Question

1. how long is the suns solar activity cycle?

a) 7 years
c) 11 years
b) 9 years
d) 20 years

1. what is a light - year?

a) the time it takes light to reach earth
c) a unit of star brightness
b) the distance light travels in one year
d) a measure of gravity strength

1. why is a light - year important to astronomers?

a) it measures the speed of a planet
c) it determines a stars age
b) it tells us the distance to stars
d) it measures the color of starlight

1. what is solar weather?

a) changes in earths climate
c) temperature of the suns core
b) radiation and particle activity from the sun
d) seasonal changes on other planets

Explanation:

• Question 19: The Sun's solar activity cycle is known to be approximately 11 years. This is a well - established astronomical fact.
• Question 20: A light - year is defined as the distance that light travels in one year. Light travels at a very high speed (\(c = 3\times10^{8}\ m/s\)), and over the course of a year (\(t=365\times24\times3600\ s\)), it covers a vast distance.
• Question 21: Since stars are extremely far away, using light - years helps astronomers express these large distances in a more manageable way. For example, if a star is \(n\) light - years away, we know the distance based on the speed of light and the time (one year).
• Question 22: Solar weather refers to the radiation and particle activity emitted from the Sun. This can have effects on Earth's space environment, such as causing auroras.

Answer:

1. C. 11 years
2. B. The distance light travels in one year
3. B. It tells us the distance to stars
4. B. Radiation and particle activity from the Sun