Dsst Astronomy (Part 3): Solar System

Front 1

___________ is the spinning of an object on its axis.

Back 1

Rotation. The rotation of a planet causes day and night.

Front 2

Earth takes _______ to complete a full rotation.

Back 2

24 hours. Our days are approximately equal to one full rotation of the Earth.

Front 3

Most planets and moons rotate from ___________.

Back 3

West to east. Most planets in our solar system rotate in the same direction as their solar orbit.

Front 4

An east-to-west rotation is considered _________.

Back 4

Retrograde. This is the opposite of most planetary rotation.

Front 5

_______, Uranus, and Pluto have anomolous rotations.

Back 5

Venus. Venus and the dwarf planet Pluto rotate east to west (in retrograde) and Uranus rotates perpendicular to its orbit.

Front 6

In 2006, Pluto was classified as a ____________.

Back 6

Dwarf planet. The presence of other large, non-planetary bodies in our solar system resulted in the reclassification of Pluto.

Front 7

The dwarf, or minor planets of our solar system include Pluto, _______ and Ceres.

Back 7

Eris. Eris is the largest known dwarf planet in the solar system.

Front 8

______ is the smallest known dwarf planet in our solar system.

Back 8

Ceres. Although smaller than the other dwarf planets, Ceres is the largest object in the Asteroid Belt.

Front 9

The orbitary movement of one object around another is a ____________.

Back 9

Revolution. Earth takes approximately 365 days to revolve around the sun.

Front 10

______ are caused by a tilt in a planet's axis in relation to its orbit.

Back 10

Seasons. On Earth, seasonal variation is opposite in the Northern and Southern hemispheres.

Front 11

_______ occurs when a hemisphere is tilted away from the sun.

Back 11

Winter. Summer occurs when a hemisphere is tilted toward the sun during a planet's orbit.

Front 12

The path of one object around another in space is it's ________.

Back 12

Orbit. An orbit is the path an object follows as it completes a revolution.

Front 13

A ________ is an object that orbits another in space.

Back 13

Satellite. Although normally synonymous with "moon" or a man-made object, a satellite can include any body that orbits another. For example, Earth is a satellite of our sun.

Front 14

A satellite's _________ orbit matches Earth's rotation.

Back 14

Geosynchronous. For an observer at a fixed location on earth, a satellite in a geosynchronous orbit returns to exactly the same place in the sky at exactly the same time each day.

Front 15

The special case of a geosynchronous orbit that is circular and directly above the equator is called a _____________ orbit.

Back 15

Geostationary. Satellite-based communications depend on objects in geostationary orbit.

Front 16

Our solar system contains two types of planets: ________ and Jovian.

Back 16

Terrestrial. The terrestrial, or rocky planets, include Earth, Mercury, Venus, and Mars. The dwarf planet Ceres is also a rocky world.

Front 17

Jovian planets are primarily ________.

Back 17

Gaseous. These "gas giants" include Jupiter, from which they draw their name, Saturn, Uranus, and Neptune.

Front 18

The center of the solar system is our _____.

Back 18

Sun. Our sun, Sol, is a Yellow Dwarf that is larger and brighter than similar stars in our galaxy.

Front 19

The Sun's interior density is high enough to sustain ___________.

Back 19

Nuclear fusion. The energy released from this process is radiated into space as electromagnetic radiation, including visible light.

Front 20

Scientists believe the Sun is growing ________.

Back 20

Brighter. As it ages, the Sun will become larger, brighter, and redder.

Front 21

The Sun is about ________ through its life cycle.

Back 21

Halfway. The Sun will continue to expand over the next five billion years.

Front 22

The primary elements in the Sun are __________.

Back 22

Hydrogen and helium. Hydrogen is the fuel for the Sun's nuclear fusion and helium is the product.

Front 23

A ________ surrounds the Sun.

Back 23

Corona. The corona is part of the heliosphere and is partly responsible for the creation of space weather.

Front 24

________ is the planet nearest the sun.

Back 24

Mercury. This rocky planet orbits the sun in about 88 Earth days.

Front 25

_________ is the smallest planet in the solar system.

Back 25

Mercury. Since the reclassification of Pluto, Mercury, which has no known moons, is the smallest planet in the solar system.

Front 26

_________ is the planet closest in size to Earth.

Back 26

Venus. The second planet from the sun resembles Earth, but, as the hottest planet, would be inhospitable to humans.

Front 27

_______ has no magnetic field to protect its atmosphere.

Back 27

Venus. The Venusian atmosphere is a blanket of greenhouse gases that are believed to be regularly replenished by volcanic erruptions.

Front 28

_______ is the "third rock from the sun."

Back 28

Earth. Earth is the largest and densest of the inner planets.

Front 29

________ is the only planet in our solar system known to have plate-tectonics.

Back 29

Earth. Earth is the only planet where plate tectonics have been observed and the only planet - but not the only solar body - where geological activity has been observed.

Front 30

The atmosphere of _______ is radically different from other known planets.

Back 30

Earth. The atmosphere on Earth contains 21% free oxygen, an anomoly in this solar system. Our hydrosphere also appears to be unique to our world.

