APOD: Spicules: Jets on the Sun (2010 Nov 02)

[APOD Robot]

Spicules: Jets on the Sun

Explanation: Imagine a pipe as wide as a state and as long as the Earth. Now imagine that this pipe is filled with hot gas moving 50,000 kilometers per hour. Further imagine that this pipe is not made of metal but a transparent magnetic field. You are envisioning just one of thousands of young spicules on the active Sun. Pictured above is one of the highest resolution image yet of these enigmatic solar flux tubes. Spicules line the above frame of solar active region 11092 that crossed the Sun last month, but are particularly evident converging on the sunspot on the lower left. Time-sequenced images have recently shown that spicules last about five minutes, starting out as tall tubes of rapidly rising gas but eventually fading as the gas peaks and falls back down to the Sun. What determines the creation and dynamics of spicules remains a topic of active research.

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[geckzilla]

New favorite APOD for me.

[Jaime]

Impressive image of the chromosphere!
But I think they meant fibrils instead of spicules.

[gmPhil]

This is great picture, but... really APOD I expect better of you than a statement such as "Imagine a pipe as wide as a state and as long as the Earth"
Which state would that be - Texas or Vermont?
And as for "as long as the Earth"... makes my head spin!

But keep up the good work - I love this site, and visit every day.

[Joe]

"the size of a State and as long as the Earth"
Well, I get the gist of what you mean, and I understand that you're also writing for young people as well as the lay person, but I would appreciate it if you call things what they really are, "hot gas" is actually plasma at these temperatures, and can only be plasma. To call it 'hot gas' is doing your readers a disservice, it makes them think it's like here on Earth only hotter, it isn't, it's fundamentally different.

Just as solids, liquids, and gasses, are different 'states' of matter, so is plasma.
And all elements when in a plasma state have an electrical conductance capacity that far exceeds their solid, liquid or gasseous state.

These 'spicules' are actually an 'anode tufting' phenomena, which is why they only last for 5 minutes or so, because that's how long it takes for 'charge equilization' to be accomplished, and they 'fade away' after that, and are replaced by a new anode tufting 'cell' after their fade-away when the charge separation potential rebuilds.

[orin stepanek]

Click to view full size image

Awesome pictures in today's APOD! Above is a favorite from today's links. It actually looks like a hole on the surface of the sun. Amazing what photography can do to the perception of what is real. The Spicules are awesome for how fast they move across the surface of the sun. Great APOD!!

[Pit]

Hihi, really fun. Anyone read the linked older APOD spicules article from 2008? At least it looks as if since then spicules doubled their length....

[León]

More than 100,000 spicules tickle the solar atmosphere, called the corona, at any time.

[ChuckN]

Hmm. Appears that today's APOD and the high resolution image you get when you click it are left-right mirror images of each other.
For a long time my computer monitor background photo has been a retrograde motion one from APOD; I'm tempted to replace it with this one.

[BMAONE23]

Hmm. Appears that today's APOD and the high resolution image you get when you click it are left-right mirror images of each other.
For a long time my computer monitor background photo has been a retrograde motion one from APOD; I'm tempted to replace it with this one.

Nice observation. It isn't a Mirror though, it appears to be a 90deg CCW rotation. APOD images are often rotated between the front image and the linked larger image though I can't say why.

[biddie67]

Awesome photo of the Sun - it almost looks like "fur"!!

[neufer]

Impressive image of the chromosphere!
But I think they meant fibrils instead of spicules.

• That's despicuble

Click to play embedded YouTube video.

Father Angelo Secchi

<<In solar physics, a spicule is a dynamic jet of about 500 km diameter in the chromosphere of the Sun. It moves upwards at about 20 km/s from the photosphere. They were discovered in 1877 by Father Angelo Secchi of the Vatican Observatory in Rome.

Spicules live for about 5–10 minutes; at the solar limb they appear elongated (if seen on the disk, they are known as "mottles" or "fibrils"). They are usually associated with regions of high magnetic flux; their mass flux is about 100 times that of the solar wind.

At any one time there are around 60,000 to 70,000 active spicules on the Sun; an individual spicule typically reaches 3,000-10,000 km altitude above the photosphere.

