# Guided Exploration: Scales of the Universe

Overview: The Scales walkway compares the relative sizes of objects, from galaxies to atoms using the central sphere as reference. As you walk along the Scales, you’ll be zooming in on ever-smaller objects in our universe, and grappling with the vast range of distances and sizes by comparing models to the giant Hayden sphere.

Introduction to Scales

1. Size Scale Measures Panel

Examine the graphic. To measure your height, what units would you use? How about the distance to another city? Distance between planets? Between stars and galaxies?

Exhibit Object

### Size Scales of the Universe

This exhibit explores the known range of size scales in the cosmos, from the observable universe at the very largest, down to the nucleus of the atom at the very smallest.

Galactic Scale

2. 1020 Panel & Models

Explore four galaxies: the Milky Way, Messier 87, Messier 101, and NGC 1365. What units do scientists use to mea­sure their size? How does the size and shape of our Milky Way Galaxy compare with the others?

Exhibit Object

### Milky Way Galaxy

If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of the Milky Way Galaxy.

Exhibit Object

### Messier 87

If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of Messier 87.

Exhibit Object

### Messier 101

If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of Messier 101.

Exhibit Object

### NGC 1365

If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of NGC 1365.

3. 1018, 1016, 1013, and 1010 Panels & Models

At each stop, use the Sphere as a reference to explore the rela­tive sizes and scales of certain cosmic objects. Each stop zooms in on smaller objects: the Milky Way (100,000 ly across), globular star cluster Messier 80 (200 ly), Oort Cloud (100,000 AU or 1.6 ly), Kuiper Belt (200 AU), star Rigel (70 million km or 0.5 AU).

Exhibit Object

### Milky Way Galaxy

If the Hayden Sphere is the size of the Local Group of galaxies, then this model is the relative size of the Milky Way Galaxy.

Exhibit Object

### Messier 80

If the Hayden Sphere is the size of the Milky Way Galaxy, then this model is the relative size of the globular star cluster Messier 80.

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### Oort Cloud

If the Hayden Sphere is the size of the globular star cluster Messier 80, then this model is the relative size of the Oort Cloud of comets.

Exhibit Object

### Kuiper Belt

If the Hayden Sphere is the size of the Oort Cloud of comets, then this model is the relative size of the Kuiper Belt of comets.

Exhibit Object

### Rigel

If the Hayden Sphere is the size of the Kuiper Belt of comets, then this model is the relative size of blue supergiant star Rigel.

Stellar Scale

4. 109 Panel & Models

Stars come in different sizes. Look at the Hayden Sphere, which represents the star Rigel, and the four models above, which (clockwise from top left) represent the stars Alpha Centauri, Sirius, Vega, the Sun. Compare and contrast their sizes. How does the size of our Sun compare?

Exhibit Object

### Alpha Centauri

If the Hayden Sphere is the size of the blue supergiant star Rigel, then this model is the relative size of Alpha Centauri.

Exhibit Object

### Sirius

If the Hayden Sphere is the size of the blue supergiant star Rigel, then this model is the relative size of Sirius.

Exhibit Object

### Vega

If the Hayden Sphere is the size of the blue supergiant star Rigel, then this model is the relative size of Vega.

Exhibit Object

### The Sun

If the Hayden Sphere is the size of the blue supergiant star Rigel, then this model is the relative size of the Sun.

Planetary Scale

5. 107 Panel & Models

Here, the Sphere represents the Sun. Look at the planet models immediately above the panel (Mercury, Venus, Earth, Mars) and to those higher up (Jupiter, Saturn, Uranus, Neptune). Compare the diameters. Then explore the “Where’s Pluto?” panel and find out why Pluto is now designated a dwarf planet.

Exhibit Object

### Mercury

If the Hayden sphere is the size of the Sun, then this model is the relative size of Mercury.

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### Venus

If the Hayden sphere is the size of the Sun, then this model is the relative size of Venus.

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### Earth

If the Hayden sphere is the size of the Sun, then this model is the relative size of Earth.

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### Mars

If the Hayden sphere is the size of the Sun, then this model is the relative size of Mars.

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### Jupiter

If the Hayden sphere is the size of the Sun, then this model is the relative size of Jupiter.

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### Saturn

If the Hayden sphere is the size of the Sun, then this model is the relative size of Saturn.

Exhibit Object

### Uranus

If the Hayden sphere is the size of the Sun, then this model is the relative size of Uranus.

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### Neptune

If the Hayden sphere is the size of the Sun, then this model is the relative size of Neptune.

Biological & Atomic Scales

6. 101, 10-1, 10-3, 10-6, 10-10, and 10-15 Panels & Models

At each stop, use the Hayden Sphere as a reference to explore the relative sizes and scales of different objects: the Hayden Sphere, the human brain, raindrop, red blood cell, rhinovirus, hydrogen atom, and proton.

Exhibit Object

### The Hayden Sphere and Humans

If the Hayden Sphere is the size of Meteor Crater, then this model is the relative size of the Hayden Sphere.

Exhibit Object

### Raindrop

If the Hayden Sphere is the size of the human brain, then this model is the relative size of a raindrop.

Exhibit Object

### Red Blood Cell

If the Hayden Sphere is the size of a raindrop then this model is the relative size of a red blood cell.

Exhibit Object

### Rhinovirus

If the Hayden Sphere is the size of a red blood cell, then this model is the relative size of a rhinovirus.

Exhibit Object

### Hydrogen Atom

If the Hayden Sphere is the size of a rhinovirus, then this model is the relative size of the hydrogen atom.