Posts Tagged ‘heliophysics’

21 February

Understanding Our Powerful Sun & Its CME (Coronal Mass Ejection)

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Dear Friends, Visitors/Viewers/Readers,

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As a result of posting The Unexpected Atmospheric Intruder on Feb. 16, 2013, I’ve received multiple  questions/concerns expressed by our viewers toward the space and our Sun.  Therefore, I’ve prepared this particular session on “Understanding Our Powerful Sun & Its CME(coronal mass ejection)” for your viewing pleasure, to further our appreciation of our Sun, and to kindle our curiosity and wonder for exploration into the space.  With the help from NASA Heliophysics (meaning Physics of the Sun),  I’d like to present to you this composite of 2 footage about the Sun, the star at the center of our Solar System, and its CME (coronal mass ejection), the massive burst of solar wind and magnetic fields rising above the solar corona or being released into space.  Be sure to stay long enough to also view the activities of CME.

 

Can you feel the light and intense warmth projected from the screen…from this giant active star ?

Our Sun, with a diamter-1,392,684 km (109 x that of Earth) (NASA)

While the origin and sustenance of life here on Earth are intimately connected to this active star of over 4.6 billion years, our fate in the next 4+ billion years will depend much on our ability to understand and predict Sun’s variability in producing streams of high energy particles and radiation that can help/harm life on Earth or alter its evolution.  Better understanding of the connections between the Sun, solar wind, planetary space environments, and our place in the Galaxy would enable us to uncover the fundamental physical processes occurring throughout the Universe and allow us to predict the impacts of solar variability on humans, our technological systems, and the presence of life here on Earth. Since heliophysics is simply too vast a field to cover in one post, we will be concentrating in some basic understanding of the Sun and its coronal mass ejection (CME) in this one.

The almost perfectly spherical Sun consists of hot plasma

Sun’s plasma  trapped by magnetic fields shows up as thin lines in extreme UV light (NASA)

interwoven with magnetic fields,

with a diameter of about 1,392,684 km (about 109 x that of earth) and a mass about 2 x 10^30 kilograms (about 330,000 x that of earth). It accounts for almost 99.86% of the total mass of the Solar System.  Chemically, about three quarters of the Sun’s mass consists of hydrogen while the rest is mostly helium…and the remainder (about 1.69%) consists of heavier elements such as oxygencarbonneoniron, etc.  The Sun formed from the gravitational collapse of a region within a large molecular cloud. Most of the matter gathered in the center, while the rest flattened into an orbiting disk that would become the Solar System. The central mass became increasingly hot and dense, eventually initiating thermonuclear fusion in its core. It is thought that almost all other stars form by this process. The Sun’s stellar classification, based on spectral class, is G2V, and is informally designated as a yellow dwarf, because its visible radiation is most intense in the yellow-green portion of the spectrum and although its color is white, from the surface of the Earth it may appear yellow because of atmospheric scattering of blue light. In the spectral class label, G2 indicates its surface temperature of approximately 5778 K (5505 °C), and V indicates that the Sun, like most stars, is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses 620 million metric tons of hydrogen each second.  The Sun (the star closest to Earth, approximately 149.6 million kilometers away or the distance that light travels in 8 minutes and 19 seconds) is brighter than about 85% of the stars in the Milky Way galaxy.

The Milky Way

Star Formatioin

Its hot corona continuously expands in space, creating the solar wind,  a stream of charged particles that extends to the heliopause at roughly 100 astronomical units. (Source: wikipedia)

Coronal mass ejections (CMEs) release huge quantities of matter and  electromagnetic radiation into space above the sun’s surface, either near the corona (sometimes called a solar prominence), or farther into the planet system, or beyond (interplanetary CME).

Sun’s CME (interplanetary)

The ejected material is a plasma consisting primarily of electrons and protons, but may contain small quantities of heavier elements such as helium, oxygen, and even iron. The theory of heavier element emissions during a CME is speculative information and requires further verification. It is highly unlikely that a CME contains any substantial amount of heavier elements, especially considering that the sun has not yet arrived at the point of helium flash and thus cannot begin to fuse elements heavier than helium. Coronal mass ejections are associated with enormous changes and disturbances in the coronal magnetic field. They are usually observed with a white-light coronagraph. Recent scientific research has shown that the phenomenon of magnetic reconnection is responsible for CME and solar flares. Magnetic reconnection is the name given to the rearrangement of magnetic field lines when two oppositely directed magnetic fields are brought together. This rearrangement is accompanied with a sudden release of energy stored in the original oppositely directed fields. Most ejections originate from active regions on the Sun’s surface, such as groupings of sunspots associated with frequent flares. Near solar maxima the Sun produces about three CMEs every day, whereas near solar minima there is about one CME every five days.

