The sun is blank–no sunspots.
Several WUWT readers have inquired about why the SOHO MDI and magnetogram image has not been updated in several days. The last update was on July 28th.
Here is the reason:
Solar and Heliospheric Observatory (SOHO) is having a minor problem. SOHO’s white light solar telescope is temporarily offline while new commands and data tables are uploaded to the spacecraft. Normal operations are expected to resume in a few days.
h/t to:
Ray (21:14:47) :
That cycle must also be regulated by internal mechanisms. But it could be possible that the expention and contraction could also influence our climate.
Some stars have an internal constitution that supports large-scale pulsations. Other stars – including the Sun – are stable against such pulsations, so the Sun does not pulsate. There are about a million random ‘ringings’ of the Sun [the 5-minute oscillations] but they do not cause systematic, overall radial pulsations. There might be some undiscovered flows inside the Sun that could cause variations in size [and that is why we are looking for them] and they would be of importance for TSI, but none have been found [yet] that are generally accepted [although there are many claims], so any changes must be very small.
Leif Svalgaard (22:28:16) :
Thanks Leif.
So when I we sending a probe crashing through the sun? Such probe could mabe be protected by a strong magnetic shield in order to get there first.
I believe that Picard and his assistants found a size change in the Solar diameter that really defies the expected range due to orbital distance. Neither proved nor disproved, as was the Maunder until several research efforts were conducted. He was able to keep time in an accurate manner only improved upon with the invention of the atomic clock, and he used that timing to measure transit of sun & features.
Such an event, dilation or expansion of the Sun beyond expected minima range AND orbital range lies as an unproved possibility in view of modern assumptions.
A dozen or so record low maximum temps yesterday across the N. portion of California.
The low pressure cell was a cutoff low, coming across the Pacific, not from Gulf of Alaska.
Ray (07:56:08) :
So when I we sending a probe crashing through the sun? Such probe could mabe be protected by a strong magnetic shield in order to get there first.
A magnetic shield would not protect against the fiery power of solar photons.
rbateman (07:58:34) :
I believe that Picard and his assistants found a size change in the Solar diameter
The ‘seismic’ radius of the Sun varies with the solar cycle:
http://arxiv.org/PS_cache/arxiv/pdf/0902/0902.1002v1.pdf
But is probably the result of solar conditions [magnetic field, density, etc] along the path of the ‘helioseismic’ waves from the backside of the Sun, and the seismic radius is not the same as the ‘visible’ radius. PICARD might clear all his up or at least tell us what questions to ask. BTW, note the annual variation of the seismic radius seen in Figure 3. This is, of course, an artifact of the data and the analysis method.
Leif Svalgaard (10:04:28) :
It was not abundantly clear from what I read that it was resolved. One of those things that left it hanging in midair. Someday we might get a surprise, but unless we enter a similar period and actually witness it happening again, for our purposes it didn’t happen. At the time, along with the extended dearth or visible solar activity, nobody knew anything was amiss. How could they?
To Picard’s credit, he did manage some very precise and way ahead of his time measurements of the planets and transits. Who knows?
With MDI, EIT and Hinode offline, our eyes in space are getting very limited.
How long are bakeouts supposed to take?
3.5 hrs in the oven is what I do for my CCD camera dessicant.
Most likely more involved in space.
Still, we’re rather blind here.
Leif Svalgaard (09:52:36) :
Ray (07:56:08) :
So when I we sending a probe crashing through the sun? Such probe could mabe be protected by a strong magnetic shield in order to get there first.
A magnetic shield would not protect against the fiery power of solar photons.
————–
What could protect such a probe? Something like the methaphasic shield used by Dr. Crusher in STNG maybe?
Looks like SOHO is back online. The latest image of a blank sun has been posted…
LOL 🙂
Ray (13:30:18) :
What could protect such a probe? Something like the methaphasic shield used by Dr. Crusher in STNG maybe?
Just a simple heat shield [umbrella] in front of the spacecraft. The spacecraft would fly in the shadow of the shield. Although the corona is millions of degrees hot, it is so thin that there is almost no heat in it, so in the shade it would be very cold. We would have to heat the spacecraft artificially even as it plunges into the Sun.
Leif Svalgaard (14:43:00) :
You saw Sunshine, too, didn’t you? LOL
http://www.imdb.com/title/tt0448134/
Yup, SOHO MDI Continuum back up. Now we’re cooking 🙂
A few notes about SOHO-MDI.
MDI is still offline. The onboard processor was disrupted on the 28th.
We do not know the cause. But reloading the software fixed the
problem. We had some further problems reloading and testing
the observing sequences this past week but are not able to test
the loads due to the very limited telemetry now. SOHO is in one
of the times of limited telemetry caused by the limited motion
of its antenna (2-3 weeks each 90 days since 2003).
We will start getting enough high-rate
telemetry around Aug 18-20 to do proper diagnosis. We have decided
to wait until then to restart normal operations. The very few images
on the 8th were part of the limited diagnostics. Do not expect further
MDI high rate (full disk continuum or magnetograms) until after
the 18th or 20th. We are presently getting low-rate data which is
needed for the farside images – but they are very very likely to continue
to be very boring. And without the MDI magnetograms we would need
to mess with the automatic processing to include GONG or SOLIS
magnetograms for the frontside. I am too busy to do that for only a week
so do not expect any MDI farside images until after the 20th either.
On a different topic, we are anticipating the launch of SDO in December
with the HMI instrumet which has a 4kx4k imager vs MDI 1kx1k.
And SDO will have continuous telemetry so there will be a LOT more
data. MDI data is a subset of HMI so we will stop MDI after an
overlap with HMI. We would like to see a quiet Sun to start HMI
helioseismic studies so are pleased that the Sun is patient with
the SDO launch schedule.