This is one big surprise. Moments of serendipity are some of the best quotes of science: “Hmmm, that’s odd”. As an amateur radio operator myself, I find this study fascinating. If you want to know more about VLF radio, see the NASA online VLF radio receiver link below.
Learn more (and listen to the signals) at NASA’s INSPIRE online VLF radio receiver. – Anthony
From Tel Aviv University: A Lightning Strike in Africa Helps Take the Pulse of the Sun
TAU discovers an accurate tool for tracking solar rotation
Sunspots, which rotate around the sun’s surface, tell us a great deal about our own planet. Scientists rely on them, for instance, to measure the sun’s rotation or to prepare long-range forecasts of the Earth’s health.
But there are some years, like this one, where it’s not possible to see sunspots clearly. When we’re at this “solar minimum,” very few, if any, sunspots are visible from Earth. That poses a problem for scientists in a new scientific field called “Space Weather,” which studies the interaction between the sun and the Earth’s environment.
Thanks to a serendipitous discovery by Tel Aviv University‘s Prof. Colin Price, head of TAU’s Department of Geophysics and Planetary Science, and his graduate student Yuval Reuveni, science now has a more definitive and reliable tool for measuring the sun’s rotation when sunspots aren’t visible — and even when they are. The research, published in the Journal of Geophysical Research – Space Physics, could have important implications for understanding the interactions between the sun and the Earth. Best of all, it’s based on observations of common, garden-variety lightning strikes here on Earth.
Waxing and waning, every 27 days
Using Very Low Frequency (VLF) wire antennas that resemble clotheslines, Prof. Price and his team monitored distant lightning strikes from a field station in Israel’s Negev Desert. Observing lightning signals from Africa, they noticed a strange phenomenon in the lightning strike data — a phenomenon that slowly appeared and disappeared every 27 days, the length of a single full rotation of the sun.
“Even though Africa is thousands of miles from Israel, lightning signals there bounce off the Earth’s ionosphere — the envelope surrounding the Earth — as they move from Africa to Israel,” Prof. Price explains. “We noticed that this bouncing was modulated by the sun, changing throughout its 27-day cycle. The variability of the lightning activity occurring in sync with the sun’s rotation suggested that the sun somehow regulates the lightning pattern.”
He describes it as akin to hearing music or voices from across a lake: depending on the humidity, temperature and wind, sometimes they’re crystal clear and sometimes they’re inaudible. He discovered a similar anomaly in the lightning data due to the changes in the Earth’s ionosphere — signals waxed and waned on a 27-day cycle. Prof. Price was able to show that this variability in the data was not due to changes in the lightning activity itself, but to changes in the Earth’s ionosphere, suspiciously in tandem with the sun’s rotation.
Taking the pulse of the sun
The discovery describes a phenomenon not clearly understood by scientists. Prof. Price, an acclaimed climate change scientist, believes it may help scientists formulate new questions about the sun’s effect on our climate. “This is such a basic parameter and not much is known about it,” says Prof. Price. “We know that Earth rotates once every 24 hours, and the moon once every 27.3 days. But we haven’t been able to precisely measure the rotation rate of the sun, which is a ball of gas rather than a solid object; 27 days is only an approximation. Our findings provide a more accurate way of knowing the real rotation rate, and how it changes over time,” he says.
Prof. Price cannot yet say how this finding will impact life on Earth. “It’s an interesting field to explore,” he says, “because nothing has been done to investigate the links between changing weather patterns and the rotation of the sun.
“Short-term changes in solar activity can also impact satellite performance, navigational accuracy, the health of astronauts, and even electrical power grid failures here on Earth. Many scientists claim that the sun’s variability is linked to changes in climate and weather patterns, so the small changes we observed every 27 days could also be related to small variations in weather patterns.
“Our data may help researchers examine short-term connections between weather, climate, and sun cycles. With this tool, we now have a good system for measuring the pulse of the sun.”
In Greece there is a popular/folk view that the weather changes with the quarter of the moon. Used in the following way:
If the weather changes, one looks at the moon and says: of course, the quarter is changing.
If the weather is not changing, particularly a week of rain/wind, one looks at the moon and says ” oh dear, another week of rain/wind”.
I do not know if this folk correlation is specific to our area and connected with the seas, because we are a sea going race ( rather were).
Now since both the moon and the sun are about 28 days, maybe folks timed the sun change to the moon quarters?
