AS101 Assignment 8

The original cloud from which the Sun and planets formed had a composition rich in hydrogen and helium.

True

When particles in the solar nebula grew large enough, they stopped growing by accretion and began growing by condensation.

False

Astronomers have been able to observe rings in dusty nebula containing young stars.

True

The condensation sequence cannot explain the composition of the terrestrial and Jovian planets.

False

The present motions of the planets were inherited from the rotation of the solar nebula.

True

The Jovian planets have lower average densities than the terrestrial planets.

True

All the planets in the Solar System revolve in a clockwise motion.

False

​Asteroids are believed to be debris left over from the failure of a planet to form at a distance of about 3 AU from the Sun.

True

Which of the following observed characteristics of the solar system is the solar nebula theory able to explain?
common direction of rotation of the planets
number of satellites of each planet
the formation of hydrogen atoms in the solar system from subatomic particles
number of planets of each type

common direction of rotation of the planets

What is an extrasolar planet?

a planet found orbiting around a star other than the Sun

How do the Jovian planets compare to the Terrestrial planets?

They have much larger diameters.

How is the presence of space debris accounted for by solar system models?

Space debris is left over material from the early solar system that never formed into a planet.

The Terrestrial planets are thought to have formed by accreting solid planetesimals, all with about the same composition. What does this mean?

They were initially collections of solid particles, which melted and then differentiated into a high-density iron metal core and low-density silicate crust.

Which of the following is a solar system object that enters Earth's atmosphere, becomes very hot due to friction between the object and Earth's atmosphere, and does not survive to reach the surface?

meteor

Which one of the following is a characteristic of outer planets?

large diameters

The asteroid belt is found between the orbits of two planets. What are they?

Mars and Jupiter

Your blood contains iron atoms. Where did most of these iron atoms come from?

supernovae

The planets all lie in nearly the same plane, resulting in a disk-like structure for the solar system. What is believed to be the reason for this disk-like structure?

The solar nebula from which the planets formed collapsed into a disk-like structure.

What kind of objects are located beyond the asteroid belt (3 AU from the Sun) and have extremely large masses with very low densities?

Jovian planets

Which of the following is a solar system object that enters Earth's atmosphere and survives its passage through the atmosphere to reach the surface?

meteorite

If our Sun were replaced by a much hotter and brighter star, what would happen to the position of the habitable zone in our solar system?

It would move outwards, away from the star.

What is accretion?

the adding of material to an object by collection of solid particles

What observations of other stars have helped to validate the solar nebula theory?

Young stars are found to have hot disks that surround them

How do we know that Jovian planets formed within about 10 million years of the formation of the solar nebula?

After 10 million years there was very little gas present in the solar nebula.

Which assumption must be true for the condensation sequence to explain the compositions of planets found in our solar system?

The planets must have formed close to where they are found today.

Which of the following is a rock in space before it enters Earth's atmosphere?
meteoroid
meteorite
comet
meteor

meteoroid

A future news release might report that a new planet has been found around a star very similar to our Sun. This newly discovered planet is claimed to have a mass 40 times that of Earth and is located nearly 25 AU from the star it orbits. Which of the following would be a reasonable prediction about this planet?

The planet will probably have a composition that is mostly hydrogen and helium.

The age of the solar system is estimated to be approximately 4.6 billion years based on which of the following types of data?

isotope ratios in meteorites

Which statement about the difference between asteroids and comets is correct?

Asteroids contain fewer volatiles than the nuclei of comets.

Which of the following best describes the origin of meteor showers?

Earth is crossing the orbit of a comet

What pushed gas and dust particles out of the solar nebula?

the solar wind

After the first solid grains formed in our solar system, by what process were these particles then able to grow?

accretion

If a star is found with five planets orbiting it, and a process like that described in the solar nebula theory formed the planets, which of the planets would be expected to have the greatest uncompressed density?

the one closest to the star

Which of the following is a streak of light produced by a small bit of matter from space burning up in Earth's atmosphere?

meteor

Why are meteorites important?

they can reveal the age of the solar system

Which best describes the appearance of an asteroid?

​irregular in shape and covered with craters

Which term is described as small, icy bodies that orbit the Sun just beyond Neptune?

​Kuiper belt objects

​What astronomical object is the most important source for determining the age of our Solar System?

meteorites

​The inner planets are composed of ____.

​rock and metal

According to solar nebula theory, what is the first step in planetesimal formation?

condensation