Lecture 31: The Sun

Q) The image shows a picture of the Sun. The dark spots located on this image are sunspots. How does the size of Earth compare to the size of the sunspot that is identified on the right side of the image of the sun

A) Earth and the sunspot are about the same size

Source of Solar Energy

Lifetime of star related to its power output Nuclear fusion: combine 2 or more nuclei to make one nucleus with greater number of protons or neutrons Sun releases energy by fusing four hydrogen nuclei into one helim nucleus e= mc ^2

Basic properties of the Sun

- radius (109 times Earth) - Equatorial rotation period: 25 days

Mass, Distance and Size of the Sun

- sun contains more than 99.85% of total mass of solar system - Earth - Sun distance - 1 Astronomical Unit - Solar Diameter (110 Suns fit between the Earth and the Sun) - Earth Diameter - 110 Earths fit across diameter of Sun

Q) The Sun has a diameter of approx 1.4 million Kilometer.s Roughly how many Earths would fit across the diameter of the Sun?

110 Earths fit across the diameter of the sun

approx how many times could the Moon's orbital diameter fit b/w Earth and sun?

220 b/c 110 Earths fit across the sun and 2 moon's orbits fit across the sun

How many moons would fit across the diameter of the sun?

440 b/c 110 earths across sun, and then 4 moons within earth

Scale model of Earth and Sun

Baseball - sun grain of sand - earth

Summary of relative distances

Earth: 4X bigger than the moon (Basketball | baseball) 30 earths fit b/w Earth and the Moon 110 Earth's fit across Sun (soccer ball - Sun | grain - earth) 2 Moon's orbits fit across the Sun 110 Suns fits between Earth & Sun

LT 113 - 115

Sun Size

The Sun:

a giant ball of hot gas **the closest star to us - "plasma" - hot gas in which most atoms are ionized - mostly Hydrogen and Helium - creates energy through fusion

What has the largest mass? a. 4 protons b. 1 helium nucleus c. 4 protons and 1 helium nucleus have the same mass

a) 4 protons is greater

Scale of Earth and Moon a) basketball and soccer ball b) basketball and baseball c) basketball and ping-pong ball d) basketball and pea e) basketball and grain of sand

basketball (earth) and baseball (moon)

Which statement do you think best represents the size comparison b/w the diameter of the Sun and the distance b/w the Moon and Earth? The Sun's diameter is... a) smaller than the distance b/w Moon and Earth b) approx equal to the distance b/w Moon and Earth c) larger than the distance b/w Moon and Earth

c) larger than the distance b/w Moon and Earth

If you were constructing a scale model of the solar system that used a Sun that was the size of a basketball (12 in) in diameter, which of the following lengths would most closely approximate the scaled distance b/w Earth and Sun? a) 3 f t b) 10 ft c) 100 ft d) 300 ft

c)c) 100 ft

If you were to use a 1 ft basketball to represent the Sun, how far would it have to be from Earth to be an accurate scale model? a) 1 ft b) 10 ft c) 30 ft d) 110 ft e) 300 ft

d) 110 ft

Let's say you use a 1 ft basketball and a 3 inch orange as your Earth and Moon. About how far apart must they be placed to represent an accurate scale model of the Earth-Moon orbital system? a) 1 ft b) 4 ft c) 10 ft d) 30 ft e) 300 ft

d) 30 ft

If you were to construct a scale model of the solar system that used a 2cm cherry to represent the Moon, how large of a ball would you need to represent the Sun? a. 4cm b. 30 cm c. 110 cm d. 440 cm e. 880 cm

e. 880 cm b/c 110 earth's b/w Sun and Earth and then there are 2 orbital periods of moon to sun and then 4 moons fit earth