The Smooth Way.


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The Smooth Way Dr Bryce 29:50 Class sees The Smooth Way universe shows up in our sky as a weak band of light "All sky see" The Smooth Path in Noticeable light The Smooth Route at 21cm wavelength Impartial hydrogen in kept to the plane of the Smooth Way The Smooth Route at X-beam Wavelengths
Transcripts
Slide 1

The Milky Way Dr Bryce 29:50

Slide 2

Class sees

Slide 3

The Milky Way cosmic system shows up in our sky as a weak band of light

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“All sky view” The Milky Way in Visible light

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The Milky Way at 21cm wavelength Neutral hydrogen in restricted to the plane of the Milky Way

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The Milky Way at X-beam Wavelengths X-beam discharge is delivered by hot gas air pockets and X-beam parallels

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Interstellar Medium Can both ingest and transmit light Most of the interstellar medium is gas and it is simplest to watch when it frames an outflow cloud/cloud Good cases of this incorporate the Orion Nebula Because the gas is transcendently hydrogen we see lines connected with nuclear or ionized hydrogen

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HII districts “H two” Strong emanation lines A focal hot star radiates UV photons which ionize the hydrogen When an electron is recovered by a proton the HII line is transmitted

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HII locales Require a hot star to have shaped in a sub-atomic cloud The more sultry the star the bigger the HII area can be HII areas have a tendency to be red – see the Rosette Nebula

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21cm line Associated with the least vitality level of Hydrogen Doesn’t include the hydrogen iota cooperating with another photon so we can “see” this line anyplace in space

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Interstellar gas temperature Molecular mists are thick and at low temperatures (~10K) Interstellar gas is substantially less thick and much hotter (~10,000K) We likewise see exceptionally hot (~1 million K) gas from Supernova stun waves, it is these locales that are in charge of the X-beam bubbles

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Gas reusing Stars make new components by combination Dying stars oust gas and new components, creating hot air pockets (~10 6 K) Hot gas cools, permitting nuclear hydrogen mists to frame (~100-10,000 K) Further cooling grants particles to frame, making sub-atomic mists (~30 K) Gravity shapes new stars (and planets) in sub-atomic mists Gas Cools

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Dark Nebula Associated with interstellar Dust particles obstruct the photons from the stars behind them Dust will re-radiate in the infra-red

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The advancement of our Model Galileo initially watched that the Milky Way is comprised of stars and numerous cosmologists have attempted to guide it For instance Herschel utilized star checks, see underneath

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Early models Were mistaken as they didn’t incorporate the impacts of interstellar dust which will diminish starlight (this impact is called eradication) and interstellar blushing It is hence that we really discover it less demanding to contemplate different worlds as opposed to the universe in which we live

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Globular bunches We know from our H-R charts that globular groups are old One approach to outline Milky Way is to consider the dispersion of globular groups

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Mapping Globular bunches

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Our understanding of the Milky Way Disk is dainty and wide Note winding arms and bar

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We see our cosmic system edge-on Primary elements: plate, swell, corona, globular bunches

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If we could see the Milky Way from over the circle, we would see its winding arms

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Stars in the plate all circle in the same heading with a little here and there movement

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Orbits of stars in the lump and corona have irregular introductions

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Sun’s orbital movement (sweep and speed) lets us know mass inside Sun’s circle: 1.0 x 10 11 M Sun speaks the truth 8kpc from the galactic focus

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Orbital Velocity Law The orbital pace ( v ) and separation from the galactic focus ( d ) of an article on a roundabout circle around the universe lets us know the mass ( M ) inside of that circle

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Rotation Possible models for pivot Wheel or Merry-go-round Planetary or Keplerian Milky Way doesn’t turn like both of these models

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Milky Way’s revolution Curve Is “flat” This implies that the circulation of mass in the Milky Way proceeds outwards past the iridescent material (stars) The dim matter could be chestnut diminutive people, white midgets, Jupiters, Black openings or basic particles, they are not radiating light but rather they are applying gravitational impact

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The noticeable bit of a world lies somewhere down in the heart of a huge radiance of dull matter

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We can quantify turn bends of other winding universes utilizing the Doppler movement of the 21-cm line of nuclear H

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Spiral universes every one of the tend to have level revolution bends demonstrating a lot of dim matter

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Gravitational microlensing A dim item in the galactic corona (MACHO) could go about as a lens as a result of the arch of spacetime around it. Dark gaps would be the most grounded sort of microlens

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Spiral Structure We can undoubtedly watch winding arms in different worlds however inside of the Milky Way our perspective is obstructed by the impacts of interstellar gas and dust

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Stars moderate down in the winding arms Density Waves

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Much of star arrangement in plate happens in winding arms Whirlpool Galaxy

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Spiral arms are floods of star development Gas mists get pressed as they move into winding arms Squeezing of mists triggers star development Young stars stream out of winding arms

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Halo: No ionization nebulae, no blue stars  no star development Disk: Ionization nebulae, blue stars  star arrangement

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Halo Stars: 0.02-0.2% overwhelming components (O, Fe, …), just old stars Halo stars framed to begin with, then ceased Disk Stars: 2% substantial components, stars of all ages Disk stars shaped later, continued shaping

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Infrared light from focus Radio emanation from focus

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Swirling gas close focus Orbiting star close focus

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Stars have all the earmarks of being circling something huge yet imperceptible … a dark gap? Circles of stars show a mass of around 4 million M Sun

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X-beam flares from galactic focus propose that tidal strengths of suspected dark gap once in a while tear separated piec

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