Astronomy Ch 5 HSU
At what point in time do we say that the protosun became the Sun?
When thermonuclear fusion reactions began at its center.
Compared to the orbital distance of Earth from the Sun, the equivalent orbital distances for the outer planets are
greater than 5 times.
Fusion is the process by which
elements are transformed into heavier elements by nuclear reactions.
In order of increasing density, the large, outer planets would be listed as
Saturn, Uranus, Jupiter, Neptune.
In our solar system, which of the following planets is NOT a member of the terrestrial group?
Jupiter
In our solar system, which of the following planets is a member of the terrestrial group?
Mars
Most of the planets orbit the Sun on or close to
the ecliptic plane.
The asteroid belt exists between the orbits of which planets?
Mars and Jupiter
The average density of the large, outer planets is
close to the density of water.
The birthplace of the Sun and planets (and of other stars and maybe their planets) is thought to have been
in cool gas and dust clouds.
The correct sequence of planets in our solar system, from the Sun outward, is
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
The dwarf planet whose orbit has the greatest inclination to the plane of the ecliptic is
Pluto.
The largest of the terrestrial planets is
Earth.
The manner in which the terrestrial planets formed was
accretion of solid planetesimals containing mostly rocky material.
The most abundant material in the universe is
hydrogen.
The most likely mechanism for the solar system is that
the Sun and planets slowly condensed to their present form from a gas and dust cloud.
The most probable theory for the formation of the solar system is
condensation of a nebula of cold gas and dust into the Sun and planets.
The overall shape of the orbits of most of the planets in the solar system is
slightly elliptical, but nearly circular.
The planet with the greatest mean density is
Earth.
The planets whose orbits are most noticeably elliptical are
Mercury and Pluto.
The smallest of the planets is
Mercury.
The smallest terrestrial planet is
Mercury.
The steps in which the large, outer planets formed were
accretion of planetesimals to form a core, followed by gravitational capture of hydrogen and helium gas.
What name is given to the concentration of mass that formed at the center of the solar nebula, and eventually became the Sun?
The protosun.
Where in the universe are heavy elements, with masses greater than that of helium, being produced at this time?
In the central cores of stars.