Anyway, that we have a week of 7 days is surely connected to the moon cycle and need to watch the weather of agriculture and fishing .
Yeah, saw that the other day.
http://www.jpost.com/servlet/Satellite?cid=1257455212868&pagename=JPost/JPArticle/ShowFull
I thought I posted it on another thread, too, but I can’t find it.
In any case, thanks for the additional info.
Conservation of angular momentum anyone? Or is that just too old-fashioned for the modern world? Of course, that is for solid objects. I do wonder what exactly is being measured. The actual rotation of the sun, or simply the movement of magnetic fields. Or something else entirely.
I believe this is also related.
http://www.jpost.com/servlet/Satellite?cid=1257455212868&pagename=JPost/JPArticle/ShowFull
I should have a listen to VLF and see what I can hear. I’m good down to 500Hz on my SDR, though my 40ft antenna is a bit on the short side.
@crosspatch (21:29:39)
Hey!
Lay off my cats’ balls.
Strunk and White says Jones’, As in Davy Jones’ locker, I guess. I am not sure it works for Americans though. I have a friend James, and I don’t know anyone who says anything but “James’s this” or “James’s that”
Reply: It is Charles’s burden to have to wade through conversations like this. ~ charles the singular possessive ending in s moderator.
LarryOldtimer (22:58:23) :
Conservation of angular momentum anyone? Or is that just too old-fashioned for the modern world? Of course, that is for solid objects. I do wonder what exactly is being measured. The actual rotation of the sun, or simply the movement of magnetic fields. Or something else entirely.
I am with you oldtimer, what exactly are they measuring. This story was mentioned here the other day in another thread where I posted a link to the paper involved. Reading through the paper it is suggesting that there must be some fixed point perhaps internal that is not subject to the differential rotation. If more research suggests this is so I would like to see a graph, as it would be a first.
At the risk of sounding like a lunatic, Ken Ring of predictweather.com has a free pdf book on his site about the moon and it’s effect on the Earth. Fascinating stuff.
For instance, the Earth doesn’t rotate on a central axis, but rather on an axis shifted about 2900 miles off the central axis because of the gravitational effects of the moon. Interestingly too, although we have two sea tides per day, we have an equivalent atmospheric tide once per day. Apparently, it is stretched on the moon-side by a factor of two. So I wonder if that also applies to the ionosphere and it is that that is causing the 27 day signature on the lightning strikes.
any news on the best science blog ie stats?
anna v (22:33:17) :
What you describe is known to weather predictors as ‘lookback periods’. Weather is fundamentally cyclical. Lives and livelihoods have hinged around interpreting those cycles correctly.
The @27 day period is quite important, along with 14 and 7 day ones. There are a few important decadal and even century long lookbacks.
“It is worthy of note that in 1948, when Jupiter and Saturn were spaced by 120º, and solar activity was at a maximum, radio signals averaged of far higher quality for the year than in 1951 with Jupiter and Saturn at 180º and a considerable decline in solar activity. In other words, the average quality curve of radio signals followed the cycle curve between Jupiter and Saturn rather than the sunspot curve…”
From Planetary Position Effect on Short-Wave Signal Quality by John H. Nelson
Susan Manuel writes in HelioGram, the newsletter of the NCGR Helio SIG in May, 1992, p.5:
“While working for RCA Communications, John Henry Nelson became a heliocentric pioneer. Nelson discovered the correspondence between certain heliocentric aspects and the quality of shortwave radio communications. Mr. Nelson’s methods, the specific aspects he used in his forecasts as well as the system he developed to evaluate the effect of various aspects on radio propagation quality (ak.a. radio weather) can guide today’s heliocentric astrologers toward developing more precise methods of studying heliocentric aspects and determining their association with things other than radio weather.
“Nelson had to make four forecasts every day–120 a month–for RCA. Once he discovered the importance of heliocentric aspects, his rate of accuracy for a given month often reached 90 percent or better. Although he found some correlation between geocentric planetary aspects and radio weather, it was the heliocentric aspects that allowed him to make such consistently accurate predictions of radio weather.”
90% accuracy beats 90% confidence every time.
DaveE (21:57:59) :
I earlier posted the location of the Rugby UK VLF communications aerial. As far as I know this is now rarely used but the whole point of VLF was that you could transmit signals around the world without the need for repeaters. Rugby was about 15kHz.
