Space Exploration - Section 1 Flashcards
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
What occurs in the death of a Sun-like star?
The Sun-like star shrinks, becoming a white dwarf and eventually the star will fade to a cold, dark black dwarf
What occurs in the death of a massive star?
In a massive star the fusion reaction stops when the star runs out of fuel
Gravity causes the star’s core to collapse rapidly on itself
The collapse will end suddenly with a shockwave which causes the outer part of the star to explode in an event known as a supernova
What happens when a star is not completely destroyed by the explosion?
The core is left as a neutron star or a black hole
What are constellations?
Grouping or patterns of stars
What are asterisms?
Unofficially recognized star groupings
What are galaxies?
Groupings of millions or billions of stars, gas and dust held together by gravity
What are the two main types of galaxies?
Elliptical
Irregular
What are elliptical galaxies?
Is in the shape of an ellipse and is made up mostly of old stars
What are irregular galaxies?
Is made up of young and old stars, but is smaller than the other galaxy types and has no notable shape
What are the three steps in the birth of a solar systems?
A cloud of gas and dust in space starts swirling
Most of the materials (more than 90%) accumulated in the centre, forming the sun
The remaining material accumulated in smaller clumps circling the centre. These form planets
What is solar wind?
Continually released charged particles from the Sun that flow in every direction
What are the inner planets?
Also called terrestrial or Earth-like
Smaller, rockier and closer to the Sun
What are the outer planets?
Also called Jovian, in reference to Jupiter
These planets are large, gaseous and located great distances from the Sun
What is the first measurement you take when locating the position of objects in space?
It’s called the altitude
It indicates the height of the object in the sky above the horizon
Ranges from 0 degrees at the horizon to 90 degrees straight overhead
What is the second measurement you take when locating the position of objects in space?
Called the azimuth
Indicates the compass direction from due north
Ranges from due north as 0 degrees rotating clockwise
Measured in degrees to a maximum of 360 degrees
What does Zenith mean?
Refers to the highest point in the sky and is directly overhead
What is a meteoroid?
A solid body, usually a fragment of rock or metal, travelling in space with no particular path
What is a meteor?
A meteoroid that enters earths atmosphere where the heat of friction causes it to glow brightly
What is a meteorite?
The remains of a meteor that do not burn up completely and last long enough to hit earths surface
