Sergey Bogachev

On another apocaliptyc conjecture about the Sun.

Sergey A. Bogachev ( «Authors»)

Not only engineering tools that allow building permanent structures – settlements or research station on the Moon, Venus or Mars – are required for the Solar system colonization. The main danger in space is solar radiation. In view of this, the problem is divided into two parts: firstly, the means of protection against solar radiation are required, and secondly, it is necessary to take into account such an important factor as the Sun’s influence on the work of spacecrafts. That is another reason why the sun is being so closely studied by leading scientific organizations around the world. However, recently, journalists have started interpreting phenomena on the Sun; these people are far from science and use various pseudoscientific ways of attracting readers’ attention. These journalists tend to turn astrophysics into a news feed filled with “horror and dismemberment “, as it is usually given in the tabloids.
The author as a scientist should not give the tabloids a chance to mislead those who are interested in space, even at the amateur level. Also, the author noticed that the press is actively distorting the words of the scientists.
So, in this article we will dispel another conjecture about the Sun, just as it was done in [1]. Author will give basic knowledge in order to prevent readers from taking conjectures as reality. Uncomplicated apocalyptic conjectures one can read in given sources. For example, in [2], the note is built on the basis of the thesis: «These bursts can lead to space storms and changes to Earth’s climate Radio and satellite communications may also be affected».
So, since the late summer of 2013, some media referring to NASA scientists [3] publish messages like: “The sun will soon swap the position of its magnetic poles” [4-7]. The Interesting thing about these posts was also the fact that experts in solar physics did not refute them, as it usually happens in the wake of such “sensations”, but confirmed them with tranquility, which could not leave a person far from science unsurprised: how can they stay calm in anticipation of changes of this magnitude. Let’s try to figure out what is behind this message and how to treat it.
First of all, let’s start with the fact that the Sun is a rotating body, although it is not noticeable from the Earth, and like any rotating body it has two poles, i.e. points of the surface through which its axis passes. In contrast to the earth-rotation period, which is measured with accuracy of split seconds, the question of the Sun’s rotation period is quite difficult. The fact is that the sun does not generally rotates as a solid body, but using so-called differential method: the angular speed of rotation depends on the heliographic latitude and, moreover, it changes with depth. Points on the equator make a full turn in a fastest way – it takes them 25 days, but near the poles this period increases almost to a calendar month – 30 days. Because the Earth is flying around the Sun in the same direction, the Sun’s rotation look even slower as viewed from our planet. To an observer on the Earth a full turn of the Sun takes at least 27 days.
Orbital position of the Earth (and all the other planets) is such that we see the sun almost exactly from one side. In other words, the ecliptic coincides almost exactly with the plane of the solar equator. If you look at the ecliptic constellations at night, you can easily imagine the direction of the axis around which the Sun rotates – it’s almost exactly perpendicular to the ecliptic circle. This gives a disappointing conclusion for science – it is almost impossible to study the solar poles from the Earth. “Almost” – because it’s nevertheless possible to look at Sun poles from the corner of an eye. The fact is that the axis of the sun is not perpendicular to the Earth’s orbit and slightly inclined – at an angle of about 6^{o}. As a result, once a year, in March, the Sun inclines to us by 6^{o} with its north pole, and six months later, in September, with the south one. Such a limited view does not seem sufficient, so in the next 5 years two spacecraft should be launched to the Sun to look at it “from above” – the European Observatory “Solar Orbiter” [8] and the Russian spacecraft “Interheliozond” [9].
The question on the magnetic poles of the Sun – the points through which the axis of the global magnetic field passes – is much more complicated, but the most important for this article. The position of an Earth magnetic pole is well known. You only need to introduce a compass into the geomagnetic field and it will show the direction to the magnetic axis. It is located so close to the axis of rotation, that this difference is often neglected in navigation and it is considered that the compass points to the geographic pole, which is of course wrong. The situation on the Sun is much more complicated, and it’s not about the fact that we cannot fly up to it with a compass. A more fundamental reason is the fact that we still don’t know for sure whether the Sun has any global magnetic field, and if it has, what is it strength.
Generally, the Sun undoubtedly has a magnetic field. It is present and is a source of energy for all solar flares. However, these fields cannot be called global. The fact is that, unlike the Earth’s field, which exists as long as far back as humanity can remember, fields on the Sun are very unstable and usually disappear after a few days or weeks after their formation. In fact, all the solar activity is a continuous process of appearing and disappearing of magnetic field regions. If you imagine this picture, it becomes clear how difficult it is to distinguish a stable component of the field similar to the Earth’s one, for which it is possible to introduce the concept of a magnetic pole.
Despite these difficulties, nowadays it is confidently said that the Sun has the global magnetic field and even its strength is specified – about 1 gauss. It’s very easy to imagine what this corresponds to: the magnetic field on the surface of the Earth has approximately the same strength. At least two relatively simple arguments can be given In support of a global field of the Sun. First, traces of the magnetic field are found in the immediate vicinity of the Earth’s orbit – this field is brought with the solar wind. The simplest explanation of its origin is that these are global field lines of the sun, which are carried along by solar wind and stretched by it to the Earth’s orbit and further to the boundaries of the solar system. Finally, the lines of a global field during modern space experiments can be seen directly – near the solar poles.
The presence of a global field of the Sun is the key to understanding the fundamental feature of our star – the 11-year solar cycle. The relationship between these two concepts is quite complex and is described with so-called theory of the solar dynamo. Without going into the details , we can say that this theory provides a mechanism due to which a weak initial field of the Sun once is intensified to large values every 11 years (it is gained hundreds of thousands of times) , giving rise to a maximum of activity, and then returns to its original state . Like any good scientific theory, the theory of the solar dynamo not only explains the observed facts, but also predicts new ones. In particular, according to it, global magnetic field of the Sun should disappear near the maximum of solar activity, and then recover back, but with a different polarity. In other words, every 11 years the north and south magnetic poles of our star must be reversed. Based on recent observations, the Sun is currently in this state of polarity changing: in the beginning of 2013 there was one direction of the field and in the end of the year there will be a different one.
How stable is this process, whether failures are possible and, if so, to what they can lead? It is not easy to give a direct answer to this question, since studies of the global component of the solar magnetic field number no more than 15-20 years and even now they are still carried at detection limits of instruments. It is sufficient to say that the strength of large-scale field of the Sun is fractions of a percentage of the field strength in sunspots. However, since the change of poles is an integral part of the solar cycle, we can ask the question about the general stability of the solar cycle.
Humanity observes changes in solar activity since 1614, when sunspots were discovered by Galileo and Christopher Steiner. Since 1749 Zurich Observatory conducts a continuous series of observations, which helped to measure 23 solar cycles. Cycle, which is observed on the Sun now, has the number 24. Even the first look at the 260-year schedule of cycles shows that they are far from being the same: the duration of the cycle varies from 9 to 13 years, and solar maximum height from 60 to 250 units, called Wolf numbers [10].
In other words, the strongest of the observed activity maxima exceeds the weakest nearly four times. The most popular explanation for this is the Sun also has a number of larger-scale cycles besides the main 11–year cycle: secular, millennial, and perhaps even more gigantic. If so, the weak activity cycles can occur in the years of secular minima and strong activity cycles – in the years of maxima. Secular cycle (the so-called Gleissberg cycle) is now widely recognized, and it is not surprising, as it is seen in the chart with the naked eye. Much more difficult is the question on large-scale changes. Currently, there are data for the period of about a thousand years, obtained from geological measurements of carbon-14 content in the Earth’s atmosphere, which is believed to be modulated by solar activity. In the above chart there are several different activity dips that can be identified with the minima of the global cycles, but in general, the accuracy of such measurements is still low. We still can’t look in the more distant past, for example, to answer the question. Whether the activity of the Sun cause ice ages.
We must say that at least one of the global minima observed in the graph for concentration of carbon-14 is historically confirmed. This is so-called Maunder Minimum [11] fallen on the period from 1645 to 1715. One of the key factors for a given period is that it roughly coincided with the so-called Little Ice age in Earth’s history, when the average temperature of the planet is believed to have fallen by 5-10 degrees. Nowadays this is the main fact confirming the influence of solar activity on the climate.
However, in general, we can say that a high solar activity has never been a particular problem for the earth. All the data that we have say that the sun, at least within a historically accurate period, never passed into a state of unusually high activity.
In conclusion, the author suggests Dr. Todd Hoeksema from Stanford University [12], who gave the interview, including [2], to explain to reporters that the problem for the Earth’s climate is not the solar activity, but rather unusually long periods of activity dips associated with failures of the solar cycles. In this sense, the swap of solar poles being observed now should reassure rather than frighten: the cycle of the Sun continues to develop by the known scheme. The Author offers professionals involved in the study of the Sun, including Dr. Todd Hoeksema discuss this perspective in the pages of this journal, which imposes no censorship on scientific views and opinions of the authors.

