Amateur telescope photographer Thierry Legault has gained renown in recent years taking photographs of spacecraft in orbit… from the ground, with them either reflecting sunlight as they cross the terminator, or silhouetted by the moon, or in recent days, silhouetted by a near spotless sun.
His most recent accomplishment is this solar silhouette of the International Space Station docked with Space Shuttle Atlantis on its STS-132 mission. While many have marvelled at his accomplishment, we’ve heard less about the continuing near-spotless state of the sun in his photograph. This one sunspot region counted enough on May 22nd to make the daily sunspot count be 15!
It appears that the sunspot and 10.7 progression for Solar Cycle 24 have hit a bit of a roadblock in recent months, according to NOAA’s Solar Cycle Progression and Prediction Center.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
oneuniverse says:
July 7, 2010 at 11:46 am
The diffusion process will lead to isotropy for all but the high energy particles, true, but the GCR flux density experienced by our solar system will change in the presence of proximate GCR sources such as SNR.
Just repeating this will not make it true, and it isn’t.
As an analogy, to show that isotropy doesn’t imply a homogenous density […]
Why is this so hard? Your analogy is false and muddled. Isotropy means that the flux is the same from any direction. And that is the issue. Because the speed is constant, density is proportional to density, but let us stick with the issue: flux.
Why not address the discrepancy between the mainstream view, which I quoted at 10:03 am just above, and your description
Why should I do that as there is no discrepancy, just a difference of emphasis? I concentrated on what happens after the particles have been accelerated enough that they can leave the SNR. This is the important point that determine their flux at Earth. I see no reason to dilute the discussion with irrelevant detail, as I strive to concentrate on the essential points to get the message across.
My view and that of Webber et al is the mainstream view.
Why should I do that as there is no discrepancy, just a difference of emphasis?
There’s more than just a difference of emphasis :
The NASA article says that particles leave the SNR possessing GCR level energies (but not ultra-high energies). You, however, say that after leaving the SNR, particles need to continue to travel for millions of years around the galaxy until they possess GCR level energies.
Just repeating this will not make it true, and it isn’t.
If particles leave the SNR as GCRs, then clearly having a proximate active CR source such as an SNR will increase the GCR flux.
I’m still waiting for an answer as to why you said that a “nearby supernova” “probably” caused the 1490 spike, if, as you also said, “proximate supernovae does not add to the GCR flux that we can observe” ? Care to explain that discrepancy instead? Just an absent-minded mistake, perhaps, but please do clarify.
Self: The diffusion process will lead to isotropy for all but the high energy particles, true, but the GCR flux density experienced by our solar system will change in the presence of proximate GCR sources such as SNR.
Leif: Just repeating this will not make it true, and it isn’t.
Perhaps we should just leave it at that.
oneuniverse says:
July 7, 2010 at 1:54 pm
The NASA article says that particles leave the SNR possessing GCR level energies (but not ultra-high energies). You, however, say that after leaving the SNR, particles need to continue to travel for millions of years around the galaxy until they possess GCR level energies.
The NASA article actually says:
“Bouncing back and forth in the magnetic field of the remnant randomly lets some of the particles gain energy, and become cosmic rays. Eventually they build up enough speed that the remnant can no longer contain them, and they escape into the Galaxy.
Because the cosmic rays eventually escape the supernova remnant, they can only be accelerated up to a certain maximum energy, which depends upon the size of the acceleration region and the magnetic field strength.”
They become low-energy cosmic rays and still need further acceleration to become ‘normal’ GCRs.
The NASA article also says [and that is the important part – one wonders why you didn’t quote that…]:
“The magnetic fields of the Galaxy, the solar system, and the Earth have scrambled the flight paths of these particles so much that we can no longer point back to their sources in the Galaxy. If you made a map of the sky with cosmic ray intensities, it would be completely uniform.”
If particles leave the SNR as GCRs, then clearly having a proximate active CR source such as an SNR will increase the GCR flux.