I may have been misinformed but I was given the impression that there were even lower frequency transmitters on the military network, (telephone frequency 3kHz & lower).
DaveE.
________________________________________________
VLF operates for communication with submarines. The Very Low Frequency enabled a little penetration into the ocean, so floating a long-wire antenna (or “noodle”) even in choppy seas was effective. There was some experimentation with ELF (Extra Low Frequency) communication, but I gather transmitter size/power requirements, diffusion of signal and minimal bandwidth killed it. Also, I have heard that VLF continues in the satellite era only as a redundant system.
Speaking of diffusion, in my casual review of global energy balance I haven’t seen anything that shows that the radiation reflected by greenhouse gasses won’t just leak out of the ionosphere after it gets bounced down to lower frequencies.
Yaakaba, the real problem with the ocean is that there aren’t enough sponges. If we were to work to increase the growth of more sponges, then they would soak up the extra water and it wouldn’t be so deep. Right?
and the Joneses got a jones for Mr. Jones’ junk.
(runs away, ducking)
Paul Hanlon (05:07:47) :
There is a 50 000 km difference between the moon’s perigee and apogee (more than 10%) so there is definitely a 27 days gravitational signal.
http://www.fourmilab.ch/earthview/pacalc.html
Strange, I had always thought that the plural of of Jones, was Jones’, but that the ” ‘ ” was to show that there was an “s” missing, rather than denoting the possessive. Perhaps Joneses is indicating that you are trying to keep up with more than one Jones family (Plural X 2) in which case it should be Jones’es.
Now lets see, I have two cars and they both have radios, Dave, would that be “Mark Webbers’ cars aerials” and Evan “Mark Webbers’s car’s antennaes” ?
null OT [on topic :)] – What about about “Ionospheric tides”? Does the moon causes tides in the atmosphere as it does in the oceans? In low latitudes, thunderstorms are most likely to occur in the late afternoon. Since the lightening from these storms tends to happen at a fairly consistent time of day, perhaps the RF noise is best reflected at times of high (or low) local ionospheric tide. If such a thing does happen, not only would the reflective layers be pulled higher or lower, they would be more or less dense since the atmoshere is gaseous and can change density, unlike the water in the oceans.
If this were the case, then the periodicity of the phenomenon would be lunar, rather than solar. I can’t help but feel that this guy needs our help, he’s a climate scientist for pete’s sake.
And Yaakoba, no, this would not change the Earth’s rotational speed.
Dave and Evan,
No you’re both wrong – remember, I have two cars.
(runs away, ducking)
Geoff Sharp (02:06:47) :
“Reading through the paper it is suggesting that there must be some fixed point perhaps internal that is not subject to the differential rotation. If more research suggests this is so I would like to see a graph, as it would be a first.”
Hi Geoff
This should not be a great surprise. There is certain axial asymmetry to solar magnetic events. It is an anomaly noticed many years ago, subsequently researched by number of solar scientists.
It generally goes under a name ‘Preferred Longitude’, it suggests that the sources of solar magnetic events including solar wind streams, are usually concentrated at ‘preferred longitude zones’ on the sun, these are rigidly locked with the rotation period of the Sun.
http://helene.ethz.ch/papers/berdyugina/alon_bonn.pdf
http://www.iop.org/EJ/article/0004-637X/604/2/944/58759.text.html
Google will point you to more papers.
“”” Yaakoba (20:48:26) :
Gravity is kinetic energy. With the earth’s population of people, animals, and modern building, there will be more gravity energy created, increasing thermal heat. As ice melts and becomes liquid, this also increases gravity pull, which creates more energy created by kinetic heat. As the gravity of the earth increases with population this will increase the earths rotation, creating more kinetic heat. Speeding up time. “””
Well that is a revelation. I always thought that gravity was one of the four forces of nature (that we know about); and since it is just a force, then it certainly isn’t any kind of energy; doesn’t even have the same dimesnions as energy.
This IS a science blog, so we should be careful about seriously misusing real scientific terms, as that can lead to confusion; specially for the many readers here who don’t have strict science backgrounds.
ctm (or should I say ctspeism) wrote:
Chucks
“”” DaveE (19:58:24) :
Yaakoba (19:37:52) :
Yes, but don’t you think that if the sea levels are rising, wouldn’t this increase the speed of the earths rotation, which of course the moon would have to also increase it’s rotating speed? Causing heat and shorter days.
