science

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what is one light wave

photon

Earth- moon

1.25 light seconds

earth-sun

8.3 light minutes

earth-next closest star

4.4 light years

earth-center of the milkyway

30000 Light years

earth-next galaxy

2.2MLY

How fast does light travel

300000 kms

what is the order of the EM spectrum

Radio micro IR VL UV xray gamma

Electromagnetism

The union of electricity and magnetism which do not exist as independent quantities

What determines the color of a beam of light

wavelength and frequency

What makes up white light

roygbiv

SPECTROSCOPY

A technique used to tell what matter is composed of…is also the analysis of the ways in which matter emits and absorbs radiation

Spectrum

 Splitting incoming radiation into its different wavelengths tells us the elemental composition make-up of an object

 SPECTROSCOPE

A device used to analyze radiation.  It can be used to separate visible light into its different  wavelengths or colors by seperating the light at different angles, so that all the colors can be seen

What are kinds of spectrums used for

telling what element are in space

Continuous spectrum

You  see all colors (ROY G BIV) blended together like a rainbow.  The Sun shows this, as does a light bulb

Emission Spectrum

thin, isolated bands or lines of color appear at specific wavelengths against black background; produced when atoms of an element are “excited” when energized and emit energy

Absorption Spectra

continuous spectrum with parts missing; produced when a source emits a continuous spectrum but something between observer and source absorbs some wavelengths

Atomic emission

gases glow when electrons jump from higher to lower energy levels

The doppler effect

 For moving objects.  As an object moves towards you, the waves ( sound or light) bunch together.  If an object is moving away from you, the waves get spread out. 

Red shift

the displacement of spectral lines toward longer wavelengths (the red end of the spectrum)

blue shift

the displacement of spectral lines toward shorter wavelengths (the blue end of the spectrum)

What does red shift mean

rotating away from earth

waht does blue shift mean

rotating towards earth

Cosmology

The study of teh struture and evolution of the universe

What is a gallaxy

~100's of billions of stars and interstellar matter that’s held together by gravity.

What can the sizes of galaxies be

1000-100000 LY

The milkyway

It is a spiral shaped galaxy with  ~ 100-200 billion stars.

Disk Galaxy

100,000 LY across.  A flat area made of gas & dust w/ stars forming. Is ~1,000 LY thick near the Sun.

Galactic buldge

10,000 LY thick, Lots of gas, and rigorous stellar formation.  It's probably a supermassive black hole

The universe is homogeneous

the same everywhere in terms of composition.  So it has no edge and no center, and there is a uniform curvature of space.

The universe is isotrorpic

The same in all directions in terms of density of material.

What do we assume about the universes laws of physics

they are the same everywhere

What is hubbles law

the further away a galaxy is the faster it appears to be moving (gave rise to expanding universe theory)

What did hubble notice about distant galaxies

They exibit red shift

What are the two schools of thought about the universe

Static and Dynamic

CBR

Penzias and Wilson picked up microwaves EVERYWHERE in space These observations fit the calculation and prediction that the universe should have “cooled down” over the last 13 + billion years to the point of emitting microwaves (proof of expanding universe)

What is the temputer of the universe

2.73 K

The big bang

13.8 billion years ago, all of the matter in the universe was at a point (a singularity).  It expanded outwards in all directions at high speeds. 

Was the big bang an expansion or explossion

It was an expansion (like an infliating ballon)

How much had the universe expanded during the first second

1050X

What was the universe like after the firt 1000 years

radiation dominated.  It was small and dense.

What was the universe like after 100000-millions of years later

matter dominated the universe with atoms, molecules and stars forming as the universe cooled and thinned.

how long did it take for galaxy clusters to form

1 billion years

How do we know the universe is expanding in all directions

by studying red shifts

What is the collaspe/raisan bread theory

If the universe has enough density (matter), then the expansion will slow down due to gravity and collapse/re-join-perhaps  into a new singularity

What is the expand forever theory

It is believed that the universe only contains 33 % of the critical density.  So the universe will continue to expand, cool, and die off-forever. stars will be further apart and the universe will dim and die.

What is the oscilation theory

There may be enough dark matter and dark energy to reach our critical density, there will be a big crunch and the universe will re expand

What is dark matter

some kind of particle that we have not yet detected in experiments here on Earth, but nevertheless comprises most of the matter in the universe

how do we know dark matter exists

We know its there because galaxies behave in a way that does not make sense with the observable matter

What is dark enrgy

it is spread uniformly throughout space, and maintains an approximately constant density as the universe expands

how do we know dark energy exists

Its effects on space-time curvature show up in two ways -- it makes the universe accelerate, and it contributes (along with matter) to the curvature of space alone.

What is a better name for dark matter

transparent matter becasue light simply passes through it