Bart De Pontieu (Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, California ), Robert Erdélyi and Stewart James (both from the University of Sheffield, Sheffield, UK) hypothesised in 2004 that spicules formed as a result of p-mode oscillations in the Sun's surface, sound waves with a period of about five minutes that causes the Sun's surface to rise and fall at several hundred meters per second. Magnetic flux tubes that tilted away from the vertical can focus and guide the rising material up into the solar atmosphere to form a spicule. There is still however some controversy about the issue in the solar physics community.>>

[Chris Peterson]

Well, I get the gist of what you mean, and I understand that you're also writing for young people as well as the lay person, but I would appreciate it if you call things what they really are, "hot gas" is actually plasma at these temperatures, and can only be plasma. To call it 'hot gas' is doing your readers a disservice, it makes them think it's like here on Earth only hotter, it isn't, it's fundamentally different.

Most physicists are comfortable considering a plasma to be a gas (but not the other way, of course). A plasma state is a gas state where a certain percentage of the atoms are ionized. So saying we are seeing a hot gas isn't wrong. Best would be to say plasma, and then define that as a hot, ionized gas, but there isn't always room in the captions. At the level the text is intended, "hot gas" by itself is arguably better than "plasma" by itself.

[bystander]

• That's despicable

Click to play embedded YouTube video.

[pnelson]

Science (by way of nature) imitating art? Looks like a van Gogh to me!

[judy]

thank you. the close-up of the sun's surface is beautiful and exciting. my idea of a great apod.

[neufer]

<<The hairy ball theorem of algebraic topology states that there is no nonvanishing continuous tangent vector field on an even-dimensional n-sphere.

This is famously stated as "you can't comb a hairy ball flat without creating a cowlick",
or sometimes, "you can't comb the hair on a coconut". It was first proved in 1912 by Brouwer.

A failed attempt to comb a hairy 3-ball (2-sphere),
leaving an uncomfortable tuft at each pole........ A hairy doughnut (2-torus) OTOH is quite easily combable.

A curious meteorological application of this theorem involves considering the wind as a vector defined at every point continuously over the surface of a planet with an atmosphere. In the case where there is at least some wind, the Hairy Ball Theorem dictates that at all times there must be at least one point on a planet with no wind at all and therefore a tuft. In a physical sense, this zero-wind point will be the eye of a cyclone or anticyclone. (Like the swirled hairs on the tennis ball, the wind will spiral around this zero-wind point - under our assumptions it cannot flow into or out of the point.) In brief, then, the Hairy Ball Theorem dictates that, given at least some wind on Earth, there must at all times be a cyclone somewhere.>>

<<Luitzen Egbertus Jan Brouwer (February 27, 1881 – December 2, 1966), usually cited as L. E. J. Brouwer but known to his friends as Bertus, was a Dutch mathematician and philosopher. In 1905, at the age of 24, Brouwer expressed his philosophy of life in a short tract Life, Art and Mysticism described by Davis as "drenched in romantic pessimism." Brouwer's thesis advisor refused to accept his Chapter II " 'as it stands, ... all interwoven with some kind of pessimism and mystical attitude to life which is not mathematics, nor has anything to do with the foundations of mathematics' "

About his last years, Davis (2002) remarks:

• "...he felt more and more isolated, and spent his last years under the spell of 'totally unfounded financial worries and a paranoid fear of bankruptcy, persecution and illness.' He was killed in 1966 at the age of 85, struck by a vehicle while crossing the street in front of his house.">>

[Kevin Reardon]

Yes, I've been excusing myself to colleagues all day about the caption. You would be hard pressed to find a clear spicule in the image. This is in large part because the image was taken in Ca II 8542, not H-alpha, and the response of the lines is quite different. This is the corresponding H-alpha image (rotated with respect to the orientation of the APOD image):

Click to view full size image

You can see the this as well as corresponding photospheric and coronal images (the latter from SDO/AIA) here:
http://www.arcetri.astro.it/science/sol ... S/gallery/

Anyway, the following is the caption we suggested, which waxes poetic as well but contains a bit more useful information:

--------------------
Gateway to the Corona

Explanation: What lies between the solar photosphere, where sunspots can be seen, and the corona, with its magnetic arches stretching outward?
It's the enigmatic solar chromosphere, the region of the solar atmosphere where the magnetic field starts to dominate, forming long, thin, dense structures. The above image shows a large area of the solar chromosphere around active region NOAA 11092 near the center of the Sun on August 3, 2010. This image, taken not in the well-known Hydrogen alpha spectral line, but in a line produced by ionized Calcium in the near infrared, covers a relatively extended area of the solar surface (170,000 km on a side), with a very high spatial resolution (160 km), allowing it show the details of the great diversity of chromospheric structures, including a myriad of fibrils, the sunspot and the small bright flare in the lower left and a filament in the upper right. Away from these fibrils, the small, round brightenings are the signature of sound waves buffeting the chromosphere from below. Complex and dynamic, the chromosphere is the gateway to the corona.
--------------------

kevin reardon

[Joe]

Thank You very much Kevin !!!

