8th Grade Science Review V2

The star 61 Cygni, in the constellation Cygnus, is a little more than 11 light-years from Earth. Which of the following correctly estimates the time it would take to reach 61 Cygni, based on speed of travel? 8.E.5.1

• 22 years traveling at twice the speed of light

• 11 years traveling at the speed of light

• 5.5 years traveling at half the speed of light

• 1.1 years traveling at one-tenth the speed of light

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NGSS.MS-ESS1-3

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Bryan is reading about space travel. He has read that maybe someday, humans will be able to travel at one-tenth of a light-year. How long, Bryan wonders, would it take to travel from one end of a galaxy to the other? He uses a diagram like the one shown here to do some calculations. Bryan calculates that if a spaceship could travel at one-tenth of a light-year, in one million years it would be able to completely cross how many of the galaxies shown in the diagram? 8.E.5.1

• 1

• 2

• 3

• 4

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NGSS.MS-ESS1-3

Maria is stargazing with her grandmother. Maria’s grandmother points out a star called Rigel Kentaurus, which she says is one of the closest stars to our solar system. Maria’s grandmother tells her that Rigel Kentaurus is about 4.3 light-years away. Which of the following is the correct way for Maria to understand this information? 8.E.5.1

• A beam of light traveling from Earth to Rigel Kentaurus would take a little more than four years to get there.

• The diameter of Rigel Kentaurus is just about four times bigger than the diameter of our Sun.

• It takes a little more than four years for Rigel Kentaurus to make one orbit around the center of the galaxy.

• The light coming from Rigel Kentauris is approximately four times brighter than the light from our Sun.

The Hertzsprung-Russell diagram is used for classifying stars based on the relationship between their brightness and their temperature and color. A diagram is provided. Which of the following is a trend among the main sequence stars? 8.E.5.5

• Most of the stars are white or red.

• The hotter the star, the more brightly it burns.

• Stars dimmer than the Sun are of class O or B.

• The larger stars emit light that is blue.

A number assigned to a star as a measure of how bright it appears to be to an observer on Earth is known as which of the following? 8.E.5.5

• Apparent magnitude

• Temperature

• Color

• Absolute brightness

Mia has created a chart listing the brightness of stars as seen by an observer on Earth. Which of the following is the best title for this chart? 8.E.5.5

• Color

• Apparent magnitude

• Size (diameter)

• Luminosity

The galaxy we live in is the Milky Way galaxy, and it is a spiral galaxy. Galaxies contains billions of which of the following? 8.E.5.2 & 5.3

• Smaller galaxies

• Black holes

• Planets

• Stars

Which of the following is the most accurate description of all known spaces? 8.E.5.2 & 5.3

• The galaxy contains thousands of universes, and each universe contains millions of stars.

• The universe contains hundreds of galaxies, and each galaxy contains thousands of stars.

• The galaxy contains hundreds of universes, and each universe contains thousands of stars.

• The universe contains billions of galaxies, and each galaxy contains billions of stars.

The number of galaxies in the universe is most accurately described as which of the following? 8.E.5.2 & 5.3

• Less than 100

• Several hundred

• A few million

• Many billions

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NGSS.MS-ESS1-2

Earth’s orbit around the Sun is determined by the balance of the Sun’s gravitational pull on Earth and Earth’s forward momentum as it travels around the Sun. If the Sun remained in place but no longer exerted a gravitational pull on Earth, what would be the resulting motion of Earth? 8.E.5.4

• Earth would rotate at the same speed, but in the opposite direction.

• Earth would continue in the same orbit around the Sun, at the same speed.

• Earth would stop orbiting the Sun and begin moving in a straight line.

• Earth would continue in the same orbit around the Sun, but begin to slow down.

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NGSS.MS-ESS1-2

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