Module 1 - Content and Scale of the Universe

Study Notes

The Universe contains various celestial bodies such as stars, galaxies, comets, and asteroids.
The Earth-Moon system is part of the Solar System, which includes terrestrial (rocky) and Jovian (gas giant) planets.
The Solar System features the Sun, asteroids from the Asteroid Belt, and comets from the Oort Cloud and Kuiper Belt.
Estimated 10^22 stars are in the universe.
Astronomical Unit (AU) measures average distance between Earth and the Sun.
Light Year (LY) is the distance light travels in one year.

Hubble operates above Earth’s atmosphere and can be serviced; optimized for UV and visible light with a 7.9-foot primary mirror.
James Webb orbits the Sun, currently has no servicing capability, and is optimized for infrared light with a 21.3-foot primary mirror.

The Solar Nebula Theory explains solar system formation through gravitational and thermal energy from a disk.
Inner disk temperatures influence planet composition; accretion of small particles forms larger clumps and planetesimals.
Protoplanets develop primary atmospheres; mini accretion disks lead to moon formation.
Solar wind can strip small planets’ secondary atmospheres.
Jovian planets (Neptune, Jupiter, Uranus, Saturn) are gas giants located far from the Sun.
Terrestrial planets (Earth, Mars, Mercury, Venus) are rocky and located closer to the Sun.

The Moon stabilizes Earth's axial tilt at 23.5 degrees, promoting a stable climate.
Formed over 4 billion years ago from a collision with a protoplanet, it is the largest moon in the inner solar system.
The densest side of the Moon always faces Earth.

The Asteroid Belt consists of asteroids and the dwarf planet Ceres, located between Mars and Jupiter.
The Kuiper Belt contains comets and dwarf planets like Pluto and Charon, located beyond Neptune.

Originating from the Kuiper Belt (short-period) and Oort Cloud (long-period), comets have solid nuclei composed of frozen gases and dust.
Coma forms a halo around the nucleus; tails always point away from the Sun.

Vary from rubble piles to dense iron; notable examples include Itokawa and Martian moons Phobos and Deimos.

Features red coloration with darkening areas over time due to tholins; theorized to harbor liquid water beneath its frozen surface.

Key indicators of life: order, growth, energy utilization, reproduction, environmental response, and evolutionary development.
Life’s evolution involves natural selection and competition for survival.

Essential elements include water, carbon (C), nitrogen (N), and oxygen (O), which are needed for reactiveness.
Energy sources can be sunlight or chemical energy; time is necessary for life development.

Carbon molecules can form four strong bonds, making them foundational for life; silicon can also form bonds but less effectively.
Evidence of a common ancestor is suggested by life's exclusive use of left-handed amino acids.

Alkalophiles thrive in high pH environments, such as soda lakes.
Halophiles reside in saline environments, including salt lakes and evaporation pools.
Psychrophiles can endure extreme pressures and cold temperatures.
Xerophiles/Endoliths inhabit dry conditions, often living within rocks.