I appreciate the added info !
Fantasticly beautiful photos, both !!!!

Reminds me of sea anemonae.

Is it correct to identify the dark central areas of sunspots as in the 'silicone layer' of the Sun, and where the fibrils and spicules are as in the 'neon layer' ?

[harry]

G'day

You may find this paper interesting in light of the above discussion

http://arxiv.org/abs/1004.1692
A Statistical Analysis of the SOT-Hinode Observations of Solar Spicules and their Wave-like Behavior
Authors: E. Tavabi, S. Koutchmy, A. Ajabshirizadeh
(Submitted on 10 Apr 2010)
Abstract: We consider a first important parameter of spicules as observed above the solar visible limb: their apparent diameter as a function of the height above the limb which determines their aspect ratio and leads to the discussion of their magnetic origin using the flux tube approximation. We found that indeed spicules show a whole range of diameters, including unresolved "interacting spicules" (I-S), depending of the definition chosen to characterize this ubiquitous dynamical phenomenon occurring into a low coronal surrounding. 1-D Fourier amplitude spectra (AS) made at different heights above the limb are shown for the first time. A definite signature in the 0.18 to 0.25 Mm range exists, corresponding to the occurrence of the newly discovered type II spicules and, even more impressively, large Fourier amplitudes are observed in the 0.3 to the 1.2 Mm range of diameters and spacing, in rough agreement with what historical works were reporting. Additionally, some statistically significant behavior, based on AS computed for different heights above the limb, is discussed. "Time slice or x-t diagrams" revealing the dynamical behavior of spicules are also analyzed. They show that most of spicules have multiple structures (similarly to the doublet spicules) and they show impressive transverse periodic fluctuations which were interpreted as upward kink or Alfven waves. Evidence of the helical motion in spicules is now well evidenced, the typical periods of the apparent oscillation being around 120 sec. A fine analysis of the time-slice diagram as a function of the effective heights shows an interesting new feature near the 2 Mm height. We speculate on the interpretation of this feature as being a result of the dynamical specificities of the spicule helical motion as seen in these unprecedented high resolution HCaII line emission time series.

[DavidLeodis]

It's a great image but it would seem that there is an error in its explanation. In that it states "Spicules line the above frame of solar active region 11092 that crossed the Sun last month" (thus October) but in the information brought up through the "Pictured above" link it states the image was acquired on August 3 2010.

I also have a query about IBIS. The information brought up through the link in the credit was the same as that brought up through the "Pictured above" link which did not state what IBIS is and seems to have no link to an IBIS website. From a search I found there is an IBIS which is the "INTEGRAL imager, IBIS (Imager on-Board the INTEGRAL Satellite)" which is surveying the X-ray and gamma ray sky, so I wonder if that actually is the IBIS in the APOD? I would be grateful if someone could please let me know what IBIS in the APOD definitely is. Thanks.

[Kevin Reardon]

It's a great image but it would seem that there is an error in its explanation. In that it states "Spicules line the above frame of solar active region 11092 that crossed the Sun last month" (thus October) but in the information brought up through the "Pictured above" link it states the image was acquired on August 3 2010.

The image was indeed taken on August 3, 2010. The "last month" is there because this caption was recycled from a previous APOD, but it isn't correct in this case.

I also have a query about IBIS. The information brought up through the link in the credit was the same as that brought up through the "Pictured above" link which did not state what IBIS is and seems to have no link to an IBIS website. From a search I found there is an IBIS which is the "INTEGRAL imager, IBIS (Imager on-Board the INTEGRAL Satellite)" which is surveying the X-ray and gamma ray sky, so I wonder if that actually is the IBIS in the APOD? I would be grateful if someone could please let me know what IBIS in the APOD definitely is. Thanks.

