Astronomy Review

Which of the following is a large clouds of gas and dust held together by a balance of pressure and gravity? It's also where stars are born.

• a nebula

• a galaxy

• a neutron star

• a globular cluster

Answer explanation

A nebula is a large cloud of gas and dust in space, where the forces of pressure and gravity create conditions for star formation. This makes it the correct answer, as galaxies, neutron stars, and globular clusters do not fit this description.

The life path of a star depends on

• its magnitude

• its composition

• its mass

• its temperature

Answer explanation

The life path of a star is primarily determined by its mass. A star's mass influences its temperature, luminosity, and lifespan, ultimately dictating its evolutionary path through different stages of stellar development.

Tags

NGSS.HS-ESS1-1

Stars spend most of their lives as

• giants

• dwarves

• main sequence

• supernovas

Answer explanation

Stars spend most of their lives in the main sequence phase, where they fuse hydrogen into helium. This stage accounts for about 90% of a star's lifetime, making 'main sequence' the correct answer.

Which is true about light years?

• it's a measure of distance

• it's a measure of time

• it's best for distance around the solar system

• it measures the magnitude of stars

Answer explanation

A light year is defined as the distance that light travels in one year, making it a measure of distance, not time. It is commonly used in astronomy to express distances between stars and galaxies.

Our sun uses a process called

• nuclear fusion

• fission

• gravity

• photosynthesis

Answer explanation

Our sun uses nuclear fusion to convert hydrogen into helium, releasing energy in the process. This is the primary source of the sun's energy, unlike fission, gravity, or photosynthesis.

Tags

NGSS.HS-ESS1-1

NGSS.HS-PS1-8

The most common element in a main sequence star is

• hydrogen

• helium

• nitrogen

• oxygen

Answer explanation

The most common element in a main sequence star is hydrogen, as it is the primary fuel for nuclear fusion in stars, powering their energy output and stability.

Tags

NGSS.HS-ESS1-1

Most stars are small or medium mass like our sun. What will they become at the end of their life-cycle?

• Red Giants

• Black holes

• White dwarves

• neutron stars

Answer explanation

Most stars like our sun end their life cycle as white dwarfs after exhausting their nuclear fuel. They expand into red giants before shedding their outer layers, leaving behind a dense core that becomes a white dwarf.

On a really dark night (without light pollution) our view from Earth looks like this. Why?

• There are dense stratus clouds in the area

• We are inside a spiral disk, so the stars are densely collected in a band from our perspective

• We still don't know why the sky looks this way sometimes.

Answer explanation

We see a dense band of stars because Earth is located within the Milky Way's spiral disk, where stars are concentrated. This perspective creates the appearance of a bright band across the night sky.

BOTH of these pictures represent our location in the Milky Way galaxy

• True

• False

Answer explanation

Both pictures accurately depict our location in the Milky Way galaxy, confirming that the statement is true.

According to Hubble and Lemaitre, the universe will likely...

• expand forever

• expand for another million years, then contract in a big crunch

• remain in a steady state

Answer explanation

Hubble and Lemaitre's observations suggest that the universe is continuously expanding. Current models support the idea that this expansion will continue indefinitely, making 'expand forever' the correct choice.

Tags

NGSS.HS-ESS1-2