ESSS1.1 Relative Brightness

The table shows the distances of the Sun and Alpha Centauri from Earth and their relative brightness. A student claims that the Sun is brighter than Alpha Centauri. Is the claim correct, and why?

• No. Alpha Centauri is closer to Earth than the Sun.

• Yes. The Sun is closer to Earth than Alpha Centauri.

• No. The Sun has a higher relative brightness than Alpha Centauri.

• Yes. Alpha Centauri has a lower relative brightness than the Sun.

Answer explanation

The claim is correct because the Sun has a higher relative brightness than Alpha Centauri. Despite Alpha Centauri being closer, the Sun's brightness is significantly greater, making it appear brighter from Earth.

A student reads that the star Vega is much brighter and farther from Earth than the Sun. It is twice as large as the Sun. The student observes that Vega appears smaller and dimmer than the Sun from the surface of Earth. Which difference between the stars best explains the student’s observation?

• the difference in the brightness of the stars

• the difference in the sizes of the stars

• the difference in the distance of the stars from each other

• the difference in the distances of the stars from Earth

Answer explanation

Vega is much farther from Earth than the Sun, which significantly reduces its apparent brightness and size when viewed from Earth, despite being intrinsically brighter and larger.

Four similar light sources are viewed from various distances by an observer. The table shows how each light source appears to the observer. What can be concluded about the distances of the light sources from the observer?

• Light Source R is farther from the observer than Light Sources P, Q, and S.

• Light Source Q is farther from the observer than Light Sources P, R, and S.

• Light Source S is farther from the observer than Light Sources P, Q, and R.

• Light Source P is farther from the observer than Light Sources Q, R, and S.

Answer explanation

Light Source S appears dimmer than P, Q, and R, indicating it is farther away. The other sources appear brighter, suggesting they are closer to the observer. Thus, Light Source S is indeed the farthest.

Which statement best explains why the Sun appears to be the brightest star when standing on Earth?

• The Sun is the biggest star in the galaxy, so it appears to be the brightest.

• The Sun is the oldest star in the galaxy, so it appears to be the brightest.

• The Sun is the closest star to Earth, so it appears to be the brightest.

• The Sun is the only star made of gas, so it appears to be the brightest.

Answer explanation

The Sun appears brightest because it is the closest star to Earth, making its light more intense compared to other stars that are much farther away.

Which statement best describes why the Sun looks brighter on Earth than other stars?

• The Sun reflects the Moon’s light.

• The Sun is the hottest star in the universe.

• The Sun creates both light and heat.

• The Sun is the closest star to Earth.

Answer explanation

The Sun appears brighter on Earth than other stars primarily because it is the closest star to us. Its proximity allows its light to reach us more intensely compared to distant stars.

The table shows the distances from Earth and the relative sizes of three stars. All three stars have the same actual brightness. When viewed from Earth, the Sun appears brightest. Which star is the least bright when viewed from Earth, and why?

• Star 1 is the least bright because it is larger than star 2.

• Star 2 is the least bright because it is smaller than star 1.

• Star 2 is the least bright because it is closer to Earth than star 1.

• Star 1 is the least bright because it is farther from Earth than star 2.

Answer explanation

Star 1 is the least bright because it is farther from Earth than star 2. Since all stars have the same actual brightness, distance affects their apparent brightness; the farther a star is, the dimmer it appears.

Tags

NGSS.MS-ESS1-3

A student uses flashlights to represent different stars and a ball to represent Earth. Which flashlight should be labeled as the Sun?

• flashlight 1

• flashlight 2

• flashlight 3

• flashlight 4

Answer explanation

Flashlight 1 should be labeled as the Sun because it represents the central star in the solar system, providing light and energy to the Earth (represented by the ball). The other flashlights represent different stars.

Tags

NGSS.MS-ESS1-1

The table shows the distances of four stars that shine the same amount of light and are visible from Earth. Which is the correct order of the stars from dimmest to brightest as seen from Earth?

• J, L, M, K

• K, M, L, J

• L, J, M, K

• M, L, K, J

Answer explanation

The brightness of stars as seen from Earth decreases with distance. Since all stars shine the same amount of light, the order from dimmest to brightest is determined by their distances. Thus, the correct order is K, M, L, J.

Which statement best explains why the Sun appears to be the brightest star when standing on Earth?

• The Sun is the brightest star in the galaxy, so it appears to be the brightest.

• The Sun is the oldest star in the galaxy, so it appears to be the brightest.

• The Sun is the closest star to Earth, so it appears to be the brightest.

• The Sun is the only star made of gas, so it appears to be the brightest.

Answer explanation

The Sun appears brightest from Earth because it is the closest star, making its light more intense compared to other stars that are much farther away.

Four students hold glowing balls to represent stars of the same size. The students position themselves at four different distances away from the door in a dark room. If the person standing in the doorway of the room represents Earth, which ball will best represent the position of the Sun compared to other stars in outer space?

• ball 1

• ball 2

• ball 3

• ball 4

Answer explanation

Ball 1 best represents the Sun's position because it is closest to the doorway, similar to how the Sun is relatively near to Earth compared to other stars in the vastness of space.

Tags

NGSS.MS-ESS1-1

NGSS.MS-ESS1-3