structure of the universe. or what’s out there and where is it?

Structure of the Universe

Structure of the Universe

Or

What’s Out There and Where is it?

The Solar System

•Note large separation of inner and outer planetsNational Geographic Magazine

Remembering the names of the planets in order:

MyVery

ElegantMother

JustSat

UponNine

Porcupines

MercuryVenusEarthMarsJupiterSaturnUranusNeptunePluto

The Inner Planets::

Mercury Venus Earth Mars Asteroids

•Close together (Relatively)•Terrestrial (made of rock like Earth)

The Outer Planets::

Jupiter Saturn Uranus Neptune Pluto

•Spread out (Relatively)•Gassy and icy giants

The Kuiper belt and Oort Cloud::•Hundreds of millions of comet like bodies•50,000 AU in radius•Total mass 10 to 100 times Earth’s mass•A tenth planet??? •Where comets come from

The Solar System (again)

•Pluto is most likely a Kuiper belt objectNational Geographic Magazine

Our Solar Neighborhood:

Galaxies (Hubble types):

Irregular Peculiar

Contemporary Astronomy, J. Pasachoff

Elliptical

Normal Spiral

Barred spiral

The Milky Way Galaxy

•100,000 LY in diameter, 16,000-3,000 LY thick•Contains a hundred billion stars (1011)•Total star mass about 3 x 1041 kg •The Sun is about 28,000 LY from the galactic center•Not very big as galaxies go.

You are Here

The Milky Way Galaxy

•The Sun orbits once every 200 million years•Our speed of orbit is about 250 km/s

National Geographic Magazine

The Milky Way Galaxy (closeup)

National Geographic MagazineWe are in the middle of a “chimney”

Elliptical Galaxy(Can you see the blackhole in the middle of this galaxy?)

The Whirlpool Galaxy

Barred spiral channeling material into its coreGiving birth to stars

Andromeda with a couple elliptical companions

There are many Galaxies...

•There are about 1011 galaxies in the visible Universe•The closest is about 2 x 106 LY from us

Star Clusters(These are much smallerthan galaxies)

This stellar swarm is M80 (NGC 6093), one of the densest of the 147 known globular star clusters in the Milky Way galaxy. Located about 28,000 light-years from Earth, M80 contains hundreds of thousands of stars, all held together by their mutualgravitational attraction. Globular clusters are particularly useful for studying stellar evolution, since all of the stars in the clusterhave the same age (about 15 billion years), but cover a range of stellar masses. Every star visible in this image is either morehighly evolved than, or in a few rare cases more massive than, our own Sun. Especially obvious are the bright red giants, whichare stars similar to the Sun in mass that are nearing the ends of their lives.

Photo and text courtesyOf the Hubble SpaceTelescope site

Nebulae•Clouds of gas and dust•Birthplace of solar systems and stars

Types of Nebulae

•Absorption Nebulae – Block the light of stars.•Planetary Nebulae – Ejected star material.

•Reflection Nebulae – Merely reflect light•Emission Nebulae – Actually emit light

Large Scale Structures

•Groups •Clusters•Super Clusters, Clouds, Walls, Voids

Groups•A few Million LY wide•3 - 6 conspicuous galaxies•A dozen or so smaller galaxies•Some of the smaller galaxies orbit the larger ones•Orbital speeds are 100-200 km/s

Our own Local Group


Clusters (of galaxies)

•10 - 20 Million LY wide•Hundreds to Thousands of galaxies•(10 - 20 times more dense than the Universe)•The largest gravitationally bound structures•Orbital speeds are around 1000 km/s (faster)

Our own cluster and supercluster:


So, putting it all together:



So where does all the structure come from??

Chaotic condensation from a superhot state…

None of the ideas in this presentation are my own.Most of the astronomical images are from the Hubble Website

at http://oposite.stsci.edu/ (unless otherwise noted)The solar system images came from The Nine Planets web page at

www.seds.org/billa/tnpThe map of the Universe came from the October 1999 National

Geographic magazine. The images of galaxy types (B+W) came from my college textbook

“Contemporary Astronomy” by Jay PasachoffThe classification of large scale structure, and most of my

knowledge of astrophysics came from the most excellent book“The Whole Shebang” by Timothy Ferris

I also read Jay Pasachoff’s book to answer reallybasic questions like “uh what kinds of galaxies, or nebulae

are there?”

Chris Murray

http://oposite.stsci.edu/

http://www.seds.org/billa/tnp

structure of the universe. or what’s out there and where is it?

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