Think of an ice skater in a spin, as the arms are extended, the rotational speed decreases, the Earth equivalent would be an increase in LOD.
DaveE. “””
If sea levels are rising (argumentative); then that would imply that it is the result of water that was stored ABOVE sea level; perhaps as ice or snow, (or in the atmosphere) getting deposited in the existing oceans; i.e. closer to the center of the earth.
As a result, of mass moving closer to the center of the earth, the moment of inertia of the earth would decrease with sea level rise; and conservation of angular momentum, would require the earth rotation speed to increase.
Then of course you might have to consider some land bounce due to removing all that water from the high lands; and that would have the effect of raising the moment of inertia; so slowing the rotation.
Also increase in ocean temperatures; which would cause sea level rise without increase in sea mass, also results in increasing the moment of inertia.
So without allowing for all of those things, calculating the effect of sea level rise on the day length would be a problem.
In case I was not clear in my previous comment – the solution to Charles’ burden is to use Chuck.
ChuckS
Reply: Chuck gets used plenty by pretty girls. ~ chuck the horribly abused moderator
“”” evanmjones (19:52:36) :
Yes, but don’t you think that if the sea levels are rising, wouldn’t this increase the speed of the earths rotation, which of course the moon would have to also increase it’s rotating speed? Causing heat and shorter days.
No, it would decrease. The extra water humps up ever so slightly in a band around the equator. Earth spins slower for the same reason a twirling figure skater extending her arms spins slower. (The differences, however, are almost immeasurably small.)
I don’t see why moon’s orbit would measurably increase. It’s just falling around the centered mass of earth. Regardless of whether that mass is rotating, it’s still the same amount of mass. “””
See the above Evan; if sea levels rise due to thermal expansion, then it would slow the earth; but if the rise is due to melting; which deposits higher altitude water at lower altitudes, then it would speed up.
The moon’s orbit is slowly increasing in radius due to the tidal forces slowing the earth’s rotation, which lowers it’s angular momentum; so the moon’s angular momentum about the earth has to increase to keep the sum constant; well cosntant other than for solar effects, and the continuous influx of materials from outer space, in comets, and meteorites; but who knows what that does, since there is a mass increase due to the material landing on earth; but also there is an angular momentum imparted to the earth in completley random directions depending on the trajectory of the incoming.
********************
R Taylor (07:01:07) :
There was some experimentation with ELF (Extra Low Frequency) communication, but I gather transmitter size/power requirements, diffusion of signal and minimal bandwidth killed it. Also, I have heard that VLF continues in the satellite era only as a redundant system.
*********************
see http://hypertextbook.com/facts/2001/LisaWu.shtml
“”” _Jim (19:38:37) :
George E. Smith (17:28:57) :
…
These very low audio frequency radio waves actually propagate across the earth along paths that are guided by the earth’s magnetic fields.
‘fraid not … (now, how those magnetic fields may affect the ionophere which affect radio waves is another issue) “””
Well I guess we must have been listening to alien transmissions then. Last time I checked, the ionosphere that affects electromagnetic wave propagation; was so-called because it has a lot of ions floating around up there, which includes free electrons, as well as other charged particles.
And somewhere I learned that these charged particles can and do spiral around the earth’s magnetic field lines; along with charged solar particles and cosmic rays, so that those directed ion streams end up creating auroral displays near the magnetic polar regions, so the earth’s field gives all the signs of creating ion pathways, that simply would not be there in the absence of a magnetic field on earth.
The radio signals that we were studying chirped from subaudible (few Hertz) to a few khz at most. I could easily hear to 20KHz in those days, and I never heard anything that high; maybe 3 kHz at best.
At those frequencies it would be pretty much ground wave anyway.
But obviously we were being fooled by Hams or aliens spinning the knob on an audio oscillator, just to keep us busy.
Or maybe I just imagined the whole experience.
tallbloke (16:11:07) :
Interesting. I wonder if there’s a second order modulation at around 13 months (396 days) frequency.
Here is a link to the original pdf:-
A new approach for monitoring the 27-day solar rotation using VLF radio signals on the Earth’s surface
(Don’t think this has been posted here yet).
In Figure 3, the data computation length of this power spectrum is 220 days (7 months), so more data is clearly needed to address your point.