The force of gravity makes the dust particles come spiralling in together. As they do so their gravitational potential energy is converted into heat energy and the temperature rises…
Eventually the temperature rises enough for the hydrogen gas to undergo nuclear fusion. A massive amount of heat and light are given out and the star is stable for around 10,000 million years.
Eventually the hydrogen begins to run out and the star swells into a red giant. (At this point our sun will suck in Earth and the planets around it)
For small stars the star will shrink into a WHITE DWARF and then it cools and fades to a BLACK DWARF (like a dying fire)
When a big star runs out of fuel it would collapse and blow off its outer layer in an enormous explosion called a SUPERNOVA (click to show picture)
The dust and gas on the outside of the supernova are thrown away by the explosion and the remaining core turns into a NEUTRON STAR. If the star is big enough it will become a BLACK HOLE. (The picture shows a black hole after forming in the middle of other stars)
The dust and gas thrown off by the supernova will form SECOND GENERATION stars (like our sun) and a new solar system
Junior cycle science physics the earth and beyond. By Theresa Lowry-Lehnen. Science Teacher.
28/05/13There are nine planets in our solar system:There are nine planets in our solar system:MercuryMarsJupiterSaturnNeptuneUranusPlutoVenusEarthMy Very Easy Method JustSpeeds Up Naming Planets
28/05/13We see planets and the moon because theyreflect sunlight:The sun is different – it produces its own light.
28/05/13The Earth orbits the sun…The Earth orbits the sun………every year (365every year (365 11//44 days)days)Ellipse
28/05/13The Earth is kept in orbit by 2 things…The Earth is kept in orbit by 2 things…GravityGravity…and by thefact that it ismoving at a highvelocity
28/05/13The Earth spins on an axis…Because of this spinthe sun and starsappear to “move”across the sky…
28/05/13GravityGravityGravity is an attractive force that affects anything with mass:Note that thisforce goes bothways – the Earthis attracted to us.
28/05/13Gravity on differentGravity on differentplanets:planets:Jupiter – gravitationalfield strength = 25N/KgEarth – gravitational fieldstrength = 9.8N/Kg
28/05/13More information on gravityMore information on gravityFF/9F/4If you double thedistance the gravitationalforce divides by 4…If you triple thedistance the forcedivides by 9…The amount of gravity attracting an objectdecreases the further out the object is…
28/05/13How much of the moon we see dependsHow much of the moon we see dependson where the moon is in its orbit:on where the moon is in its orbit:Appearance:
28/05/13CometsCometsComets are balls of dust and frozengas. They have very elliptical orbits:As the comet approaches the sun gasesevaporate from it, forming a “tail”. Thistail always faces AWAY from the sun.
28/05/13Artificial SatellitesArtificial Satellites1) Observation (e.g. Hubble Space Telescope) –these are in orbit high above the Earth and canobserve the universe without interference by the____________2) Communications (e.g. ___, phone, car“SatNav” systems) – these satellites arein “geostationary” orbits. This meansthat the satellite always stays above____ ____ point on the Earth and takesa ______ to complete an orbit3) Monitoring (e.g.weather, spysatellites) – thesesatellites have a“___ _____” orbitand may scanaround the Earthseveral times a dayArtificial satellites have been around for 50 years and have 3 main uses:Words – the same, atmosphere, low polar, TV, day
28/05/13Solar systems, galaxies and the UniverseSolar systems, galaxies and the UniverseOUR SUN is one ofmillions of stars thatorbit the centre of…THE MILKY WAY,which is one of a billiongalaxies that orbitAND move away fromthe centre of…THE UNIVERSE(Basically, everything in the universe orbits around something else)
28/05/13Quiz..Quiz..1) What is the sixth planet in the solar system?2) What is the biggest planet in the solar system?3) Name 2 differences between stars and planets4) How long does the Earth take to orbit the sun?5) What 2 things keeps the Earth in orbit?6) Why does Mars take longer to orbit the sun thanEarth?7) How long does the moon take to orbit the Earth?8) Would the acceleration due to gravity on Mars bebigger or smaller than on the Earth and why?9) Which hemisphere is Britain in?
28/05/13Quiz..Quiz..10)What is the name of the line that divides the twohemispheres?11) How long does the Earth take to rotate?12)Where does the sun rise and set?13)If you double the distance between two objects whathappens to the force of gravity between them?14)What shape describes the shape of a comet’s orbit?15)What is a comet made up of?16)Where does a comet’s tail point and why?17)What keeps stars in orbit around the centre of agalaxy?
