Space Flashcards
WHAT IS A PROJECTILE
Something that moves under the influence of gravity.
- A football kicked through the air.
- Satellite orbiting earth.
WHY DOES A PROJECTILE FOLLOW A CURVED PATH
Horizontally, the projectile is not affected by gravity and moves at a constant velocity.
Vertically the projectile is at a constant acceleration due to gravity.
The two motions combined give a curve.
HOW DO THE PROJECTILE FORMULAS WORK
(H) constant velocity - Vh = s/t
Vh = horizontal velocity
s = displacement (distance) travelled by projectile
t = time taken to fall
(V) Accelerates due to gravity - Vv = Uv + at
Uv = initial vertical velocity
Vv = final vertical velocity
a = acceleration due to gravity (9.8ms^-2 on earth)
WHAT TYPE OF GRAPH CAN HELP US WITH PROJECTILES
Velocity time graph
WHAT IS A SATELITE (ARTIFICAL AND NATURAL)
Anything that orbits another body (eg earth).
Natural satellite - the moon around the earth.
Artificial satellites - Satelite machines to orbit another body in space.
HOW DOES A SATELLITE STAY IN ORBIT
Isaac Newtons thought experiment.
Satellites stay in orbit because they are “falling round” the earth. The curve of the satellites fall matches the curve of the earth.
WHY IS THE SATELLITE A SPECIAL KIND OF PEOJECTILE
The satellites horizontal velocity stays constant as it orbits the earth. The weight of the satellite provides a force which makes it accelerate towards the centre of the earth. If the horizontal velocity is high enough, then the curve of the fall matches the curve of the earth.
WHAT IS A SATELLITE ORBIT
The time taken for a satellite to complete one orbit is called the period.
The period depends on the altitude of the satellites orbit.
THE GREATER THE ALTITUDE OF THE ORBIT, THE GREATER THE PERIOD OF THE SATELLITE.
WHAT IS A GEOSTATIONARY SATELLITE
If a satellite orbits at the right altitude, It will have a period of 24 hours - The same time it takes the earth to turn once. This means the satellite will stay above the same point on the earth at all times. It is useful as we can communicate with the satellite at all times.
PURPOSES OF A SATELITE
GPs, weather forecasting, communications, scientific discovery, space exploration
THREE FAMOUS SATELLITES
- Hubble space telescope
- MetOp
- Echostar 23
HOW DOES A ROCKET TAKE OFF
Two forces acting on it - It’s weight downwards and the thrust of the rocket engines upwards, if the thrust is bigger than the weigh, there will be an unbalanced force upwards.
Newton’s second law tells us that, if there is an unbalanced force, the rocket will accelerate.
ROCKET TAKING OFF ON DIFFERENT PLANETS EXPLANATION
Easier in places where the gravitational field strength is lower.
HOW DOES A ROCKET MOVE IN SPACE
Newtons 3d law
The rocket engines apply a force to the exhaust gasses
The exhaust gasses apply a force to the rocket engines, rocket will then accelerate.
CHALLENGES WITH SPACE TRAVEL
Travelling large distances - The devices involved in space travel require large amount of energy to reach high velocities. Much of the fuel is used during launch. We therefore require result engines which will be able to increase the velocity of the device whilst using small amounts of fuel - ion drives.
Travelling large distances using the catapult affect - As the rocket moves towards an object such as the moon, planet or large asteroid, the object that is travelling accelerates meaning it flies past at a greater velocity than before.
Manoeuvring a spacecraft - It is difficult as a spacecraft is weightless on space. There is no friction in space so once the spacecraft starts it wont stop (Newtons first law).
In order to stop the vehicle we need to fire a thruster in the opposite direction.
Maintaining sufficient energy to operate life support systems in a spacecraft - Solar energy is the best source of power as it is free and efficient. Spacecrafts are build so that solar panels can be pivoted as the space craft moves and always point at the sun.
