An Ecosystem of Magnetized Plasmas

Have you ever considered the fact that the Sun and the Earth are in direct communication? I mean yea it is obvious that the  ‘heat’ of the Sun effects life processes on this planetary sphere but what is that nebulous term ‘heat’ really when understood on the cosmic scale?

A plasma physicist from the University of Iowa, Jack Scudder, using observations from NASA’s THEMIS spacecraft and Europe’s Cluster Probing, has been researching a phenomenon which has many different names: x-points, electron diffusion regions or, and this is my personal favorite, magnetic portals [1]. A NASA article from July 2, 2012 stated that these portals are places where the magnetic field of Earth joins with the magnetic field of the Sun, creating an uninterrupted path leading from our planet to the Sun’s atmosphere 93 million miles away [ibid]. NASA has taken a serious interest in this body of knowledge and this researcher’s work. As of the data of that article NASA researchers were planning a mission called Magnetospheric –Multiscale Mission[2]. The focus of the mission will be to surround the portals with energetic particle detectors and magnetic sensors to observe how they work. Data is already available which demonstrates that these portals, which can be small and short lived to gigantic and sustained, open dozens of times a day[1]. When opened they allow a great deal of energetic exchange between the Sun and the Earth[2].

On planet Earth are an inconceivable number of lifeforms. Most are quite  far from the self-aware consciousness of homo-sapien, but I strongly believe that each is unique and conscious in its own way. Life on this scale would not be possible if it were not for one crucial factor – the magnetic field of the Earth. Without it creating layer upon layer of magnetized plasmas the solar wind would have long ago stripped away our atmosphere, including the oxygen so necessary for complex organisms[3]. What is the solar wind? How is the Earth’s magnetic field put together? And how do these phenomena interact?

Before elaborating on these phenomena I would like to take some time to focus on some interesting celestial mechanics that will affect the operation of this Sun-Earth system.

In the Northern Latitudes, starting in later March, a special point is reached called the vernal equinox. At this time the Sun is exactly perpendicular to the equator of Earth and as a result 12 hours of day and 12 hours of night occur as the Earth revolves around this location. Three months later the angle which the Sun’s rays hit the Northern Latitudes is at its maximum, which is termed the summer solstice. Later on there is an autumnal equinox and a winter solstice. When the winter solstice is reached the angle of declination of the sun is the same amplitude but it is now maximized in the opposite direction relative to the summer solstice.

apparent path of sun around earth

[4] Apparent path of the Sun from the Earth reference frame

The net effect of all these angles is that a magnetic field of similar strength (intensity) and direction will have very different effects on the planet at varying time periods during the year. Another way to visualize what I just said is the following: imagine you are holding two bar magnets.

MagneticMap_bar magnets[5] Bar magnet. Iron filing help illustrate the magnetic field lines. 

Both magnets will have a north and south pole or positive and negative ends. If you hold one steady and revolve another along a 30 degree angle you’ll notice that there are four significant points. Two points are when the center of the magnets are in the same horizontal plane and the other two will be when the magnets centers are maximally displaced from each other vertically. At these two points one of two things will occur: 1) the south pole of the stationary magnet is closer to the north pole of the revolving magnet or 2) the north pole of the stationary magnet is closer to the south pole of the revolving magnet. In a nutshell that is the Earth-Sun system and will explain a lot of the seasonal phenomena that we Earth Humans experience. But you did not come to this blog to get the super simple so let dive a bit deeper into this system.

Any investigation of the solar wind must first begin with the Corona (Spanish to English translation = crown) of the Sun. In much the same way that the Earth is layered from the lithosphere to the ionosphere to the magnetosphere, the Sun is also a layered construct. The corona is thousands of times higher, approximately 10 million times less dense than the surface of sol and contains extremely energetic particles [6]. Most astrophysicists are baffled by the energy gradient from the Sun’s surface to the corona [ibid]. Through the NASA mission IRIS comes one possible explanation. It was observed that “heat bombs” or in other words, spherical packets of high energy plasma, travel from the sun’s interior to the corona; when the conditions are right the packets explode, releasing heat in the process [7]. This newly introduced energy will accelerate the particles of the coronal layer to such speeds that the gravity of the Sun is no longer adequate to keep them bound to the sphere. This exodus of particles, whose mission it will be to traverse the solar system, are what astrophysicists have termed the solar wind.

