The Sun's Magnetic Field is about to Flip | Hacker News Reader

The Sun's Magnetic Field is about to Flip

science.nasa.gov

197 pointsrms95 comments

Apparently this happens every 11 years. Nothing to panic, but an interesting astronomical phenomena nevertheless.

So this is an alternating current, but with a cycle time of 22 years instead of a fraction of a second?

No, it's a chaotic system that is quasistable for an average of 11 years at a time before it flips to the opposite orientation with respect to the spin axis. The Earth's magnetic field, generated by currents in the liquid outer core, is a similar magnetohydrodynamic system that has no apparent periodicity.

So astronomical objects are classifiable under a magnetic AC/DC onotology? Wow. Seems like dualism dies hard.

How can you get that from that reply? He specifically said they are not.

Err, I'm not sure how your brain works but it's obviously different to mine. Fear not, in heterogeneity lies strength!

Disclaimer: I worked on the solar magnetic field for two summers.

Whether the sun is chaotic in the technical sense (i.e. the butterfly effect) is still open to question [1]. The solar magnetic field is poorly understood. In the 1980s, everybody thought that a particular model (mean-field dynamos IIRC) had it all figured out, but new observations from helioseismology showed them wrong. Wikipedia has a good article on the solar cycle: https://en.wikipedia.org/wiki/Solar_cycle My advisor wrote a more technical overview: http://solarphysics.livingreviews.org/Articles/lrsp-2010-3/a...

[1] See: https://en.wikipedia.org/wiki/Chaos_theory#Distinguishing_ra...

Part of me kind of wishes that this had some trivial, totally safe and innocuous consequence that you could still appreciate somehow with a Mr. Wizard type experiment.

The last time a geomagnetic reversal occurred on Earth was 780,000 years ago (with a possibility of a brief one occurring 41,000 years ago) [1]. I wonder what it will feel like when it happens again...

[1] http://en.wikipedia.org/wiki/Geomagnetic_reversal

Great, now we can market our app as "solar magnetic field reversal-proof".

... and you have a BOFH-style excuse in case something goes wrong!

The article includes the following quotation:

"The sun's north pole has already changed sign, while the south pole is racing to catch up," says Scherrer.

Does that not suggest that the sun is currently a magnetic monopole? Or is that too simplistic?

Of course it's not a monopole, but the dipole idea is also too simplistic, as is the idea of "poles". Presumably, the dipole moment of the Sun has become very small but there are still higher orders at work. Thus, the field of the Sun will look very much more complex than the simple dipole field [0].

A possible configuration would be that both geographicals poles of the same sign, but the field around the equator is of a different sign, like a quadrupole perhaps.

Disclaimer: I'm a physicist but not an astrophysicist.

0: http://upload.wikimedia.org/wikipedia/commons/1/17/Earths_Ma...

Correct. I'll do some digging around to find the polarity maps we have around the lab here and post them if I find them. At times, there really isn't a clear 'pole' of the sun, and octopoles can sometimes be found.

E: Here's a link to one of those maps. I'll see if I can find any better.

http://www.bibliotecapleyades.net/imagenes_ciencia/ciencia_s...

How do they measure it? There was nothing in the article about how this is observed?

It's an inset picture and link[0]. They collect quite a bit of data[1] (that you can ask for[2]).

"Astronomers at the Wilcox Solar Observatory (WSO) monitor the sun's global magnetic field on a daily basis."

[0] http://wso.stanford.edu/

[1] http://wso.stanford.edu/words/plots.info

[2] http://wso.stanford.edu/forms/prsyn.html

They fired a load of iron filings at the sun.

Observing the behavior of plasma around the Sun is probably one of the indicators. Also, the Zeeman effect in the Sun's spectrum measures the absolute intensity quite directly; I'd assume that the zero transition could be observable this way.

Once they observe the photospheric magnetic field, they use it as a boundary condition for models that project upward into the corona. They can't observe the field directly in the corona (this might be an experimental capability somewhere, but it is not done observationally anywhere).

