Unit 1 quiz

Which of the following is the first step of the nebular theory?

• Formation of planetesimals

• Collapse of a gas cloud

• Formation of a protoplanetary disk

• Accretion of dust and gas.

Answer explanation

The first step of the nebular theory is the collapse of a gas cloud due to gravity, which initiates the formation of stars and planetary systems. This collapse leads to the subsequent formation of a protoplanetary disk.

Terrestrial planets are primarily composed of ______.

• Gas

• Ice

• Rock and metal

• Liquid

Answer explanation

Terrestrial planets, such as Earth and Mars, are primarily composed of rock and metal. This distinguishes them from gas giants, which are mainly made of gases. Therefore, the correct answer is 'Rock and metal'.

Which of the following is a dwarf planet?

• Mars

• Pluto

• Venus

• Jupiter

Answer explanation

Pluto is classified as a dwarf planet because it meets the criteria set by the International Astronomical Union, which defines a dwarf planet as a celestial body that orbits the Sun and is not a satellite.

List the order of planets in the solar system starting from the sun.

• Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

• Venus, Earth, Mars, Mercury, Jupiter, Saturn, Uranus, Neptune

• Earth, Mars, Mercury, Venus, Jupiter, Saturn, Uranus, Neptune

• Mars, Mercury, Venus, Earth, Jupiter, Saturn, Uranus, Neptune

Answer explanation

The correct order of planets in the solar system starting from the sun is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. This matches the first answer choice.

Kepler's 1st law states that the orbit of a planet is ______.

• Circular

• Elliptical

• Parabolic

• Hyperbolic

Answer explanation

Kepler's 1st law states that the orbit of a planet is elliptical, meaning planets move in oval-shaped paths around the sun, with the sun at one focus of the ellipse. This distinguishes it from circular or other types of orbits.

Tags

NGSS.HS-ESS1-4

Kepler's 2nd law is also known as the law of ______.

• Equal areas

• Universal gravitation

• Inertia

• Motion

Answer explanation

Kepler's 2nd law, known as the law of equal areas, states that a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time, highlighting the relationship between a planet's speed and its distance from the Sun.

Kepler's 3rd law relates the square of the orbital period to the cube of the ______.

• Planet's mass

• Semi-major axis

• Orbital speed

• Distance from the sun

Answer explanation

Kepler's 3rd law states that the square of a planet's orbital period is proportional to the cube of its semi-major axis. This means that the correct answer is the semi-major axis, not mass, speed, or distance.

Tags

NGSS.HS-ESS1-4

In the equation E=c/a, what does 'E' represent?

• Energy

• Eccentricity

• Electric field

• Entropy

Answer explanation

In the equation E=c/a, 'E' represents eccentricity, which is a measure of how much an orbit deviates from being circular. The other options like energy, electric field, and entropy do not fit this context.

Tags

NGSS.HS-PS3-1

What is a barycenter?

• The center of a planet

• The center of mass of two or more bodies

• The center of a star

• The center of a galaxy.

Answer explanation

A barycenter is defined as the center of mass of two or more bodies, such as a planet and its moon. This is why the correct answer is 'The center of mass of two or more bodies', as it accurately describes the concept.

Tags

NGSS.MS-ESS1-2

NGSS.MS-PS2-4

What is responsible for the seasons on Earth?

• Earth's distance from the sun

• Earth's axial tilt

• Earth's rotation

• Earth's orbit shape

Answer explanation

The seasons on Earth are primarily caused by Earth's axial tilt. This tilt affects how sunlight is distributed across the planet, leading to variations in temperature and daylight throughout the year.

Tags

NGSS.MS-ESS1-1