Transcript SOLAR PHYSICS

SOLAR PHYSICS
Advanced Space Academy
U.S. Space & Rocket Center
SOLAR PHYSICS
Why the Sun?
The Ozone Hole
Solar Structure
Solar Features
Solar Missions
Why The Sun?
Clues to our origins
Curiosity
Avoid endangering
astronauts and
spacecraft
Energy Source
Predict
communication
problems
The Ozone Hole
 16,000,000 square miles
(26,000,000 square km)
in size
 Mainly located over
Antarctica; however, its
boundaries can extend
upward uncovering
portions of Australia,
South America, and South
Africa
 Exacerbated by CFC’s
http://science.nasa.gov/headlines/y2001/ast17sep_1.htm
Solar Structure
Early Life
– Gas & dust
– Shock waves & gravity
– Contraction increased
pressure and temperature
– Fusion at 15 million
degrees F (8.3 million
degrees C)
– Electromagnetic radiation
Sun Facts
Mass - 1 billion trillion trillion tons
330,000 times the Earth’s mass
Diameter - 864,000 miles (1,390,000 km)
75% Hydrogen and 25% Helium by mass
93,000,000 miles (150,000,000 km) from
Earth
The sun is an average G2 star
(classification on next slide)
http://www.windows.ucar.edu/tour/link=/sun/statistics.html&edu=high
Sun Facts: Classification G2
Solar Structure
Midlife
Our Sun contains 99.9% of the
matter in our solar system
 4 layers:
–
–
–
–
Core
Photosphere
Chromosphere
Corona
 Radiation Travel Times:
– millions of years from core
to chromosphere
– 8 minutes to Earth
 Striated rotation
http://windows.arc.nasa.gov/tour/link=/sun/sun.html&edu=high
The Solar Cycle
The Sun goes through a cycle every 11
years
Solar Minimum
Solar Maximum
The 11 year sunspot cycle is actually
related to a 22 year cycle for the reversal of
the Sun's magnetic field.
http://windows.arc.nasa.gov/tour/link=/sun/activity/solar_cycle.html&edu=high
Our Sun is an Active Star
Solar Midlife - Core
 Temperature –
27,000,000°F
(15,000,000 °C)
 Pressure - 250 billion
atmospheres
 The Radiative Zone
 The Interface Layer
 The Convection Zone
http://science.msfc.nasa.gov/ssl/pad/solar/interior.htm
Solar Midlife - Core
 MAGNETISM – the
key to understanding
the Sun
 The magnetic field is
produced in the Sun
by the flow of
electrically charged
ions and electrons
most likely in the
interface layer
Solar Midlife - Photosphere
 Temperature - 10,500°F
(5,800ºC)
 The sun’s lower
atmosphere
 62 miles (100 km) thick
 It gives off most of its
energy as visible light and
heat
 Sunspots originate on this
layer
http://science.msfc.nasa.gov/ssl/pad/solar/surface.htm
Photospheric Features
 SUNSPOTS
 appear as dark spots on
the sun
 They are really several
spots clustered together
 They originate at the
poles
 They are magnetic
 Sunspots are “cool”
regions - 6,800°F
(3,800ºC) compared to
their surroundings
http://www.space.com/scienceastronomy/top10_2002_021224-8.html
Photospheric
Features
SUNSPOTS
– Observing sunspots
“moving” across
the Sun was how
scientists figured
out that the Sun
actually rotated
Photospheric Features
 FACULAE
– Bright areas seen near
the edge of the solar
disk
– These are magnetic
areas but the magnetic
field is in smaller
bundles than in
sunspots
http://science.msfc.nasa.gov/ssl/pad/solar/feature1.htm
Photospheric Features
 GRANULES
– Small cellular features that
cover the entire Sun except
for those areas covered by
sunspots
– Individual granules last for
only about 20 minutes
– The flow within the
granules can reach
supersonic speeds and
produce sonic “booms”
that generate waves on the
Sun’s surface
http://science.msfc.nasa.gov/ssl/pad/solar/feature1.htm
Photospheric Features
 SUPERGRANULES
– Much larger versions of
granules
– The fluid flows observed in
supergranules carry
magnetic field bundles to
the edges of the cells where
they produce the
chromospheric network
http://science.msfc.nasa.gov/ssl/pad/solar/feature1.htm
Solar Midlife - Chromosphere
 Faint and red - seen
only briefly during an
eclipse
 Temperature rises
from 10,800°F
(6,000ºC) to 36,000°F
(20,000ºC)
Chromospheric Features
 CHROMOSPHERIC
NETWORK
– Web-like pattern
– Outlines the
supergranule cells
seen on the
photosphere
http://science.msfc.nasa.gov/ssl/pad/solar/feature2.htm#Network
Chromospheric Features
 FILAMENTS
– dense, somewhat
cooler, clouds of
material suspended
above the
chromosphere by loops
of magnetic field
 PLAGE
– bright patches above
sunspots
http://science.msfc.nasa.gov/ssl/pad/solar/feature2.htm#Network
Chromospheric Features
 PROMINENCES
– dense clouds of material
suspended above the
surface of the Sun by loops
of magnetic field
http://science.msfc.nasa.gov/ssl/pad/solar/feature2.htm#Network
Chromospheric Features
SPICULES
– Small jet-like
eruptions seen
throughout the
chromospheric
network
http://science.msfc.nasa.gov/ssl/pad/solar/feature2.htm#Network
Chromospheric Features
SOLAR FLARES – can release as much
energy as a billion megatons of TNT
Transition Region
 A very thin, irregular layer of the Sun that
separates the chromosphere from the corona
 Temperature changes very rapidly in this region
and causes hydrogen to become stripped of its
electrons.
