group 1 sUN POWERPOINT PRESENTATION 2017

PPT

2. The Sun

3. The Sun
•Is a star
•Made of gases
•Is our primary
source of
energy
70% hydrogen and 28% helium
Light (radiation)
Image at
http://science.nasa.gov/headlines/y2007/images/chromosphere/LimbFlareJan12_strip2.jpg

4. How Big is the Sun?
About 110 times
wider than Earth
Or
1.3 million times
bigger than
Earth

5. How does our Sun compare to other
Stars?
•Active stars range in
size from supergiants
to dwarfs
•Stars range from very
bright (supergiants) to
very dim (dwarfs)
•Stars range from very
hot blue on the
outside (O class) to
cool red on the
outside (M class)
Our Sun is in-between--yellow
Our Sun is a dwarf—medium
mass
Our Sun is a medium-bright
dwarf

6. 10 Facts about the SUN
1.The sun is most massive object in the solar system.
2.The sun is actually the closest star to Earth.
3.The sun is made up of distinctive layers and regions.
4.Since its formation, the sun has used up about half of the hydrogen in its core
5.The sun’s strong gravitational pull holds Earth and the other planets in place
6.The greeks named the sSn Helios
7.We’ve always known the sun.
8.Ulysses was the first spacecraft to study our sun’s poles.
9.The sun’s surface compared to planets.
10. Scientists long puzzled over how the corona got so hot.

7. •Sun’s magnetic field
Winds up due to differential rotation
Eventually forms loops and becomes tangled
•Rotation
At the equator, the Sun rotates once every 25.4 days.Near its
poles, the Sun rotates once every 36 days. Known as
“differential rotation”
•Orbits
–The Sun’s powerful gravity keeps the planets in orbit

8. Inside the Sun
•Core
•Radiative Zone
•Convection zone
Image at http://solarscience.msfc.nasa.gov/interior.shtml

9. The Sun’s Atmosphere
•Photosphere
–The luminous envelope of a star
from which its light and heat
radiate
•Chromosphere
A reddish gaseous layer immediately
above the photosphere of the sun
or another star. Together with the
corona, it constitutes the star’s
outer atmosphere
•Corona
–Is an aura of plasma that
surrounds the sun and ather
stars. The sun’s corona extends
millions of kilometeres into space
and is most largely seen during
total eclipses

10. Features in the Photosphere
•Sunspots
–Dark and small (but brighter than Full Moon and
big as Earth)
–Cool-- temperatures only 6,200 F (Sun’s surface is
10,000 F)
–Associated with magnetic fields: one set of spots is
positive, other is negative

11. Energy from the Sun
•Nuclear chain reaction (hydrogen
forming helium)
•Releases radiation (gamma rays)
•The gamma ray loses energy as it
bounces around inside the Sun
•It is finally released at the photosphere,
primarily as visible light

12. Solar Wind
•Blows charged particles and magnetic fields away from the Sun
•Charged particles captured by Earth’s magnetic field
•Create Auroras or Northern and Southern Lights

13. Radiation
•Our Sun (and all active stars) emits radiation
–Radio, infrared, visible, ultraviolet, x-ray and even some
gamma rays
–Most of the sunlight is yellow-green visible light or close
to it
The Sun at X-ray wavelengths
Image and info at
http://imagine.gsfc.nasa.gov/docs/teachers/gammaraybursts/imagine/page18.html and
http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/sun.html
.

14. Sun’s Radiation at Earth
•The Earth’s atmosphere filters out some
frequencies
–Ozone layer protects us from some ultra-violet, and most
x-rays and gamma rays
–Water and oxygen absorb some radio waves
–Water vapor, carbon dioxide, and ozone absorbs some
infrared

15. Sunlight is absorbed by Earth
•The Sun does NOT send “heat rays” into space.
Some of its light is infrared, but that is not the
same thing as heat.
•The Sun’s light is absorbed by Earth (clouds,
plants, oceans, rock…)
•By absorbing the light, we are transforming it into
heat energy

16. Sun as a Source of Energy
•Light from the Sun is absorbed by the Earth,
unevenly to:
–drive wind bands – which drive surface currents
–drive deep ocean currents
–drive water cycle
–drive weather
NASA image at http://visibleearth.nasa.gov/view_rec.php?id=107
Credit: NASA GSFC Water and Energy Cycle
http://www.nasa.gov/centers/jpl/news/grace-20061212.html

17. Sun as a Source of Energy
•Plants need light for photosynthesis
•Without its heat, the only inhabitable areas on
Earth would be near volcanic vents
Images from http://nasadaacs.eos.nasa.gov/articles/2005/2005_rainforest.html and
http://planetquest.jpl.nasa.gov/TPF/tpf_book/gallery/4-2a.html

18. Our Sun is a Regular/ Small Star
Image at http://www.gsfc.nasa.gov/topstory/20011210insidesun.html

19. •Like any other energy source, Sun is not
FOREVER.
• It is roughly middle-aged and has not
changed dramatically for over four billion
years and will remain fairly stable for about
five more billion years.
• However, after hydrogen fusion in its core
has stopped, the sun will undergo several
changes.

20. •The sun will expand to about a hundred times its
current size, swallowing probably Mercury, Venus
and Earth.
• It will burn as a red giant for another five billion
years and then collapse into a white dwarf about
the size of planet Earth.

21. In a few Billion years… Red Giant
Image at http://hubblesite.org/newscenter/archive/releases/1997/26/image/a/

22. By 5 billion years… White Dwarf
Image at http://hubblesite.org/newscenter/archive/releases/nebula/planetary/1998/39/results/50/