But then the GCR flux from the direction of the source would be higher and we would not have isotropy.
oneuniverse says:
July 7, 2010 at 2:29 pm
I’m still waiting for an answer as to why you said that a “nearby supernova” “probably” caused the 1490 spike,
This is speculation by some people [not generally shared]. One way out for these people might be that it was a pulse [very sharp and short-lived] of ultrahigh energy CRs passing through the solar system. Such rare short pulses do not raise the general isotopic background. Bottom line: we don’t know what caused the spike, could even be some local phenomenon on the Sun, or new physics, or something other exotic.
Perhaps we should just leave it at that.
If you wish, but I deplore a missed opportunity to set a student right. I feel like teaching Evolution to a Creationist or a Young Earther. Same kind of hopeless effort.
Leif: They [Cosmic rays escaping the supernova remnant] become low-energy cosmic rays and still need further acceleration to become ‘normal’ GCRs.
As I mentioned above, according to NASA and the mainstream view, backed up by research in the peer-reviewed literature etc, it’s considered that SNRs can accelerate particles beyond ‘normal’ to much higher energies. Here’s another article from NASA, stating that SNR are understood to accelerate particles up to 10^14 eV. (10,000 GeV). This is a far higher energy than ‘normal’ GCRs (say 0.1 – 100 GeV) , and so the spectrum of CR energies produced by the supernova and remnant will include these ‘normal’ GCRs.
Question:
Supernovae occur periodically producing a burst of galactic cosmic rays. Many are very far away. Have scientists ever detected a spike in cosmic ray flux rates which they attribute to a nearby supernova? If so, how long was the pulse (minutes, days, weeks)? How much higher than background cosmic ray levels was the spike?
Answer:
One would think that we could measure such spikes in the cosmic ray intensity from a neighboring supernova. And it is certainly a good idea. But there are a few complications.
First we must consider the typical energy of a cosmic ray, which is around 1 GeV (1 giga-electron volt is equivalent to the rest mass energy of a proton). At these energies, cosmic rays are affected by the ambient galactic magnetic fields, which are typically 10-6 Gauss. Remember, cosmic rays are charged and the trajectory of a charged particle will curve under the influence of a magnetic field.
Consider a cosmic ray with energy of roughly 10,000 GeV. At this energy, cosmic rays will spiral with a radius of curvature of roughly ~10^16 m (which is much less than the distance to the Crab nebula, for instance). Considering the size of our galaxy (the radius of our galaxy is 1021 m), this means that by the time cosmic rays reach the Earth, they have been spiraling and diffusing through stray magnetic fields so that we see a distribution of cosmic rays arriving at Earth that is roughly equal from all directions (isotropic). Information concerning the original direction is lost at these energies. This is further exacerbated by the interaction of the Sun’s magnetic field with these in-coming cosmic rays. Finally, we should remember that the typical rate for supernovae is roughly 1 every 50 years in our galaxy!
But there is a caveat to all of this. We do see cosmic rays at even higher energies, even up to 10^21 eV! These are called ultra-high energy cosmic rays (UHECR). A cosmic ray with energy of 1020 eV has a radius of curvature of 1 megaparsec (~10^22 m) — much greater than the diameter of our galaxy. These cosmic rays have the potential to point to a particular source, although the current number of these nuclei measured at Earth is extremely low. So far we haven’t observed any clear evidence that the quantities of these UHECRs vary depending upon the direction from which they arrive (anisotropy).
In fact, theorists are still having difficulty explaining how a supernova can accelerate particles beyond 10,000 GeV, and it has been postulated that these very rare UHECRS are coming from more exotic sources, possibly including gamma-ray bursts, dark matter, or some brand new physics. You can learn more about UHECRs on the OWL website.
Dr. Georgia de Nolfo
(July 2004)
By the way, Dr.de Nolfo wrote here (in 2004) that “So far we haven’t observed any clear evidence that the quantities of these UHECRs vary depending upon the direction from which they arrive (anisotropy)”. The two papers I cited earlier (Erlykin & Wolfendale 2006, and The Tibet AS Association 2006), show some progress in this regard eg. from the former paper: “It is shown that the excessive cosmic ray flux from the Outer Galaxy can be due to the location of the Solar System at the inner edge of the Orion Arm which has the enhanced density and rate of supernova explosions.”