They do observe the movement of plasma in the corona, to check the field lines predicted by the models.

Good question.

The light spectrum emitted by the Sun has "spectral lines", or emission features (deep dips or strong peaks) that are determined by light-absorption or light-emission from specific elements (e.g., Nickel, Iron, and of course Hydrogen) in the Sun's atmosphere.

If the little packet of stuff that was absorbing light is moving toward or away from you, the characteristic frequencies of all its spectral lines will be Doppler shifted. So, you can measure the velocity of that packet of stuff by seeing how much the line is shifted. Since you have a lot of photons, you can do this independently across the Sun's surface and get a spatially-resolved map of velocity ("Dopplergram", http://solar-center.stanford.edu/dopplergram.html).

If the little packet of stuff was in a magnetic field, its spectral lines will be split into sub-lines due to the Zeeman effect. So, you can also measure the spatially-resolved magnetic field of the Sun, and this is called a "magnetogram".

It is kind of surprising that this measurement can be made at all.

Doppler shift. One of the simplest and most deeply useful physics principles. Things you learned in high school that are actually useful way down the road. Basic trigonometry (Sohcahtoa) falls in the same category for me.

So true. I have been watching an excellent lecture series by Prof. Charles Bailyn (Yale U.) where he goes into some current work in astrophysics (2007) using calculus-free physics. (It's at http://oyc.yale.edu/astronomy/astr-160, and other places like iTunes U.)

It's amazing how deeply useful Doppler shift is; he returns to it thematically at least twice, talking about exoplanets as well as black holes. "We can't see them directly, but we can see them through the way they interact with other things."

Do I need to change any settings on my computer?

Take out the power socket and plug it back in upside down.

There are people who do this for others for a living.

That won't work in the UK. :-D

Sorry for you, you'll have to take out the whole socket and mount it again upside down.

At least you can mount the light bulb "the other way" with the bayonet mount while screw light bulbs are screwed

It does if you smash the earth pin enough times with a hammer first :)

Nope, because you won't get any current to live.

Our UK household plugs and sockets really are a fine piece of engineering.

as long as you don't step on one barefoot

Even worse than stepping on a LEGO brick.

Really? Happy to be only threatened by LEGO then. Postive side effect, I'm also driving on the right side of the road! ;-)

EDIT: this has to change now, too, right?

Come on, this is Hacker News - stepping on an upturned PCB in the dark has to be some sort of prerequisite of membership? ;)

You overestimate the quality of most of them.

A common trick to insert a EU-style plug into a UK-style socket is to temporarily insert something in the ground pin socket. An ordinary house key works well, and has the added bonus of shocking bystanders.

Granted, UK-style plugs really are excellent pieces of engineering, best appreciated when upturned and trod upon in the dark.

The earth pin is needed to open the covers of the other two holes.

That actually only happens on reasonable quality ones. Old and cheap shitty ones usually get stuck open or break off very rapidly. The BS spec is only good until 1 insertion after the point of sale.

Source: I was a part time sparky for a few years.

This statement "This change will have ripple effects throughout the solar system" will sound like an doomsday event to an average reader, in reality there nothing that would affect you.

At least they almost immediately mention that it is a common event.

Just to be safe I upgraded my tinfoil hat to Mylar.

No good. You need to line your walls with at least 2mm thick aluminum sheets with welded seams and 5cm overlap at the doors.

Edit: I guess it's true, HN is forever meant to be devoid of humor.

Personally I prefer a humorless HN. A culture of humur on the internet devolves fairly quickly into 4chan themed cat pictures and nothing but funny pics.

If you're still using magnetic platters, it would be a good idea to take them apart and flip the disks to reduce data corruption. There are also tools that will do this for you in software by flipping every bit on the disk and using 1 for 0 and vice versa. You can also do this with dd in Linux, just make sure you flip the binary description bit in the Disk Parameter Table.

That's pretty easy, imagine the fun the NMR/MRI people are about to have. Those suckers are heavy.

