Astronomy exam 1 Chapter 1

What did Newton Beleive/formulate

• Space and time are continuous, smooth (flat), and endless 

• It is an absolute pre-existing container 

• All matter, energy, and information (including all of us and all of our wisdoms) are contained in this container 

Leibnitz work/beleifs

• Time is a succession of events, rather than an absolute entity 

  • There is no absolute time 

• Space is not a real entity itself but an abstract, relational concept. Its existence and properties were derived from the relationships between real objects and their properties 

  • Space does not exist without real objects 

• If all physical objects ceased to exist, so too would specs and time

what was leibniz’s relationsism view of space

an order of coexisitng objects. space doe snot exist independtly of the mater within it, it is simply the relationships betwee objects

what was leibniz’s relationsism view of time

an order of successive eents, time does not flow independently, but is a record of the succession of changes in events

what was leibniz’s relationsism view of motion

inherently relative. the true motion of a body is defined only by its relative change in position compared to other bodies

what was leibniz’s relationsism view of principle of sufficant reason

used to argue against absolute space. leibniz asked why would god have created the universe at one speciffic location in absolute space over another, if all locations are identifical? a sufficient reason for this choice cannot exist

Newton’s substantivalism view of space

an empty, absolute, and indpeendent container that exists even without matter insdie it. all objects are situated within this pre-exisitng entity

Newton’s substantialism view of time

absolute time flows uniformly without relation to anything external

Newton’s substantivalism view of motion

can be absolute an object’s true motion is defined by its movement through absolute, unmoving space

Newton’s substantivalism view of princples of suffcient reason

rejects this argument. the existence of absolute space is a metaphysical reality indpeendent of a creator’s arbitrary choice

what is our cosmic address

Universe > Local Supercluster> Local Group > Milky Way Galaxy > Solar System> Earth

Star

a large, flowing ball of gas that generates heat and light through nuclear fusion

planet

• A moderately large object that orbits a star; it shines by reflected light. Planets may be rocky, icy, and gaseous in composition 

moon (or satellite)

• An object that orbits a planet 

comet

• A relatively small and icy object that orbits a star

solar (star) system

A small and all the material that orbits it, including its planets and moons

Nebula

An interstellar cloud of gas and/or dust

Galaxy

A great island of stars in space, all held together by gravity and orbiting a common center

Supernova

the catastrophic death of stars

Universe

the sum total fo all matter and energy; that is, everythign within and between all galaxies

• Light travels at a finite speed (300,000 km/s) Thus…

• we see objects as they were in the past 

• The farther away we look in distance, the further back we look in time 

Light-year

• The distance light can travel in 1 year 

• About 10 trillion kilometres (6 trillion miles)

Let's reduce the size of the solar system by a

factor of 10 billion; the Sun is now the size of a

large grapefruit (14 cm diameter)

a tip of a ballpoint pen

what is the sun on the 1-to-10 billion scale

Sun is the size of a large grapefruit (14 centimeters)

how big is the Milky Way Galaxy

100 billion stars

what is our place in the universe

Earth is part of the solar system, which is in

the Milky Way Galaxy, which is a member of

the Local Group of galaxies in the Local

Supercluster

how big is the universe

The observable universe dwarfs our Milky

Way Galaxy, which in turn dwarfs our solar

system. Scale models can help with

visualizing such distances

Cosmic Calender

A scale on which we compress the history of the universe into 1 year

How did we come to be

The matter in our bodies came from the Big Bang,

which produced hydrogen and helium.

– All other elements were constructed from H and He in

stars and then recycled into new star systems,

including our solar system.

How do our lifetimes compare to the age of the universe

On a cosmic calendar that compresses the history of

the universe into 1 year, human civilization is just a

few seconds old, and a human lifetime is a fraction of

a second

what is the average distance that the earth orbits the sun

1 AU ≈ 150 million km.

what is the tilt of Earth’s axis and what does it point at

23.5 point at polaris

what direction does the earth orbit the sun from above the North Pole

counter-clockwise as viewed from above the North Pole

what does the sun’s speed compare similar to in our local solar neighborhood

other stars movment

how fast is our sun

typical relative speeds of more than 70,000 km/hr

why can we not easily notice star’s motion

they are so far awy

the sun orbits the galaxy every ______ million years

230

how do galaxies move within the universe

Galaxies are carried

along with the

expansion of the

universe

and all galaxies outside our Local Group are moving

away from us.

• the more distant the galaxy, the faster it is racing

away.

who discovered how galaxies move in the universe

-Hubble

what are modern challeneges in Astronomy

-Dark Matter and Dark Energy

-Black Holes

-Origins of Spacetime, Origins of matter and

-Origins of life