REFERENCES:

[1] Sergey A. Bogachev. Giant UFO near the Sun is this reality or fiction? Brief Nites of the Space Colonization Journal, 2013. URL: http://spacecolonization.ru/notes/giant-ufo/.
[2] Miriam Kramer. Sun Will Flip Its Magnetic Field Soon. Published by space.com. URL: http://www.space.com/22271-sun-magnetic-field-flip.html
[3] New NASA Visualization Shows Sun’s Magnetic Flip. NASA. URL: http://www.nasa.gov/content/goddard/new-nasa-visualization-shows-suns-magnetic-flip/#.UqVkKPRdUrp
[4] Victoria Woollaston. A storm is coming: Sun’s poles are set to FLIP within four months and it could lead to bad weather and radio disruption. Daily Mail. Associated Newspapers Ltd. URL: http://www.dailymail.co.uk/sciencetech/article-2385401/A-storm-coming-Suns-magnetic-field-set-FLIP-lead-bad-weather-radio-disruption.html
[5] Journal “Science and Life”. URL: http://www.nkj.ru/news/18651/
[6] NASA. URL: Sun soon swaps magnetic poles. RBC. URL: http://top.rbc.ru/society/06/08/2013/868986.shtml
[7] NASA: Sun’s magnetic poles will change places before the New Year. RBC. URL: http://top.rbc.ru/society/20/11/2013/889924.shtml
[8] ESA Science & Technology: Solar Orbiter. URL: http://sci.esa.int/solar-orbiter/
[9] URL: http://ofo.ikiweb.ru/en/p_ih.php
[10] URL: http://en.wikipedia.org/wiki/Wolf_number
[11] URL: http://en.wikipedia.org/wiki/Maunder_Minimum‎
[12] J. Todd Hoeksema, Senior Research Scientist. URL: http://sun.stanford.edu/~todd
[13] Изображение для заметки (captured by NASA’s Solar Dynamics Observatory (SDO), NASA’s Solar Terrestrial Relations Observatory (STEREO), and the joint ESA/NASA Solar Heliospheric Observatory (SOHO).