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am_Unition's comments

We didn't find it until 40 days after perihelion? It had already passed Earth's orbit and was quite a bit of the way out to Mars's orbital. Ugh. Can we never let this happen again?

Solar wind density is directly proportional to 1/r² (r=distance from the sun), but the speed is not a function of distance. Both are subject to significant variations related to processes on the sun's surface and in the solar corona. So you could absolutely model future anomalous acceleration in addition to what we've seen already, but the question is always how well we can resolve it, as the density will continue to drop off pretty quickly, and thus the magnitude of any pushing grows less. Maybe we have some earth-orbiting black ops imaging tech pointed up instead of down that can help us out?

Edit: There is one possible alternative explanation, but it doesn't make much sense: 'Oumuamua could be strongly magnetized, and would interact with the solar wind's magnetic field. But I dunno, if you look at 'Oumuamua's trajectory:

you'll see that the path we've gathered data for is only ~20 degrees outside of the ecliptic plane, so the solar wind magnetic field orientation might still be somewhat chaotic (reference, I will explain if prompted), which doesn't favor imparting a net force, i.e. some anomalous acceleration. But wait! This entire paragraph's worth of speculation is totally invalidated by the fact that Oumuamua is tumbling, a chaotic motion (see the intermediate axis theorem), which is guaranteed to lead to no net accrued time of some embedded magnetic field oriented in a particular direction.

Still edit: It could be possible that the object is engineered to cleverly extract energy out of electromagnetic fields like those present in a star's "solar wind".

We should send something after it. The project might take 30 years for launch and rendezvous, and then several months to send back data, but it can be done. We should look and see if we can catch it pinging somewhere else. Maybe bring a compact neutrino sensor (LOL, physics joke), 'cuz if I were an advanced species, I'd encode messages in neutrinos. It'd prevent filthy casual civilizations from detecting my interplanetary sexts (encoding information electromagnetically was so pre-post-re-evolution, circa only 2 Gyears post-Big Bang for my world, ya know?).

Devac  ·  2 days ago  ·  link  ·  

According to this article, the strongly magnetized object hypothesis is unlikely to be the only source of anomalous acceleration. To quote:

    If ‘Oumuamua had a strong magnetic field, then interaction with solar wind could affect its motion. Assuming a dipole field, a plasma-fluid model and typical solar wind speed and proton number density, we find the resulting acceleration for an object of the nominal size of ‘Oumuamua to be only 2 × 10^(-11) m/s², too small by a factor of about 10^5, even if we adopt the high magnetization and density of asteroid (9969) Braille.

(Changed some of the typography to make it more readable.)

I'm somewhat interested in the odds of an interstellar object not having a neutral magnetic field. Intuitively, lack of net charge or magnetization should be the norm but I'm far out of my depth here.

Also: consider yourself prompted.

bhrgunatha  ·  2 days ago  ·  link  ·  

    We didn't find it until 40 days after perihelion? It had already passed Earth's orbit and was quite a bit of the way out to Mars's orbital. Ugh. Can we never let this happen again?

I don't think it is, but f it is first contact. we're just sitting here watching and pointing at it as it's flying past pointing and going "ooooooh"....

Here's hoping we're better prepared for second contact.

We're constantly discovering new things we can't explain or understand about space, the universe in general, even our own solar system. To me it feels like true hubris to assume it's evidence of anything other than our lack of knowledge about the universe and how it works. We've just discovered something else we can't explain. WHoop de doo - add it to the list.

kleinbl00  ·  2 days ago  ·  link  ·  

1) From an astronomical standpoint, it ain't a big thing. We're talkin' about an object around the rough size of a football stadium.

2) If I had something shaped like a giant cigar and I were trying to not get noticed, I'll bet my AI would go "quick, act like an asteroid" as soon as I had a reasonable read on my observed race's intelligence. "Tumbling" is such a nasty word. It's got a periodicity of 8 hours. Sucker's "tumbling" about 1/10th as fast as your average revolving restaurant.

3) We should totally send something after it. That's the sort of speedboat space exploration your average Red Stater can get behind.

am_Unition  ·  2 days ago  ·  link  ·    ·  parent  ·  post: Oligarch 'made threat' after Trump inauguration

I've been quite relieved that Robert Mueller hasn't "shot himself" and left behind a "suicide note" scrawled out in the cyrillic alphabet. I mean obviously it'd be more subtle than that, but nothing suspicious has befallen anyone working on the case or even journalists covering it, AFAIK. The feeling of "that shit don't play in mah 'Murica" is comforting.

am_Unition  ·  8 days ago  ·  link  ·    ·  parent  ·  post: Weekly Photo Challenge: Natural Light

Thank you! The moral of the story is that I need to buy him some Natural Light socks.

