“The ability to listen and learn is key to mastering the art of communication. If you don’t use your verbal skills and networking, it will disappear rapidly.” -Rick Pitino

It’s been a week full of amazing and controversial stories about the Universe here at Starts With A Bang! Did you catch the fantastic live event on Wednesday at Peddler Brewing Company in Seattle: Astronomy on Tap, starring me and the incredible Sarah Tuttle? If not, you can catch it now!

If you’re in a multimedia mood, you’re in luck, because the newest (and twentieth!) Starts With A Bang podcast is now live: on the Fate Of The Universe. It took us 13.8 billion years to get to this point; learn about all the rest to come in just 20 minutes!

This past week has been filled with some great stories that I hope you enjoyed, including:

As always, I’ve had my chance to put what I think is important out there, but you’ve had plenty to say, too! Let’s see what we can add to the ongoing conversation in this edition of our comments of the week!

The three valence quarks of a proton contribute to its spin, but so do the gluons, sea quarks and antiquarks, and orbital angular momentum as well. Image credit: APS/Alan Stonebraker.

The three valence quarks of a proton contribute to its spin, but so do the gluons, sea quarks and antiquarks, and orbital angular momentum as well. Image credit: APS/Alan Stonebraker.

From Elle H.C. on real vs. virtual particles: “Ah well, is virtual quark still a quark?!”

This is a good question, but I am not 100% certain you understand what you’re asking in this context. You learn to visualize the quantum vacuum as “particle/antiparticle pairs” popping in and out of existence, and that’s fine. You also learn that there are “real” particles that exist if you try and scatter other particles off of them, and “virtual” particles that are useful as calculational tools to visualize the forces as exchanges of particles. But if you fire a high-energy particle into a proton at a few TeV, you will only hit a valence quark (up, up or down) about 10% of the time. The rest of the time, you hit a gluon or a “sea quark”, which is a member of a particle/antiparticle pair “popping” into existence very briefly.

These gluons and quarks are “real” in the deep-inelastic-scattering sense, which is as real as it gets. (Considering that cross sections and scattering amplitudes are the “measurables” that come out of quantum field theory.) Just because you don’t last forever doesn’t mean you aren’t real!

Relic microbes revealed by a scanning electron microscope in the ALH84001 meteorite, which originated on Mars. It is unknown whether the microbes are of Martian origin or not. Image credit: NASA, 1996.

From eric on an earthly vs. martian origin for fossils in a Mars meteorite: “Oh, just to be clear I don’t think the things we’re discovering are purely or even mainly a result of contamination. I think they’re martian.”

I think this is terrestrial. I think the rock is from Mars and the “life” in the rock is from Earth. It’s possible I’m wrong, but much, much more evidence is needed.

I will also add that I am optimistic about the probability/possibility of life having existed on Mars in the past, but just not optimistic about the direct evidence we have for it today. Chandra Wickramasinghe disagrees with me, and I am just fine with that.

Mars, along with its thin atmosphere, as photographed from the Viking orbiter in the 1970s. Image credit: NASA / Viking orbiter.

Mars, along with its thin atmosphere, as photographed from the Viking orbiter in the 1970s. Image credit: NASA / Viking orbiter.

From Sean T on the timeline for Mars exploration: “I’m not talking about reducing the risk to zero; of course that isn’t possible. I am talking about not flying completely blind. If it will take a few more years or even a few more decades, but will significantly increase the probability of success, is there not at least a reasonable argument for delaying the final human mission?”

I think you make a fair point on the topic of reasonable risk reduction, but I think we are still going to disagree as to what constitutes reasonable (or, perhaps, “reasonable enough”) in this circumstance. We already have everything we need in order to know about the safety and short-term dangers (and many medium-term dangers) of landing humans on Mars. We understand radiation and shielding; we understand the dangers of interplanetary space; we understand long-term effects of zero gravity on human physiology; we understand how to get spacecraft to Mars; we understand the martian terrain and atmosphere. I would argue that we understand all of these things “well enough” that no additional missions are necessary to be ready for crewed exploration of Mars.