Front 31

_______'s moon is unusually large, relative to the planet.

Back 31

Earth. Our moon, Luna, is the fifth-largest natural satellite in the solar system and the largest to orbit a terrestrial body.

Front 32

_____, the Red Planet, takes its color from its iron-rich soil.

Back 32

Mars. Mars shows evidence of past geologic activity, including large volcanoes like Olympus Mons.

Front 33

_____ satellite(s) orbit(s) Mars.

Back 33

Two. The moons of Mars, Deimos and Phobos, are believed to be captured asteroids.

Front 34

An _______________ lies between the inner and outer planets

Back 34

Asteroid Belt. The Asteroid Belt orbits between Mars and Jupiter. The largest body of the Asteroid Belt is the dwarf planet Ceres.

Front 35

The nearest of the outer planets is _______.

Back 35

Jupiter. The gas giant Jupiter is often visible from earth due to its proximity and its massive size.

Front 36

__________ is the largest planet in the solar system.

Back 36

Jupiter. At 2.5 times the mass of the seven remaining planets put together, Jupiter's gravitational attraction can have a tremendous effect on other objects in the system.

Front 37

The __________ is perhaps the best-known feature of Jupiter's atmosphere.

Back 37

Great Red Spot. This shifting, massive storm has been raging on Jupiter for at least 178 years, although some estimates place the storms age at greater than 343 Earth years.

Front 38

Jupiter's four largest moons were discovered by _________.

Back 38

Galileo. The largest moon, Ganymede, exceeds Mercury in diameter.

Front 39

________ is known for its rings.

Back 39

Saturn. Although not the only ringed planet in our system, Saturn is the planet most identified with its rings. The largest of Saturn's rings were first observed from Earth in 1610.

Front 40

Saturn has ______ known satellites.

Back 40

Sixty. Two of Saturn's moons, Titan and Enceladas, show signs of geologic activity, while many of the smaller moons act as "shepherds" to keep the matter in the rings in place.

Front 41

The only moon in the solar system with a substantial atmosphere is __________.

Back 41

Titan. This icy satellite, larger than Mercury but smaller than Jupiter's Ganymede, orbits Saturn approximately every 16 days.

Front 42

Stable bodies of surface liquid have been observed on Earth and on _____.

Back 42

Titan. Liquid hydrocarbon lakes have been observed in the polar regions of this Saturnian satellite.

Front 43

_______ orbits the Sun on its side.

Back 43

Uranus. Its axial tilt is over ninety degrees relative to its solar orbit.

Front 44

Uranus has ____ known satellites.

Back 44

27. Of these, the largest are Titania, Oberon, Umbriel, Ariel, and Miranda.

Front 45

_________ is the outer-most planet in the solar system.

Back 45

Neptune. Slightly smaller than Uranus but more dense, Neptune is sometimes called Uranus' "twin."

Front 46

____ known satellites orbit Neptune.

Back 46

Thirteen. The largest, Triton, exhibits a retrograde orbit. Triton is a geologically active moon; its crust is dotted with nitrogen-spewing geysers.

Front 47

There are _______ ringed planets in our solar system.

Back 47

Four. While Saturn's are the most famous, the other gas giants also possess planetary rings. Saturn's moon, Rhea, may have rings of its own, making it unique among satellites in this system.

Front 48

The __________ lies beyond Neptune.

Back 48

Kuiper Belt. This ring of debris lies in the largely unexplored trans-Neptunian region.

Front 49

The largest known object in the Kuiper Belt is _________.

Back 49

Pluto. Other large Kuiper Belt objects may be reclassified as dwarf planets.

Front 50

Pluto's moon, ________, may not be a moon at all.

Back 50

Charon. Pluto and Charon appear to be a binary system orbiting a barycenter of gravity between them. Two smaller moons, Nix and Hydra, orbit these larger bodies.

Front 51

A ___________ overlaps the Kuiper Belt.

Back 51

Scattered disc. This region is thought to be the source of short-period comets.

Front 52

The largest known object in the scattered disc, ________, caused the debate over what constitutes a planet.

Back 52

Eris. At 5% larger than Pluto, Eris is the largest of the known dwarf planets. It exhibits an orbit similar to Pluto's and is orbited by one known moon, Dysnomia.

Front 53

The range of the Sun's gravitational influence extends up to ________ times its distance from Pluto.

Back 53

1,000. The Sun's gravitational influence, or Roche Sphere, extends much farther into space than the effects of its solar wind, which are believed to end around four times the distance between Pluto and the Sun.

Front 54

The hypothetical _______ is believed to be the source of all long-period comets in the solar system.

Back 54

Oort cloud. This great mass of trillions of icy bodies lies between 1 and 1.87 light years away from Earth.

Front 55

_______ is believed to be the largest Oort Cloud object.

Back 55

Sedna. A red, Pluto-like body, Sedna may be part of the "inner Oort Cloud."

Front 56

The boundaries of our solar system are ______.

Back 56

Unknown. The regions between the Kuiper Belt and the Oort Cloud are largely uncharted. There is also great scientific interest in the region between Mercury and the Sun.