The birth of nebulae and stars
Gravity and form particle swarm on each particle, which attract more particles, gas ball under appropriate conditions, in the center of the hot, dense enough, can generate burning helium and hydrogen producing stars. Born in the right as the stars in the Eagle nebula.
The formation and early history of the earth
4.6 billion years ago, the primitive earth, dead frozen world, through three effect to gain energy and began to evolution and development. • 1 ° impact effect: interstellar dust high-speed collision, the kinetic energy to heat energy • 2 ° compression effect: interstellar dust landing on the surface, increase external quality, internal squeezed, compression can be converted into heat energy. • 3 ° radioactive decay effect: radioactive elements in the interior of the earth (uranium, thorium, rubidium, etc.). Release huge energy • Evolution results: composition of the molten iron flows to the center of the earth, the formation of iron core, it is a rocky composition form structures (silicate).
The original star (proto - star) early evolution stage
The formation of the earth
• Origin of the earth is also a variety of theories since the middle of the 18th century. At present more popular view is that around 4.6 billion years ago, from the solar nebula began to differentiate into the original earth, low temperature, light and heavy elements one integrated mass, there is no hierarchical structure. Primitive earth once formed, is conducive to continued accretion the solar nebula material is increasing volume and quality, at the same time due to gravitational differentiation and radioactive elements change with increasing temperature. When the original material in the interior of the earth warming to molten state, than big iron acceleration toward the center of the earth sinking, become a nickel iron core, the proportion of small lithophile elements buoyancy of mantle and crust, lighter liquid and gas composition, overflow surface formed by volcanic eruption original hydrosphere and atmosphere.
Adult stars and nucleosynthesis
Nuclear change function expansion, the star for gravity made the contract, adult stars is the result of this two kinds of balance.
From the universe to the earth
This picture shows the process of planet form born 13.7 billion years ago, It originated as a singularity. In a very short period of time, it has formed most of the material.
supernova
One of the most energetic explosive events known is a supernova. These occur at the end of a star's lifetime, when its nuclear fuel is exhausted and it is no longer supported by the release of nuclear energy. If the star is particularly massive, then its core will collapse and in so doing will release a huge amount of energy. This will cause a blast wave that ejects the star's envelope into interstellar space. The result of the collapse may be, in some cases, a rapidly rotating neutron star that can be observed many years later as a radio pulsar. While many supernovae have been seen in nearby galaxies, they are relatively rare events in our own galaxy. The last to be seen was Kepler's star in 1604. This remnant has been studied by many X-ray astronomy satellites, including ROSAT. There are, however, many remnants of Supernovae explosions in our galaxy, that are seen as Xray shell like structures caused by the shock wave propagating out into the interstellar medium. Another famous remnant is the Crab Nebula which exploded in 1054. In this case a pulsar is seen which rotates 30 times a second and emits a rotating beam of X-rays (like a lighthouse). Another dramatic supernova remnant is the Cygnus Loop.
From galaxies to giant molecular cloud
Molecular clouds contain the raw material of stars and planets. A diameter of 300 light-years clouds contain enough for 10000 to 1 million large mass of stars like the sun. Giant molecular cloud before they dissipative sustainable from 10 million to 1 billion.
The impact of the solar system's early frequent events
The impact hypothesis
Now equal to 9/10 the mass of the earth "earth" and the other a mars-sized celestial collision "the moon" Intense collision not only make the "the earth's rotation produces a deflection, and makes" the moon "fracture Fly away from the role of gas and dust material by gravity, the distribution outside the roche limit disk space, they through accretion, have formed a few small objects, and then like a snowball accretion increased continuously, and eventually formed the moon now.