The novel system that propelled curiosity to a successful landing on Mars. Image credit: NASA.

The one thing we don’t yet understand is how to land a payload as massive as once that could contain human beings and their life-sustaining materials on Mars. I do very much think more research is necessary for that, but that research is including in the preparatory plans for any and all Mars missions begin considered today. (Even, inadequately, in the case of the doomed Mars One plans.) I would rather see humanity make the attempt and fail in the 2020s and attempt and fail again in the 2030s than wait until the 2040s to even try. Not trying, to me, is the thing that shouldn’t be an option. If we want to go, we have to try to go. We might not make it, but we surely won’t make it if we don’t venture the chance.

IBM's Four Qubit Square Circuit, a pioneering advance in computations, could lead to computers powerful enough to simulate a Universe. Image credit: IBM research.

IBM’s Four Qubit Square Circuit, a pioneering advance in computations, could lead to computers powerful enough to simulate a Universe. Image credit: IBM research.

From Denier on computing limits: “It is true that Moore’s law has to come to an end. In fact current manufacturing is already behind the curve so Moore’s law in purest terms of transistors per square inch is already dead. That said, it hasn’t stopped the increase of computing power. Right this moment you could purchase off the shelf components to assemble a single 4U server for under $30k (Supermicro 4028GR-TRT2 + 10x Nvidia GTX1080 Ti + 3TB RAM + SSD storage array) that is an order of magnitude more powerful than the IBM Watson room-sized cluster than won Jeopardy!”

I agree with you that things will get cheaper, and that by increasing the number of “computing machines” (e.g., processors, cores, parallel devices, etc.) you can have working on a problem at once, you will continue to achieve faster computers. But this, too, cannot continue ad infinitum. You will run into limits there, too, in terms of the number of particles that exist in your computational cluster. It might be large — much larger than the computational power we’re seeing today — but don’t expect it to continue forever. There is a fundamental limit to computational power: the particles within your computer(s) bound by the speed of light. You will never overcome that.

There is one more chip left, and it, too, must be destroyed. Image credit: TriStar Pictures / James Cameron.

From Denier in response to eric, about AI and ethics: “Easy one. If an accident cannot be avoided then take the path that does the least damage to the car.”

I will accept that as one option to consider. But do not pretend that is evident as “the answer,” as the idea of a machine that values its own self-preservation is eerily reminiscent of a very particular line I remember vividly… I cannot self-terminate.

The event horizon of a black hole is a spherical or spheroidal region from which nothing, not even light, can escape. But outside the event horizon, the black hole is predicted to emit radiation. Image credit: NASA; Jörn Wilms (Tübingen) et al.; ESA.

The event horizon of a black hole is a spherical or spheroidal region from which nothing, not even light, can escape. But outside the event horizon, the black hole is predicted to emit radiation. Image credit: NASA; Jörn Wilms (Tübingen) et al.; ESA.

From Kasim Muflahi on a black hole: “I thought that the event horizon is determined by the mass of the blackhole. To me, this means that the event horizon radius will get smaller and smaller as the mass decreases. The escape velocity will also decrease until it reaches sublight speeds; at which point a neutron star becomes visible.”

You are partially right and then very wrong. The radius of the event horizon is determined by the mass of the black hole. The event horizon itself is defined by the location in space where the escape velocity equals the speed of light. So as the mass of the black hole decreases, the radius of the event horizon decreases, but the escape velocity at the event horizon is always the speed of light in vacuum: c.

While Einstein’s theory makes explicit predictions for a black hole’s event horizon and the spacetime just outside, quantum corrections could alter that significantly. Image credit: NASA.

From John on Hawking radiation: “As the Hawking Radiation originates from outside of the [Black] Hole, it is not obvious to me how it could carry information from the other side of the Event Horizon.”

Do you accept that radiation originating from outside the black hole will decrease the mass from inside the black hole? Energy and mass are two examples of information, in the sense that they are quantum properties that are conserved in a system. It is not obvious, by the way; you cannot even derive the spectrum of the radiation using standard quantum mechanics (this particle-pair analogy) in curved space. You must use the full quantum field theory calculations in order to get it. That is a calculation I did back in graduate school, and I hope you won’t be disappointed when I tell you that showing and explaining the calculation itself goes well beyond the scope of this blog.

