The sunspot butterfly diagram. This modern version is constructed (and regularly updated) by the solar group at NASA Marshall Space Flight Center.

Breaking News: The Sun Worked 175 Years Ago!

Article Updated: 24 Dec , 2015


You’ll have to forgive my title. After writing so many articles as moderately as I could, I couldn’t help but engage in a bit of sensationalism of my own, especially in the interest of sarcasm. Although it’s not especially exciting that the sun has indeed been working for nearly two centuries (indeed, much longer than that), what is interesting is how using historical data, scientists have confirmed that process we see today have been relatively consistent since 1825.

The observations revolve around a familiar diagram known as the Butterfly diagram (pictured above). This diagram depicts the position of sunspots at various latitudes on the sun’s surface as time progresses. At the beginning of a cycle, sunspots start of at high latitudes and as the cycle progresses, appear at lower and lower latitudes until they disappear and the cycle repeats. The pattern formed resembles the wings of a butterfly, thereby giving the diagram its name.

Although sunspots have been observed as far back as 364 BC by Chinese astronomers, telescopic observations of them did not start until the early 1600’s. Continuous observation of the sun and its spots started in 1876 at the Royal Greenwich Observatory. There Edward Maunder recognized the pattern of sunspots and published them in the format that is the now famous Butterfly diagram in 1904. The diagram, as its usually shown only comprises data starting from around 1876 and continuing until present day. But the use of new records have extended the diagram back an additional 51 years, covering four new solar cycles. Although many observations exist with total sunspot counts, this new set of data includes detailed documentation of the position of the spots on the solar disc.

The observations were created by German astronomer Heinrich Schwabe. Originally an apothecary, he won a telescope in a lottery in 1825 and was fascinated, selling his family business four years later. Schwabe observed the Sun compulsively attempting to discover a new planet with an orbit interior to Mercury by witnessing it transiting the Sun. Although this effort was doomed to failure, Schwabe maintained detailed records of the sunspots. He even recognized the pattern of spots occurred in an 11 year cycle and published the discovery in 1843. It was met with little attention for several years until it was included in Alexander von Humboldt’s Kosmos. Due to this discovery, the 11 year solar cycle is also referred to as the Schwabe cycle.

From 1825 until 1867, Schwabe compiled at least 8468 observations of the Sun’s disc, drawn on 5cm circles. On his death, these documents, as well as the rest of his scientific works, were donated to the Royal Astronomical Society of London, and in 2009, were provided to a team of researchers for digitization. From the 8468 drawings, 7299 “have a coordinate system which is found to be aligned with the celestial equator” making them suitable for translation into scientific data.

Thus far, the team has converted 11% of the images into usable data and already, it has created a detailed butterfly diagram preceding those produced elsewhere. From it, the astronomers undertaking the conversion have made some interesting observations. The cycle beginning around 1834 was weaker than others around that time. The following one, starting around 1845, displayed a notable asymmetry where sunspots in the southern hemisphere were conspicuously lacking for the first 1-2 years of the cycle, whereas most cycles are fairly well mirrored. Although unusual, such phase shifts are not unprecedented. In fact, another study using historical records has demonstrated that, for the last 300 years, one hemisphere has always led (although not usually so greatly) for several cycles before trading off.

As with the recently discussed historical project on weather trends this reanalysis of historical data is one of many such projects giving us a broader picture of the trends we see today and how they have changed over time. While undoubtedly, many will be demonstrated to be mundane and familiar, undeserving of the exaggerated significance of my title, this is how science works: by expanding our knowledge to test our expectations.

NOTE: I’d Emailed the team asking for permission to show their image of the historical butterfly diagram, but since I haven’t gotten permission, I didn’t reproduce it here. But you can still view it in the paper. Go do so. It’s awesomely familiar.


7 Responses

  1. Torbjorn Larsson OM says:

    Damn, so if solar spot mechanisms are as semi-chaotic as they seem, it is true what they say about butterflies and (space) weather! I didn’t know about this behavior, so it’s thrilling to see, like seeing a diagram of nerve pulses (or EKGs!) for the first time.

  2. Emilio says:

    It reminds me of Monarch Butterfly.

  3. IVAN3MAN_AT_LARGE says:

    At the third paragraph, in the fifth line: “The diagram, as its usually…”

    That should be it’s (it is), not an “its”.

  4. HeadAroundU says:

    Just F die, Ivanman. 😀

  5. Torbjorn Larsson OM says:

    With the syncronicity of the web, here is a post from the Bad Astronomer titled “Grammar nazis get Fryed” which seems germane to the topic of “it’s” vs “its”.

    Fry take on linguistic pedantry in general with his usual swerve in an *awesome* video you shouldn’t miss! Among other pearls we can note the observation that this “silly approach to language” that makes people “add apostrophes on public signs” is the area of a “sorry bunch of semi-educated losers”.

    Oh, and I like Fry’s characterization of taking joy in functional evolving language as opposed to artificial rule-making as the “sound-sex of it”. It sounds down-right good and naughty.

  6. Torbjorn Larsson OM says:

    No, no.

    It’s a little known etymological fact, but before bits there were its, now only memorized in terms like “itty bitty objects”.

    Presumably then Voisey is correctly referring to the “basic its” (“bits”) of data shown.

  7. Aqua says:

    Interesting how the sun spot patterns migrate toward the solar equator during solar max. I’m trying to imagine the underlying magnetic field patterns that flow through highly energetic yet gravitationally compressed plasma condensate layers below. Hard to imagine gigatesla quantum scale magnetic fields or they’re 3 dimensional structure and how they expand outward from the center of mass…. possibly in an equatorial quadripolar rotation?

    A visualization: Everyone knows the six pointed metal object from the simple child’s game – Jacks. Imagine one of the axis as the ‘major’ rotational axis of Sol and the other two axis able to process North/South as they rotate….

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