I promise better adherence to typical photo challenge standards in the weeks to come, I think.

am_Unition  ·  9 days ago  ·  link  ·    ·  parent  ·  post: Pubski: January 9, 2019

Congratulations, Devac, it sounds like you're straight-up slaying right now :).

I get the skepticism, but I think quite a bit of the (admittedly generous) speculation surrounding Mueller will pan out.

Donald Trump himself be damned, imagine if you were going to attempt implicating this president's son in any sort of criminal charges for something like the Trump Tower meeting with Veselnitskaya. The prosecution's case would need to be built into an airtight configuration hinging on a small domino guaranteed to fell a well-built legal castle as soon as things were set in motion. That would take a looooong time. If he were to dare file charges against a Trump family member, Mueller would expect immediate termination, and should thus be expected to engineer contingency plans guaranteeing the eventual public release of his comprehensive report, additional pending and/or sealed indictments, etc., etc.

All that said, it could be that he'll uncover no definitive evidence of conspiracy/collusion with Russia on behalf of Trump Sr. himself, but I think that the obstruction of justice case is all but inevitable. And maybe I'm wrong. I mean, hell, I was just wrong a few hours ago about Trump making some official declaration of an emergency at the border.

I just want the government back open. If I were a foreign adversary, right now looks like a bitchin' time to strike.

goobster  ·  10 days ago  ·  link  ·  

IIRC it took two years for the Watergate investigation to levy charges. And they had physical evidence of break-ins, etc.

Muller is being very careful. I expect the ONLY charges levied against Trump and his family will be absolutely air-tight. He can't risk anything being thrown out or dismissed.

kleinbl00  ·  10 days ago  ·  link  ·  

When you strike at a king you must kill him.

- Ralph Waldo Emerson

am_Unition  ·  10 days ago  ·  link  ·    ·  parent  ·  post: Weekly Photo Challenge: Natural Light

This week, I cheated. I asked my friend (let's call him Natthew, or "Natty", for short) to send me a pic, and he delivered:

(plz zoom)

Thanks, Natty!

psychoticmilkman  ·  9 days ago  ·  link  ·  

This is the best.

am_Unition  ·  8 days ago  ·  link  ·  

Thank you! The moral of the story is that I need to buy him some Natural Light socks.

I promise better adherence to typical photo challenge standards in the weeks to come, I think.

am_Unition  ·  10 days ago  ·  link  ·    ·  parent  ·  post: Reports out of China suggest first human gene-edited babies have been born

Wow! I'm thankful that the threshold for the death penalty is markedly higher here in the states. I'm not sure I ever want to travel to China.

Seriously? Like with to-go orders? I've never had that. How does it perform compared to typical plastics?

kleinbl00  ·  10 days ago  ·  link  ·  

Yeah it's pretty common. Seattle also requires public places to have garbage, recycle and compost so there's an impetus to go with things that'll compost. Chipotle uses them, most food courts use them, they have them at the airport.

It's smoother and cooler to the touch than polystyrene, in part due to the texture - it feels more like finely sanded wood than plastic. They're constructed thicker than typical plasticware, more like the stuff you buy for your picnic than the stuff you're used to at Taco Bell. They're bendier, though, so the thickness doesn't gain you the rigidity of picnicware. And you only ever see them in bigger places; I suspect they break down too quickly to sit on the shelf for a year or whatever.

You can buy 'em on Amazon. Just search for "biodegradable plastic forks" or the like and you'll see a dozen different companies selling xyleco plastics.

Prediction: The gov't will be re-opened tomorrow after Trump declares a "STATE OF TOTAL AND EXTREME EMERGENCY, THE WORST OF ALL TIME, PEOPLE ARE SAYING, AT THE SOUTHERN BORDER, A TERRIBLE PLACE, INCREDIBLY TERRIBLE" tonight. The ensuing legal battle deciding the constitutionality of this little political stunt will take years to play out in the courts. He might get a little bit of wall in the meantime.

Update: I was wrong.

am_Unition  ·  11 days ago  ·  link  ·    ·  parent  ·  post: The Strong Law of Small Numbers

Yes, I think my statement needs to be amended to say:

    ...no known set of functions, mappings, transformations etc. that generates ALL prime numbers.

