Space - Topic 2 Flashcards
What method was used in the past before navigation tools were invented?
They would use their naked eyes to observe space leading to very limited knowledge
What were quadrants?
Navigational instruments in the shape of a quarter circle used for measuring altitudes of astronomical objects
What were sextants?
Navigational instruments similar to quadrants but in the shape of a sixth of a circle they where used for measuring the position of stars
What are the disadvantages of optical telescopes?
They can only be used at night
They cannot be used if the weather is poor or cloudy
What are the advantages do radio telescopes have over optical?
They can be used in daytime as well as night
Hey can be used in bad weather because their radio waves are not blocked by clouds
How does a radio telescope work?
First Weak radio waves from space are reflected by a large curved reflector which brings the waves to a focus at the antenna
At this point the weak radio waves combine to give a strong signal at the antenna
The reflector should be as big as possible so that the many weak radio waves are collected giving as strong a signal as possible
What does the diagram of a radio telescope have?
A curved reflector (dish) reflecting the waves
A focus in the middle focusing on the waves (the centre)
The antenna marking the connection stronger (box)
Radio waves being collected and going into the dish
What are the advantages of space telescopes?
They can observe the whole sky
They operate in day and at night
Wha are the disadvantages of space telescopes?
They are expensive to launch
They are difficult to maintain and if anything goes wrong only astronauts can fix them
What is a space probe?
A probe is an unmanned spacecraft that travels through space to collect information
What are space robots?
NASA space robots are robotic devices used to aid augment or substitute for astronauts in order to perform difficult or routine tasks
What is an AU?
An AU is an astronomical unit
What is 1 AU defined as
1 AU is defined as the distance between the earth and the sun
What is 1 AU in meters (standard form)?
1AU is 1.5 x 10¹¹ meters
What is a light year?
A light year (ly) is the distance that light travels in 1 year
(IT IS NOT A TIME)
What is one light year the equivalent to in meters?
One light year is the equivalent of 9.46 x 10¹⁵ meters
What is the formula for distance, velocity and time?
d = vt
What is the Big Bang theory?
The Big Bang theory is an effect to explain what happened at the very beggining of this universe
It suggest that there was a ‘big bang’ and the universe was formed and that there universe continues to expand to this day
What happened in the Big Bang?
The universe is thought to have started at an infinitely small, hot and dense singularity.
The universe inflated, expanded and cooled, going from very small to very hot to the size and temperature it is today
What evidence is there for the Big Bang theory?
Expanding universe and galaxy’s moving away from each other. It implies a starting point.
A radiation detected evenly across space spread after the Big Bang called cosmic microwave background radiation
An abundance of light elements like hydrogen and helium has produced at the time of the Big Bang
What is the age of the universe?
13.8 billion (or 13.8 x 10⁹) years
What is the moon?
The moon is the satellite of the earth
Not that important:
It was formed billions of years ago when the earth collided with its twin planet, Theia. It’s held in orbit around the earth by the earth gravitational pull and takes one month (and 27 days) to complete its orbit.
Why can we see the moon at night?
The light from the sun is reflecting through it (/the moon reflects the light from the sun) making it so it shines
Why is the moon Important for life on earth?
It stables the climate,
Helps keep earths axis the same,
It helps us balance and stay in a cycle of sun equally around the world,
Life couldn’t exist if the moon weren’t there,
It prevents the earth from wobbling on its axis stopping the sun being on one side for half a year and then switching
How many phases of the moon are there?
8
Why does the moon appear in different shapes through the year?
It doesn’t always appear the same because of its position in relation to the sun.
What is a solar eclipse?
A solar eclipse occurs when the moon passes between the sun and the earth. It casts a shadow over the earth turning it dark for a small amount of time
What is a lunar eclipse?
A lunar eclipse happens when the earth passes between the sun and the moon. This cast a shadow on the moon because the earth is blocking the suns light
What would happen if the sun was located between the earth and the moon?
An apocalypse. The earth would end up inside the sun because the sun is giant and the temperature would be too high for us to survive
What is a star?
A star is a large ball of hot gasses that is undergoing nuclear fusion and emitting electromagnetic radiation (i.e. light)
What colour is the coldest and warmest in stars?
Red is the coldest and blue is the warmest
What is the sun and how does it live?
The sun is the star at the centre of our solar system
It stays alive through a process called nuclear fusion that is in the suns core which provides it with fuel to keep it burning
what is nuclear fusion?
Nuclear fusion is the process of small nuclei joining together to form a larger nucleus, with energy being released as it happens
How are stars formed?
They are formed from massive clouds of gas and dust in space
What are the stages of star formation?
First gravity pulls the gas and dust together to form a protostar
Then the protostar will continue to contract due to gravity until the core becomes hot enough for nuclear fusion to begin
These fusion reactions then provide a thermal pressure outwards that balances the gravitational force
What phrase is used to describe the formation of a star?
Hydrostatic equilibrium
What is an exoplanet?
An exoplanet is a planet outside of our solar system
Exoplanets are planets in our galaxy (the Milky Way) that like us orbit around stars in their surroundings
What is a galaxy?
A cluster of gas, dust and many different types of stars, and various strange objects such as black holes
What galaxy do we belong to?
The Milky Way
What is the region around a star that an exoplanet must be in for it to be habitable?
Habitable zone or Goldilocks zone
How do you detect exoplanets?
Through methods like direct imaging, transit, and radial velocity
What is the direct imaging method?
Rarely exoplanets can be seen directly using a telescope as they orbit stars
What is the transit method?
When an exoplanet passes in front of its star, the star gets a bit dimmer and Astronomers can measure this decrease in brightness.
What is the radial velocity method?
when an exoplanet goes around it due to the exoplanets gravitational pull the star will wobble slightly. Astronomers can measure this wobble since it makes the light coming in from the star appear bluer of redder
What is the difference between mass and weight?
Mass is the quantity of particles that make up an object and weight is the force due to gravity acting upon an object.
M = kg
W = N
What is gravitational field strength?
The gravitational force (or weight) per unit mass
What are earth, mars and the moons gravitational field strength
Earth = 9.8
Mars = 3.7
Moon = 1.6
What is the gravitational field strength in comparison to a planet?
The larger mass a planet has the greater its gravitational field strength and therefore gravitational pull
What is the formula for mass, weight and gravitational field strength?
W = mg