This is not INTEGRAL/IBIS, but rather the Interferometric BIdimensional Spectrometer, a ground-based imaging spectrometer based on dual Fabry-Perot interferometers in series which allows us to take very narrowband images sequentially through a variety of spectral lines (like H-alpha 6563 or Ca II 8542) in the visible and near-infrared. At the wavelength of the Calcium line in the APOD image, the passband is 0.045 Angstrom (and 0.025 Å at H-alpha). This very narrow passband is one reason the structures are so well resolved. Some dated web pages about the instrument are available here:

http://www.arcetri.astro.it/science/sol ... /ibis.html

kevin

[DavidLeodis]

Thanks Kevin. Your help is greatly appreciated.

[neufer]

Reminds me of sea anemonae.

Eelgrass bed beneath the waters of New Hampshire's Great Bay

---

<<Eelgrass beds are a type of subtidal natural community that occur exclusively below mean low tide, although upper reaches may be briefly exposed during the lowest spring tides. Common eel-grass (Zostera marina) is the dominant rooted vegetation. This continually submerged aquatic community performs important ecological functions including supporting eelgrass and fish populations, providing refuge for fish and invertebrates that retreat from exposed intertidal flats and estuarine marshes at low tide, and serving as a spawning and nursery area for numerous species of aquatic animals.>>

What Does Calcium Have To do With The Sun? by Erleen Tilton

<<Calcium is the most abundant mineral in the body with more than 99% present in the bones and teeth. Calcium is also important in the activity of many enzymes, contraction of muscles, release of neurotransmitters, regulation of heartbeat, and clotting of the blood. Calcium deficiencies can results in bone deformities, growth retardations in children, osteomalacia (softening of the bones), and osteoporosis in adults.

Most of us have been brainwashed through textbooks and advertisements to believe that our best and highest sources of calcium are from milk products. However, most have not learned that there are many great sources of calcium from SEAWEEDS, leafy greens, legumes, fruits, vegetables, and more. Most people probably eat enough foods that provide ample sources of calcium, yet most people are very deficient in calcium. Why? Because it’s not just getting the calcium that is important, it’s absorbing the calcium that is key! Absorbing calcium depends on a very important vitamin – Vitamin D.

Our best source of natural Vitamin D actually comes from the Sun. And since many of us have been roped into the myth that the sun is our enemy and we need to avoid the sunshine unless we are slathered with sunscreen, we block the possibility of getting our most important source of Vitamin D which leaves us deficient in calcium.

The sun is really our friend, and we need to get at least 20-30 minutes of sunshine daily between the hours of 10:00 am and 4:00 pm – without sunscreen! Before or after those times, we don’t get enough Vitamin D absorption.>>

[neufer]

This is not INTEGRAL/IBIS, but rather the Interferometric BIdimensional Spectrometer, a ground-based imaging spectrometer based on dual Fabry-Perot interferometers in series which allows us to take very narrowband images sequentially through a variety of spectral lines (like H-alpha 6563 or Ca II 8542) in the visible and near-infrared. At the wavelength of the Calcium line in the APOD image, the passband is 0.045 Angstrom (and 0.025 Å at H-alpha). This very narrow passband is one reason the structures are so well resolved. Some dated web pages about the instrument are available here: http://www.arcetri.astro.it/science/sol ... /ibis.html

[url=http://www.astrosurf.com/~buil/lhires_ir/obs_us.htm]H and K lines of ionized Calcium[/url]

---

<<Visible spectra of many stars, including the Sun, exhibit strong absorption lines of singly ionized calcium. Prominent among these are the H-line at 3968.5 Å and the K line at 3933.7 Å of singly ionized calcium, or Ca II. For the Sun and stars with low temperatures, the prominence of the H and K lines can be an indication of strong magnetic activity in the chromosphere. Measurement of periodic variations of these active regions can also be used to deduce the rotation periods of these stars.>>

Ca II 8542

---

Temperature of the objects drops while going from the top down

---

INFRARED OBSERVATIONS WITH LHIRES III

<<We presents some images of 2D spectra of the sun light
(daylight in cloudy weather) in the infrared domain.
Spectrograph LHIRES III is simply held with the hand.
The grating used is the 1200 lines/mm.

The selected area of the spectrum contain the infrared triplet of ionized calcium.
The interest of the choice:

• - the presence of the calcium lines, but also the beginning of the Pashen sequence of hydrogen (the infrared equivalent of the Balmer series of in the visible spectrum, which ends with the famous Ha line),
  
  - an atmospheric window, quasi free from telluric water vapor lines,
  
  - the presence of many emission lines produced by the internal lamp of LHIRES III for a simple and precise spectral calibration,
  
  - one seen it, the CMOS of the Canon detector become a black and white sensor in this part of the spectrum.