Transcript 7.1 Space Flight to the Stars

7.1 Space Flight to the Stars
Humans have been studying the sky for millennia. Outer
space has fascinated and continues to fascinate people
all over the world. Although we have discovered much
about space, it remains a mystery to humankind.
Gravity Trailer [2013]
http://www.youtube.com/watch?v=OiTiKOy59o4
Astronomy
-Astronomy is the study of the universe and all its objects.
This is a very broad range of study.
-Some more specific studies pertaining astronomy:
cosmology, astrophysics, celestial mechanics, planetary
science, etc.
-These sub disciplines are studied to give humans a
specific look at certain parts of the universe and its
properties.
Our Solar System
We will discuss our solar system in more detail later in this unit, but
here is a brief overview:
-A series of planets and celestial objects orbit around the Sun
because of the Sun’s gravitational attraction
-There are two parts to the solar system: Inner and Outer Solar
Systems
-Inner Solar System: Mercury, Venus, Earth, Mars
-Outer Solar System: Jupiter, Saturn, Uranus, Neptune
-We can understand the distances of some of the closer planets,
Measuring Distances in Space
-Planets in the outer solar system are so far away that we cannot
fathom the distance in units like metres and kilometres.
-For this reason, we use units such as the astronomical unit (AU)
-One astronomical unit is equal to the average distance between the
Sun and Earth, which is about 150 million kilometres.
-Once we get past our solar system, the distance to other celestial
objects is so great that we must use larger units. Astronomers use a
distance measure called the light-year (ly)
So what is a light year?
Light-Years
A light year is a unit of distance, not time! There is a reason why it is
called a light-year: it is equal to the distance that a beam of light can
travel through space in 1 year. It is equivalent to:
-63 000 AU
-9000 billion kilometres
Speed of light= 3 x 108 metres/second
Think about this: it takes about 8 minutes 20 seconds for light from
the Sun to reach Earth, 150 000 000 kilometres. THAT IS FAST!!!!!!
To the Stars
-Unlike what you might have thought when you were younger, the
“Sun” is just another star, and is not by any means a giant
intimidating beast to the other stars in our galaxy.
The planets of our solar
system compared to the
Sun
Bigger stars
compared to the Sun
(1 pixel)
To the Stars
There are many other solar systems far away from ours. Our closest
neighbours are from the Centauri system (4.3 light-years away)
-Some systems have more than one star!
-Solar system with two stars: Binary system
-Eventually, stars explode. They have life spans just as humans do.
When a star explodes, it is called a supernova! Some stars can live
for millions or even billions of years and suddenly explode in a
matter of minutes. This is caused by a gradual buildup of heavy
More stars in space!
-After a supernova occurs, new elements form as a result of high
pressure and high temperature. Debris from the explosion provides
the matter for another celestial object, the nebula.
-A nebula is a large cloud of dust and gas. From a nebula, a star can
eventually emerge
SPACE IS COOL