How did planetesimals form planets?

Answer 1

2 most common scenarios:

1 - early universe was a cloud of gases (mainly hydrogen), so a certain part of the cloud starts to collapse dragging more and more gas by the force of gravity, enough for a gas planet to form, but not too much that a star forms.

2 - After a huge star burns out its fuel, it collapses or explodes in a huge supernova shooting off material containing all chemical elements. A planet might form from these material when they collapse under the force of gravity.

Answer 2

Space is not empty. It contains tenuous amounts of elements, mostly hydrogen, which can gather along with particles of dust when affected by gravity. Astronomers do not yet know the exact process, but gases and other elements are thought to form vast accretion disks of matter in space. These can then coalesce into stars and their planets.

Heavier elements form inside stars and are constantly being released into space by the explosions of supernovas. These are the elements that form terrestrial planets.

Answer 3

In the outer parts of the disk, gas and dust formed small astroid-like and comet-like bodies called PLANETESIMALS. These formed the building blocks of the planets. Planetesimals collided and grew larger by sticking together eventually combing to form the planets.
The planetesimals were just large enough for their own gravity to start pulling in material. They would therefore grow by pulling in dust and rocks and by colliding with other planetesimals, forming growing masses of rock. As they grew their gravity would get stronger, allowing them to pull in even more material. This process would continue until most of the matter orbiting the sun was collected in a handful of large objects we know as planets.

Answer 4

Sometimes, a generally large rock can steer smaller rocks and bits of dust into it by its gravitational pull. Over time, the rock will get bigger, and bigger, until it might become the size of your neighborhood. But after millions of years, the rock will be the size of Earth, and by then will start to form characteristics of its own. Then, it will be called a planet.

Answer 5

The planets don't really float. They orbit the sun, which requires moving very fast.

When you think about it, an orbit is something of a strange concept.

When you throw and object it follows a path that curves downward.

The faster you throw it, the broader the curve.

A similar principle applies to orbits. An planet in orbit is essentially in perpetual freefall, but its "sideways" motion creates a curve large enough that it continuously misses the Sun. All orbits work in this way

Answer 6

This is not intended to be a highly technical answer; you could do a little research on some of the terms I'm going to use if you want more details (including mathematical treatments of how this all works).

The current theory is something called the Nebular Hypothesis, which basically says that the Solar System condensed from a huge cloud of dust and gas. Most of the material ... over 99% ... wound up in the middle and formed the Sun, but the laws of angular momentum predict that some (relatively small, but still large in an absolute sense) amount of material would end up in a disk on the "equator" of the original rotating body.

The material making up this disk then undergoes planetary accretion, which just means the small bits bump into each other and stick together to form larger clumps. These larger clumps then accumulate more material due to their gravity, until you wind up with something like planets.

At one time it was thought that the asteroid belt might have been a former planet that somehow broke apart. It's now believed that it represents something similar to a portion of the original disk that never formed into a planet largely because of the gravitational influence of Jupiter.

Answer 7

the growth of planets began as sold bits of matter began to collide and clump together through a process known as accretion.

Answer 8

Current thinking is that planets are built up out of dust clumps called "proplyds" (proplanetary disks). Gravity draws them into spheres and heat from their cores fuses them solid.

Answer 9

First of all the don't "move" they orbit around the sun ; and gravity holds them up .

Answer 10

The planetesimal theory of planet formation states that small rock fragments combined together to form the planets. This theory was first suggested by Russian astronomer Viktor Safronov.