What is so incredibly fascinating about this solar wind is that it is a plasmatic imprint of the Sun’s magnetic field [8]. Eventually this field will come into contact with Earth’s field and, if at the contact point Earth’s field is the opposite orientation or significantly different, then the lines of Earth’s field will break and reconnect to the whatever is attractive. Here is an explanation from a NASA site on the Magnetosphere Multiscale Mission:

” Magnetic fields serve as a “connective tissue” that binds plasmas together into cohesive cells sharing the same magnetic field lines. When different parts of a magnetized plasma cell move relative to each other, the magnetic field within it fights back and energy is stored in the stretched and deformed magnetic field. This energy is released when the plasma cell is divided by reconnection of the magnetic fields, disconnecting the magnetic linkage between the two regions in relative motion, and creating two distinct cells that are no longer linked, allowing the relative motion to proceed.”

This process is termed magnetic reconnection and effectively the Sun is converting magnetic energy to kinetic energy! [8,9]

As the solar wind approaches the Earth it comes into contact with a multitude of different plasmas, which are collectively termed the magnetosphere[10]. Breaking the magnetosphere into its major constituent layers yields the following domains: 1) the magnetopause 2) the Van Allen radiation belts 3) the plasmasphere and 4) the ionosphere. Shaped by the Earth’s magnetic fields as well as the impact of the solar wind, one will find highly energetic plasma consisting of free protons and electrons as well as ions of heavier elements emitted from the Sun in these layers [ibid]. The outer edge of this oval is 28 x RE (Earth Radius) at some places and an astonishing 200 x RE in other locations. According to i-sis.org.uk the main function of the magnetosphere is to form an obstacle to the flow of the solar wind, oftentimes diverting it by approximately 11 RE.

Dipole_vs_Magnetosphere of Earth

[11] Earth’s magnetosphere: Interaction of Earth magnetic field with the solar wind. Visible are the outermost layers of the magentosphere. 

As we move from the interplanetary space towards the Earth’s core we next come across the magnetopause. This region exists at a distance of between 6 to 15 RE. Functionally, this layer acts as a sieve, allowing some particles carried by the solar wind to enter while rejecting others. One must recognize the dynamic nature of the outer magnetosphere and the magnetopause. While the magnetopause acts as a filter of solar-wind particles, it is very much affected by the composition and velocity of the solar wind.

In 1958 when the US satellite Explorer I was launched its first discovery was the Van Allen radiation belts. Originally two were discovered with a very pronounced null zone, which lacked electron presence. Since the 50’s it has been observed that the belts flux, merge and even separate into three bands. Between 600 and 9600 km above the Earth’s surface is the first belt and the second belt is bounded by the distance of 13500 to 58000 km (8.4 RE)[10]. The outer belt is quite the boundary. Unless there are strong winds or a coronal mass ejection of exceptional magnitude, even the fastest electrons cannot penetrate[ibid].

For the moment let’s proceed to the ionosphere and then we will return to a brief discussion of the plasmasphere. Many are in awe of the auroras produced within the high Northern Latitudes. What incredible sights these phenomena are! As I grow older I will travel extensively and to see these beauties with my own two eyes is something which I really desire. Norwegian plasma physicist and Nobel Laureate Hannes Alfvén proposed that Birkeland currents play a crucial role in “transmitting electromagnetic energy from the Sun to the Earth and in creating the auroras.” [ibid]. The theory goes that spiraling down electric field lines are 1-20 keV electrons and 200 keV ions which collide with particles in the ionosphere, exchanging energy in the process[ibid]. Those green emissions in the featured picture are oxygen excitations. Birkeland currents are theorized to be sheet-like. That being said, space and ground-based technology reveal a significantly more complex pattern of current flows in the ionosphere.

ionosphere currents

[ibid]. Currents projecting into and out of Earth’s ionosphere at the North magnetic pole connecting it to the plasmasphere and magnetospher

In 1963 both Grange and Carpenter using the Lunik Moon probes and propagating radio waves (Whistlers),respectively,  to identify a steep density gradient which corresponded to the outer plasmasphere [12]. The outer magnetosphere is hot, low-density plasma and the ionosphere is cool, high-density plasma[ibid]. The plasmasphere is located between these two regions. The temperature gradient is not continuous, as evidenced by the fact that the coldest plasma is in the plasmasphere according to NASA [13]. Torus-like in shape, the plasmasphere consists of closed, approximately dipolar electric field lines. This space can be dynamic and highly structured. [12]

When we think of the complexity of life we tend to anthropomorphize it. The development of a hominid brain from four nucleic acids that allows for interaction with the amorphous, cloud-like space of the internet or the Iphone is certainly astonishing. However I would argue that the development of relatively stable plasma differentials between fluxing magnetic and electrical fields which allows for timed physical cycles (i.e geomagnetic storms, climates, pole shifts) at regular intervals is pretty damn complex! In fact I would venture to say that the complexity of this cosmic ecosystem is many exponential factors removed from our own hominid complexity.

