Front

Why is Mars never visible as a tiny black dot on the sun’s bright disk when it passes between the Earth and the sun?

Back

The orbit of Mars is outside that of the Earth’s orbit.

Answer explanation

Mars is never visible as a dot on the sun because its orbit is outside that of Earth's orbit. This means Mars cannot transit between the Earth and the sun like Venus does.

Front

Which evolutionary stage of a massive star is called a supernova?

Back

4

Answer explanation

A supernova occurs at the final evolutionary stage of a massive star, specifically when it exhausts its nuclear fuel and undergoes a catastrophic explosion. This corresponds to stage 4 in the evolutionary sequence.

Front

Photographs of the surface of Mars reveal the presence of sand dunes that shift over time. These dunes demonstrate the presence of what phenomenon on Mars?

Back

Winds

Answer explanation

The shifting sand dunes on Mars indicate the presence of winds, which are responsible for moving and reshaping the dunes over time. This phenomenon is similar to how winds affect sand dunes on Earth.

Front

Because of the unique position of the Earth in the solar system, life has flourished due to the presence of __.

Back

liquid water

Answer explanation

Liquid water is essential for life as we know it, providing a medium for biochemical reactions and supporting various ecosystems. Its presence on Earth, unlike other planets, has allowed life to thrive.

Front

At what position would Earth be found in the solar system diagram shown above?

Back

2

Answer explanation

In the solar system, Earth is the third planet from the Sun. Therefore, in the diagram, Earth would be found at position 2, as the positions typically start counting from the Sun.

Front

What element is the main component of most stars?

Back

Hydrogen

Answer explanation

Hydrogen is the most abundant element in the universe and makes up about 74% of the mass of stars. It is the primary fuel for nuclear fusion in stars, making it the main component of most stars.

Front

Why do stars appear to change position during the night?

Back

Earth rotates on its axis.

Answer explanation

Stars appear to change position during the night because Earth rotates on its axis. This rotation causes the stars to appear to move across the sky, creating the illusion of changing positions.

Front

Why does erosion not occur on the moon?

Back

There is no wind or rain.

Answer explanation

Erosion on the moon does not occur primarily because there is no wind or rain to facilitate the process. Unlike Earth, the moon lacks an atmosphere, which means these erosive forces are absent.

Front

Which planet has a fierce hurricane-like storm that is several times the size of Earth?

Back

Jupiter

Answer explanation

Jupiter is known for its Great Red Spot, a massive storm larger than Earth that has been raging for centuries. This makes it the correct answer, as neither Mars, Venus, nor Saturn has a storm of comparable size.

Front

In 1912, an astronomer at Arizona’s Lowell Observatory noticed that the lines in the spectra of most galaxies shifted toward the red end of the spectrum. Another American astronomer, Edwin Hubble, later used this discovery as evidence that __.

Back

galaxies are moving away from each other in a constantly expanding universe

Answer explanation

The redshift observed in galaxy spectra indicates that they are moving away from each other, supporting Hubble's conclusion of a constantly expanding universe.