Question

which of the solar system characteristics below have led astronomers to believe that the objects in our solar system all formed from the same \mother cloud\ (solar nebula)? (please note: select all that apply.)

the sun rotates in the same direction that the planets revolve.
there are a large number of planets.
venus rotates backward.
large gas giants have the same composition as the sun.
all planets orbit in nearly the same plane.
comets typically have highly eccentric orbits.
all planets revolve in the same direction.

Explanation:

• All planets revolve in the same direction: This is a key characteristic of the solar system's formation. The nebular hypothesis (the leading theory for solar system formation) suggests that the solar system formed from a rotating cloud of gas and dust (the "mother cloud"). As this cloud collapsed, conservation of angular momentum caused it to spin faster, and the planets formed in a disk - like structure, all revolving in the same direction around the Sun.
• All planets orbit in nearly the same plane: This also supports the nebular hypothesis. The rotating disk from which the planets formed was relatively flat, so the planets' orbits are in nearly the same plane.

• The Sun rotates in the same direction that the planets revolve: This is consistent with the conservation of angular momentum in the solar system's formation. The Sun, as the central object, rotates in the same direction as the orbital motion of the planets.

• Venus rotates backward: This is an exception. Venus' retrograde rotation is thought to be due to gravitational interactions (possibly with other planets during the solar system's early history) or impacts that altered its rotation.
• There are a large number of planets: The number of planets (8 major planets) doesn't directly relate to the solar system forming from a single "mother cloud". The formation process involves accretion in the protoplanetary disk, but the number is more about the specific conditions and accretion rates in different regions of the disk.
• Large gas giants have the same composition as the Sun: While gas giants (like Jupiter and Saturn) have a composition rich in hydrogen and helium (similar to the Sun), this is not a characteristic that directly implies a common origin from a "mother cloud" in the same way as orbital direction and plane. The Sun's composition is due to its nuclear fusion - driven nature, and gas giants' composition is due to their ability to accrete large amounts of hydrogen and helium in the outer solar system.
• Comets typically have highly eccentric orbits: Comets come from the outer regions of the solar system (like the Oort Cloud and Kuiper Belt). Their highly eccentric orbits are due to their formation in these regions and gravitational perturbations (e.g., from passing stars for Oort Cloud comets), rather than being a characteristic that shows a common origin from the "mother cloud" in the same sense as planetary orbital properties.

Answer:

• The Sun rotates in the same direction that the planets revolve.
• All planets revolve in the same direction.
• All planets orbit in nearly the same plane.