RISKS OF SPACE TRAVEL
Fuel load on take off - If a rockets fuel load isn’t properly controlled, it can cause an external tank explosion and cause the spacecraft to explode - The challenger in 1986.
Potential exposure to radiation - The earths atmosphere shields us from radiation in space, gamma radiation. Astronauts in space don’t have this protection. Can increase cancer risk
Pressure differential - There is no air pressure in space. If there is any damage to the space shuttles, the difference in pressure inside the spacecraft and outside can cause the spacecraft to be blown apart - sudden decompression.
Re-entry through the atmosphere - The rocket will be moving at high speed, It is vital that the rocket hits the atmosphere as the right angle - between 5^ and 8^. If it hits at less it will bounce off of the atmosphere and probably won’t have enough fuel to turn around and try again. Greater than 8 the spacecraft can be destroyed due to the heating caused by friction with the atmosphere
WHAT IS A LIGHT YEAR
The distance travelled by light in one year
(3x10^8 x 60 x 60 x 24 x 365)
There is approximately 9.5 x 10^15 meters in a light year.
WHAT FORMULA CAN BE USED FOR ROCKET TAKE OFF
Fun = engine thirst - weight
Acceleration = Fun/mass
F = ma
WHAT IS THE DEFINITION OF A PLANET
A planet is a rocky or gaseous body that orbits a central star.
WHAT IS THE DEFINITION OF A DWARF PLANET
Planets which have not cleared the neighbouring region of small objects.
WHAT IS THE DEFINITION OF A MOON
A rocky body that orbits a planet and reflects light. (natural satelite)
WHAT IS THE DEFINITION OF A SUN
A star, it is the largest and heaviest object in our solar system.
WHAT IS THE DEFINITION OF AN ASTEROID
Small rocky objects that orbit the sun, much smaller than planets.
WHAT IS THE DEFINITION OF A SOLAR SYSTEM
Consists of the sun and everythings bound to it by gravity - planets, dwarf planets etc
WHAT IS THE DEFINITION OF A STAR
A ball of gases which produces heat and light by the process of nuclear fusion reactions
WHAT IS THE DEFINITION OF AN EXOPLANET
Planet that orbits a star outside our solar system
WHAT IS THE DEFINITION OF A GALAXY
Huge collection of gas, dust, stars and solar systems all held together by gravity.
WHAT IS THE DEFINITION OF A UNIVERSE
contains everything - all of space and all the matter and energy.
HOW OLD IS THE EARTH
13.8 billion years old
BIG BANG THEORY
The universe is still expanding.
There was nothing before the big bang. Everything began with the big bang - time, matter, space.
ELECTROMAGNETIC SPECTRUM AND SPACE
Astronomers can build telescope which can pick up all parts of the EM spectrum.
By looking at the emissions (EM spectrum) of a star, we can tell its temperature, mass, size, composition.
Visible light can be split into its component using two methods - prism and diffraction grating.
Prism - Each colour is
diffracted at a different angle, how much its diffracted depends on its wavelength. ROYGBIV - red being least diffracted and with the longest wavelength.
WHAT IS A LINE SPECTRA
When an electrical current is passed through a gas - or if the gas is very hot - energy is emitted in the form of light.
If we pass that light through a diffraction grating we see lines of different colours.
Each element produces a unique pattern of coloured lines - line spectrum.
Using the line spectra of a star - how much of what element there is.
WHAT DO THE HUBBLe TELESCOPE AND ISS DO
Hubble telescope is used to observe distant stars, galaxies and planets.
ISS researches about long term space exposure on the body.
KEY POINTS TO THE BIG BANG THEORY
- There was a rapid expansion till sub-atomic particles were formed.
- A further period existed, known as the dark ages, with no light.
- Atoms combined, first stars formed, fusion produced light from the stars.
- Black holes, stars and galaxies followed.
- Universe is continuing to expand.
