Nebular Hypothesis TheoryNebular Hypothesis Theory

What is a Theory?What is a Theory?

A theory is both a goal and a tool of A theory is both a goal and a tool of researchresearch

Theories ask the questions that look Theories ask the questions that look beyond the facts and laws of sciencebeyond the facts and laws of science

Theory statements can be refuted, but not Theory statements can be refuted, but not verified, no matter how strongly we believe verified, no matter how strongly we believe in the truth of a theory. It is always in the truth of a theory. It is always possible for it to be falsified. possible for it to be falsified.

Nebular Hypothesis TheoryNebular Hypothesis Theory

The birthplace of our solar system was a The birthplace of our solar system was a NEBULANEBULA– A nebula is a “fuzzy” patch in the sky, either A nebula is a “fuzzy” patch in the sky, either

light or dark; a cloud of gas and dustlight or dark; a cloud of gas and dust– Our solar system evolved from a swirling Our solar system evolved from a swirling

cloud of dust (cloud of dust (Nebular Theory)Nebular Theory)– Gravity caused the gases and dust to be Gravity caused the gases and dust to be

drawn together into a denser cloud (rate of drawn together into a denser cloud (rate of rotation increased)rotation increased)

Nebular Hypothesis Theory cont.Nebular Hypothesis Theory cont.

– As a result the cloud collapsed to resemble As a result the cloud collapsed to resemble a disk. Most of the mass collapsed in the a disk. Most of the mass collapsed in the centercenter

– Matter in the rest of the disk clumped Matter in the rest of the disk clumped together to form planetesimals = together to form planetesimals = protoplanetary bodiesprotoplanetary bodies

– Hydrogen gas combined or fused to form Hydrogen gas combined or fused to form helium atoms (nuclear fusion – a source of helium atoms (nuclear fusion – a source of energy from the sun!)energy from the sun!)

The Sun was born!!!The Sun was born!!!

Examples of NebulasExamples of Nebulas

Eagle NebulaEagle Nebula

One last exampleOne last example

Cats Eye NebulaCats Eye Nebula

Examples of NebulasExamples of Nebulas

Orion NebulaOrion Nebula– Located in the Located in the

constellation Orionconstellation Orion

Our solar systemOur solar system

Terrestrial planets: Terrestrial planets: inner part of solar inner part of solar systemsystem

Characteristics: small Characteristics: small and rockyand rocky– MercuryMercury– VenusVenus– EarthEarth– MarsMars

Our solar systemOur solar systemGas giants: larger planetsGas giants: larger planetsCharacteristics: colder and covered with Hydrogen (gas & liquid)Characteristics: colder and covered with Hydrogen (gas & liquid)– JupiterJupiter– SaturnSaturn– UranusUranus– NeptuneNeptune

Pluto: no longer considered a planet but still there!!!Pluto: no longer considered a planet but still there!!!

Planets (continued)Planets (continued)

Rotation is how long it Rotation is how long it takes for a point on takes for a point on planet to spin around planet to spin around and face the sunand face the sun– Length of dayLength of day

Revolution is how Revolution is how long it takes a planet long it takes a planet to go around the Sun; to go around the Sun; also known as orbitalso known as orbit– Length of yearLength of year

Other stuff in the solar systemOther stuff in the solar system

CometsCometsAsteroidsAsteroidsMeteoroidsMeteoroidsGasGasDustDustSatellitesSatellitesSpace “Junk”Space “Junk”Can you think of Can you think of anything else?anything else?

Comets – Halley’s Comet – 76 yrs 2052Comets – Halley’s Comet – 76 yrs 2052– Mixtures of frozen gases, ice and rocky debrisMixtures of frozen gases, ice and rocky debris– Outer solar systemOuter solar system– Looping orbits bring close to the Sun, ice melts thus having Looping orbits bring close to the Sun, ice melts thus having

streaming tailsstreaming tails

AsteroidsAsteroids– Dark, rocky bodies that orbit the SunDark, rocky bodies that orbit the Sun

Milky Way GalaxyMilky Way Galaxy

Swath of light formed Swath of light formed by the glow of billions by the glow of billions of starsof starsFlat spiral collection Flat spiral collection of starsof starsLargest celestial Largest celestial featurefeatureFormed 10 billion Formed 10 billion years agoyears ago

Other GalaxiesOther Galaxies

Whirlpool Galaxy Andromeda Galaxy

Sombrero Galaxy Large Magellanic Cloud

Created by:-Created by:-

PRABHAT RAUSHANPRABHAT RAUSHAN