An artist’s impression of two similar black holes that have slightly different masses. Image credit: NASA/Ames Research Center/C. Henze.

From Anonymous Coward on the math of black hole evaporation: “It would take something like 1060 years for a solar mass black hole to shrink to that size though, and if proton decay happens, with a half-life of about 1036 years, there would be precious little ordinary matter left by that time.”

Unfortunately, those are not good time estimates. I want you to consider a black hole of 1 solar mass and a black hole of 1.00001 solar masses. That’s right: just one-thousandth of 1% difference in mass. It takes 10^67 years for a solar mass black hole to evaporate, but what does that mean? It means that after 10^66 years, it’s still approximately a solar mass black hole; it’s lost just a small percent of its mass. It means that after 9.99 × 10^66 years, the black hole will “finally” be down to a 0.1 solar mass black hole. If you wait until the 1 solar mass black hole evaporates — 10^67 years — the 1.00001 solar mass black hole will still have 10^52 years to go before it evaporates, and you will not have any visible-light photons coming out of it until the final few seconds.

Also, the lower limit on proton decay half life is about 10^35 years. There are very good reasons to think it is infinite; don’t bet on it just because it hasn’t been ruled out.

This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. A tidally disrupted star may be responsible for the matter, and for the luminous emissions that result. Image credit: ESA/Hubble, ESO, M. Kornmesser.

From Robo on an additional black hole question: “You said no threshold for the evaporation of a black hole but i thought that something like the Plank lenght were the threshold, if it’s true that space under this misure has no meaning…What am i not understanding about this issue?”

The Planck length has a particular definition, which is to say a particle of the Planck mass would have a physical size of the Planck length and it would take the Planck time for the speed of light to traverse a black hole of that size. Also, a black hole of the Planck mass has an evaporation time that’s about 10^-39 seconds, which is close to the Planck time of ~10^-43 seconds. But they are not equivalent.

Also, if gravitons are real or not doesn’t really change the fact that the speed of gravity — the speed at which the gravitational force propagates through the Universe — is exactly equal to the speed of light in a vacuum: c. It is not instantaneous.

Image credit: Infrared: IPAC/NASA (2MASS), at left; Ultraviolet: STScI (GALEX), at right.

From Tom P. as the first comment on the article about Tabby’s star: ““Boyajian’s Star”, please.”

Is it really so threatening that one of the three acceptable nicknames for the star known officially as KIC 8462852 — the Where’s The Flux? star, Tabby’s star and Boyajian’s star — allows you to deduce that the discoverer of the interesting behavior is a woman who refers to herself as Tabby? This seems like it should be a non-issue, but your insistence makes me more determined than ever that “Tabby’s Star” is the way this star should be referred to.

An illustration of a storm of comets around a star near our own, called Eta Corvi. The comet scenario is one explanation for the dimming around Tabby's star, one that a high-quality astronomical spectrum should be able to validate or rule out. Image credit: NASA / JPL-Caltech.

An illustration of a storm of comets around a star near our own, called Eta Corvi. The comet scenario is one explanation for the dimming around Tabby’s star, one that a high-quality astronomical spectrum should be able to validate or rule out. Image credit: NASA / JPL-Caltech.

From Blackaddar on the aliens that are coming: “While everyone is watching tabby dim, that’s when the aliens will strike!”

But will they be using breakthrough starshots to attack us?

The infamous ‘shoe computer’ used to beat the casino by the Eudaemon group. Photo of The Eudaemonic Pie display at the Heinz Nixdorf Museum. Image credit: Hydro.tiger / Wikimedia Commons.

From Sinisa Lazarek on the shoe computer: “Eudaemons shoe computer used a legendary 6502 in 70’s.
If you’re a geek and find this cool… here is a javascript emulator of 6502 ?
http://www.visual6502.org/JSSim/

It’s pretty remarkable to think that the core hardware architecture of one of the most successful gambling/cheating devices is the same as the computer hardware used to power Apple IIs, Ataris and even the original Tamagotchi pets. As Michael Kelsey points out:

A monster version of the famous 6502 circuit board, capable of interfacing with oh so many classic devices! Image credit: Makezine.

