Download 10 -2 meters = 0.01 meters

Traveling the Universe
Using the
Powers of 10
Think about this…
In
a model of the
universe where the sun
was the size of a grain of
sand, how far would it be
to the closest star?
Four
Miles!
Cosmic Voyage:
Exploring the Universe Using
Powers of 10
https://www.youtube.com/watch?v=qxXf7AJZ73A
SO…
 By
using powers of 10, we can explore
both the miniscule and the vast
BUT…
 What about all those zeroes?????
Scientific Notation
 The
system of recording very large or very small
numbers using powers of 10
6,450,000,000
becomes
6.45 x 109
4.526 x
 Which
6
10
number is the coefficient?
 Which number is the exponent?
 SO…
we use scientific notation when we
are talking about very large or very small
numbers.
 But what about the UNITS?
SI: Système Internationale d’Unités
 International
System of Units
 Used by all scientists to avoid confusion
 SI units:
SI – based on powers of 10
Other Units of Measurement
in Astronomy
 In
addition to the meter/kilometer,
astronomers use other measures of
distance…



Astronomical Unit (AU)
Light year (ly)
Parsec (pc)
How do Astronomers
Measure Distance?

https://www.youtube.com/watch?v=_Lsj-Hz-NS4
Astronomical Unit (AU)



The average distance between Earth and the sun
Approximately 1.5 x108 km (149,597,871 km)
Used when discussing distances within our solar system
Light-year (ly) = A unit of Distance
 The
distance light travels in one year
 9.461
X 1012 km/year
 About 300,000 km/s
 Used
when discussing distances to the stars
Parsec (pc)
 The
distance at which two objects that
are 1 AU apart appear at an angle of
1arcsecond
 Equal to about 3.26 ly or 3.09 x 1013 km
Degrees, Arcminutes and Arcseconds
 Astronomers
measure angular separation
and apparent size of objects in the sky
using degrees, arcminutes, and
arcseconds


One degree = 60 arcminutes
One arcminute = 60 arcseconds
 This
is used to describe how things appear
from Earth, not how big or far they
actually are
Today we learned about:
 Scientific
Notation and the powers of 10
 The SI system of measurement
 The units used for measuring distances in
astronomy
 The units used for measuring the apparent
size or angular separation between
celestial objects