- 4415 - SOLAR ECLIPSE - in 2024, what we hope to learn? - A total solar eclipse will be seen across the United States in April 2024. When a rare total solar eclipse sweeps across North America on April 8, scientists will be able to gather invaluable data on everything from the sun's atmosphere to strange animal behaviors and even possible effects on humans.
------------------------- 4415 - SOLAR ECLIPSE - in 2024, what we hope to learn?
- This solar eclipse comes with the sun near
the peak of its 11-year solar cycle, setting the stage for a breathtaking
display. The corona will glow spectacularly from the moon's silhouette along
the path of totality, a corridor stretching from Mexico to Canada across the
United States.
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- When the moon passes directly in front of the
sun and blocks it, the elusive outermost edge of the sun's atmosphere, or
corona, will be visible in a very special way.
Things are happening with the corona that we don't fully understand.
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- The heat within the corona intensifies with
distance from the sun's surface. This is
a counter-intuitive phenomenon that scientists struggle to fully comprehend or
explain.
-
- Solar flares are a sudden explosion of
energy that releases radiation into space.
They take place in the corona as do solar prominences, enormous plasma
formations that loop out from the sun's surface.
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- During an eclipse, the bottom most part of
the corona is more clearly visible than when using specialized instruments to
block the central part of the sun. This
will afford scientists a chance to study changes in part of the Earth's upper
atmosphere known as the ionosphere, important because it affects radio waves
used for communication and navigation.
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- The ionosphere, which is where Earth's
atmosphere meets space, is affected by the sun, which electrically charges the
particles there during the day. NASA's
three sounding rockets will be launched before, during and just after the
eclipse from Virginia to measure these changes.
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- The major decrease in sunlight provoked by
the eclipse should allow researchers to learn more about how light affects the
ionosphere so they can better predict potential problematic disruptions.
-
- Beyond the drop in sunlight, temperatures
and wind, conditions to which animals are sensitive can also decrease
significantly during an eclipse.
Eclipses affect birds. Weather
surveillance radar are used to detect birds in flight to learn how migrations
are affected.
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- The 2017 eclipse disrupted the daily
activities of insects and birds, but did not trigger usual animal nocturnal
behaviors such as birds migrating or bats emerging. This time around, birds might be more apt to
migrate during the eclipse, given that it's in April.
-
- Eclipses have a special power. They move
people to feel a kind of reverence for the beauty of our universe. Scientists in the United States were excited
to use the October "ring of fire" eclipse as valuable practice for a
total eclipse in the Americas in 2024.
-
- An annular eclipse occurs when the moon is
further away from Earth, causing it to be slightly smaller than the sun in the
sky. The smaller moon is unable to block the entire disk of the sun, creating a
"ring of fire" for a few minutes when the moon passes in front of the
sun.
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- The total solar eclipse that passes across
the United States on April 8, 2024. You can get viewing details for totality at
Space.com.
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- “Inouye”, the world's largest solar
telescope, will not be in the eclipse path during April 2024's events. But
Inouye will provide a high-resolution "unobstructed view of the sun while
the eclipse is happening. Inouye's results can then be compared with other
telescopes to get a fuller picture of solar activity and its effects on Earth,
particularly with the sun at a height of solar activity.
-
- Iinouye is like a microscope, essentially to
zoom in and look at features we wouldn't be able to see otherwise without this
type of high resolution, and then connecting it to other telescope
observations.
-
- It will be able to view a very active
corona, or upper atmosphere of the sun, during the precious minutes that the
sun is nearly completely blocked by the moon. The sun is nearing its maximum of
solar activity in its 11-year-cycle, unlike the last U.S. total solar eclipse
of 2017, meaning that "the corona will be very active this time around.
-
- Solar activity has an immense impact on the
ionosphere, which is a layer of Earth's atmosphere that interacts with
electromagnetic radiation from above and below its extent. These interactions
affect the propagation of radio signals.
-
- With the sun mostly blacked out temporarily
by the eclipse, NSF will be carefully watching what happens when you suddenly
turn off that X-ray and the ultraviolet rays from the sun that usually filter
into the ionosphere and affect its extent.
The ionosphere actually expands and contracts depending on how much
energy it is absorbing from the sun.
-
- The ham radio community will also help with
ionospheric studies during the eclipse, using their GPS receivers to help
professional scientists track changes in that layer of the Earth's atmosphere.
