Unit E | Topic 1.1-1.5 | Basics of space Flashcards
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Definition of:
Solstice
Represents the shortest and longest periods of daylight
What and when is the summer solstice?
The summer solstice occurs on June 20th and represents the longest amount of daylight
What and when is the winter solstice
The winter solstice occurs on December 21st and represents the shortest amount of daylight
Definition of:
Equinox
days with equal periods of day and night
What is the geocentric model of the universe?
A model of the universe where:
- Planets revolved around the earth
- The earth was stationary
What was the issue with the geocentric model of the universe?
It couldn’t explain why some planets would seem to reverse direction
Who made the geocentric model of the universe?
Aristotle (Greek philosopher)
What is the heliocentric model of the universe?
A model of the universe where:
- Planets revolved around the sun
- Earth was not stationary
- Planets rotated
True or false:
Planets revolve in a circle around the sun
False:
Planets revolve around the sun in an elliptical pattern, not a circular one
What does a full rotation of the earth represent?
One rotation = one day
What does a full revolution of the earth around the sun represent?
One revolution = one year
Definition of:
Quadrant
A device that measures a star’s height above the horizon
Definition of:
Astrolabe
A device that measures a star’s angle above the horizon and could predict future star positions
Definition of:
Cross staff
A device that measures a stars angle between the moon and any given star
Definition of:
Telescope
A device that allowed scientists to “get even closer” to the night sky
What does “AU” stand for?
Astronomical Unit
What is the distance of one AU?
149 599 000km
(aka distance from the center of the sun to the center of the earth)
Definition of:
Light year
The distance it takes for light to travel in one year
What is the sun mostly made of?
Hydrogen and Helium
Definition of:
A star
A large celestial body of gas that gives off light and thermal energy
What kind of stars are the hottest?
Blue giants and white dwarfs
What kind of stars are the coolest?
Red giants and red supergiants
What are the two forms of stars (by mass)
high mass and low mass stars
What is the life of a low mass star?
- Clouds of dust and gas (a nebula) gather due to gravity
- A low mass star is created
- The star fuses hydrogen atoms into helium atoms using nuclear fusion
- after a few billion years, there are no more light elements to use and it collapses into a white dwarf
- the star “burns out” and turns into a black dwarf
What is the life of a high mass star?
- Clouds of dust and gas (a nebula) gather due to gravity
- A high mass star is created
- The star eventually forms into a red super giant, and the star runs out of hydrogen to fuel it so it cools down and expands
- Elements from helium to iron are formed
- Eventually, the core can’t support the mass of the star and collapses in the form of a supernova
Definition of:
Supernova
A huge explosion caused by a collapsing star where all elements heavier than iron are formed
What are the three possible results of a supernova?
- Gas and dust are flung into space
- A neutron star is formed
- A black hole is formed
What is the order of the planets?
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Characteristics of Terrestrial planets
- Rocky
- Solid surfaces
- Don’t have rings
- Few moons
- Usually small
Characteristics of Jovian planets
- Many moons
- No solid surface
- Ring systems
- Usually large
Definition of:
Galaxy
Groupings of millions or billions of stars, gas, and dust held together by gravity
Definition of:
Comets
Objects in space made up of ice and dust that leave a trail of gas after being heated up by the sun
Definition of:
Asteroids
Large rocky objects that revolve around the sun
Definition of:
Meteoroid
small rocky or metallic objects that travel in space
Definition of:
Meteor
The trail of light emitted by a meteoroid as it enters earths atmosphere
Definition of:
Meteorite
Meteors that successfully pass through the atmosphere
Definition of:
Altitude (in astronomy)
How far a star is above the horizon
What does “Zenith” refer to in astronomy
The location in the sky directly above an object
Definition of:
Azimuth (in astronomy)
A measure of which compass direction a star can be found in the sky
Definition of:
Solar eclipse
A point in time where the moon is between the earth and the sun, casting a shadow on the earth
Definition of:
Lunar eclipse
A point in time where the earth is between the moon and the sun, casting a shadow on the moon
