Through
the concerted efforts of Japan, the United States, and the United Kingdom, the satellite
known as Hinode (formerly Solar B) was successfully launched September 26, 2006
from Uchinoura Space Center. Equipped with a high-resolution optical telescope,
an X-ray telescope, and an Extreme Ultraviolet Imaging Spectrometer, this
innovative spacecraft was developed to “reveal the mechanisms of solar
variability and study the origins of space weather and global change,”
according to the NASA Heliophysics Roadmap.1 These telescopes would
be used simultaneously to observe the photosphere all the way to the corona
while stockpiling data in their respective wavelengths. The underlying goal of
the mission was to “help solve the mysteries of the Sun.”2
Hinode—still
in operation well beyond its 3 year design lifetime—has allowed astronomers to gain
a much more robust understanding of the source of extreme heating of the corona
while also acting as a wellspring for several other important discoveries about
this giant plasma ball that is Earth’s life source. One of the aforementioned
mysteries was the cause of monumental temperature increases from the
photosphere, through the chromosphere, to the corona. Using the EUV Image
Spectrometer, high-speed plasma flows have been observed that are thought to be
the result of magnetic reconnection causing “the energy stored in the magnetic
field [to change] into heat and plasma motions”.3 The high
resolution of each telescope, coupled with the high-altitude orbit outside of
the influence of atmospheric distortion at roughly 680 km, has allowed
unprecedented views of the polar regions of the Sun otherwise extremely
difficult to observe from Earth’s surface at such highly oblique angles. “As a
result, Hinode found strong magnetic fields in the solar polar regions. Until
then, it had been thought that only weak and diffuse magnetic fields existed in
those regions. But, the Hinode Solar Optical Telescope (HSOT) discovered that
strong magnetic fields, which exceed 1,000 Gauss (0.1 Tesla) similar to the
sunspots, exist as compact magnetic patches throughout the polar regions” (NAOJ).4
Other observations of the Sun’s magnetic field through the HSOT “made it
possible to verify the magnetic field structure which triggers solar flares by
comparing simulation models to actual observations” (NAOJ).5 The
common theme here is the interplay between differential rotation, magnetic
field generation, and temperature disparities between the three outermost solar
layers: the photosphere, the chromosphere, and the corona.
Again
using the HSOT and working with the idea of convective plasma movement, Hinode
made a rather surprising discovery:
The Hinode Solar
Optical Telescope discovered that these magnetic fields cover the whole Sun. These magnetic fields are much smaller and have shorter lifetimes than
sunspots. In addition they point horizontally along the solar surface. These
magnetic fields are called transient horizontal magnetic fields. This result
was made possible by Hinode's high precision spectro-polarimetry. Since these
magnetic fields exist everywhere on the Sun, the total amount of their energy
becomes potentially enormous, and there is a possibility that this could
provide the energy for the coronal heating (NAOJ).6
Of course, the
possibility remains that a combination of these several factors is what causes
the corona to heat to a whopping 1,000,000 K and beyond. However, it can at
this point be confidently asserted that continued operation of Hinode will only
enhance our understanding of the dynamics of solar magnetic fields throughout
the Sun. Indeed, it already has!
As with any spacefaring mission, the machines we build and fire out of our atmosphere must be resilient and capable of withstanding the unforgiving, extreme conditions of space. This typically results in spacecraft capable of continuing data collection far beyond their intended mission lifetimes. It can also lead to observing Earth-related astronomical phenomena, such as solar eclipses7, from a completely different perspective. Assuming funding is extended, scientists could be collecting and analyzing data from Hinode and other missions for years, perhaps decades, to come. And with the advent of faster, more compact computer chips, artificial intelligence, memory metals, more advanced EM shielding, and many other innovations of the 21st century, humankind is on a path to colonize another world—perhaps Mars—within only ten years or so while continually minimizing the risks involved. The data collected from such pre-space-colonization missions can only enhance our ability to overcome the enormous challenges that the Sun alone presents in moving from this beautiful world to the next.
Fig. 1. A processed image from Hinode, dated 02 February 2018.8 ©NAOJ/JAXA/MSU
References
7. http://www.isas.jaxa.jp/home/solar/eclipse20170821/index_e.html
8. http://hinode.nao.ac.jp/en/gallery/latest/
No comments:
Post a Comment