 The light emitted by the transition region is
dominated by ions illustrated in the pictures
http://science.msfc.nasa.gov/ssl/pad/solar/t_region.htm
Solar Midlife - Corona
 The Sun’s outermost
atmosphere
 Temperature is
1,800,000°F
(1,000,000°C)
 The Solar Corona
– The White-Light Corona
– The Emission Line Corona
– The X-Ray Corona
http://science.msfc.nasa.gov/ssl/pad/solar/corona.htm
Solar Midlife - Corona
 EMISSION LINE
CORONA
 Since hydrogen atoms
have been ionized only
the heavier trace elements
like iron and calcium are
able to retain a few of
their electrons in this
intense heat
 It is emission from these
elements that produce the
color associated with the
emission line corona
http://science.msfc.nasa.gov/ssl/pad/solar/corona.htm
Solar Midlife - Corona
 X-RAY CORONA
 The corona shines
brightly in x-rays because
of its high temperature
while other layers of the
Sun do not emit x-rays
 This allows us to view the
corona across the disk of
the Sun when we use an
X-Ray telescope
http://science.msfc.nasa.gov/ssl/pad/solar/corona.htm
Coronal Features
 HELMET
STREAMERS
 Large cap-like coronal
structures with long
pointed peaks that
usually overlie
sunspots and active
regions formed by a
network of magnetic
loops
http://science.msfc.nasa.gov/ssl/pad/solar/feature3.htm
Coronal Features
 POLAR PLUMES
 Long thin streamers
that project outward
from the Sun’s north
and south poles
 They are associated
with the “open”
magnetic field lines at
the Sun’s poles
http://science.msfc.nasa.gov/ssl/pad/solar/feature3.htm
Coronal Features
 CORONAL LOOPS
 Found around sunspots
and in active regions
 Associated with the
closed magnetic field
lines that connect
magnetic regions on the
solar surface
 Some loops appear after
solar flares
http://science.msfc.nasa.gov/ssl/pad/solar/feature3.htm
Coronal Features
 CORONAL HOLES
 Regions where the corona
is dark
 Associated with “open”
magnetic field lines and
are often found at the
poles
 The solar wind originates
in coronal holes
http://science.msfc.nasa.gov/ssl/pad/solar/feature3.htm
Coronal Features
 CORONAL MASS
EJECTIONS (CMEs)
 huge bubbles of gas threaded
with magnetic field lines that
are ejected from the Sun over
the course of several hours.
 CMEs can disrupt the flow of
the solar wind
 CMEs are often associated
with solar flares and
prominence eruptions but they
can also occur in the absence
of either of these processes.
http://www.gsfc.nasa.gov/topstory/20021030solar.html
The Solar Wind
 The solar wind streams off
of the Sun in all directions
at speeds of about 1 million
miles per hour
 The source of the solar wind
is the Sun's hot Corona
 The temperature of the
corona is so high that the
Sun's gravity cannot hold on
to it
http://antwrp.gsfc.nasa.gov/apod/ap020101.html
The Solar and Heliospheric
Observatory (SOHO)
 The SOHO spacecraft is a
joint effort between
NASA and ESA
 It was launched on
December 2, 1995
 SOHO will take
measurements of the solar
interior, the solar
atmosphere, and the solar
wind
http://sohowww.nascom.nasa.gov/
SOHO Images
 Composite picture of 3 images
taken by the EIT instrument on
board SOHO
 Each individual image shows a
different temperature in the
upper solar atmosphere and
was assigned a specific color
 Red at 2 million degrees F
 Green at 1.5 million degrees F
 Blue at 1 million degrees F
http://antwrp.gsfc.nasa.gov/apod/ap021221.html
Transition Region and Coronal
Explorer (TRACE)
 TRACE will explore
the magnetic field in
the solar atmosphere
 TRACE will work in
conjunction with
SOHO for part of its
mission
 It was launched by a
Pegasus rocket in
April 1998
http://vestige.lmsal.com/TRACE/
TRACE Images
 Solar flare observed
on May 19,1998
 A solar flare is a rapid
release of energy from
a localized region on
the Sun in the form of
electromagnetic
radiation, energetic
particles, and mass
motions
http://vestige.lmsal.com/TRACE/Science/ScientificResults/trace_cdrom/html/trace_images.html
GENESIS – Search for Origins
 What is the Sun made of?
 Launched August 8, 2001
 Genesis will collect solar
wind samples for 2 years
 Libration points
 22.3 ft (6.8m) solar panel
length
 1402 lbs (636 kg) at
launch
http://genesismission.jpl.nasa.gov/
Solar Structure
•The End
•Hydrogen depletion
•Red giant
•Fusion stops,
outward pressure
decreases
•Collapse
•Planetary Nebula
•White Dwarf
http://www.astronomynotes.com/evolutn/chindex.htm