The original hardware version has been increased in size by a factor of 7000, and is available from Makezine. It looks pretty amazing to me!

A large section of the concrete roadway in the center span of the new Tacoma (Wash.) Narrows bridge hurtled into Puget Sound, Nov. 07, 1940. Image credit: Seattle Post Intelligencer, 1940.

From Li D on resonance and flutter: “So are the sheetmetal spirals on smokestacks
for resonance or flutter?
Until reading this i had assumed resonance.
Thanks if the author or anyone knows.”

Although PWInn gave the answer, “the spirals are to break up any Karman vortices that can cause flutter,” I’d like to speak to another thing that people have been saying: that flutter is just a form of resonance and therefore “resonance” is still the right answer. Flutter is a common word for the much more intricate phenomenon of self-excitation that occurs in the presence of the right external conditions.

Aerospace engineers use wind tunnels to test the effect of flutter on airplane wings. Image credit: NASA.

The self-induced periodic impulses (rather than the externally induced phenomenon of resonance) are supplied by an external power (the wind) and the motion of the bridge is what taps the power from the wind. But the fact that the impulses are self-induced rather than externally induced makes this qualitatively and fundamentally different from resonance. The airplane model, above, is in flutter, not resonance, and its wings will eventually be torn off entirely due to this phenomenon. This is also why additional reinforcements — like the kind the Brooklyn bridge was built with — will prevent flutter. Fun stuff!

Acting NASA Administrator Robert Lightfoot discusses the proposed 2018 budget put forth by the White House during an address on the State of NASA. Image credit: Bill Ingalls/NASA.

Acting NASA Administrator Robert Lightfoot discusses the proposed 2018 budget put forth by the White House during an address on the State of NASA. Image credit: Bill Ingalls/NASA.

From Art Glick on painting with a broad brush: “Science facts are the enemy of this administration and their ilk.”

Although there are lots of pieces of supporting evidence that you can point to here, I prefer not to do so. Rather, you may do better treating each individual issue that comes up on the values of its own merits. Eliminating NASA’s Education Office removes and worsens a large number of programs, and that is worth fighting against. But if you paint the administration as an enemy, pure and simple, how can you hope to engage with any of its supporters? How will you change anyone’s mind? In short, how will you educate them if you alienate them?

From In Hell’s Kitchen (NYC) on Forbes’ availability: “forbes.com has been down and out for some time now…”

I do not know what you’re referring to, as I haven’t gotten an error once from any browser or computer in many months. What are you experiencing? Also, if you absolutely cannot access it, do remember that all of my articles are available ad-free on a 1-week delay on Medium.com here.

No matter how we change the entropy of the Universe around us, time continues to pass for all observers at the rate of one second per second. Public domain image.

From Denier on public education: “Giving tax breaks to poor people?!? Ewww. Besides, that isn’t trickle down economics. Secondly, teachers and school administrators are already eligible for MASSIVE tax giveaways far larger than what they pay in taxes. It is called the Public Service Loan Forgiveness (PSLF) Program and teachers are using it to wipe out six-figure student loan debts.”

Are they now? That would be an interesting feat, consider the program you’re citing — the PSLF program — was passed on September 10th, 2007, and only begins to wipe out any student load debt after 120 consecutive monthly on-time payment on loans (many, but not all, of which amortize on 10 year timescales). This means you need to work in public service for at least 10 consecutive years and never be late for one payment. Assuming you do that, the first loans to be eligible for this forgiveness will not occur until later this year.

How much debt do you think will remain for an educator after 10 years of on-time payments, versus how much they’ve paid in taxes over those 10 years? Again, hyperbole is fun, but where are your numbers to back up your assertions?

There's an extensive network of helium plants and pipelines located above where the United States has a naturally rich store of helium, but if we don't conserve it, it will take hundreds of millions of years to replenish. Image credit: Bureau of Land Management.