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- Scientists will be watching local weather
to see how it is affected by the lack of solar radiation. The moon's shadow
traverses across the atmosphere at supersonic speeds, so things change fast and
very quickly throughout the eclipse region.
-
- In April, 2024, scientists will chase the
total eclipse in the Gulfstream-V aircraft to study the elusive "low
corona," referring to the parts of the upper atmosphere of the sun that
are not observable from space.
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- Once this eclipse campaign is over, NSF
says no other total solar eclipse will be visible in the United States until
2044.
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- This total solar eclipse in North America
could shed light on a persistent puzzle about the sun. During the eclipse, the path of totality,
where observers experience the darkest part of the moon's shadow (the umbra),
crosses Mexico, arcing north-east through Texas, the Midwest and briefly
entering Canada before ending in Maine.
-
- Total solar eclipses occur roughly every 18
months at some location on Earth. The last total solar eclipse that crossed the
US took place on August 21, 2017.
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- We can observe the sun's faint corona with
incredible clarity, from distances very close to the sun, out to several solar
radii. One radius is the distance equivalent to half the sun's diameter, about
696,000km (432,000 miles).
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- Measuring the corona is extremely difficult
without an eclipse. It requires a special telescope called a coronagraph that
is designed to block out direct light from the sun. This allows fainter light
from the corona to be resolved. The clarity of eclipse measurements surpasses
even coronagraphs based in space.
-
- We can also observe the corona on a
relatively small budget, compared to, for example, spacecraft missions. A
persistent puzzle about the corona is the observation that it is much hotter
than the photosphere (the visible surface of the sun). As we move away from a
hot object, the surrounding temperature should decrease, not increase. How the
corona is heated to such high temperatures is one question to be investigated.
-
- We have two main scientific instruments.
The first of these is Cip (coronal imaging polarimeter). Cip is also the Welsh
word for "glance," or "quick look." The instrument takes
images of the sun's corona with a polariser.
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- The light we want to measure from the corona
is highly polarized, which means it is made up of waves that vibrate in a
single geometric plane. A polarizer is a filter that lets light with a
particular polarization pass through it, while blocking light with other
polarizations.
-
- The Cip images will allow us to measure
fundamental properties of the corona, such as its density. It will also shed
light on phenomena such as the solar wind. This is a stream of sub-atomic
particles in the form of plasma, superheated matter, flowing continuously
outward from the sun. Cip could help us identify sources in the sun's
atmosphere for certain solar wind streams.
-
- Direct measurements of the magnetic field
in the sun's atmosphere are difficult. But the eclipse data should allow us to
study its fine-scale structure and trace the field's direction. We'll be able
to see how far magnetic structures called large "closed" magnetic
loops extend from the sun. This in turn will give us information about
large-scale magnetic conditions in the corona.
-
- The second instrument is “Chils” (coronal
high-resolution line spectrometer). It collects high-resolution spectra, where
light is separated into its component colors. Here, we are looking for a
particular spectral signature of iron emitted from the corona.
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- It comprises three spectral lines, where
light is emitted or absorbed in a narrow frequency range. These are each
generated at a different range of temperatures (in the millions of degrees), so
their relative brightness tells us about the coronal temperature in different
regions.
-
- Mapping the corona's temperature informs
advanced, computer-based models of its behavior. These models must include
mechanisms for how the coronal plasma is heated to such high temperatures. Such
mechanisms might include the conversion of magnetic waves to thermal plasma
energy. If we show that some regions are hotter than others, this can be
replicated in the models.
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- This year's eclipse also occurs during a
time of heightened solar activity, so we could observe a coronal mass ejection
(CME). These are huge clouds of magnetized plasma that are ejected from the
sun's atmosphere into space. They can affect infrastructure near Earth, causing
problems for vital satellites.
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- Many aspects of CMEs are poorly understood,
including their early evolution near the sun. Spectral information on CMEs will
allow us to gain information on their thermodynamics, and their velocity and
expansion near the sun.
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- Our eclipse instruments have recently been
proposed for a space mission called moon-enabled solar occultation mission
(Mesom). The plan is to orbit the moon to gain more frequent and extended
eclipse observations.
-
- We will also have an advanced commercial
360-degree camera to collect video of the April 8 eclipse and the observing
site.
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March 29, 2023 SOLAR
ECLIPSE - in2024, what we hope to learn? 4412
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