The Universe

The UniverseBy: Dhruv, Sahil, Viraj, Rishab

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Before man was ever createdBefore dinosaurs roamed the EarthBefore Earth was createdBefore our galaxy was ever bornSomething created the UniverseSomething, like the Big Bang

What Is the UniverseUniverse can be defined as all the things present that we can see and feel including matter, stars, planets, galaxies and the content present in the intergalactic space.

What is it made of

How Was it CreatedAccording to the studies carried out, the universe was formed by expanding of hot, dense phase called Planck epoch.This was further known as the Big Bang.The universe that we see today was stored in a very concentrated form inside Planck epochIt is believed that Planck epoch expanded in a very brief period (less than 10-32 seconds)

The Big BangMany scientists today believe that the whole entire universe was created because of this phenomenon.In the most common models, the Universe was filled homogeneously andisotropically with an incredibly high energy density, hugetemperatures andpressuresThis caused the energy to escape and spread out throughout forming what we know now as the universe.

The Cosmos

Our view of the CosmosAstronomy has seen 3 scientific revolutions in cosmology2nd Century: Claudius Ptolemy (Physics of Aristotle) (Geo-centric)

16th Century: Nicolaus Copernicus (Physics of Newton) (Helio-centric)

20th Century: Edwin Hubble (Physics of Einstein) (Big Bang Theory)

Claudius Ptolemy (Physics of Aristotle)

Nicolaus Copernicus (Physics of Newton)

Edwin Hubble (Physics of Einstein)

Black Holes, Stars, and Dark Matter

Black holesAblack holeis a region of space from which nothing, not evenlight, can escape.It is the only place in space where space and time do not existClassified into three classes: Super Massive, Intermediate Mass, Stellar, and MicroA portion of the black hole is called the event horizon and is undetectable.One light has gone to the horizon there is no turning back

StarsAstaris a massive, luminous ball ofplasmaheld together bygravity.Classified with the letters O, B, A, F, G, K, and MO is the hottest and M is the coldest They are very hot and can also be very brightThere are many stars in the sky and some more are being discoveredStars have been observed by many ancient civilizations

Dark MatterInastronomyandcosmology,dark matterismatterthat is inferred to exist fromgravitationaleffects on visible matter and background radiation, but is undetectable byemittedorscatteredelectromagnetic radiation.70-80% of the universe is made of dark matterObserved by Fritz Zwicky when he found missing mass

Galaxies

GalaxiesAgalaxyis a massive,gravitationally boundsystem that consists ofstarsandstellar remnants, aninterstellar mediumof gas, dust, and an important but poorly understood component tentatively dubbeddark matter.

Types of GalaxiesGalaxiesEllipticalSpiralIrregularDark Galaxies

EllipticalClassified based on the Hubble Classification System.Classified with the letter E followed by a number from 0 to 7Dominated by older stars as star formation in this types of galaxies are very lessCan be very big unlike spiral galaxiesStars revolve around the center (or the core) of this galaxy but in random pathsExamples:M32M49M59M60 (NGC 4649)

M87 (NGC 4486)M89M105 (NGC 3379)Maffei 1, the closest giant elliptical galaxy

SpiralClassified with the same systemClassified with Ss followed by a, b, or cArms rotate around a central pointBarred galaxies with a barred centerExamples:Triangulum GalaxyWhirlpool GalaxyAndromeda GalaxySunflower GalaxyPinwheel GalaxyThe Milky Way

IrregularThese type of galaxies posses an irregular formation of starsThis is usually caused by tidal interaction between the galaxy and other galaxiesExamples:Andromeda (multi-ringed)(controversial)Haogs Object (ring galaxy)Cartwheel galaxy (lenticular galaxy)

Dark GalaxiesThere is a group of scientists that believe there are dark galaxies in the universeThey are theoretically invisible because no light is emitted from itTheory based on a collision between two galaxies where one was visible (NGC 4254) and an invisible galaxy

Formation

ExtraTime Travel interactive simulation

http://science.discovery.com/interactives/time-machine/time-machine.html