There’s an extensive network of helium plants and pipelines located above where the United States has a naturally rich store of helium, but if we don’t conserve it, it will take hundreds of millions of years to replenish. Image credit: Bureau of Land Management.

From Potato Planter on helium conservation and a whole lot more: “We are in an unstable period of our human development. As evidence, please note that the violent conservative American who just won the congressional special election in Montana believes in creationism! We live in a world where it is possible to be a billionaire wizz in computer “science”, and a complete moron in actual science. The spottiness of modern education is appalling.”

I think you lambast modern education unnecessarily. The issue isn’t that education is appalling (although there are a whole lot of ways I’d like to see public education changed on a national level), but rather that people vote along ideological lines. A large fraction of Trump supporters that I knew in November didn’t like Trump, agree with Trump or believe in Trump, but they believed that he would appoint a SCOTUS judge who was in line with their ideology, and that was enough to make them vote for someone they reviled. Someone like the body slammer or Ted Cruz or even Paul Ryan doesn’t believe what they say (I don’t think), but rather says what they say in order to reap the benefits of the response it elicits. That’s what modern politics is. I don’t know that it’s ever been any better.

Helium balloons, where the vast majority of the helium inside will escape the Earth. Image credit: HilkeFromm / Pixabay.

And finally, from Carl on using nuclear fusion to save our helium crisis: “How much Helium would we potentially create if all Earth’s electrical energy were generated using fusion?”

Carl, you gave a valiant attempt, but your numbers are a bit off. Let’s go with the International Energy Agency’s numbers: the Earth supplies approximately 158 PetaWatt-hours of energy per year (as of 2013), and that we are going to supply 100% of that energy with nuclear fusion of hydrogen into helium, producing 100% helium-4 as a result.

World energy consumption estimates, based on figures provided by BP. Image credit: Martinburo of Wikimedia Commons.

That amount of energy is approximately 5.67 × 10^20 Joules, which is the equivalent of turning 6,300 kg (or 6.3 tons) of mass into pure energy. But nuclear fusion of hydrogen into helium is only 0.7% efficient, so it would require the production of 900,000 kg (900 tons) of helium to liberate that much energy.

If the USA uses 15,000,000 kg of helium per year… even nuclear fusion for the whole world won’t supply even 10% of just one country’s needs. Fusion isn’t the answer.

Thanks for playing, folks, and see you back here next time for more science on Starts With A Bang!

Comments

  1. #1 Michael Mooney
    May 28, 2017

    “Do you accept that radiation originating from outside the black hole will decrease the mass from inside the black hole?”

    No. Accepting that requires evidence that something besides Hawking’s imagination can escape the gravity well inside the event horizon.

  2. #2 Michael Kelsey
    SLAC National Accelerator Laboratory
    May 28, 2017

    @Ethan, regarding your, “I haven’t gotten an error once from any browser or computer in many months. What are you experiencing?” I use MacOSX, and have tried both Safari and Firefox (which I have in my Dock). They both fail completely accessing Forbes.com (including the main page, *not* just your blog), with an error which supposedly implicates the Forbes.com server:

    Safari can’t open the page “https://www.forbes.com”. The error is: “cannot parse response” (NSURLErrorDomain:-1017)

    I’ve posted comments about this to both your Questions and Comments thread, and over on Chad Orzel’s blog (because he also puts up stuff on Forbes).

    I’ve given up being able to read your articles in a timely fashion, but I do try to follow the comments.

  3. #3 Ethan
    May 28, 2017

    Hi Michael,

    That’s actually useful, and I think that you might be able to help me out. Can you:

    1.) Open Developer Tools.
    2.) Click on the ‘Network’ Tab.
    3.) Go to, say http://www.forbes.com/
    4.) Copy any 400 (4xx) or 500 (5xx) errors that show up there by right clicking the “copy as cURL” option, and then
    5.) Paste it in an email and send it to me at my firstname dot lastname at gmail dot com?

    If you are getting an error, that should allow me to send some useful information to Forbes that might help them resolve it.

