Constellations

Question 1

What are constellations?

Answer 1

Names given to groups of stars by ancient astronomers, often named after mythical heroes.

Question 2

How many constellations are recognized today?

Answer 2

88 constellations are recognized today.

Question 3

What do constellations do?

Answer 3

They divide the sky into units, similar to state boundaries.

Question 4

How are the brightest stars in a constellation identified?

Answer 4

The brightest stars are identified in order of their brightness by the letters of the Greek alphabet.

Question 5

Name a few constellations associated with Spring.

Answer 5

Ursa Major, Cassiopeia, Cepheus.

Question 6

Name a few constellations associated with Summer.

Answer 6

Ursa Minor, Draco, Big Dipper.

Question 7

What are circumpolar constellations?

Answer 7

Constellations that can be seen all year round, typically near the poles.

Question 8

What is light?

Answer 8

Light is a form of electromagnetic radiation (energy that travels in waves).

Question 9

What is the speed of light?

Answer 9

The speed of light is 300,000 Km/s or 186,000 mi/s.

Question 10

What is the electromagnetic spectrum?

Answer 10

The electromagnetic spectrum is a continuum depicting the range of electromagnetic radiation.

Question 11

What are the components of the electromagnetic spectrum?

Answer 11

The components include radio, microwave, infrared, visible, ultraviolet, X-ray, and gamma ray.

Question 12

What is spectroscopy?

Answer 12

Spectroscopy is the study of the properties of light that depend on wavelength.

Question 13

What is the visible light spectrum?

Answer 13

The visible light spectrum is an ordered array of the components of visible light.

Question 14

What is a continuous spectrum?

Answer 14

A continuous spectrum is an unbroken band of colors.

Question 15

What produces a continuous spectrum?

Answer 15

A continuous spectrum is produced by lightbulbs, molten liquids, and not gases inside stars.

Question 16

What is an emission spectrum?

Answer 16

An emission spectrum is a series of unevenly spaced lines of different colors and brightness.

Question 17

What produces an emission spectrum?

Answer 17

An emission spectrum is produced by specific glowing gases such as H, He, and Ar.

Question 18

What is an absorption spectrum?

Answer 18

An absorption spectrum is a continuous spectrum crossed by dark lines.

Question 19

What produces an absorption spectrum?

Answer 19

An absorption spectrum occurs when light from a glowing object passes through a cooler gas, such as a star’s atmosphere.

Question 20

How is the mass of a star calculated?

Answer 20

The mass of a star is calculated based on its apparent gravitational pull on other objects.

Question 21

What is the standard of mass for a star?

Answer 21

The standard of mass for a star is our sun.

Question 22

What is the solar mass of our sun?

Answer 22

Solar mass = 1.

Question 23

What does the temperature of a star depend on?

Answer 23

The range of colors a star emits depends on its surface temperature.

Question 24

What is luminosity?

Answer 24

Luminosity is the actual brightness of a star, measured by determining the ‘Absolute magnitude’ value.

Question 25

What factors does luminosity depend on?

Answer 25

Luminosity depends only on a star's size and temperature.

Question 26

Does distance from Earth affect a star's luminosity?

Answer 26

No, distance from Earth is not a factor.

Question 27

How is a star's composition determined?

Answer 27

A star's makeup is determined by using spectral analysis.

Question 28

What are main sequence stars?

Answer 28

Stars that vary in size, surface temperature, and absolute magnitude but are thought to be actively fusing hydrogen into helium. ## Footnote They make up 90% of all stars.

Question 29

What are giant stars?

Answer 29

Stars with diameters from 10 to 100 times greater than our sun.

Question 30

What are supergiants?

Answer 30

Stars with diameters more than 100 times greater than our sun.

Question 31

What is the Hertzsprung-Russell Diagram?

Answer 31

A diagram that classifies stars based on their luminosity and surface temperature.

Question 32

What is the luminosity of the sun in the context of star classification?

Answer 32

The luminosity of the sun is considered to be 1.

Question 33

What is the surface temperature range for stars?

Answer 33

Surface temperatures can range from 2,500 K to 30,000 K.

Question 34

What higher than a super giant?

Answer 34

Hyper-giant

Question 35

What are dwarf stars?

Answer 35

Dwarf stars are stars of relatively small size and low luminosity.

Question 36

What is the life stage of dwarf stars?

Answer 36

Dwarf stars are thought to be at the end of their life cycles.

Question 37

What percentage of all stars are dwarf stars?

Answer 37

Dwarf stars make up less than 10% of all stars.

Question 38

What is the approximate size of dwarf stars?

Answer 38

Dwarf stars are about the size of Earth.

Question 39

What is a Nebula?

Answer 39

A cloud of dust and gas in space.

Question 40

What is a Planetary Nebula?

Answer 40

A glowing halo of gases formed by the expelled layers of a main sequence star's atmosphere. ## Footnote Not really a planet or a nebula!

Question 41

What is a supernova?

Answer 41

The brilliant burst of light that follows the collapse of the iron core of a massive star.

Question 42

What is a Neutron star?

Answer 42

The core left behind after a massive star (greater than 20 Msun) goes supernova; thought to give off bursts of radio waves along its magnetic axis.

Question 43

What is a Pulsar?

Answer 43

A neutron star which has its pulsating radio wave bursts aimed at Earth. ## Footnote Pulsating star = pulsar!

Question 44

What is a Black Hole?

Answer 44

Thought to be the remnant of a massive star (more than 20 Msun) with a gravitational force so strong that light cannot escape. The size is determined by the mass.

Question 45

What is a Supermassive Black Hole?

Answer 45

A type of black hole with a mass significantly greater than that of a typical black hole.

Question 46

What is the mass of the Milky Way Black Hole?

Answer 46

4,000,000 Msun / 8 Rsun.

Question 47

What are galaxies?

Answer 47

Galaxies are systems made of billions of stars comprising most of the visible mass of the universe. ## Footnote Astronomers estimate 100 billion galaxies in the observable universe and 200 billion stars per galaxy.

Question 48

What are the three main types of galaxies?

Answer 48

The three main types of galaxies are: 1. Spiral 2. Elliptical 3. Irregular.

Question 49

Where is our solar system located?

Answer 49

Our solar system is located in an outer edge of the disc-shaped Milky Way galaxy.