Dsst Astronomy (Part 8): Galaxies And Star Maps

Front 1

A large group of stars, gas, and dust held together by gravity is a __________.

Back 1

Galaxy. The major types of galaxies are spiral, elliptical, lenticular, and irregular.

Front 2

A ________ galaxy is characterized by its arms.

Back 2

Spiral. A spiral galaxy has a dense, disc-shaped central region surrounded by arms.

Front 3

A spiral galaxy's _________ stars tend to be in its arms.

Back 3

Younger. The older stars tend to organize in the dense center of the galaxy, while young stars, gas, and dust populate the arms.

Front 4

A spiral galaxy with a flat, rectangular central mass is a ______ spiral galaxy.

Back 4

Barred. Named after the central regions' characteristic bar shape, these appear to be far more common than "regular" spiral galaxies.

Front 5

_________ galaxies range from nearly spherical to flattened ellipsoids.

Back 5

Elliptical. Most elliptical galleries are formed of old, low-mass stars and contain little or no gas and dust.

Front 6

_________ galaxies are characterized by their bulging, disc-like appearance and weak or absent arms.

Back 6

Lenticular. These galaxies are believed to be intermediaries between the older elliptical and the younger spiral galaxies.

Front 7

________ galaxies are patchy, sprawling, and young.

Back 7

Irregular. These galaxies are those that are not easily classified into the other types.

Front 8

Earth is located in the __________ Galaxy.

Back 8

Milky Way. Our home galaxy is named after the broad band of faint light that stretches across the sky.

Front 9

The closest star system to ours lies _______ away.

Back 9

4.37 light years or 1.3 parsec. Alpha Centauri, our nearest interstellar neighbor, is visible from Earth's Southern Hemisphere.

Front 10

We group recognizable star patterns into _________.

Back 10

Constellations. Groupings into constellations is essentially arbitrary.

Front 11

Perhaps the most well known constellation, _____________, contains the Big Dipper.

Back 11

Ursa Major. The seven brightest stars of Ursa Major form the Big Dipper.

Front 12

The North Star is called __________.

Back 12

Polaris. This star is also called the Polestar because it lies very close to the celestial north pole.

Front 13

Polaris sits at the tip of the handle of the Little Dipper, also called _____________.

Back 13

Ursa Minor. Polaris is the brightest star in this constellation.

Front 14

____________ resembles the letter "W".

Back 14

Cassiopeia. Cassiopeia includes two of the most luminous stars in the galaxy.

Front 15

_________ contains the former polestar, Thuban.

Back 15

Draco. Though now faint, the northern polestar of the ancients, Thuban, lies within the Dragon's tail.

Front 16

__________, the fishes, lies between Aquarius and Aries.

Back 16

Pisces.

Front 17

The Ram, ________, lies to the east of Pisces and the west of Taurus.

Back 17

Aries.

Front 18

________ includes the Seven Sisters of the Pleiades.

Back 18

Taurus, the Bull.

Front 19

_________ contains the stars Pollux and Castor.

Back 19

Gemini, the Twins. The Project Gemini space program was named for this constellation.

Front 20

The Beehive Cluster can be found in ___________.

Back 20

Cancer, the Crab.

Front 21

Regulus and Denebola are found in _______.

Back 21

Leo, the Lion.

Front 22

The brightest star in ________ is called Spica.

Back 22

Virgo, the Virgin. Spica is the fifteenth brightest star in the nighttime sky.

Front 23

The Balance, _________, contains no first magnitude stars.

Back 23

Libra, the Scales.

Front 24

Antares is the brightest star in ________.

Back 24

Scorpius, the Scorpion.

Front 25

___________, the Archer, points his bow at Scorpius.

Back 25

Sagittarius.

Front 26

The canoe-shaped _________ contains the M30 globule cluster.

Back 26

Capricornus.

Front 27

The Water Bearer, ___________, lies in a region sometimes called the Sea.

Back 27

Aquarius. This region is called the Sea because of the number of water-related constellations visible.

Front 28

__________ is also known as the Northern Cross.

Back 28

Cygnus, The Swan. This constellation contains the star Deneb.

Front 29

The Hunter, _________ is perhaps the largest and most conspicuous is the sky.

Back 29

Orion.

Front 30

The red supergiant __________ lies at Orion's "right shoulder".

Back 30

Betelgeuse.

Front 31

_________, at Orion's left knee, is a large blue-white star and one of the brightest in the sky.

Back 31

Rigel.

Front 32

The star __________ lies at Orion's left shoulder.

Back 32

Bellatrix.

Front 33

The ___________ is an imaginary extension of the corresponding lattitude on Earth into space.

Back 33

Celestial equator. Objects at the celestial equator are visible from any point on Earth.

Front 34

The point where earth and sky meet is the ________.

Back 34

Horizon. The horizon is always 90 degrees from the zenith, or point directly overhead.

Front 35

________ is the angle between an object and the horizon.

Back 35

Altitude.

Front 36

Which stars are visible from a given point depend on the observer's _________.

Back 36

Latitude. The time of year and time of night also impact which stars are visible.

Front 37

The ___________ is the point where the Sun first appears on the first day of Spring.

Back 37

Vernal Equinox. This point serves as the zero-point reference for measuring ascension and declination in the equatorial coordinate system.

Front 38

________ measures how far east of the Vernal Equinox a given point lies.

Back 38

Right Ascension. Right Ascension (or RA) measures celestial longitude.

Front 39

__________ measures celestial latitude.

Back 39

Declination. Declination is used to describe the position of a point in degrees north or south of the celestial equator.

Front 40

The imaginary rotating sphere that surrounds the earth is the _____________.

Back 40

Celestial sphere. This sphere is used to model the positions and motions of celestial bodies.

Front 41

The __________ is the point in the celestial sphere directly above the observer.

Back 41

Zenith. The zenith is opposite the nadir.

Front 42

Literally, "opposite," ________ is the point in the celestial sphere directly below the observer.

Back 42

Nadir. The nadir of an object lies at the opposite point in the celestial sphere from its zenith.

Front 43

Earth's _______ is an imaginary line passing through both poles.

Back 43

Axis. This is the line around which the Earth rotates.

Front 44

_________ measures distance from the equator.

Back 44

Latitude. Latitude is expressed in degrees north or south on a scale of 0 to 90.

Front 45

On the solstices, the noon sun is directly overhead at _____ degrees North or South.

Back 45

23.5. The earth is tilted directly toward or away from the Sun on these days.

Front 46

The _________ represent the two days per year when neither hemisphere is tilted toward the sun.

Back 46

Equinoxes. On the equinoxes, the noon sun is directly overhead at the equator.

Front 47

The beginning of Spring in the Northern Hemisphere is marked by the ______________.

Back 47

Vernal Equinox. This day falls around March 20.

Front 48

The first day of Fall in the Northern Hemisphere is the _____________.

Back 48

Autumnal Equinox. This equinox occurs around September 23.