Another analogy, using air again : imagine that there’s a bottle of scent. If the bottle is opened, a nearby observer registers the scent on their olfactory receptors. If a second bottle is opened, the observer will register an increase in intensity, even though the isotropy of the scent molecules remains constant.
A more direct analogy: consider solar cosmic rays, which are of lower energy than GCRs. According to Bryant et al. 1965’s analysis of Explorer II observations, solar protons have a path length of 10-15 AU before reaching Earth – not sure what the most up-to-date estimate is. Anyway, the solar proton population at the top of the atmosphere is considered to be isotropic, yet instruments observe that the population density changes over time. If the Sun increases its proton output by 10%, say, this will be recorded on Earth. Isotropy will still be nearly total, yet the number of particles impacting Earth will necessarily increase.
So, contrary to your contention, a constant level of isotropy over time doesn’t imply a constant density of CR particles over time.
Also contrary to your contention, supernovae and their remnants are understood to accelerate particles to energies well over the ‘normal’ ~ 1 GeV range, so SNR can be considered to be GCR sources in themselves.
I feel like teaching Evolution to a Creationist or a Young Earther. Same kind of hopeless effort.
I feel like I’m speaking with an unpleasant and possibly pathologicaly dishonest person.
I should add that feelings are fickle and notoriosly unreliable indicators of reality.
oneuniverse says:
July 8, 2010 at 4:06 am
“First we must consider the typical energy of a cosmic ray, which is around 1 GeV (1 giga-electron volt is equivalent to the rest mass energy of a proton). At these energies, cosmic rays are affected by the ambient galactic magnetic fields, which are typically 10-6 Gauss. Remember, cosmic rays are charged and the trajectory of a charged particle will curve under the influence of a magnetic field.
SNs can [and do] accelerate particles. And SNRs provide shocks in the interstellar medium [which is full of overlapping shocks] that further accelerate particles. It is not a question of ‘all or nothing’. You assume that SNs produce all the acceleration within the expanding shell and that thereafter no further acceleration takes place. This is incorrect.
If a second bottle is opened, the observer will register an increase in intensity, even though the isotropy of the scent molecules remains constant.
Here you assume that the diffusion of the scent is instantaneous. It is not [and for CRs especially not, since they take a long time to get here]. With slow diffusion an observer near the bottle will smell the scent coming from a certain direction. Animals can use smell to find their food because of this directionality.
If the Sun increases its proton output by 10%, say, this will be recorded on Earth. Isotropy will still be nearly total, yet the number of particles impacting Earth will necessarily increase.
I think you are confusing this with the solar wind.
So, contrary to your contention, a constant level of isotropy over time doesn’t imply a constant density of CR particles over time.
Since your analogies didn’t work, the ‘so’ is inappropriate.
Also contrary to your contention, supernovae and their remnants are understood to accelerate particles to energies well over the ‘normal’ ~ 1 GeV range, so SNR can be considered to be GCR sources in themselves.
Certainly, but not the only way the GCRs get accelerated. And most of the low-energy CRs escaping from SNs keep being accelerated by shocks and waves and ‘bubble’ boundaries [overlapping SNRs] as the diffuse through the Galaxy.
I feel like I’m speaking with an unpleasant and possibly pathologicaly dishonest person.
It is always unpleasant to have one’s convictions/beliefs challenged, so I would not put much credence in your judgement of my personal traits, either.
Leif Svalgaard : You assume that SNs produce all the acceleration within the expanding shell and that thereafter no further acceleration takes place. This is incorrect.
I didn’t assume this. My contention was that SN/SNR’s are sources of GCRs at ‘normal’ energies, I never denied the existence of further acceleration, and queried you for details of the mechanism.
Certainly, but not the only way the GCRs get accelerated.
Ok, it seems that we now agree that supernovae and their remnants are sources of
‘normal’ energy GCR’s.
Here you assume that the diffusion of the scent is instantaneous.
