Which of the following is an accurate description of cosmic microwave background (CMB) radiation? (1 point)

CMB produces differing temperatures across the universe

Multi-choice

Apologies for the confusion. The accurate description of cosmic microwave background (CMB) radiation is:

- CMB is remnant radiation from the Big Bang.

Which event triggers the start of black hole formation?(1 point)

Responses

A supernova blows a massive star apart.
A supernova blows a massive star apart.

A massive star depletes its stores of hydrogen and helium.
A massive star depletes its stores of hydrogen and helium.

Radiation emitted by a massive star increases.
Radiation emitted by a massive star increases.

The gravitational forces acting on a massive star decline rapidly.

A supernova blows a massive star apart.

Galaxies can be grouped by the age of the stars they tend to contain, with (elliptical / spiral / irregular) galaxies having the youngest stars and (elliptical / spiral / irregular) galaxies having the oldest stars.

Elliptical galaxies tend to have the oldest stars, while irregular galaxies tend to have the youngest stars.

Which of these describes a nebula?(1 point)

Responses

cloud of gravity and pressure
cloud of gravity and pressure

star close in size to the sun
star close in size to the sun

cloud of gas and dust
cloud of gas and dust

star much larger than the sun

A nebula is described as a cloud of gas and dust.

The universe's galaxies have evolved since what point in time?(1 point)

Responses

800 million years ago, when gas concentrations were optimal for galaxy formation
800 million years ago, when gas concentrations were optimal for galaxy formation

13.8 billion years ago, right after the universe first formed
13.8 billion years ago, right after the universe first formed

approximately 50 million years ago, after initial clumps of material were formed
approximately 50 million years ago, after initial clumps of material were formed

23.4 billion years ago, when the universe first formed

The answer is:

13.8 billion years ago, right after the universe first formed.

What do supernova remnant and planetary nebulae have in common? Select the THREE correct answers.(2 points)

Responses

They are composed of matter from dying stars.
They are composed of matter from dying stars.

They emit non-visible radiation.
They emit non-visible radiation.

They are composed only of hydrogen and helium.
They are composed only of hydrogen and helium.

They contribute matter to interstellar space.
They contribute matter to interstellar space.

They have planets circling them.
They have planets circling them.

They are diffuse.

The three correct answers are:

- They are composed of matter from dying stars.
- They contribute matter to interstellar space.
- They are diffuse.

Which proportion of the universe's galaxies can be seen from Earth?(1 point)

Responses

far less than 1 percent
far less than 1 percent

approximately 10 percent
approximately 10 percent

nearly half
nearly half

approximately 25 percent

The proportion of the universe's galaxies that can be seen from Earth is:

- far less than 1 percent.

Why are most stars not destroyed in a galaxy collision?(1 point)

Responses

Galaxies move too slowly for that type of damage.
Galaxies move too slowly for that type of damage.

Galaxies are mostly empty space.
Galaxies are mostly empty space.

Gravity keeps them away from each other.
Gravity keeps them away from each other.

Galaxies don't have stars.

The correct answer is:

- Gravity keeps them away from each other.

One model of galaxy formation occurs when sections of gas clouds collapse into small pieces and then merge into larger pieces due to gravity. The Milky Way is an example of the (outside-in / inside-out) model of the (bottom-up / top-down) model.

The Milky Way is an example of the:

- Inside-out model
- Bottom-up model

Which was used to create the first image of a black hole?(1 point)

Responses

visible light from the black hole
visible light from the black hole

x-rays from inside the black hole
x-rays from inside the black hole

radio waves from matter at the edge of the black hole
radio waves from matter at the edge of the black hole

ultraviolet light from objects in the black hole

The correct answer is:

- Radio waves from matter at the edge of the black hole