Planets in Science Fiction

The Solar System

a variety of objects that can be divided into different categories: the central star, the planets, comets, asteroids, etc

all large bodies orbit in a near-circular orbits in a

pro-grade (anti-clockwise) direction

Orbital Resonances

asteroids in orbital resonance with Jupiter experience periodic nudges that eventually move asteroids out of resonant orbits - leaving gaps in the belt

Earth is special because

it is rare for a planet to have a moon

Theory for the moon’s formation

is made up of the remains of an impact from really long time ago

5,849

confirmed exoplanets

Kepler results show

planet frequency increases towards smaller (terrestrial) size

Orrery

a mechanical model of the Solar System that illustrates or predicts the relative positions and motions of the planets and moons

Mercury

the smallest planet in our solar system

Jupiter

the largest planet in our solar system

Uranus

planet tilted on its side

what counts as a planet according to the International Astronomical Union (IAU) 2006

the object is in orbit around the Sun, has sufficient mass to be round, and has “cleared the neighborhood” around its orbit

Pluto is NOT a planet because

it does not meet the IAU criteria of having cleared its orbital neighborhood

Exoplanet

a planet outside our solar system that is named after the star AND in order of discovery - NOT distance from the star

Direct Planet Detection

uses either starlight reflected from or thermal radiation emitted by the planet

Indirect Planet Detection

uses effects of the planet on the parent star or random background star

Astrometric Technique

can detect planets by measuring the change in a star’s position in the sky

Doppler Technique

measures a star’s doppler shift can tell its motion toward and away from us

Gravitational Tugs

the Sun and Jupiter orbits around their common center of mass

Transit

when a planet crosses in front of a star

Planet’s radius

the resulting eclipse from he transit that reduces the star’s apparent brightness

transit method works for

large planets in edge-on orbits

Planet mean density & composition

combination of transit radius with Doppler mass

Terrestrial Planets

c

Gas (gas, Jovian) planets

far from the sun, much more massive than earth, doesn’t have a solid surface

Planets are made out of

c

Uranus

tilted on its side therefore rotates on its side like a wheel

Lunar phases

27.3 days orbit around earth

Waxing moon

visible in the afternoon/evening and becomes “fuller” and rises later each day

Waning moon

is visible in late night/morning and becomes “less” and sets later each day

Microlensing

when a foreground star passes in front of a background star, the light from the background star is bent and amplified

Kepler

NASA’s first mission capable of finding earth size and smaller planets

Transiting Exoplanet Survey Satellite (TESS): observing bright stars over the whole sky, enabling detailed follow up

Asteroids were discovered when

the telescope was discovered

Jupiter and the Sun orbit the center of mass every

12 years

the approximate maximum size of a terrestrial (rocky) planet

twice the size of earth

the Habitable Zone

the region around a star where water COULD exist in a liquid state on the surface of a planet if it has sufficient atmospheric pressure

Proxima Centauri

the nearest star to the Sun

Astrometry (Indirect)

detects planets by measuring the changes in the star’s position in the sky