Also my wife is a member of the "interior decoration means covering your fridge with magnets" tribe, so now I have to flip all of them over. Someone, please create a startup for online classes for interior decorating.

Unfortunately it wont do any good because you can't buy taste

If you're using a tablet you should face away from the sun and turn the screen facing away from you. You can then use a mirror to see the screen.

    > Wow, our sun is BIG...

Even bigger. The solar system you linked to is not even near to having the correct proportions.

http://upload.wikimedia.org/wikipedia/commons/8/82/Solar-sys...

Although that would make for an interesting sunrise. "Here comes the su- POOF"

That one is not to scale, either. That one is: http://mishkahenner.com/filter/works/Astronomical

404

This is pretty misleading. The sun's diameter is much less than 1 AU.

Im pretty sure the sun is bigger than 1 Australia.

Sorry had to, for the confused: http://en.m.wikipedia.org/wiki/Astronomical_unit

Finally found a good version: http://www.scalesolarsystem.66ghz.com/

Yes, delete system32.

P.S. Just kidding, don't do it.

Isn't that just for cached files anyways? I don't see any documents in there that I actually use.

Our firm can ensure your computers are free of SMR-related effects for a modest fee. Please call 1-800-SUNWANTSTOKILLME

Will this undo the horrible decade we've had since 9/11 ?

probably.

last time it flipped was in 2001 [1].

[1] http://science1.nasa.gov/science-news/science-at-nasa/2001/a...

Actually, this looks more interesting than at first look. The previous flip was around '89, which saw the Eastern Europe wave of 'change'. Then 9/11. Now we have the 'Arab Spring'.

But, correlation is not causation so all remains just pure coincidences.

Not that I think that geopolitical happenstance is affected by solar magnetism, but I'm getting a bit fed up with the 'correlation is not causation' police.

No it's not, but nor is it a blanket reason not to investigate apparent parallels.

Just because the 'correlation = causation' is used to dis-infrom through findings that are bolstered by correlations, doesn't mean there's no reason to try and explore a reasonable case as to why the correlation reflects actual causation.

Correlation can infer causation in many instances.

But the GP's mention of the 'correlation is not causation' is completely warranted in this case. He doesn't think 'geopolitical happenstance is affected by solar magnetism' either. And that's exactly what is said. Though there seems to be a correlation, politics is not actually affected by the phenomenon.

> politics is not actually affected by the phenomenon.

What makes you think it does not?

It has been now shown that weather patterns in Europe during the middle ages are correlated with both warfare[1] and witch hunts [2]. Theories that explain these phenomena have been proposed.

The thing is, any astrologer during that period would get the correlation part right but the causal mechanism completely wrong. Move forward 500 years and believers in Scientism (not Science) will take the mistaken causal mechanism, confirm that it does not match with their a priori belief system, and wave off the real correlation as "fudge" or "coincidence".

Sometimes the lack of an explanation lies in the observer, for all/most of the obvious stuff has already been discovered. Lazy evaluation will take you a long way in terms of keeping an open mind.

[1] http://en.wikipedia.org/wiki/Little_Ice_Age

[2] http://home.uchicago.edu/eoster/witchec.pdf

Correlation is not causation.

> What makes you think it does not?

Its mostly my own ignorance I am admitting. :) I believe the true spirit of the 'Causation is not correlation' phrase is that if the mechanism isn't obvious, don't jump to the conclusion. As your link points out, correlation is a good reason to carry further investigation.

I thought it was just a warning, like we should remember to also make hypotheses about phenomenon X that causes both the Sun's magnetic field to flip and Arab Spring events.

"Causation creates correlation."

Anecdote is not correlation.

Also, it's worth noting that the US has a quasi-stable cycle of invading other countries for about a decade, then a roughly decade long policy of non-interventionism while they try to forget what a horrible quagmire they got themselves into the last decade.

Nice conspiracy theory!