Edit: Actually I wasn't sure there exists even a single algorithm capable of producing only prime numbers as n -> infinity, even if the results for n below a "really large" were a subset of all primes. But Rowland (from wasoxygen's wiki article above) apparently managed to do exactly that.

Can you imagine being a reviewer for this article? It would be incredibly punishing to go through every problem and substitute increasing n until you saw whether or not it continued to meet the criteria after leaving the "small n" domain. In fact, a reviewer wouldn't do that, they'd write code to do it for them, even in 1988.

bfv  ·  11 days ago  ·  link  ·  

Generating all primes is just as easy as testing for primes:

    import math

def is_prime(n):

for m in range(2,int(math.sqrt(n))+1):

if n%m == 0:

return False

return True

def primes():

n = 2

while True:

if is_prime(n):

yield n

n += 1

for p in primes():

print p

it's just that we don't have useful ways to generate primes.

wasoxygen  ·  11 days ago  ·  link  ·  

And in 2019, I just entered the phrase "is 4294967297 prime" into a search engine. That level of effort might explain why I only got two out of three of the examples above correct (no better than chance!) before looking at the solutions.

But #1 stumped Fermat too! I didn't know that this problem sparked Euler's interest in number theory, according to "How Euler Did It" (4-page PDF). It was one of the many problems left over from the famous Fermat-Descartes correspondence.

    Fermat and Descartes did not like each other very much. In fact, some people describe their relationship as a “feud,” but it seems that Descartes resented Fermat more than Fermat disliked Descartes. They probably never met.

I figured Euler must have scribbled out a lot of long division problems to crack the Fermat number conjecture. But apparently he found a shortcut.

[SPOILER]

    Euler’s mentor in St. Petersburg, Christian Goldbach, alerted Euler to the conjecture in 1729. Euler responded almost immediately that he could make no progress on the problem, but by 1732, close to a hundred years after Fermat had originally made the conjecture, Euler had a solution: Fermat was wrong. In Euler’s first paper on number theory [E26] Euler announced that 641 divides 4,294,967,297.... What Euler did not tell us in E26 was how he thought to try to divide 4,294,967,297 by 641. He hadn’t simply been dividing by prime numbers until he got to 641. He had a much better way, but he waited about fifteen years, until E134, to reveal that secret.
am_Unition  ·  12 days ago  ·  link  ·    ·  parent  ·  post: The Strong Law of Small Numbers

Well this isn't fair because everybody already knows that there exists no known set of functions, mappings, transformations etc. that generates prime numbers.

What kills me is when mathematicians turn to wordsmithing:

    Superficial similarities spawn spurious statements.

    Capricious coincidences cause careless conjectures.

    Early exceptions eclipse eventual essentials.

    Initial irregularities inhibit incisive intuition.

And when I say "kills me", I secretly love it.

wasoxygen  ·  11 days ago  ·  link  ·  
am_Unition  ·  11 days ago  ·  link  ·  

Yes, I think my statement needs to be amended to say:

    ...no known set of functions, mappings, transformations etc. that generates ALL prime numbers.

Edit: Actually I wasn't sure there exists even a single algorithm capable of producing only prime numbers as n -> infinity, even if the results for n below a "really large" were a subset of all primes. But Rowland (from wasoxygen's wiki article above) apparently managed to do exactly that.

Can you imagine being a reviewer for this article? It would be incredibly punishing to go through every problem and substitute increasing n until you saw whether or not it continued to meet the criteria after leaving the "small n" domain. In fact, a reviewer wouldn't do that, they'd write code to do it for them, even in 1988.

bfv  ·  11 days ago  ·  link  ·  

Generating all primes is just as easy as testing for primes:

    import math

def is_prime(n):

for m in range(2,int(math.sqrt(n))+1):

if n%m == 0:

return False

return True

def primes():

n = 2

while True:

if is_prime(n):

yield n

n += 1

for p in primes():

print p

it's just that we don't have useful ways to generate primes.

wasoxygen  ·  11 days ago  ·  link  ·  

And in 2019, I just entered the phrase "is 4294967297 prime" into a search engine. That level of effort might explain why I only got two out of three of the examples above correct (no better than chance!) before looking at the solutions.

But #1 stumped Fermat too! I didn't know that this problem sparked Euler's interest in number theory, according to "How Euler Did It" (4-page PDF). It was one of the many problems left over from the famous Fermat-Descartes correspondence.

