The Solar System
Hostile environments can create reactions within characters.
Orrery is a mechanical model of the solar system. It can predict the positions and motions of planets and moons.
Voyager 1 took advantage of its placement and flew past Neptune in 1989.
Voyager Two took footage of the planets.
Loss of the ability to travel between stars causes civilizations to fall.
There are many moons in our solar system, and exoplanets are the ones found outside of the solar system. There are more than 5,000 planets outside of our solar system. The bigger the planet, the more gravity.
Gravitational pull is the force that pulls objects with mass towards each other. It's also known as gravity or gravitation.
An indirect form of planet detection refers to a method of identifying a planet not by directly seeing it through a telescope but by observing the effects its gravitational pull has on its host star, such as the "transit method" where a planet passing in front of a star causes a slight dimming in the star's brightness, or the "radial velocity method" which detects a star's wobble caused by a planet orbiting it; essentially, inferring the planet's existence through its influence on the star
Mars and Jupiter has an asteroid belt in between them
Beyond Neptune, there is a capier belt, which is another asteroid belt.
Orbit of the planets is in the same direction which is called circular orbits. Prograde direction means anticlockwise.
The moons orbit the planets.
Inner planets mercury venus earth and mars
Venus is the evening star to earth.
Giant planets: jupiter, saturn, urunus and neptune
Jupiter is more massive than other planets and has a huge gravitational influence on other planets.
Uranus and Neptune are ice-giant planets.
Planets are formed from material around the sun. Asteroids, comets and ect are materials that weren’t used in the formation of planets.
"Surface-level planets" refers to planets that have a solid or liquid surface that can be considered a distinct boundary, like the terrestrial planets (Mercury, Venus, Earth, and Mars) and some dwarf planets and moons.
Essentially, it means planets with a defined "ground" or "surface" that you could, in theory, stand on. This contrasts with gas giants (Jupiter, Saturn, Uranus, and Neptune) the ice giants, which lack a solid surface and are primarily composed of gas and/or ice with a gradual transition into their interiors.
Terrestrial Planets:
These planets have a solid, rocky surface. Think of Earth's landmasses or the rocky surfaces of Mars, Venus, and Mercury.
Gas Giants:
These planets are primarily composed of gas and do not have a defined surface. Their atmospheres gradually become denser and transition into their interiors.
Planetary Surface:
In general, a planetary surface is the point where the planet's solid or liquid material meets the atmosphere or outer space.
Exoplanet Surface:
For exoplanets, the concept of a surface can be more complex. Scientists sometimes define the "surface" as the point in the atmosphere where the pressure reaches 1 bar (similar to Earth's sea level pressure).
Other Considerations:
Some moons and dwarf planets, like Titan (a moon of Saturn) or Pluto, also have solid surfaces that are considered planetary surfaces.
About the Planets - NASA Science
Inner Planets The first four planets from the Sun are Mercury, Venus, Earth, and Mars. These inner planets also are known as terrestial planets...
NASA Science (.gov)
Chapter 1: The Solar System - NASA Science
The Terrestrial Planets * The planets Mercury, Venus, Earth, and Mars, are called terrestrial because they have a compact, rocky surface ...
NASA Science (.gov)
Planetary surface - Wikipedia
A planetary surface is where the solid or liquid material of certain types of astronomical objects contacts the atmosphere or outer
Asteroids are far apart from each other and aren't as close together as the media portrays.
If they are too close, they will bounce off each other or shatter or erode each other and become dust level.
Jupiter’s gravity, through the influence of orbital resonances, stirred up asteroid orbits and prevented their accretion into a planet.
The asteroid belt comes from a region of space where no large planet formed because Jupiter's gravity kept it from forming.
An orbital Resonance is the Location where planets are pulled out.
Note: Jupiter removed asteroids from orbit.
Uranus is tilted on its side
Features of the solar system?
1. All large bodies in near-circular orbits in a pro-grade or anti-clockwise direction
2. Terrestrial planets - closer to sun and have rocky surface
3. Giant Gas planets - far from sun, larger than Earth, no solid surface
4. Kuiper belt - Asteroids
Earth’s moon is large and it is rare for planets to have a moon–exceptionally as large as ours is. The moon formed from the remains of a giant impact.
Theia is hypothesized to have been about the size of Mars, and may have formed in the outer Solar System and provided much of Earth's water.
If there are more moons than one, we need to keep in mind the phases of the moon, aka moon’s orbit.
Sometimes, the moon looks bigger or smaller depending on the orbiting distance.
The waxing moon is when people can see the moon during the day or evening; it becomes "fuller" and rises later each time.
The Waning moon is visible at night and in the morning time. It becomes "less" and sets later each day.
The orbit around the moon takes 27 and a half days to complete on orbit around earth.
Lunar phases are a
consequence of the
Moon’s 27.3-day orbit
around Earth.
• Half of the Moon is
illuminated by the Sun
and half is dark.
• We see a changing
combination of the
bright and dark faces as
the Moon orbits Earth
As the moon moves it isn’t as visible to earth.
We see phases of the moon because Half the Moon is lit by the Sun, half is in shadow, and its appearance to us is determined by the relative positions of the Sun, Moon, and Earth.
There are eight distinct locations for the moon.
People can only see the moon at a certain time of day
Solar eclipses can only happen during new moon.
New moon is between earth and sun
Crescent is first quarter and gibbous is waxing
Full moon
Last quarter crescent
The earth in a different place and sun means that there is an extra two days.
waxing
• Moon visible in afternoon/evening
• Becomes “fuller” and rises later each day
Waning Moon is visible late at night and morning, it becomes “less” and sets later each day
9am is third quarter
Waning crescent and new moon means that it is right before or around sunset/sunrise
If there are more moons than one, they should be in the same phase.
The days sides of the planet gives direction of the star.
Surface gravity is important to keep in mind
If mars is terraformed gravity has to be kept in mind
High surface gravity big weight can lead to organisms requiring stronger skeletal structures to support their increased weight, leading to denser bones or exoskeletons.
Enhanced musculature would be necessary for basic locomotion, resulting in bulkier bodies or more efficient energy use.
Cardiovascular System:
Hearts would need to work harder to circulate blood against the force of gravity, possibly leading to larger or multiple hearts in some species.
Blood pressure in upright organisms could become a limiting factor, making smaller or horizontally-oriented body shapes advantageous.
Respiration:
Breathing could be more challenging due to the compression of lung structures and the added effort of diaphragm movement.
Behavior and Movement:
Mobility might be slower and more energy-intensive, favoring shorter bursts of movement over long sprints.
Flight or jumping might be nearly impossible, with flying species potentially evolving reduced or no wings.
Surface gravity can be the same but because of where it is located there is more sun.
Pluto is only six percent of surface gravity.
Eg. sources that lean into the reality of planets: Harry harrison Deathworld trilogy, Tales of known space Larry Niven, Warhammer, The Expanse
What Counts as a Planet?
Definition from the International Astronomical
Union (IAU) 2006:
● The object is in orbit around the Sun.
● Has sufficient mass to be round.
● Has “cleared the neighborhood” around its orbit.
New horizons took pictures of pluto.