GA“You are Galileo!” Project

Observe the Milky Way!

2011

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LIObservation & Sketch

In 1609, Galileo Galilei, the Italian Scientist,
began using a telescope to observe the sky. In
1610 he made a great discovery concerning
the Milky Way. What did he find? Re-visit his
discovery using our own telescope!

Name■Let’s observe inside and outside of the Milky Way, and sketch what we see.
Date and Time of Observation

Inside the Milky Way

Location of Observation
Diameter of Telescope

cmPower of Telescopex

The Power of the Telescope can be calculatedby dividing the focal length of the telescopeby the focal length of the eyepiece.

■ Mark points that you observed in the star chart below.

Outside the Milky Way

Images provided by Stellanavigator / AstroArts Inc.

© “You are Galileo!” Project

“You are Galileo!” ProjectObserve the Milky Way!
Post Observation StudyName■Write down what you noticed when sketching the Milky Way.

■Check what you were able to do.

□Find many stars that can’t be seen with the naked eyes.
□Notice that there are more stars inside than outside of the Milky Way.
□Sketch many stars as like Galileo’s sketch.
■The Milky Way has led like surround us. The Milky Way is visible in winter even it is pale comparedto the Milky Way in summer.
When you observe carefully, you can see dark parts in the Milky Way of summer. There are dark
nebulae in the parts. The starlight behind the dark nebula is hidden because it is made of gases
which is lightproof.
← View of the Milky Way in summer.
View of the Milky Way in winter.

↓Images provided by National Astronomical Observatory of Japan.

© “You are Galileo!” Project“You are Galileo!” Project

Observe the Milky Way!
Post Observation StudyName■Sun and its planets are part of a grouping

called the Galaxy.
It is thought that our galaxy is disk shaped
like the figures on the right.
This was deduced from observing the MilkyWay.
An image from above.

An Image from the side.

■Let’s consider the relationship between the Milky Way and the Galaxy by looking at the shapeof the Milky Way in summer. With a colored pen or pencil, highlight the shape of the Milky Way
in the inverted black and white image below.
What kind of shape does it have?
Why does it look like it does?
Write down your thoughts.

Image provided by National Astronomical Observatory of Japan.

■What part of the Galaxy are we in?

Make your guess and mark it on the images
on the right.

© “You are Galileo!” ProjectObserve the Milky Way!

2011★

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LEOLIPost Observation StudyName

The Milky Way provides a view of the Galaxy from inside. We live at the edge of the Galaxy. Thecenter direction of the Galaxy is seen brighter, and the other side is seen fainter.

Fainter

Brighter

The Solar System

fewer stars

Images provided by
the National Astronomical Observatory of Japan

many stars
Some areas of the Milky Way are blockedfrom our sight by a dark nebula.

fewer stars

The Sun and its planets as well as the stars that form the constellations all exist in the same
Galaxy. Many astronomers used to consider that the Galaxy was the whole of the Universe.

■80 years ago, an astronomer claimed that a celestial

object called the M31 (the Andromeda Nebula)existed outside of the Galaxy.
Later, observations by other astronomer proved that
M31 was located far outside of our Galaxy and that
it was in fact a separate galaxy. (M31 was renamed
the Andromeda Galaxy)

M31 (The Andromeda Galaxy) →Images provided by the National Astronomical Observatory of Japan
画像提供：国立天文台

This led to the recognition that the Universe extended way beyond our own Galaxy.
© “You are Galileo!” Project

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Observe the Milky Way!

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Post Observation StudyName■Astronomers have continued to look for new galaxies and keep ﬁnding them.
Now we know that there are countless galaxies in the Universe.

←Images taken by theSubaru Telescope.
Many different kinds ofgalaxies have beenobserved.

Images provided by the National AstronomicalObservatory of Japan.

画像提供：国立天文台■To distinguish the galaxy we live in from the other galaxies, we call our galaxy“The Milky Way Galaxy”.
The Milky Way Galaxy is just one of many galaxies that exists in this Universe.

■Write down what you learnt in this lesson, and what you would like to learn more about.

© “You are Galileo!” Project