Transcript Space - mrbemrose

Grade 9 Science
Space Part 2
The sun and our solar system
Key Terms
Astronomy: The branch of science that
studies objects beyond the Earth (in “outer
space”)
Celestial body: Any object in space
The Universe: Everything that exists
Star: A massive celestial body composed of hot gases that
radiates large amounts of energy
Luminous: glowing, light producing
Planet: a celestial body which orbits a star
Satellite: a celestial body which orbits another body
Orbit: the closed path an satellite takes around another
body
Moon: a natural satellite of a planet
Solar system: the Sun and all of the celestial bodies that
orbit it
Our Star: The Sun
http://www.universetoday.com/18847/life-of-the-sun/
Core Temperature: 15,000,000 °C
DID YOU KNOW?!?
• 100 billion tonnes of Dynamite would have to
be detonated every second in order to match
the Sun’s energy output!!
• The sun is getting hotter…becoming 10% more
luminous every billion years
• If the sun where to “turn off”, within a week
the temperature of the earth would be zero
degrees F
Age: 5 billion years
Diameter: 1,391,000 km
(109 X the size of Earth)
Composition:
94% Hydrogen
6% Helium
0.13% other
http://www.funonthenet.in/articles/scale-of-the-universe.html
The Sun’s Energy Source: Nuclear Fusion
High temperature + High pressure
=
Particles moving quickly and colliding at high speeds
and fusing
Releases enormous amounts of energy
What human energy source does this remind you of?
http://www-istp.gsfc.nasa.gov/istp/outreach/workshop/thompson/sundiag.html
Layers of the Sun
Core:
- 2% of Sun’s volume, 50% of Sun’s mass. DENSE!!!
- nuclear fusion happens here…600 tonnes of H to He per
second
- 15000000°C
Radiative zone:
- Energy moves away from the core
- Photons can take up to 1 million years to reach the next
layer
- 380,000 km thick
- 32% of sun’s volume, 48% of sun’s mass
- 5000000 °C
Layers continued…
Convective zone:
- 66% of Sun’s volume, 2% of Sun’s mass (LOW DENSITY)
- Convective currents form “cells”
- hot gas rises (away from core)
- cool gas falls (toward core)
- 5500°C
Photosphere:
-
Visible “surface” (NOT solid!) looks like boiling liquid
Light and other radiation begins to escape
6000°C
140,000 km thick
The Sun’s “Atmosphere”
Chromosphere:
- 6000-20000°C
- Thousands of kilometers thick
- Composed of spicules
Corona:
- Visible during a full solar eclipse
- 1,100,000°C
http://www.nasa.gov/vision/universe/solarsystem/ring_of_fire_mm.html
http://www.enchantedlearning.com/subjects/astronomy/sun/sunstructure.shtml
Virtual Tour
http://climate.nasa.gov/interactives/sun
Video
https://www.youtube.com/watch?v=C2FE
TG7tCF0
Sunspots on the Photosphere
• Cooler regions on the photosphere (1000-1200ºC cooler)
• Do not emit as much light and appear darker.
• Can last a few days to a few months.
• Largest ever: 1.8*10 10 km2 (36 x Earth’s surface area!!)
http://broadcast.homestead.com/Swedish_20sunspots1.jpg
http://www.crh.noaa.gov/fsd/?n=sunspots
http://oneminuteastronomer.com/wp-content/uploads/2009/09/sunspots_recent_history.jpg
Solar Storms
- Gas and charged particles emitted from the
sun’s surface
Coronal Mass
Flare:
• Higher energy
• Gas and charged particles
ejected
• last a few minutes to a few
hours
• Occur near sunspots
http://www.youtube.com/watch?v=HFT7ATLQQx8
Ejections
• Lower energy
• Ejection of gas
• last several days to
several weeks
http://www.spaceweather.sflorg.com/space_w
eather/sob_multimedia/flvswm_15
http://www.spaceweather.sflorg.com/space_weathe
r/sdo_2010/sdo_02
http://en.wikipedia.org/wiki/Coronal_mass_ejection
Solar Activity Affects the Earth
1. Solar winds are guided by the Earth’s
magnetic field (strongest near the poles)
• They interact with particles in the Earth’s
atmosphere, creating the aurora borealis and
aurora australis
http://en.wikipedia.org/wiki/Aurora_(astronomy)
http://en.wikipedia.org/wiki/Aurora_(astronomy)
http://en.wikipedia.org/wiki/Aurora_(astronomy)
2. Solar activity/storms can…
•
•
interfere with satellites and cellphone/TV
connections
Cause increased radiation for astronauts
3. The sun provides all of our incoming energy!
•
In the form of electromagnetic radiation
Electromagnetic (EM) radiation
http://upload.wikimedia.org/wikipedia/commons/c/cf/EM_Spectrum_Properties_edit.sv
Role of our Atmosphere
• Blocks (reflects) bad radiation (UV)
• Lets in (absorbs) good radiation (infrared and visible)
• Insulates the Earth: keeps us warm, keeps temperatures
from swinging drastically in the day and the night, the
summer and winter.
EM radiation = heat
CO2 traps heat!
http://uhaweb.hartford.edu/GKAUFMAN/
Homework
Reading: 320-328
Textbook questions:
#2-3 on pg. 308, #2-5, and 8-9 on pg. 312
The solar system
Sources
http://www.iflscience.com/space/take-virtual-tour-sun
http://www.astronomynotes.com/starsun/s2.htm#A1.3
http://sunearthday.nasa.gov/2006/educators/lp_k5.php
http://www.youtube.com/watch?v=UgpIy4tUjFI