Early and modern theories

The modern model connects many evidences and processes together. In exams, link scientific value with evidence and explanatory power.

Kant imagined gaseous matter concentrating by gravity. In exams, connect Kant with a natural gravitational explanation.

Laplace's idea was historically important, but its modern physical explanation was incomplete. In exams, write both contribution and limitation.

The joining of small bodies matches the modern idea of accretion. In exams, identify useful parts of old ideas.

The tidal theory is weakened by rarity and orbital-order problems. In exams, write both probability and orbit limitations.

Expansion of extremely hot matter and formation of stable planets is a major problem. In exams, connect physical behavior with limitation.

Schmidt linked planet formation with interstellar material such as gas and dust. In exams, identify the source-material difference.

The vortex idea was linked with motion and organization of matter within the nebula. In exams, connect Weizsäcker with modern planet-origin ideas.

A rotating cloud becomes a flat disk during collapse. In exams, link disk origin with rotation and gravity.

Bodies formed from the same rotating disk show similar motion. In exams, connect similar direction with common source.

Beyond the frost line, accumulation of ice and gases was more possible. In exams, write distance, temperature, and composition together.

Temperature differences affected planetary material and size. In exams, connect temperature gradient with planetary composition.

Solar winds reduced light gases in the inner region. In exams, also link the rocky nature of inner planets with solar winds.

Cold outer regions and more material made gas giants large. In exams, remember cold region and stronger gravity together.

Disks around young stars match the modern planet-formation model. In exams, treat such observations as support for the solar nebula idea.

Remnant bodies give information about early solar-system material. In exams, treat them as remnant clues of planet formation.

Red shift indicates receding galaxies. In exams, write the reasoning from evidence to conclusion.

This radiation points to an early hot state. In exams, also remember it as a challenge to steady state theory.

In the Big Bang model, the early universe was extremely hot and dense. As space expanded, the same general energy became distributed through an increasingly larger volume, and the average temperature fell. This expansion and cooling allowed particles, atoms and later larger structures to form. Hence option A gives the relevant cosmological relationship. Rivers, a static universe and the disappearance of the Sun are unrelated conclusions.

Light elements were early material of cosmic chemical evolution. In exams, remember basic matter before large bodies.

The steady state theory imagined new matter forming during expansion. In exams, keep average density and continuous creation together.

Background radiation was considered evidence of the early hot universe. In exams, write it in favor of the Big Bang.

First the universe, then galaxies, then the solar system and Earth formed. In exams, remember the order from larger to smaller scale.

Accretion builds the planetary body and differentiation forms its internal structure. In exams, match process and function correctly.

Heavy metallic materials moved to the center and helped form the core. In exams, connect iron-nickel with the core.