    Fermat and Descartes did not like each other very much. In fact, some people describe their relationship as a “feud,” but it seems that Descartes resented Fermat more than Fermat disliked Descartes. They probably never met.

I figured Euler must have scribbled out a lot of long division problems to crack the Fermat number conjecture. But apparently he found a shortcut.

[SPOILER]

    Euler’s mentor in St. Petersburg, Christian Goldbach, alerted Euler to the conjecture in 1729. Euler responded almost immediately that he could make no progress on the problem, but by 1732, close to a hundred years after Fermat had originally made the conjecture, Euler had a solution: Fermat was wrong. In Euler’s first paper on number theory [E26] Euler announced that 641 divides 4,294,967,297.... What Euler did not tell us in E26 was how he thought to try to divide 4,294,967,297 by 641. He hadn’t simply been dividing by prime numbers until he got to 641. He had a much better way, but he waited about fifteen years, until E134, to reveal that secret.
am_Unition  ·  16 days ago  ·  link  ·    ·  parent  ·  post: Where to watch the New Horizons Ultima Thule Encounter

Got a good pic in (source):

Eerily similar to the Rosetta Comet (a.k.a. 67P/Churyumov–Gerasimenko):

Maybe we're going to find that merger events between once-separate Kuiper Belt objects are quite common.

francopoli  ·  16 days ago  ·  link  ·  

A while back, they got a stellar occultation of Ultima. They got data that it was a contact binary

The results match what these images show.

The 20 months it will take to get all the data are going to drag on! Also there was a comment in the press conference that they are looking for one more target. That will be fun!

am_Unition  ·  17 days ago  ·  link  ·    ·  parent  ·  post: Knockdown of the year? The super rare double knockdown in Japan.

Video did not embed for me, just a blank space.

cgod  ·  17 days ago  ·  link  ·  

Fixed, strange youtube link issue that I found a way around

Thanks

am_Unition  ·  21 days ago  ·  link  ·    ·  parent  ·  post: Capitalism

Your obsession with abs, anal, and dystopian societies is tearing this community apart.

But mk, #bugski cuz I’ve never been able to change a community tag. I get served the monktightrope.jpg 503 and then cannot edit anymore. It’s like Hubski thinks I’ve made a successful edit, but it wasn’t actually accepted. Not a huge deal, obvz.

Also, I took 3 Lyfts last night, and I’m sorry :/. 75%+ tips though

am_Unition  ·  28 days ago  ·  link  ·    ·  parent  ·  post: Stock buybacks hit a record $1.1 trillion, and the year’s not over

It'd be fun to cross-correlate buybacks with the nasdaq, spx, fed interest rates, categories of debt per capita, etc.

People are probably already doing that, but I'm not gonna read those papers, got a long queue, etc.

And what do you think, 'bl00, is Trump right to blame the fed, to some degree, for the poor market performance this week?

The graph suggests that we should fit some exponential decay factor (with a peak near 1982), and implies we're just as sensitive to fed interest rates crashing "the market" as we were in 1957 or so. I don't understand why that might be the case.

kleinbl00  ·  28 days ago  ·  link  ·  

    It'd be fun to cross-correlate buybacks with the nasdaq, spx, fed interest rates, categories of debt per capita, etc.

https://fred.stlouisfed.org/graph/?g=HfT

That's really the only one you need.

    And what do you think, 'bl00, is Trump right to blame the fed, to some degree, for the poor market performance this week?

One of the guys I follow, can't remember which one, pointed out that Jerome Powell is on the record as arguing that recessions are a normal part of the market cycle. This is the rhetorical equivalent of arguing that what goes up must come down but from a Capitalist standpoint it's deepest heresy. Even Bernanke saw it as his duty to pop the bubble with the least bloodshed; neither Yellen nor Powell faint at the sight of blood. The real problem is you can't inflate a bubble forever, it will pop at some point and Bernanke was so terrified of the Great Depression that he pumped up the banks like Macy's balloons.

Eventually the air has to come out. And then people freak out.

    The graph suggests that we should fit some exponential decay factor (with a peak near 1982), and implies we're just as sensitive to fed interest rates crashing "the market" as we were in 1957 or so.

Fitting curves to chaos only allows you to backtest your math. The problem with math and markets is that we can only suss out what factors matter after the fact. I think David Rosenberg pointed out last week that nobody rings a bell at the top of the market and that while it may be obvious in retrospect, in the moment you have no more assurance as to the next day as you do to the provenance of a coin toss.