  4. #4 Denier
    United States
    May 28, 2017

    @Ethan wrote:

    A large fraction of Trump supporters that I knew in November didn’t like Trump, agree with Trump or believe in Trump, but they believed that he would appoint a SCOTUS judge who was in line with their ideology, and that was enough to make them vote for someone they reviled.

    Please be careful with even handed statements like that. In your profession, especially in the Pacific Northwest, adopting a position any less screechy than outright vilification to paint the center and right as jackbooted Nazis can end your career. I’m sure you’re familiar with the Bernie-voting Biology Professor teaching about 2 hours up the road from you who dared to blaspheme by stating that it was wrong to discriminate based on skin color, and now is in fear for his life because students have labeled him as “anti-black”.

    http://www.king5.com/news/local/olympia/professor-told-hes-not-safe-on-campus-after-college-protests/443098670

    ‘Sane’ seems to no longer be the safe position in academia.

  5. #5 PJ
    Perth, West Oz
    May 29, 2017

    I have Firefox in Windoze 7; no failed access as yet.
    🙂

  6. #6 Elle H.C.
    May 29, 2017

    … you hit a “sea quark”, which is a member of a particle/antiparticle pair “popping” into existence very briefly.

    The waves that the wings of a helicopter make are not wings, they are waves, even if these waves can ‘hit’ you hard.

    So it does not seem correct to talk about the multitude of possible quark-formations.

    I guess it is also no surprise that you get these hard waves the faster you go.

    To me it seems like you’re fooling yourself when you are doing an investigation to find an “entire spectrum of these new sets of particles”.

    This research is similar to dropping a ball in to a bucket of water, and the higher drop the bigger the splash. The silly thing with this is that we already have balls hitting the bucket from the highest heights possible namely Cosmic-rays, and we know already that nothing significant has popped up.

    Physicists should acknowledge that there is most likely a medium with waves and look for a model in that direction, because a model with “sea quarks” and “spectrum of sets of particles” is probably fallacious and only a excuse to keep doing this experiment.

  7. #7 eric
    May 29, 2017

    I will also add that I am optimistic about the probability/possibility of life having existed on Mars in the past, but just not optimistic about the direct evidence we have for it today.

    I don’t think we disagree too much, then. Past life on Mars: credible possibility. Current life: very unlikely. As a non-expert I’m generally willing to accept that the structures we see are martian, but not willing to say they support the conclusion of current life.

    The one thing we don’t yet understand is how to land a payload as massive as once that could contain human beings and their life-sustaining materials on Mars.

    I would think that a natural intermediate step would be to land automated heavy construction vehicles on the planet. Use them to build pits, walls, underground tunnels, etc. If you can’t safely land them, then you can’t safely land humans that would require the same tonnage. And if you can land them, then you should land them months or years before the humans arrive anyway, so that some basic environmental protection structures are already in place when the humans arrive.

  8. #8 CFT
    May 30, 2017

    @eric #7,
    You speak of intermediate steps, but going to Mars to do anything in the first place isn’t exactly intermediate.
    Before we go traipsing around on Mars, why don’t we perfect this technology of ‘automated’ construction relatively nearby, like on earth in some desert first, then if that successful, on the moon. Baby steps. If we can’t make it work for whatever reason in a desert or on the moon, it would be far less costly than going all the way to Mars to find out…and then have to justify the cost, a failure of that magnitude if something went wrong would have negative ramifications to other such future endeavors ever being financed (it always has to be paid for).
    .
    Propulsion and light weight radiation shielding should really be where the research science focuses. If you can lick those two problems, many of the other difficulties become much smaller. I don’t think any country in the world can presently justify the sheer cost of a brute strength approach to space exploration. Putting a single person on Mars alive, much less to live there would cost billions, for the purpose of mass colonization, that makes little sense economically at such a high cost.

  9. #9 Narad
    May 30, 2017

    4.) Copy any 400 (4xx) or 500 (5xx) errors that show up there by right clicking the “copy as cURL” option

    NSURLErrorCannotParseResponse is an OS X client-side error, not a server-side error. HTML return codes aren’t going to tell you anything.

