Stars and Galaxies Review

What is Kelvin?

• A way of measuring brightness

• A way of measuring color

• A way of measuring temperature

• 100° Fahrenheit

Answer explanation

Kelvin is a unit of measurement for temperature, commonly used in scientific contexts. It is part of the International System of Units (SI) and is based on absolute zero, making it the correct choice for measuring temperature.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What is a galaxy?

• A system of stars and other objects held together by a gravitational force.

• A single star in the universe.

• A planet in the solar system.

• A type of comet.

Answer explanation

A galaxy is defined as a system of stars and other objects, such as gas and dust, that are bound together by gravity. This distinguishes it from a single star, a planet, or a comet, which are all smaller components of the universe.

Tags

NGSS.HS-ESS1-2

What causes a protostar to heat up?

• Nuclear fusion

• Chemical reactions

• Gravity pulling gas and dust together

• Solar radiation

Answer explanation

A protostar heats up primarily due to gravity pulling gas and dust together. As these materials collapse under their own gravity, they increase in pressure and temperature, leading to the formation of a protostar.

What is a protostar?

• A dying star

• A planet

• A baby star formed by gravity pulling gas and dust together

• A type of comet

Answer explanation

A protostar is a stage in star formation where gravity pulls together gas and dust, leading to the birth of a new star. This makes 'A baby star formed by gravity pulling gas and dust together' the correct choice.

What is the characteristic of red giants?

• They are smaller and dimmer

• They are cooler and brighter

• They are hotter and smaller

• They are the same as protostars

Answer explanation

Red giants are characterized by being cooler in temperature compared to main sequence stars, yet they are much brighter due to their large size. This makes the correct choice 'They are cooler and brighter'.

Tags

NGSS.HS-ESS1-3

What type of stars are located at the top right of the Hertzsprung-Russell diagram?

• White Dwarfs

• Main Sequence

• Supergiants

• Giants

Answer explanation

Supergiants are located at the top right of the Hertzsprung-Russell diagram. They are massive stars with high luminosity and large radii, distinguishing them from other types like white dwarfs, main sequence, and giants.

Which type of stars are located at the bottom left of the Hertzsprung-Russell diagram?

• White Dwarfs

• Giants

• Supergiants

• Main Sequence

Answer explanation

White dwarfs are found at the bottom left of the Hertzsprung-Russell diagram, indicating they are hot but have low luminosity. This distinguishes them from giants and supergiants, which are located in other regions of the diagram.

Tags

NGSS.HS-ESS1-3

What is the luminosity of a typical Main Sequence star compared to the Sun?

• 10 times the Sun

• Equal to the Sun

• It depends on the temperature and color.

• 100 times the Sun

Answer explanation

The luminosity of a Main Sequence star varies based on its temperature and color. Hotter stars are more luminous, while cooler stars are less so, making the correct answer "It depends on the temperature and color."

What is the surface temperature range for M-type stars in the diagram?

• 30,000 K

• 10,000 K

• 6,000 K

• 3,000 K

Answer explanation

M-type stars, also known as red dwarfs, have surface temperatures ranging from about 2,500 K to 4,000 K. Therefore, the correct answer is 3,000 K, which falls within this range.

How does the temperature on the x-axis of an HR diagram change?

• From lowest to highest

• From highest to lowest

• Remains constant

• Randomly fluctuates

Answer explanation

In an HR diagram, the x-axis represents temperature, which decreases from left to right. Therefore, the correct answer is 'From highest to lowest', indicating that hotter stars are on the left and cooler stars on the right.