Chapter 8 Flashcards
What can the inner planets be described as
Solid and rocky
What can the outer planets be described as
Gaseous and liquid
How long ago did the solar system develop
4.5 billion years
What are the suns main elements
Hydrogen (71%) and helium (27%)
How large is the sun compared to the mass of the rest of the solar system combined
700 times
What can the planets orbits be described as
Almost circular lying on nearly the same plane
What planets travel counterclockwise
Six planets; mercury,earth,mars,Jupiter, Saturn and Neptune
What planet travels clockwise
Venus
What planet appears to rotate on its side
Uranus
What are the inner planets
Mercury, Venus, earth, and mars. They are known as terrestrial planets
What are the outer planets
Jupiter,Saturn,Uranus,Neptune. Also known as Jovian planets. They are gaseous, liquid, or icy
How comparable is the size of Jovian planets next to terrestrial planets
They are much larger, and do not have a well defined surface
What are dwarf planets
They are a group of planets such as Pluto that fail to fit in either family.
What are asteroids
They are rocky or metallic bodies that range from a few km to 1000km across
What are comets
They are icy bodies that are about 10km or less and have very long tails of gas and dust as they near the sun
Where are most asteroids found
Within the asteroid belt between mars and Jupiter
Where are most comets from
From a disc like swarm of icy object that lay beyond Neptune called the Kuiper belt
Where do most comets orbit the sun from
From the Oort Cloud that is 40,000 to 100,000 AU from the sun
How do we measure a planets mass
Keplers modified third law
How do we measure a planets volume
We measure it’s radius
What is a planets reflection spectrum
It is a way to reveal a planets atmospheric contents and the nature of surface rocks
Do mercury and Venus have moons
No they are moonless
What planet has the most moons
Jupiter then Saturn and then Uranus
How did we determine the age of the solar system
Radioactive dating of rocks
What is the theory on how the solar system formed
The solar nebula hypothesis
What is the solar nebula hypothesis
It proposes that the solar system evolved from a rotating flat disc of gas and dust called an interstellar cloud
How did the solar nebula form
A collision with another cloud of nearby exploding star
How was the temperature of the solar nebula before planets formed
The inner part of the disc was hot, and the outer disk was colder than the freezing point of water
What is condensation
It is when gas cools below a critical temperature
What is the role of condensation in the solar nebula
The sun kept anything until Jupiter unable to condense and this helped the planets form
What is accretion
Tiny particles sticking together by electrical forces into bigger pieces. If they don’t undergo too violent of impacts they become planetesimals
What are planetesimals
They range from millimeters to kilometers in size, are mainly rocky iron composites in the inner solar nebula while the outer had more icy rocky iron composites
How did planetesimals evolve
Different ones slowly merged together to form circular orbs that grew in size and began to develop planets
Where was planetary growth the fastest
The outer solar nebula
How were these planetesimals impacted
They received continuous bombardment and this he,led internal radioactivity melt the inside and lead to different interiors
How did atmospheres form for inner planets
From the continuous bombardment by asteroids and comets craters and volcanos started to form on the surface of these planets and the volcanic activity together with their gravity helped form it
How did atmospheres form for outer planets
They captured their atmosphere from the solar nebula gravitationally
Why does mercury and the moon not have an atmosphere
Because they are too small and there is not enough gravity to retain gases on their surface
What are exoplanets
Planets around other nearby stars
How do we detect exoplanets
The Doppler shift method, gravitational lensing, or the transit method
What is gravitational lensing
Gravity bends the path of light when it passes near a massive object, we detect this light
What is the transit method
We detect if there is a dimming of light from the central star at any point