 

[1] www.nasa.gov/mission_pages/sunearth/news/mag_portals.html ).

[2] http://www.dailymail.co.uk/news/article-2168938/NASA-discovers-portals-space-Earth-Sun-dont-book-ticket-just-yet.html

[3] https://en.wikipedia.org/wiki/Earth%27s_magnetic_field

[4] http://www.opencourse.info/astronomy/introduction/02.motion_stars_sun/

[5] http://en.wikipedia.org/wiki/File:Magnet0873.png

[6] http://spaceplace.nasa.gov

[7] http://earthsky.org/space/mystery-of-corona-sun-upper-atmosphere-heating

[8] http://solar-center.stanford.edu/sun-on-earth/sun-earth.html

[9] https://mms.gsfc.nasa.gov/science.html

[10] http://www.i-sis.org.uk/Earths_Magnetized_Plasma_Shield.php

[11] https://commons.wikimedia.org/wiki/File:Dipole_vs_Magnetosphere.jpg

[12] http://www.johnstonsarchive.net/physics/ps-paper.html

[13] https://plasmasphere.nasa.gov/

Contemporary Attempts to Order the Celestial Sphere

Our cosmological models have been written and rewritten so many times, if another advanced species were observing us they would have to wonder if us Earth humans are ever going to get it right. First, the Earth was the center of the universe, and then it was one of the heavenly bodies that revolved around a pretty interesting but relatively stationary and lonely star within the great cosmos (which at that point was just the solar system). And then came along three celestial mechanics giants and our consciousness jumped exponentially with each one of their entrances to the conversation.

Henrietta Swan Leavitt attended the Society for the Collegiate Instruction of Women in Massachusetts, which would later be known as Radcliffe College. After her graduation she found a post at the Harvard College observatory under the direction of Charles Pickering. Over her career she discovered and made a thorough study of over 2000 stars, specifically a grouping of stars known as the Cepheid Variables[1].

Cepheids I and II trans background-402x308

[2] Using Cepheid variables to measure distance

Leavitt noticed that these stars contracted and expanded in a very predicable way and this rate was directly related to the maximal brightness of the star. By closely observing these stars she was able to deduce what is known as the Cepheid Variable Period Luminosity.  These data allowed researchers to begin to measure cosmic distance and was integral to the contribution made by the next gargantuan researcher.  In addition to these contributions Leavitt also developed a 17 scale measurement tool for star brightness through the usage of logarithmic equations and data from 299 stars and 13 telescopes[1].

Edwin Hubble, after which NASA’s Hubble telescope is named, studied physics at the University of Chicago and astronomy at Cambridge. Shortly after leaving Cambridge he received a post at the Mount Wilson Observatory in California, where he remained until his death in 1953. Using the newly constructed Hooker telescope he also made a study of the Cepheid variable stars[3].

Heic1323a_-1243686232 [4] RS Puppis – one of the brightest Cepheid Variables

His early research led him to conclude Andromeda was not merely a spiral of the milky way but a galaxy in its own right [3]. His further research allowed him to not only put to death the theory that our galaxy is the only one in the universe but he was able to correlate spectral data with distance. His theory, and what has been used in the astrophysics community since, is that red-shift in galaxy light emissions is related to distance between galaxies in a linear fashion [5]. This research lead Hubble to the conclusion that the cosmos is expanding. If most people had a hard time accepting that the universe was made up of an non-quantifiable number of other galaxies their minds had to have just blown-up when it was also demonstrated that the universe is expanding.

