Sem#2 Chap 9 Flashcards
Solar Storm
Sun emitted billions of tons of charged particles
* Protons, electrons, and helium nuclei
* Traveled through space at 1.6 million km/h
Society must consider risks
from outer space: List them:
- Space weather from the Sun
- Asteroid and comet impacts
Fusion reactions combine _____ to form _______.
hydrogen to form helium.
Matter exists as ______on Sun
plasma
Plasma
- Hydrogen and helium atoms without their electrons
- Free electrons
Corona
The top of solar atmosphere
Solar wind
Corona’s plasma that escapes the Sun’s gravity
Solar plasma particles
- Travel ~400 -750 km/s
- Reach Earth’s orbit in 2.3 to
4.3 days - Density is ~5 particles/cm3
Electrically charged particles create a ______.
magnetic field
Sunspots appear as ______. (physical looks)
dark patches
Sun’s magnetic field reverses
polarity once every ______.
11 years.
- Field strengthens and
weakens within this period
A magnetic field has two
poles. List them:
(north and south).
Field lines arc into space
when ________.
field is strong.
- Plasma upwelling is slowed.
- Cooler patches develop.
Plasma Arc (look like )
Slide #9 Chap 9
Prominences:
- Release glowing gas and plasma
- Arc from one sunspot to another, within a pair
- Arcing magnetic field lines become visible.
- Last hours, days, or weeks
Flares
- Release large amounts of electromagnetic energy
- Last minutes to hours
Flares may disrupt _______.
Earth’s atmosphere
Radio waves disruption is
likely.
CMEs:
- Release plasma into space
- Plasma travels faster than
typical solar wind. - CME plasma speed can reach
~3,000 km/s.
CMEs affect Earth if _______-.
planet is within plasma’s path
- Disturbances in Earth’s magnetic field are likely.
- Severe space weather is likely.
- Human activities are at risk.
Class Question #1
How is a solar flare different from a coronal mass ejection?
a) A solar flare expels electromagnetic radiation into space, while a
coronal mass ejection expels plasma.
b) A solar flare’s plasma travels at the speed of light, while plasma
from a coronal mass ejection travels at the speed of sound.
c) Solar flares are expelled from the sun’s convective zone, while
coronal mass ejections are expelled from the sun’s core.
d) Solar flares create space weather within the Sun’s atmosphere,
while coronal mass ejections create space weather in Earth’s
atmosphere.
(NOT GIVEN)
3 types of ultraviolet (UV)
radiation:
UV-A; UV-B; UV-C
Some UV-A and UV-B reach
Earth’s surface. Affects people how?
Cause skin damage, wrinkles, and sunburns
The stratosphere stops ______ (radiation).
UV-C
_______ breaks molecular bonds
in stratospheric O2
UV-C
- Creates free oxygen atoms
- O and O2 merge to form O3.
Ozone (O3):
- Mostly in stratosphere
- Absorbs UV-C radiation
- Protects Earth’s surface from
harmful, high-energy UV-C
Chlorofluorocarbons (CFCs)
break up ______.
O3 molecules
Ozone hole:
a region of reduced stratospheric ozone
- Mostly over Antarctica
- Global O3 reductions occur
due to worldwide air mixing. - More UV-A and UV-B reach
Earth’s surface. - Skin cancer risk increases.
Earth’s outer core consists of
rotating______.
liquid iron
Rotating liquid metal
generates a magnetic field.
Solar wind distorts field into a _____ shape.
teardrop
Magnetotail points away
from Sun.
Magnetic field shields Earth
from ______.
solar wind
Magnetosphere
the region inside the magnetic shield
Solar wind creates electric
currents in _______.
magnetosphere
Van Allen radiation belts
- 1,000 and 12,000 km from
Earth - Ions oscillate rapidly back
and forth between poles.
Aurorae:
- Develop as solar wind electrons descend over poles
- Electrons excite atmospheric gases, creating gauzy lights.
- Aurora Borealis is over the northern pole.
- Aurora Australis is over the South Pole.
Heating of the thermosphere:
- Solar wind and radiation heat up thermosphere’s gasses.
- Thermosphere expands into region where satellites orbit.
- Satellite orbits become less predictable.
Radio transmissions disruption:
- Modern communications depend on radio waves.
- Satellites, cell phones, and the global positioning system (GPS)
Electrical Currents can damage???
Electrical discharges can damage satellites.
Rogue electric currents can disrupt power grids.
* In 1989, a solar storm blacked out Quebec’s grid.
* Cascading failure is possible, since most grids are connected.
Rogue electric currents can damage electronic equipment.
Mitigating Space Weather
- Electronic equipment can be radiation hardened.
- Electric grids can be designed to stop surges.
- Power companies can stage replacement equipment.
- Equipment can be shut off before space weather arrives.
The Space Weather Prediction Center:
- Watches for solar storms
- Issues warning to utilities and governments
Class Question #2
Why is the magnetosphere important?
a) It shields Earth from UV-A and UV-B radiation.
b) It heats up the thermosphere, thereby ensuring that satellite orbits
remain stable and predictable.
c) It shields Earth from hydrogen and helium atoms, as well as from
free electrons, emitted from the Sun.
d) It stops aurorae from forming over the South Pole.
(NOT GIVEN)
Asteroids:
rocky or metallic objects mostly in asteroid belt
Comets:
ice and rock masses from the Kuiper Belt, or beyond
Meteoroids:
rocky or metallic objects traveling through space
Planets, moons, and dwarf planets pose ____ threat to Earth.
no