’t.
From Michael Kelsey on the difference between a pulsar and a magnetar: “Pulsars and magnetars are both neutron stars with magnetic fields. Pulsar fields are typically a few megateslas (MT), and produce (due to their rotation) repeating signals in radio and microwaves, from the cyclotron motion of electrons around the field lines. Millisecond pulsars have even weaker magnetic fields, just tens of kT (the mechanism thought to spin them up to such high rotation rates would also reduce their initial pulsar-like magnetic field).
Magnetars have much, much stronger magnetic fields, of the order of GT. They produce periodic x-ray and gamma ray signals, likely from sychrotron radiation.”
The big question that’s still being worked on in this field is why most neutron stars become pulsars (and most don’t “pulse” at us), but some become magnetars. Obviously, magnetars — with higher magnetic fields by a factor of 1,000 or more — produce radiation of higher energies, but why? There are pulsars that rotate faster, after all. The key seems to be temperature, which likely comes from the mass of the progenitor star and, hence, the mass of the neutron star. But this is something where we haven’t had the key, deciding observations come in. We have good theories and models, but not the confirmation we’d seek; we need better observatories for that.
And finally from John on black dwarfs: “Stars going dark in “only” around 1,000 times or “only” a million times the age of the Universe! Astronomical numbers again!”
The first white dwarfs to go “dark” will probably do so in about 2,000 times the present age of the Universe, when they will be “cool” enough that they no longer emit visible light. Given our Universe’s current age, that’s roughly when the Universe will be 30 trillion years old. In order to cool enough that they’re only a few degrees above absolute zero, that’s more like 100-1000 trillion years, depending on the model of cooling used.
But yes, no matter how you slice it, it is an astronomical undertaking! Thanks for an interesting week, and see you back here for more stories about the Universe soon!