Space Exploration - Section 1 Flashcards
(43 cards)
Cosmos
The universe, especially when it is understood as an ordered system
What is the summer solstice?
Occurs between June 20 and 22
This is the longest period of daylight hours of the year
Marks the beginning of summer
What is the winter solstice?
Occurs between December 20 to 23
The shortest period of daylight hours
Marks the beginning of winter
When are the two equinoxes?
The first is in spring around March 21
The second is in the fall around September 22
What is the Geocentric Model?
A model that Aristotle proposed with Earth at the centre in an attempt to explain the motion of the planets
What is the Heliocentric Model?
A model that Copernicus proposed that suggested that the Sun was actually the centre and Earth and the other planets revolves in orbits around it
What was the one problem with the Heliocentric Model?
It was unable to accurately predict the motion of the planets
German mathematician, Kelper, discovered the problem
He realized the orbit of the planets were ellipses not perfect circles
What is a sundial?
Indicates the local solar time through the use of shadows
What is a merkhet?
Used to chart astronomical positions and predict the movement of stars
What is a quadrant?
Measured the stars height above the horizon
What is a astrolabe?
Charted stars positions
What is a cross-staff?
Measured angle between the moon and any given star
What are Astronomical Units?
Used to measure distances within our solar system
One AU is equal to the average distance from the centre of that Earth to the centre of the Sun
What are light years?
The unit used to measure distances beyond our solar system
It’s the distance that light travels in one year
What is a star?
A hot, glowing ball of gas (mostly hydrogen) that gives off light energy
Stars vary in their characteristics including mass, density, colour, and surface temperature
What are some types of matter found within our solar system?
Planets The sun Asteroids Comets Meteors Gases and dusts
What are some types of matter found outside of our solar system?
Gases and dust Stars Black holes Constellations Galaxies
What is a Hertzsprung-Russell diagram?
Shows how the surface temperature of a star will actually determine the colour of the star and it follows the colour spectrum from coolest (red) to hottest (violet)
How do stars form?
Stars form in regions of space where there are huge amounts of gas and dust called nebulae (or nebula)
The particles that make up the nebula are known as interstellar matter which has come from other exploding stars
How is a protostar formed?
The force of gravity between the atoms of gas and grains of dust causes a small part of the nebula to collapse into a smaller, rotating cloud
As more material is drawn in the mass at the core increases, as does the temperature
If the core gets hot enough it will start to glow
What is the final stage in the process of becoming a star?
The interior of the protostar continues to get hotter
When the core reaches a temperature of 10 000 000 degrees Celsius, hydrogen will begin to change to helium
This process is known as fusion, releases a great deal of energy and radiation
What is the main sequence in a star?
Depending on the mass, the star that formed will be classified as either Sun-like or massive
Converting hydrogen to helium is the main process always occurring in stars
How does a star turn into a red giant or red supergiant?
When the hydrogen in the core is used up, the star begins to shrink
Gravity causes the star to contract and as it does more nuclear reactions occur, this leads to expansion of the outer layers
What is the final stage of a stars life?
Occurs when the fusion reaction stops because the core temperature is no longer hot enough to keep the reaction going
The star slowly collapses in on itself
