Answer: The Nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). The widely accepted modern variant of the nebular theory is the solar nebular disk model (SNDM) or solar nebular model.

Terms in this set (5)

• step one(4) -The solar nebula consisted of. -hydrogen,
• step two(2) -A disturbance.
• step three(2) -The solar nebula assumed a flat, disk shape.
• step four(2) -Inner planets began to form from metallic.
• step five(2) -Larger outer planets began forming from fragments.

The main problem involved angular momentum distribution between the Sun and planets. The planets have 99% of the angular momentum, and this fact could not be explained by the nebular model. As a result, astronomers largely abandoned this theory of planet formation at the beginning of the 20th century.

Gravity

Jupiter, Saturn, Uranus and Neptune collectively make up the group known as the jovian planets. The general structures of the jovian planets are opposite those of the terrestrial planets.

Problems: Although the nebular theory is widely accepted, there are still problems with it that astronomers have not been able to resolve. For example, there is the problem of tilted axes. According to the nebular theory, all planets around a star should be tilted the same way relative to the ecliptic.

Kant’s central idea was that the solar system began as a cloud of dispersed particles. His model does not account for planets moving around the Sun in the same direction and in the same plane, as they are observed to do, nor does it explain the revolution of planetary satellites. …

Kant

Eris; b. Pluto is most similar to Eris, a. Both Kuiper Belt Objects are a mixture of ices and rock, which is typical of Kuiper Belt Objects (abbreviation KBO). Earth and Moon are mostly rock and metal.

Why did the solar nebula heat up as it collapsed? A) Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. As the cloud shrank, its gravitational potential energy was converted to kinetic energy and then into thermal energy.

Distance of a planet from the Sun determined the temperature and thus the materials which condensed first. Metals condensed first, then rocks, then the lighter compounds, then the light gasses.

Step 5: Accretion o After condensation, growth of solid particles occurs due to collisions. o Accretion is growth of grains through collisions – the real planet building process.

The key ingredient in the modern Condensation Theory is dust, which helps to cool the gas, and forms the nuclei for planetesimals to grow.

What is the difference between the processes of condensation and accretion? Condensation is the building of larger particles one atom (or molecule) at a time, whereas accretion is the sticking together of larger particles. The planets swept up gas, dust, and small particles.

In planetary science, accretion is the process in which solids agglomerate to form larger and larger objects and eventually planets are produced. The initial conditions are a disc of gas and microscopic solid particles, with a total mass of about 1% of the gas mass. Accretion has to be effective and fast.

A first process is the sticking of microscopic dust into larger grains and pebbles. A second process is the formation of an intermediate class of objects called planetesimals. A third accretion process has to lead from planetesimals to planets.

Accretion, the gradual clumping together of dust, rocks and meteorites into larger and larger bodies, eventually creates rocky planets, provided no larger gravitational bodies stop the process.

Accretion is the process in which material from the outer plate and trench (during the periods of discontinuous subduction) is removed and added to the outer continental margin or by other mechanisms such as imbricate thrusting or a combination of folding and thrusting (Karig, 1974; Karig and Sherman, 1975).

accretion. The process by which planets form as material orbiting some stars gathers together through collisions and gravitational or electrostatic attraction, eventually forming larger and larger bodies.