Chemical Properties of the Universe Astronomers Hypothesize

Chemical Properties of the Universe

Astronomers hypothesize that about 5 million years ago, the Solar System was filled with a plethora of hot gases and dust, swirling around a hot core. They think that once the core approached about 1 million degrees, the physics and chemical properties caused the gases to coalesce, forming the sun. During this time, there were millions and millions of asteroids. As these asteroids collided with one other, some combined and as their mass increased, gravity pulled more and more particles and debris in, and the planetoids became larger and larger until the planets of the solar system were formed. This was a process known as accreation, and over hundreds of millions of years, the solar system formed -- the continual bombarding of asteroids changing the planets, forming the rings of Saturn, and the landscapes of others, including the moons -- which were just smaller planetoids caught in the gravitational pull of the planet (Palmer). Earthlike planets are typically closer to their sun, allowing for their temperatures to be more moderate. Depending on the distance from the sun and the characteristics of the atmosphere, they may have liquid water, and may develop plant life through photosynthesis. The gas-giants in the outer solar system, however, are far enough away from the sun that temperatures are quite low, and contain a higher portion of volatile chemicals like ammonia and methane, which because of the cold, remain somewhat solids. The four outer planets make up about 99% of the mass in our solar system. Jupiter and Saturn are more gaseous, while Uranus and Neptune more icy (Jet Propulsion Laboratory).

Of course, there are several ways we can approach the chemical nature of the universe. First, we may look at the elemental chemicals that make up most of the universe; second, we can look at the way these chemicals combined in certain environments to produce carbon-based life. The universe is something larger and more complex than many can describe -- it includes the totality of existence (planets, stars, galaxies, space, matter and energy). The observable part of this totality is almost 100 billion light years in diameter, suggesting that the universe has been governed by the same physical laws throughout its history, and those laws then translate into laws that govern solar systems, then planets, then micro-properties. There are also a number of theories from physicists that indicate the universe may be one of many that exist at the same time, as well as the idea that the universe is expanding at an accelerating rate (J. Palmer).

Most scientists believe that the universe is made up of a number of chemicals that also exist on earth and other planets. This is not surprising since for those chemicals to occur on a planet, they must be formed somewhere. However, stars, nebulae, and interstellar clouds seem to be largely formed from hydrogen which fuses into helium, which then fuses into heavy metals (the type depend on the mass of the star). The ration shows that the primordial abundance of hydrogen and helium is: #of hydrogen atoms/# of helium atoms = 12.5. For instance, see Figure 1 for the relationship of hydrogen to helium:

Hydrogen - Hydrogen has an atomic number of 1 and is the most abundant (75%) of the mass of the universe and 90% of the number of atoms. It is the lightest element, and at standard Earth temperature and pressure is colorless, odorless, tasteless, non-toxic, non-metallic, yet highly combustible gas. The element plays a significant role in acid-base chemistry as it allows reactions that exchange protons between soluble molecules. Molecular clouds of hydrogen are thought to be vital to star formation because it plays a vital role in the proton-proton reaction and resultant nuclear fusion fueling of the star. In the universe, though, hydrogen is found largely in the atomic and plasma states. As plasma, hydrogen's electron and proton properties are not bound together, resulting in robust electrical conductivity and high emissivity (producing light). The charged particles are also highly influenced by magnetic and electrical fields. Molecular hydrogen (protonated molecular hydrogen or H3+) is found in interstellar gases. This form is generated by the ionization of molecular hydrogen from cosmic rays and becomes relatively stable in low temperatures of space (Gagnon).

Helium -- Helium, atomic number 2, is also colorless, odorless, tasteless, non-toxic, and inert with boiling and melting points the lowest among the elements and existing as a gas only in extreme conditions. It is the second lightest and second most abundant element in the universe, or about 24% of the total elemental mass, or more than 12 times the mass of all the other heavier elements combined. Helium is rare on earth, and the vast majority was formed by nuclear synthesis during the Big Bag event. It is formed by the nuclear fusion o9f hydrogen as part of stellar nucleosynthesis. This is a process in which chemicals assemble inside the cores of stars. Then, as the star ages, there are chemical changes of the elements within the stars. In other words, as stars lose their mass the abundance of elements heavier than helium increase (Jones).