No such assumption – the Brownian motion mentioned implies a diffusive, non-
instantaneous action. The efficacy of the analogy doesn’t depend on instantaneous action. One can confirm this by observing that the experience described in the analogy is easily recreated in the real world.
Animals can use smell to find their food because of this directionality
The molecules have more or less 100% isotropy (~ 1 billion collisions/sec) . The
direction is probably determined by the spatial density gradients due to the non-instantaneous nature of the diffusion process. Twin nostrils can aid spatial resolution . Macro-scale advection of air is another phenomenon that can be detected by most animals and could be included in their calculation of the location of the source.
Leif: Since your analogies didn’t work, the ‘so’ is inappropriate.
The ‘so’ is not dependent on an analogy.
As evidence that CR density can vary while the isotropy remains nearly constan, one can consider the plentiful contemporary measurements of varying CR counts at the TOA, and nearly constant isotropy. A nearly constant isotropy over time therefore doesn’t imply that the coeval density over time won’t vary significantly.
oneuniverse says:
July 8, 2010 at 3:22 pm
I never denied the existence of further acceleration, and queried you for details of the mechanism.
And I have you several short explanations and referred you to several detailed papers.
Ok, it seems that we now agree that supernovae and their remnants are sources of
‘normal’ energy GCR’s.
But as those are further accelerated on their way us, they are not the ‘normal’ GCRs we observe, so the agreement is irrelevant.
“Here you assume that the diffusion of the scent is instantaneous.”
No such assumption
You must be use the right time scale, e.g. one second is instantaneous compared to a day.
The ‘so’ is not dependent on an analogy.
You bring out some analogies, and then say ‘so’.
As evidence that CR density can vary while the isotropy remains nearly constan, one can consider the plentiful contemporary measurements of varying CR counts at the TOA, and nearly constant isotropy.
You must be confusing things. What CR counts?
I’m always on the lookout for a better way to view what has happened so far with SC23/24.
So…
http://www.robertb.darkhorizons.org/TempGr/uvpSC2324.jpg
Plotting the Butterly with Umbra as black and Penumbra as grey.
Is this of interest to anyone?
‘Plotting the Butterly with Umbra as black and Penumbra as grey.’
should read
Plotting the Butterly with Umbra as black and Penumbra-only as grey.
rbateman says:
July 8, 2010 at 9:00 pm
I’m always on the lookout for a better way to view what has happened so far with SC23/24. […]
Is this of interest to anyone?
Looks nice, keep it up.
rbateman says:
July 8, 2010 at 9:00 pm (Edit)
http://www.robertb.darkhorizons.org/TempGr/uvpSC2324.jpg
Plotting the Butterly with Umbra as black and Penumbra as grey.
Is this of interest to anyone?
Looks Utterly Butterly to me. Well done Rob. 🙂
Leif Svalgaard says:
July 8, 2010 at 11:59 pm
I’ll keep it current, then.
You probably already know the answer, but I’m curious as to how this transition has compared to the previous records, as far as the prevalence of penumbra-only spots. I’ll be doing those too.
How often do I get more of the joke after I laugh?
================
rbateman says:
July 9, 2010 at 3:22 am
prevalence of penumbra-only spots. I’ll be doing those too.
Check your definitions. Come to think about it, you can have spots without penumbra, but not without umbra, so something is backwards…
Leif Svalgaard says:
July 9, 2010 at 6:28 am
In both Greenwich and Debrecen systems, there are spots measured with an umbral area of zero.
However that works out in the Solar Physics world, this is what my butterfly diagram is depicting.
18761120. 97 229 0 2 16 122 8 63 0.233 168.5 219.9 -10.9 -2.7
18761121. 21 229 0 2 8 129 4 67 0.274 217.5 220.2 -10.9 9.8
187611 9.572 30801 0 0 0 27 0 28 0.870 98.5 301.1 -6.1 -60.3
g 2010 06 30 14 23 32 11085n 0 3 0 2 37.32 172.75 3.55 355.04 0.5719 -257.0 -280.4
g 2010 07 01 13 57 32 11084 48 294 26 160 -19.14 144.72 -11.48 153.27 0.4200 -1434.4 -546.0
g 2010 07 02 14 23 32 11084 49 292 26 156 -19.05 144.42 1.69 184.25 0.3776 -1539.3 -555.6
rbateman says:
July 9, 2010 at 4:37 pm
In both Greenwich and Debrecen systems, there are spots measured with an umbral area of zero.