Earlier one: 1979

USSR Invades Afghanistan, Margaret Thatcher elected as the Prime minister in UK, Ruhollah Khomeini returns to Tehran

Yes, it's well-documented that the polarity of the Sun's magnetic field is highly correlated with the prevalence of evil in the world.

If we stop doing evil, important solar processes will stop, leading to the collapse of the sun.

save it for the judge.

For ham radio HF propagation above 20 meters? Well, not really. Enjoy 10M while you can... I hope the next cycle in about a decade has better flux numbers. Es on 6M is fun, but I want some months long round-the-world F2 propagation modes.

(Seriously its interesting the article didn't mention how unusually weak the latest cycle has been. Usually the peak is much higher leading to happier ham radio operators. So the "news" or "journalism" is the unusual weakness of this cycle, but instead we get human interest story...)

Aside from the stereotypical "this individual cycle is weak" most recent solar coverage has contemplated Maunder Minimum effect and stuff like that. The wiki article is pretty good, summary is every time a cycle is wimpy everyone temporarily jumps on the bandwagon that its a semi-permanent long term decline etc etc.

http://en.wikipedia.org/wiki/Maunder_Minimum

In these ways, its a somewhat atypical solar news story. Which is cool.

What an awesome answer to my facetious question :-) I know nothing about ham radios or frequencies but it sounds interesting nonetheless.

Amateur radio can be rewarding. You can build radios/antennas, explore physics, yak with folks around the world without internet/telecom companies or do public service. Current nifty ham technology is SDR, (Software Defined Radio).

Just because you mentioned the internet and "everything must be connected with Snowden," I wonder if the NSA is tapping all short-wave comms? You'd think yes, because that is what spooks on all sides used for encoded messages. But then again, with the focus on internet, maybe the SW-recorder got neglected in a back-room (unlikely, probably just another pipe into that Utah data center).

It's easier than you think to "capture" selected chunks of the RF spectrum. DOD, etc, have had this capability for decades, civilians have had scanners and broadband radios for decades. Amateurs can record entire HF bands and decode multiple CW and other signals in real time with modern receivers and computing power.

Tapping a thing and understanding what you are listening to are two totally different things. Theoretically broadcasting an encrypted message in which third parties cannot possibly have access to the endpoints is still the safest way to handle sensitive data. This is part of the reason why 'Numbers Stations' are so popular with us geeks.

Most likey: https://en.wikipedia.org/wiki/Numbers_station

Mid way through the opening paragraph mentions several people charged with spying based on surveillance of short-wave number stations.

+1 for ham radio!

Here's a good page with total solar irradiance measurements. The peak has been quite low so far indeed. http://spot.colorado.edu/~koppg/TSI/

Let's hope it merely correlates with a nicer one. I liked the 90s a lot better than the last decade in many respects.

Is this due to our Sun's rotation or because it revolves around the center of the Galaxy?

It's caused by the sun's rotation, mostly. There are some complex magnetics that go on inside the sun, but the gist of it is that there is a differential in rotation rates between the poles and the equator of the sun. This causes field lines to be dragged along the equator, which then get knotted up and form coronal holes and other phenomena. Eventually, along an 11-year cycle, the field flips orientation.

Source: I work in a solar research lab at the University of New Hampshire

There's evidence it happens to the Earth too: http://en.wikipedia.org/wiki/Geomagnetic_reversal seems like it's probably a fairly common thing with any spinning core.

(╯°□°)╯︵ pʃǝıɟ ɔıʇǝuƃɐɯ

Some comments in this thread are completely surreal.

Just wait until it happens again here on Earth.

Birds and people who haven't adopted GPS will be screwed... http://en.wikipedia.org/wiki/File:NASA_54559main_comparison1...

This entire thread has turned into 2005 Slashdot.

Nothing to do with global warming people. That's still cow farts. Move along. Nothing to see here.

So the Myans were right all along!

Nope.

What about homoeopathy - will that still work?

Yes, but you'll have to shake it upside down

I know I'm stating the obvious though these comments are hilarious. Keep'em coming.

Reply on news.ycombinator.com