Question

problem 11
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.)
comets typically have highly eccentric orbits.
venus rotates backward.
there are a large number of planets.
all planets orbit in nearly the same plane.
large gas giants have the same composition as the sun.
the sun rotates in the same direction that the planets revolve.
all planets revolve in the same direction.

Explanation:

• All planets orbit in nearly the same plane: This is a key characteristic that supports the idea of a common origin. In the nebular hypothesis (formation from a solar nebula), the flat - plane formation of the solar system is expected as the nebula collapses and spins, forming a disk - like structure.
• Large gas giants have the same composition as the Sun: The solar nebula was composed mainly of hydrogen and helium (similar to the Sun's composition). The gas giants, being large and able to hold onto these light elements, having a similar composition supports a common origin.
• The Sun rotates in the same direction that the planets revolve: In the nebular model, as the nebula contracts, conservation of angular momentum causes the central mass (the Sun) to rotate and the surrounding material (that forms planets) to revolve in the same general direction.
• All planets revolve in the same direction: This is consistent with the idea that they formed from a rotating disk (the solar nebula). As the disk material coalesced to form planets, the direction of revolution (orbiting) was maintained.

• Comets typically have highly eccentric orbits: Comets are thought to be remnants from the outer parts of the solar system formation. Their highly eccentric orbits are more of a result of their formation in the Oort cloud or Kuiper belt (not directly related to the main - disk formation from the solar nebula that the planets and Sun are part of).
• Venus rotates backward: This is an anomalous rotation (retrograde rotation) which is likely due to some post - formation event (like a large impact) rather than a characteristic of common origin from the solar nebula.
• There are a large number of planets: The number of planets alone does not indicate a common origin. The formation process (from a nebula) can lead to a certain number of planets, but the number is more a result of the accretion and gravitational processes in the disk rather than a direct indicator of a common origin.

Answer:

All planets orbit in nearly the same plane, Large gas giants have the same composition as the Sun, The Sun rotates in the same direction that the planets revolve, All planets revolve in the same direction.