18761120. 97 229 0 2 16 122 8 63 0.233 168.5 219.9 -10.9 -2.7
18761121. 21 229 0 2 8 129 4 67 0.274 217.5 220.2 -10.9 9.8
The examples you give:
have umbral areas of 16 and 8, respectively…
Leif Svalgaard says:
July 9, 2010 at 9:57 pm
The examples you give:
have umbral areas of 16 and 8, respectively…
Yes, I gave you both types. The ones you quoted I plot as having umbra.
This one has zero * 10E6 umbra area, uncorrected and corrected:
187611 9.572 30801 0 0 0 27 0 28 0.870 98.5 301.1 -6.1 -60.3
I plot that one as not having an umbra.
Whatever you want to call that “not having a measured umbra”.
You will find both types in the pdfs of the Greenwich reports, the Final(.FIN) files, the group (.gp) files and the sum(sum.txt) files.
rbateman says:
July 9, 2010 at 10:35 pm
This one has zero * 10E6 umbra area, uncorrected and corrected:
187611 9.572 30801 0 0 0 27 0 28 0.870 98.5 301.1 -6.1 -60.3
I plot that one as not having an umbra.
When a spot is very small [e.g. a pore] there is no distinctive division into an umbra and a penumbra. So the ‘umbral’ area will be zero [as no distinct umbra is present], but that does not mean that the rest [all of it in this case] is a ‘penumbra’ with the characteristic horizontal rolls. This is semantics only, but it is not quite correct to label these weak pores as ‘penumbra’. Better would be ‘non-umbral’ spots.
Leif Svalgaard says:
July 9, 2010 at 11:09 pm
Non-umbral is fine by me, but pores of the size of 45 x 10E6?
Sounds vaguely familiar with the problems associated with the Hubble Tuning Fork classification scheme.
Are the Greenwich plates still behind a digitized paywall?
25Lbs sterling per copy sight unseen is out of my ballpark.
oneuniverse says:
July 8, 2010 at 3:22 pm
Ok, it seems that we now agree that supernovae and their remnants are sources of
‘normal’ energy GCR’s.
Nigel Calder’s blog has an update on GCR’s origins and timings:
http://calderup.wordpress.com/2010/06/18/star-positions-matter/
tallbloke says:
July 10, 2010 at 9:09 am
Nigel Calder’s blog has an update on GCR’s origins and timings
Since GCRs takes millions of years to reach us [even from nearby sources] there will be variations on that time scale, but not on a time scale of centuries. This is the main point.
Leif Svalgaard says:
July 10, 2010 at 9:55 am
tallbloke says:
July 10, 2010 at 9:09 am
Nigel Calder’s blog has an update on GCR’s origins and timings
Since GCRs takes millions of years to reach us [even from nearby sources] there will be variations on that time scale, but not on a time scale of centuries. This is the main point.
—…—…—…
True, the delay (from formation due to (quantity unknown) causes) between GCR birth and delivery here is on the order of millions of years. But the sudden rise need not be longer than days (if a supernova or black hole collapse or black hole “collision” with a second black hole. A “sudden” change – expansion of star into a red giant – may be on the order of years or centuries, and so we would see an equal time change.
Or, reversing the matter, assume a more gradual rise or fall in GCR background levels that vary over the centuries. Then, the source is occluded by another star or galaxy or gravitational field focus point. “Suddenly” that gradual change in GCR would be changed by the intermediate object. Certainly, that would be a “local” effect – like an eclipse is a small local effect compared to the size of the sun. But in that local area under the eclipse shadow zones, there is a very drastic sudden effect that can vary in effect significantly (complete darkness, umbra, annulus, duration, and temperature effects) all changing based on where the observer happens to be.
And then there is the theory of shock waves in the spiral arms causing star formation. Do the GCR’s pile up ahead of the theoretical shock wave?