28/05/13Searching for ETSearching for ETIn any scientific enquiry you have to OBTAIN some evidence andthen ANALYSE it. Consider searching for extra-terrestrial life onMars:OBTAINING EVIDENCE•Fly to Mars yourself (takes ages)•Use robots to bring back samples (not very reliable)•Use robots to take pictures and send them back (also not very reliable)ANALYSING EVIDENCE•Use microscopes to search for fossilised remainsinside the samples•Place the sample in a container and monitor changesin the environment due to living organisms beingpresent in the sample
28/05/13Evidence about the origins ofEvidence about the origins ofthe universe…the universe…
28/05/13If you pass the light through a gas somethingdifferent is seen…heliumSome wavelengths of lightare absorbed by the gas –an “absorption spectrum”.
28/05/13AfterheliumIf the light source is moving away the absorption spectra looka little different…heliumBefore
28/05/13The absorption lines have all been “shifted”towards the longer wavelength end (red end)…AfterBeforeThis is called redshift. The fasterthe light sourcemoves the furtherits light will be“shifted”A similar effect happens with sound– this is called “The DopplerEffect”Hear Doppler Effect
28/05/13Light from different stars and from theedge of the universe also shows this “red-shift”. This suggests that everything inthe universe is moving away from a singlepoint.This is the BIGBANG theory
28/05/13Red shift summaryRed shift summaryLight from other galaxies has a longer _________ thanexpected. This shows that these galaxies are moving ____from us very quickly. This effect is seen to a greaterextent in galaxies that are _______ away from us. Thisindicates that the further away the galaxy is, the ______it is moving.This evidence seems to suggest that everything in theuniverse is moving away from a single point, and that thisprocess started around 15 _____ years ago. This is the____ ________ Theory.Words to use – faster, away, big bang,billion, wavelength, further
28/05/13The Life Cycle of a StarThe Life Cycle of a Star
28/05/13Stage 1: NebulaeStage 1: NebulaeA nebulae is a collection of dust, gas and rock.Some examples of nebulae…
28/05/13Gravity will slowly pull theseparticles together…As they move inwardstheir gravitationalpotential energy isconverted into heat anda PROTOSTAR is formedStage 2: ProtostarStage 2: Protostar
28/05/13Stage 3: Main SequenceStage 3: Main SequenceOur sun is an example of a main sequence star –it’s in the middle of a 10 billion year life spanIn a main sequence star theforces of attraction pullingthe particles inwards are_________ by forces actingoutwards due to the huge__________ inside the star.Stars are basically ________ reactors that use _______as a fuel. During its main sequence a star will releaseenergy by converting hydrogen and helium (light elements)into _________ elements.Words – heavier, balanced, hydrogen, nuclear, temperatures
28/05/13Eventually the hydrogen and helium will run out. Whenthis happens the star will become colder and redder andstart to swell…If the star is relatively small(like our sun) the star willbecome a RED GIANTIf the star is big (atleast 4 times the sizeof our sun) it willbecome a REDSUPERGIANTStage 4: Red GiantStage 4: Red Giant
28/05/13What happens at this point depends on the size of thestar…1) For SMALL stars the red giant will collapse under itsown gravity and form a very dense white dwarf:Stage 5: The DeathStage 5: The DeathWhite dwarf Black dwarfRed giant
28/05/132) If the star was a REDSUPERGIANT it will shrink andthen EXPLODE, releasing massiveamounts of energy, dust and gas.AfterBeforeThis explosion iscalled aSUPERNOVA
28/05/13The dust and gas on the outsideof the supernova are thrownaway by the explosion and theremaining core turns into aNEUTRON STAR.If the star is bigenough it couldbecome a BLACKHOLE.
28/05/13The dust and gas thrown out by a supernova can be used toform a new star…Stage 6: Second generation starsStage 6: Second generation starsOur sun is believed to be a “______ ______ star” – this isbecause it contains some __________ elements along withhydrogen and ________. These heavier elements would havebeen the products of a previous star that have been thrownout by a ________. These heavier elements are also found onplanets, indicating that they might have been made fromremains of previous _______ as well.Words – helium, heavier, second generation, stars, supernova