  10. #10 Narad
    May 30, 2017

    ^ I’m loathe to invoke this site, as the denizens generally have no idea what they’re talking about (e.g., the “solution” to everything always involves “repair permissions”), but the Forbes problem is not unknown.

  11. #11 Sean T
    May 30, 2017

    Ethan,

    I do think we are in fundamental agreement on the goal: putting a human colony on Mars. However, I don’t know that your idea is feasible from a political/sociological standpoint, no matter how much sense it makes scientifically. From a scientific point of view, yes, it makes sense to make an effort, fail, learn from that effort’s failure and try again. I’m not so sure that’s viable from a sociological and political standpoint, though. The initial effort is likely to be very expensive. If it does fail, there will be enormous political opposition to a second attempt. It would be wise, at least in my opinion, to delay the attempt until we make sure we know everything we can know to make the attempt successful.

    You obviously are in a better position than I to determine exactly where along that road we are currently. I defer to your knowledge in that regard. However, you did point out one possible roadblock in the need to safely land a multiton payload on Mars. I think it’s reasonable to delay a human mission until such time as such a payload has been successfully landed and we know how to do so.

    You are absolutely correct: to accomplish the goal, an attempt must be made. I just fear that a single attempt may be all that we get, and that an expensive failure might well make a further attempt impossible politically.

  12. #12 Lloyd
    May 30, 2017

    Here is a great and clear example of how you can tell when someone is bullshitting. I think I’ll use it in my classes. Denier claims teachers are currently getting special 6-figure payouts unavailable to me and thee via a loan forgiveness program. Cue the outrage machine. Ethan points out why this is totally not actually happening. Denier’s response: nada. Crickets. If you or I made a claim like that and were revealed to be so utterly and baldly misleading, we would experience something called shame–shame either at having been taken in by right-wing nonsense, or shame at having knowingly spread lies and been called on it. We would either try to get to the bottom of it and let Ethan know why in fact his response was incorrect, or we would acknowledge having been wrong. Shame: Denier has none. And this, kids, is how you know his main schtick, climate change denial, is similarly bogus. He gets his tired old canards about the climate from a few rightwing fossil-fuel shills, and spins his denial as a fresh take unencumbered by dogma and group-think. The situation is sometimes complex, and so it might take some skill and patience to point out what is misleading about these false claims, and he will blithely ignore what is inconvenient, latching onto superficial details to discredit. But the net result is as wholly dishonest and intellectually empty as this clearcut case where he’s shown to be wrong on a simple matter. Follow the arguments, and not the bullshit flung against the wall to see what will stick, and it will not remain a mystery who is arguing honestly and who isn’t.

  13. #13 Alan G.
    George, WA
    May 30, 2017

    ^^^^^^ Having watched the exact dynamic described above turn every place of information (and even entertainment) online into mush through sheer invasive volume of dysfunction, from BBS’s (1985), to forums (1990’s), to social media (2000’s-present), using the exact same MO, it is astounding how effective the virus-like behavior remains after all all this time. In the past, the only treatment was to figuratively burn the house down and build a new one with a few more barriers to entry in hopes of keeping the infection at bay for a little longer then the previous time. Now, the platforms are too expensive and complex to keep razing/rebuilding.

  14. #14 Alan G.
    West, Texas
    May 30, 2017

    Also, that virtually every entity looking to gain something dishonest online, whether personal satisfaction or financial gain, all use the same methods. From the pink sheets stock promoters/scammers, to con artists of every sort, to the criminal element. They are all using the same playbook.

  15. #15 fred
    May 30, 2017

    “The radius of the event horizon is determined by the mass of the black hole. The event horizon itself is defined by the location in space where the escape velocity equals the speed of light. So as the mass of the black hole decreases, the radius of the event horizon decreases, but the escape velocity at the event horizon is always the speed of light in vacuum: c.”

