What is our solar system like?

The center of the solar system is the sun, and all celestial bodies revolve around it. Most celestial bodies close to the sun will revolve around the same plane, and the discrete celestial bodies at apogee will deviate from this plane and revolve around the sun. Except comets and asteroids, they all have orbital characteristics.

Figure: Planets and dwarf planets in the solar system. The size is only drawn to scale, and the distance is out of proportion.

Photo: The eight planets in the solar system are out of proportion.

Our sun is located in the center of the solar system.

First of all, we have to explain that the oldest in the solar system family, that is, our sun, is located in the center of the solar system. All our light and heat come from the sun, which is closely related to our survival.

Almost all celestial bodies in the solar system revolve around the sun, from mercury and the sun-grazing comet to the theoretical Oort cloud and the farthest known comet West.

According to the solar wind, the edge of our solar system is where the solar wind stops, which is about four times the distance from Pluto. According to the gravity controlled by the sun, the edge of our solar system is about 2 light years away.

All celestial bodies controlled by the sun's gravity

The first is the family of planets close to the sun, and our satellites, as well as some sun-grazing comets, asteroids and so on. Except some satellites, comets, asteroids and so on. Most other celestial bodies revolve around the sun on the same plane (ecliptic). Only outside Pluto, the orbits of some discrete celestial bodies called ecliptic are far away from this plane. The farthest is a hypothetical source of comet theory, called Oort Cloud, whose orbit is like a sphere around the whole solar system at the outermost layer.

Shrinking solar system: photo access to the public domain

Inner solar system and Jupiter

The outer solar system and Pluto

Sedna orbit (independent celestial body)

The interior of the Oort cloud.

Schematic diagram of Oort cloud: spherical outer cloud, disc-shaped inner cloud. Photographed by NASA

Further reading: the formation of the solar system

Whenever we think of the solar system, we will be curious, how was the solar system born? When was it born?

The earliest time to study this problem can be traced back to18th century, by three famous foreign astronomers (Emanuel? Emanuel Swedenburg, Emanuel? Kant and Pierre Simon? Laplace nebula hypothesis.

The nebula hypothesis holds that the solar system was originally formed in a huge molecular cloud. About 4.6 billion years ago, this large molecular cloud was disturbed by the explosion energy of nearby supernovae, which led to a gravitational collapse of one piece in the molecular cloud. The center of this gravitational collapse area became hotter and hotter with the absorption of surrounding materials, thus forming the original sun. The rest of the matter forms a protoplanetary disk, and the region near the sun (terrestrial planet) forms a solid planet with high melting point because of its high temperature. Because the stellar wind of the sun is more stable, what will be the earth-like planet region? Blow it clean? . What about terrestrial planets? Grow up? At the end of the formation, the stellar wind blows to the molecular clouds outside, and Jupiter, Saturn, Uranus and Neptune with low melting points are formed due to the low temperature. Due to the gravity of planetary migration (mainly Jupiter and Neptune), some small ice-like objects that failed to form planets at first were scattered out of Neptune's orbit. These small ice-like celestial bodies are today's Kuiper Belt and distant ecliptic discrete celestial bodies. Due to Jupiter's strong gravity, some of them are even ejected to more distant areas, which we now know as Oort Cloud (near the edge of the solar system).

The eight planets in the solar system (in descending order) are Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars and Mercury. Figure: Lsmpascal