Stages of Star System Formation

• Contraction: The cloud starts collapsing under its own gravity; over 100,000 years, it shrinks down to 100 AU, heats up (thermal energy), and compresses in the center.
• Accretion disk: The matter around the center spins up and flattens into a disk, while heat vaporizes the dust.

Our universe began with an explosion of space itself – the Big Bang. Starting from extremely high density and temperature, space expanded, the universe cooled, and the simplest elements formed. Gravity gradually drew matter together to form the first stars and the first galaxies.

The core accretion model Approximately 4.6 billion years ago, the solar system was a cloud of dust and gas known as a solar nebula. Gravity collapsed the material in on itself as it began to spin, forming the sun in the center of the nebula. With the rise of the sun, the remaining material began to clump together.

According to NASA, after inflation the growth of the universe continued, but at a slower rate. As space expanded, the universe cooled and matter formed. One second after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons and neutrinos.

Short answer: Hydrogen and helium (and tiny amounts of lithium). That’s it. Astronomers know that the first stars, officially known as Population III stars, must have been made almost solely of hydrogen and helium—the elements that formed as a direct result of the big bang.

According to the big bang theory, equal amounts of matter and antimatter were created at the birth of the universe, but precious little antimatter is to be found in the universe today. Everything we see, from our bodies to our cars to the stars in distant galaxies, is made of matter.

Antimatter may exist in relatively large amounts in far-away galaxies due to cosmic inflation in the primordial time of the universe.

Matter and antimatter annihilate each other on contact, and researchers believe such collisions destroyed almost all of the antimatter (and a large chunk of the matter) that initially existed in the cosmos.

Two of the most intriguing mysteries in modern cosmology are the apparent preponderance of ordinary matter over antimatter and the nature of dark matter, which accounts for about 85% of the mass in the Universe1. Dark matter has made its presence known only through its gravitational effects on astrophysical objects.

Particles from empty space Quantum mechanics tells us that there is no such thing as empty space. Even the most perfect vacuum is actually filled by a roiling cloud of particles and antiparticles, which flare into existence and almost instantaneously fade back into nothingness.

As the universe cooled, conditions became just right to give rise to the building blocks of matter – the quarks and electrons of which we are all made. A few millionths of a second later, quarks aggregated to produce protons and neutrons. Within minutes, these protons and neutrons combined into nuclei.

Gravity is the force that all objects with mass exert upon one another, pulling the objects closer together. The tiny particles that make up matter, such as atoms and subatomic particles, also exert forces on one another. These forces are not gravity, but special forces that only these particles use.

‘Nothing exists’ is simple in the sense of being an easy to remember generalization. There is no such thing as nothingness, and zero does not exist.

The idea that matter was built of discrete building blocks, the so-called particulate theory of matter, independently appeared in ancient Greece and ancient India among Buddhists, Hindus and Jains in 1st-millennium BC.

About 99 percent of your body is made up of atoms of hydrogen, carbon, nitrogen and oxygen. You also contain much smaller amounts of the other elements that are essential for life. The hydrogen atoms in you were produced in the big bang, and the carbon, nitrogen and oxygen atoms were made in burning stars.

Eoraptor

Other than birds, however, there is no scientific evidence that any dinosaurs, such as Tyrannosaurus, Velociraptor, Apatosaurus, Stegosaurus, or Triceratops, are still alive. These, and all other non-avian dinosaurs became extinct at least 65 million years ago at the end of the Cretaceous Period.