The Sun is blank again

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More signs that we are easing down to solar minimum: After a period of two weeks of sunspots, the Sun has once again gone blank.

It takes the Sun’s about four weeks to rotate and complete one “day”. What has essentially happened is that right now one face of the Sun is blank while the other face has sunspots. For two weeks, from the last week in June to the first week in July, the blank face was turned towards the Earth. Then the face with sunspots rotated into view for two weeks, and now the blank face has rotated back to face us.

Though new sunspots can always form on either face, I expect this blank stretch to last a few days, at least.


  • Garry

    When I go to the link, there’s a story about transitioning to a new sunspot number. Taking the article at face value it seems like an honest effort, but having seen lots and lots of cases of data manipulation, my suspicions are aroused.

    What do you make of it?

  • Garry

    To be clear, I mean the last link in your posting

  • Garry: I am only mildly skeptical. In this case I don’t think there was any significant effort to change the results to achieve a political gain. Nonetheless, it never pays to lose one’s suspicions, especially in any science field even mildly related to climate, as is the monitoring of the Sun’s activity.

    Having said that, I must add that I have found no evidence of misuse here. The data change seems entirely legitimate.

  • Willi

    Bob, excellent explanation of how rotation affects the appearance of spots, THANKS!

  • Localfluff

    Heliophysics should be the top priority in space exploration and astronomy. It is so very important. Just have a look at the sky, every animal and plant knows that the Sun is the most important thing of all. People built the pyramids to honor and oblige the Sun. NASA spends like 3% of its budget to study it. It is exotic physics. 99.9% of the mass of the Solar system is the Sun’s plasma. Its magnetic field and proton wind and extreme gravity, and flares, should be what most science on Earth should be about. Instead it is just taken for granted as a constant. Space exploration is instead about the robots or field geologists picking up rocks from the Moon or from Mars.

    If the Sun sneezes, like dampens or intensifies its radiation for a thousand years, none of that would be possible anyway. The most exceptional instrument has been built to detect black holes. Well, look up a sunny day, there’s the closest thing to a black hole we have around here. Actually not far from it at all, it will one bad day become a white dwarf, which is a very strange kind of object itself. Black holes aren’t that exotic, they just leave spacetime and have no properties at all.

  • Phill O

    The standard way to re calibrate any system is to collect data under both conditions and look for a fudge fact to convert. This would need to be done for a few years with few and lots of sun spots.

  • Edward

    Localfluff wrote: “it will one bad day become a white dwarf”

    Before that, it will become a red giant, larger in diameter than the Earth’s orbit. One bad day indeed!

    “NASA spends like 3% of its budget to study it.”

    I used to work in a solar astrophysics lab, but I never thought how little we spent on learning about this important part of our lives. It isn’t just counting sunspots, it is figuring out the magnetic fluxes at and near the surface, the magnetic field throughout the solar system, the corona, the roiling and convection of the surface, the dynamics below the surface, and other phenomena, observed or deduced.

    “If the Sun sneezes, like dampens or intensifies its radiation for a thousand years”

    This may be why we are living in an interglacial period of the current ice age, or why this period has remained warmer for longer than some previous ones. We often refer to the cold, glacial periods as ice ages, but that is misleading, as the cold periods have been normal for the past few million years. The interglacial periods are fairly brief, relative to the cold periods.

    Another (more favored) school of thought is that the precession of the Earth’s axis (kind of like a top or toy gyroscope) may be a major source of glacial and interglacial periods. Right now, the North Pole points to the star Polaris (coincidentally named, huh?), but that changes with time.

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