planets Flashcards
(25 cards)
nebula
A nebula is a distinct body of interstellar clouds. Originally, the term was used to describe any diffused astronomical object, including galaxies beyond the Milky Way.
Solar Nebula
Solar nebula, gaseous cloud from which, in the so-called nebular hypothesis of the origin of the solar system, the Sun and planets formed by condensation. Swedish philosopher Emanuel Swedenborg in 1734 proposed that the planets formed out of a nebular crust that had surrounded the Sun and then broken apart.
Nuclear Fusion
Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles.
Sunspot
Sunspots are temporary phenomena on the Sun’s photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sunspots appear within active regions, usually in pairs of opposite magnetic polarity.
Terrestrial Planets
A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
Prograde Rotation
Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object. It may also describe other motions such as precession or nutation of an object’s rotational axis.
Retrograde Rotation
Retrograde refers to an object that spins in the opposite direction of its orbit. Earth has a prograde rotation, and asteroid Bennu has a retrograde rotation, which means the two bodies rotate in opposite directions.
Gas Giant
A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System
Satellite
In the context of spaceflight, a satellite is an object that has been intentionally placed into orbit. These objects are called artificial satellites to distinguish them from natural satellites such as Earth’s Moon. On 4 October 1957, the Soviet Union launched the world’s first artificial satellite, Sputnik 1.
New Moon
In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the unaided eye, but its presence may be detected because it occults stars behind it
Waxing Crescent
The Waxing Crescent is an intermediate phase of the Moon, which starts after the New Moon and lasts until the First Quarter. In this phase, the Moon’s light begins to increase from 0.1% to 49.9%. Even though it is not a major phase, it lasts longer, about 21.6% of the lunar month.
1st Quarter Moon
First quarter: The moon is 90 degrees away from the sun in the sky and is half-illuminated from our point of view. We call it “first quarter” because the moon has traveled about a quarter of the way around Earth since the new moon. Waxing gibbous: The area of illumination continues to increase.
Waxing Gibbous
The Waxing Gibbous is an intermediate phase of the Moon that starts right after the First Quarter when the illumination is 50%. The name Gibbous comes from the Moon’s shape, which is less than a Full Moon but more extensive than the Third Quarter’s semicircle shape. Waxing means that the Moon is getting bigger.
Full Moon
A full Moon occurs when the Moon has moved in its orbit so that Earth is “between” the Moon and the Sun. Between the new and full Moon, the amount of Moon we see grows — or waxes from its right side toward its left side.
Waning Gibbous
The Waning Gibbous is an intermediary Moon phase. It starts right after the Full Moon, and it lasts until the Third Quarter. When the Moon is in the Waning Gibbous phase, the sunlit part of the Moon is decreasing from 99.9% to 50.1%.
Last Quarter Moon
A last quarter moon appears half-lit by sunshine and half-immersed in its own shadow. It rises in the middle of the night, appears at its highest in the sky around dawn, and sets around midday. A last quarter moon provides a great opportunity to think of yourself on a three-dimensional world in space.
Waning Crescent
The Waning Crescent phase occurs when the illumination of the Moon decreases from 49.9% to 0.1%. It is an intermediary phase between the Third Quarter and the New Moon (when the Moon is almost invisible). The term Crescent refers to its shape. In this phase, the Moon looks like a boat or a banana
Solar Eclipse
A solar eclipse occurs when a portion of the Earth is engulfed in a shadow cast by the Moon which fully or partially blocks sunlight. This occurs when the Sun, Moon and Earth are aligned. Such alignment coincides with a new moon indicating the Moon is closest to the ecliptic plane.
Lunar Eclipse
A lunar eclipse occurs when the Moon moves into the Earth’s shadow. This can occur only when the Sun, Earth, and Moon are exactly or very closely aligned with Earth between the other two, and only on the night of a full moon.
Comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail.
Asteroid
An asteroid is a minor planet of the inner Solar System. Historically, these terms have been applied to any astronomical object orbiting the Sun that did not resolve into a disc in a telescope and was not observed to have characteristics of an active comet such as a tail.
Asteroid Belt
The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes but much smaller than planets, called asteroids or minor planets
Meteoroid
A meteoroid is a small rocky or metallic body in outer space. Meteoroids are significantly smaller than asteroids, and range in size from small grains to one-meter-wide objects. Objects smaller than this are classified as micrometeoroids or space dust.
Meteorite
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon.