    I was curious as to how one would tell the difference between a heavy neutron star within an extraordinarily deep gravity well from a black hole that had full gravitational collapse of the core into a singularity. It’s my understanding that a singularity is inevitable once a certain density is reached, meaning that density could never be diluted by loss of mass via Hawking radiation, so it’s “once a black hole, always a black hole”, until their fizzle-bang Hawking radiation death far down the road. But these event horizons define a rather voluminous space, and who knows what goes on in there. Is it necessary that once escape velocity exceeds the speed of light that whatever lies behind the curtain must be a singularity as predicted by the maths?

  16. #16 fred
    May 30, 2017

    For context, the question to which Ethan was replying, which failed to paste over in my first post:
    From Kasim Muflahi on a black hole: “I thought that the event horizon is determined by the mass of the blackhole. To me, this means that the event horizon radius will get smaller and smaller as the mass decreases. The escape velocity will also decrease until it reaches sublight speeds; at which point a neutron star becomes visible.”

  17. #17 Li D
    Australia
    May 30, 2017

    #12 Good post.

  18. #18 Michael Kelsey
    SLAC National Accelerator Laboratory
    May 30, 2017

    @Ethan #3: Apologies for the delay; my family went on a short vacation for the Memorial Day holiday. I hope to get the details you asked for soon.

  19. #19 Michael Kelsey
    SLAC National Accelerator Laboratory
    May 30, 2017

    @fred #15: You asked, “I was curious as to how one would tell the difference between a heavy neutron star within an extraordinarily deep gravity well from a black hole that had full gravitational collapse of the core into a singularity.”

    In pragmatic terms, it might be difficult, but there’s a guaranteed method which works in principle, and which is what is planned for use with the Event Horizon Telescope (type that into Wikipedia to learn more :-).

    The answer is that a neutron star or any other compact object other than a black hole, has a physical surface from which its emission originates. A black hole does not have a surface at all (the event horizon, or ergosphere for a spinning BH, is merely a region of space). The difference leads to observable differences for black holes large enough to be imaged in a telescope (hence the EHT connection).

  20. #20 eric
    May 30, 2017

    CFT:

    Before we go traipsing around on Mars, why don’t we perfect this technology of ‘automated’ construction relatively nearby, like on earth in some desert first

    We should definitely have such tech perfected (well…highly confident it works) before we spend $billions shipping it to Mars. No question there. However give the long lead times for mars launches, and the fact that swapping out software and chips is only part of the R&D required, I’d say we should probably do both in parallel as smartly as we can. THat is to say, get a best estimate on how long it might take to develop the control systems. Plan for a launch window some time after that. And spend the time between now and that launch window working furiously to bring the vehicles, hardware, software, rocket, landing technology etc. all to full development.

    IOW yes I think caution is warranted in the development. But it might be overcautious to wait until we’ve complete and utterly finished the development of the automation systems before starting to work on all the other stuff or (before) starting the launch planning. Instead, work all these R&D pathways in parallel.

  21. #21 John C Schaefer
    San Diego, CA United States
    June 4, 2017

    Being a retired web nerd I was interested in the ‘Forbes does not load’ issue commented on above. I run Windows 7. I have Firefox, Chrome, Safari & IE loaded.
    One of the interesting things I see is that Forbes does a redirect form “http://www.forbes.com” to “https://www.forbes.com”. This switch to the ‘secure’ version in which user communications between server and client are done using SSL (Secure Sockets Layer) appears to fail on Safari for Windows. Since the website design forces the switch, there is no way to load the unsecure website. Safari consistently fails when the switch is performed. Since all browsers implement the http and https standards as they see fit, the only solution to Michael Kelsey’s problem is to switch platforms and use Chrome. An ugly solution but getting Forbes’ IT department to fix the problem may not happen in our lifetime!

  22. #22 Ken Mitchell
    Sacramento, CA
    October 10, 2017

    Going to Mars: I agree that we’ve already done all of the basic “research” that we need to send people to Mars (or to the Moon) to survive and thrive for the long term. We know what’s needed. What still needs to be done is ENGINEERING. It’s not enough to make it “possible”; it needs to be reliable, with redundant systems already in place for when stuff breaks – because Murphy assures is that things WILL break , and at the worst possible moment.