So 1 star became 10^11(100billion)  and that morphed into at least 10^23 [6]. Maybe our estimates are a bit off and its really 6.022 x 10^23 (gotta give my chemistry guys a shout out). So whats the next step? Each jump is so unimaginably large that it boggles the mind to think there could be more but….is there a chance that we will discover the universe is finite and just one of many within the multiverse? Does it ever end or do we just get to a point where we can perceive another boundary limit more distinctly? Utterly mind-bending…

The last of the gargantuan astronomers for today is the man who characterized the planet Uranus in this age, William Herschel (1783-1822), but that was far from his greatest contribution, in my opinion. I could imagine that astronomers of deep antiquity all the way up to the 18th century were convinced that our stars existed without partner. After all it is Newton’s theory of gravity that gives proof of the attraction of bodies at a distance. Without his theory, heavenly bodies were just pretty stationary objects. And then came Herschel. From his mind came the colossal works the “New General Catalog” and “Catalog on Double Stars”. It is this final work that has me truly fascinated. He discovered that certain stars existed quite close to each other and his observations led him to the conclusion that gravity exists outside of our solar system and that these stars were in fact gravitationally attracted to each other[7]. His was a strong career that lead to a personal cataloging of more than 2500 stars and 145 double (or binary) stars [8]. Some of these systems are incredible to say the least. According to the Binary Research Institute astronomers from the United Kingdom working on Hawaii with an Infrared telescope just recently  discovered four pairs of binary systems in which the stars orbit each other in under four hours [9]. Imagine the short distance that must exist between them…

So this all begs the question, does solar system sol have a binary companion around which it dances? In the Milky way approximately half of all stars are binary stars so the chances are quite high[10]! Surely William Herschel must have thought that the binaries were rarities but he couldn’t have been more wrong. Amazingly a physicist from Berkeley and a radio astronomer from Harvard are suggesting that all stars are formed in pairs [10]. Perhaps our sun did have a dancing partner but instead of a social companion it was a nemesis which had to be vanquished. So naturally us Earth humans living so long after the formation of the binary system would not have any knowledge of its existence. What a warrior sun we had! Well anyways our sun seems to be quite unique in the universe in that it has a planet that can support life. Did its former twin also have this ability? Perhaps more scans of the sky with the Hubble telescope will yield the answers to these late night metaphysical musings.

 

[1] http://www.pbs.org/wgbh/aso/databank/entries/baleav.html

[2] https://lco.global/spacebook/cepheid-variable-stars-supernovae-and-distance-measurement/

[3] https://www.biography.com/people/edwin-hubble-9345936

[4] https://en.wikipedia.org/wiki/Cepheid_variable

[5] https://starchild.gsfc.nasa.gov/docs/StarChild/questions/redshift.html

[6] https://www.nasa.gov/feature/goddard/2016/hubble-reveals-observable-universe-contains-10-times-more-galaxies-than-previously-thought

[7]  https://www2.hao.ucar.edu/Education/FamousSolarPhysicists/william-herschel-1738-1822

[8] https://www.space.com/17432-william-herschel.html

[9] http://binaryresearchinstitute.com/bri/astronomers-discover-impossible-binary-systems/

[10] http://news.berkeley.edu/2017/06/13/new-evidence-that-all-stars-are-born-in-pairs/

 

A Budding Interest

A friend of mine recently starting working with the house committee on Science, Space and Technology. When she told me I immediately imagined a future where she would be a part of a cool secret think tank whose purpose it was to develop awesome new technologies that would assist humanity in our quest to understand the cosmos. In this made up reality I envisioned her leading groups of biologists and climatologists to the surface of Mars to see the state of our next door neighbor with observational and intuitive skills that are the hallmark of our species. I want to believe that what her team will discover will forever change how we Earth humans understand ourselves in this great cosmic game.

Truth be told I have no idea what the job entails. For all I know she could be working on something super mundane like categorizing galaxies based on their geometries or looking at  NASA photos for iron oxide composition. All the PhD’s out there know that data analysis can be one of the most mind-numbing tasks at times but hey every dream has got to start somewhere!

When I first heard her speak about the possibility of getting this super futuristic position I had this extreme urge to know more about the subjects that had recently made a bid for my friends future. So I began researching and compiling an understanding of the current states of our physics and astrophysics. We live in a weird-ass, beautiful cosmos and with this blog I intend to share with the readers my newfound interest in these bodies of knowledge ( and in the process consolidate my own understanding.) My interests are quite diverse! and every now and then I plan to write about advances and discoveries in many other other ares of natural philosophy besides physics and astrophysics. Let the journey begin