As magnetic fields of the sun rearrange and realign, sunspots can appear on its surface. From Feb.19-20, 2013, scientists watched a giant sunspot form in under 48 hours. The sunspot shown in this image from the SDO (Solar Dynamics Observatory) has grown to over six Earth diameters across, but its full extent is hard to judge since the spot lies on a sphere not a flat disk. (NASA)

NASA-Another CME from Sunspot, via coronograph spectrometers

 

 

 

 

 

 

 

 

On the sun, magnetic reconnection may happen on solar arcades—a series of closely occurring ropes of magnetic lines of force. These lines of force quickly reconnect into a low arcade of ropes,

Sun’s CME flux ropes

Sun’s CME flux ropes in figure 8

leaving a helix of magnetic field unconnected to the rest of the arcade. The sudden release of energy in this reconnection causes the solar flare. The unconnected magnetic helical field and the material that it contains may violently expand outwards forming a CME.This also explains why CMEs and solar flares typically erupt from what are known as the active regions on the sun where magnetic fields are much stronger on average.

Sun’s CME flux ropes seen from different angles

NASA SDO (Solar Dynamics Observatory) telescope (NASA)

 

 

 

 

 

 

 

 

I hope you enjoyed viewing/reading this piece as much as I had in researching and composing this piece.

~have a bright and sunny day~

Gathered, written, and posted by sunisthefuture-Susan Sun Nunamaker

Any of your comments/suggestions/questions are welcomed at sunisthefuture@gmail.com

Homepage:  http://www.sunisthefuture.net


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22 August

Understanding the Sun

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Dear Friends & Viewers/Visitors/Readers,

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Yes, as I’ve titled our previous post, dated Aug. 20, 2012, The Most Intensely Heated & Dangerous Relationship Research Project: Improving Earth’s Future Environment-Radiation Belt Storm Probes (RBSP) & Green Fuels, full appreciation of our relationship with the Sun will be forever paramount for Earth’s environment, energy, communications, climate/weather, and last but not least, Earth’ s longevity.  This bubbling, boiling, fireball in the sky at ninety-three million miles (149.6 million kilometers) away, supporting almost all life on Earth by photosynthesis and driving Earth’s climate and weather ….matters a great deal to us earthlings.  Some modern experts of the Sun are predicting the most violent solar activities in our modern history.

According to wikipedia:

The Sun is gradually becoming more luminous (about 10% every 1 billion years), and its surface temperature is slowly rising. The Sun used to be fainter in the past, which is possibly the reason life on Earth has only existed for about 1 billion years on land. The increase in solar temperatures is such that in about another billion years the surface of the Earth will likely become too hot for liquid water to exist, ending all terrestrial life.

Solar Evolution (wikimedia commons)

Solar Life Cycle (wikimedia commons)

Sunlight is Earth’s primary source of energy. The solar constant is the amount of power that the Sun deposits per unit area that is directly exposed to sunlight. The solar constant is equal to approximately 1,368 W/m2 (watt per square meter) at a distance of one astronomical unit (AU) from the Sun (that is, on or near Earth). Sunlight on the surface of Earth is attenuated by the Earth’s atmosphere so that less power arrives at the surface—closer to 1,000 W/m2 in clear conditions when the Sun is near the zenith.

Zenith (wikimedia commons)

Actual Sunset (wikimedia commons)

Actual Sunrise (wikimedia commons)

Solar energy can be harnessed by a variety of natural and synthetic processes—photosynthesis by plants captures the energy of sunlight and converts it to chemical form (oxygen and reduced carbon compounds), while direct heating or electrical conversion by solar cells are used by solar power equipment to generate electricity or to do other useful work, sometimes employing concentrating solar power (that it is measured in suns). The energy stored in petroleum and other fossil fuels was originally converted from sunlight by photosynthesis in the distant past.

 

We are living in a world that is increasingly susceptible to space weather disturbances.  Many interconnected physical processes strongly influenced by solar variability, affect the health and safety of travelers in space and the habitability of alien environments.  This science of the Sun-Solar System Connections is termed “Heliophysics“.

Based on NASA’s rich history of exploration of the Earths neighborhood and distant planetary systems, we are developing the quantitative knowledge needed to help assure the safety of the new generation of human and robotic explorers. The Heliophysics Program has been completely reevaluated to address the needs of the Vision for Space Exploration.

NASA’s future research and exploration within its Heliophysics program aims to explore the Sun-Earth system to understand the Sun and its effects on Earth, the solar system, and the space environmental conditions that will be experienced by explorers, and to demonstrate technologies that can improve future operational systems.  Hear! Hear! Let’s optimize our use of the Sun’s energy and learn to protect ourselves from its potential hazards. Below, we see how NASA uses high resolution images of the sun and modeling of solar storms, to improve our ability to predict when solar storm hits and how it will affect our daily lives. NASA’s study of sun’s variability, solar storms, and solar wind will also increase our understanding of Sun’s  effect on Earth and Earth’s magnetic field.  The most important researches of Heliophysics program concerns our daily lives:  effects on satellite and ground communications, aircraft navigation systems, power grids, etc. Let’s take a look at the three broad science and exploration objectives of NASA’s Heliophysics Program in the video clip below: to open the frontier to space weather prediction, to better understand the nature of Earth in space, and to safeguard the journey of exploration.

~have a bright and sunny day~

gathered, written, and posted by sunisthefuture-Susan Sun Nunamaker, sunisthefuture@gmail.com
Homepage: http://www.sunisthefuture.net


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