Physics - Space

Light Year

Light Year

Distance that light travels in 1 year

in one year, light travels a distance of 3x10^8 ** 60 60* * *24 ** 365.25 =9.5x10^15

Light year worked example:

The Star Gliese 581 is 20.22 light years away from Earth. How far away is the star in metres?

d = 20.22ly

d = 20.22 *3x10^8 ** 60 * 60 * 24 * 365.25

d = 1.01x10^17m

Planet

A body revolving around the sun (sufficiently large to be spherical, and to clear away other objects of similar size near their orbits)

Dwarf Planet

Smaller than a planet, has not cleared away other objects of similar size in its orbit

Asteroid

Small rocky objects that orbit the sun, they have jagged and irregular shapes

Exoplanet

A planet orbiting a star other than the sun

Moon

A natural satellite of a planet, dwarf planet, or even an asteroid

Star

A large ball of matter that is undergoing nuclear fusion and emitting light and other forms of electromagnetic radiation.

Solar System

A star and everything that orbits it

Sun

The star at the centre of our solar system

Galaxy

A grouping of gas, dust, stars and their solar systems

Universe

All the matter that we know of

Satellite

anything that orbits a planet or a star

Artificial satellite uses

Communication - GPS, TV and Radio

Observing the Earth - Weather, Geographical

Exploring the solar system - Telescopes

Scientific Research - I.S.S.

Other - Spying, Military

Geostationary Satellites

Orbit the Earth at 36000km and take 24hrs to orbit the earth/ a period of 24hrs

Period and Speed of Satellites in relation to orbit

A satellite’s period (time to orbit the Earth) is higher at a altitude orbit than a lower altitude orbit.

Risks to Space exploration

Fuel - Extremely flammable

Radiation - Radiation from space sources such as cosmic rays, solar flares and particles trapped in our magnetosphere

Pressure differential - Microgravity

Re-entry - While re-entering, travelling very fast through air creates very high frictional forces generating extremely high temperatures.

Challenges of Space Travel

Manoeuvring in space

increasing magnitude of velocity

Ion drive

Catapult

Age of Universe

13.8 billion years

The Big Bang theory

Predicts that as the universe expanded, iit cooled.

Evidence: Cosmic Microwave Background Radiation in space. Average temperature is 2.7K

Red shift - The wavelengths have been “stretched”, this means that in the visible light spectrum, wavelengths move towards the wavelengths of red light.

Use of electromagnetic spectrum in obtaining information about astronomical objects.

Ultra violet from the sun is studied to predict solar flares

Microwaves are short wavelength radio waves, and the Cosmic Microwave Background Radiation is a major piece of evidence of the big bang theory

Spectroscope

An instrument which splits up light into its components