Solar System Flashcards
LIGHT SPEED
The rate at which light travels through space
LIGHT YEAR
The distance that light travels in one year
Nearly 9,500,000,000,000 km
ASTRONOMICAL UNIT
The average distance between the Earth and the Sun
DRAKE EQUATION
An equation used to estimate the number of intelligent, extraterrestrial civlizations that exist in the Milky Way galaxy.
SOLAR SYSTEM
A star (or stars) and all objects held by it’s gravity
INNER SOLAR SYSTEM
The region of our Solar System between the Sun and the Asteroid Belt that contains the 4 terrestrial planets.
ASTEROID BELT
A collection of rocky/metallic objects between Mars & Jupiter. Believed to have once been a planet that was unable to form. Most known asteroids can be found in a donut-shaped orbit between the planets Mars and Jupiter. Scientists estimate there might be between 1.1 and 1.9 million asteroids larger than 1 km in diameter and millions of smaller ones. Early in the history of the solar system, the gravity of Jupiter did not allow planets to form in this area and this resulted in a lot of smaller bodies.
OUTER SOLAR SYSTEM
The region of our Solar System between the Asteroid Belt and Kuiper Belt that contains the 4 giant planets.
KUIPER BELT
The region beyond Neptune that is filled with icy objects left over from the early solar system. This is where Pluto and many dwarf planets can be found. ‘Home of the short-term comets.’
OORT CLOUD
Believed to be a thick, bubble-like shell of icy debris that surrounds our solar system and marks the outer limits of the Sun’s gravitational pull. The outer limits of our solar system. ‘Home of the long-term comets.’ This distant ‘cloud’ is believed to extend about a third of the distance from our Sun to the next, closest star (5,000 to 100,000 AU).
THE SUN
The smallish, medium-sized star located at the center of our Solar System.
PLANET
Must comply with these criteria:
- Directly orbits a star but is not a star itself.
- Has enough mass for its own gravity to cause it to form into a sphere.
- Has cleared its orbital area.
DWARF PLANET
Meets all criteria for a planet but has not cleared its orbital area. One dwarf planet (Ceres) is located in the Asteroid Belt. The remaining dwarf planets are located beyond Neptune in the Kuiper Belt (Pluto, Eris, Makemake, and Haumea are some of the named dwarf planets found there).
MOON
A natural satellite of another celestial object that does not directly orbit the Sun. Planets can have moons. Even the asteroid “Gaspra” has a tiny moon named “Ida”.
ASTEROIDS
Solid, rocky/metallic objects orbiting the Sun. Most are found in the main asteroid belt between Mars & Jupiter. Currently (as of January 14, 2019), 791,571 have been discovered. Usually having an irregular shape, asteroids can range in size from 940 km in diameter (Vesta) to just 10 m in diameter. Ceres, a former asteroid, with a diameter of 952.4 km, is the only dwarf planet located in the asteroid belt.
COMETS
Solid objects made mostly of frozen gases and embedded with dust, grains of sand, and small rocks. When near the inner Solar System, they become active. Ices vaporize in sunlight forming an ‘atmosphere’ (coma) of gas and dust and a tail of gas and/or dust. “Dirty Snowball.” Early remnants of Solar System formation that are located in Kuiper Belt and Oort Cloud.
METEROIDS
Bits of, solid, rocky metallic interplanetary material that are typically only millimeters in size (grains of sand) but can range in size up to large rocks. For example, if a piece of an asteroid, comet, moon, etc. breaks off, it could become a meteoroid. Smaller than comets or asteroids. Scientists estimate that about 48.5 tons (44,000 kg) of meteoritic material falls on Earth each day!
TERRESTRIAL PLANET
A smaller, dense, rocky, solid planet. In our SS, the four inner planets.
GAS GIANT
A large planet made up mostly of gas. In our SS, Jupiter and Saturn are composed of mostly hydrogen and helium, with large mantles of metallic hydrogen (which acts like a metal, due to the pressure and temperature within these planets) and only small cores of rock and ice. This is why they are called gas giants: They are mostly gaseous, with very little rock and ice.
ICE GIANT
A large planet made up mostly of frozen gas. In our SS, Uranus and Neptune are composed of some hydrogen and helium, but they also contain heavier elements such as oxygen, carbon, nitrogen, and sulfur. Beneath their relatively thin outer shells of hydrogen and helium, these planets’ mantles are largely made of compressed, slushy water and ammonia. The ice giants’ rocky, icy cores are also proportionally larger than the amount of gas they contain, unlike the gas giants.
PLANETARY RING SYSTEM
A disc made up of different combinations of ice, dust, and rocks that orbit’s a planet.
SMALL SOLAR SYSTEM BODIES
Objects smaller than dwarf planets that are not moons. Chunks of ice, rock and metal leftover from the formation of our solar system 4.6 billion years ago. Asteroids, comets, and meteoroids fall into this category.
EXOPLANET
A planet that orbits a star(s) outside of our solar system.
METEOR
A meteoroid that has entered Earth’s atmosphere and vaporizes in a flash of light (a.k.a., “shooting stars”). Small, broken off pieces of planets, moons, asteroids, or from debris left in comet trails. Typically no larger than a grain of sand. Most meteoroids that enter Earth’s atmosphere are so small that they vaporize completely and never reach the planet’s surface.
Meteorite:
Any part of a meteoroid that has enough mass to survive its fall through the atmosphere and land on Earth.
METEOR SHOWERS
Occur annually at regular intervals as Earth passes through the trail of debris left by a comet. There are several meteor showers that occur throughout the year. The Perseids (mid August), Orionids (later October), and the Gemenids (mid-December) are the best meteor showers.
PARTS OF A COMET
- Nucleus: The main, icy part of a comet that is made up of frozen gases embedded with dust, grains of sand, and small bits of metal and rocks.
- Coma: The mini-atmosphere of gas that surrounds the nucleus of a comet when its outer layer of ice vaporizes as it gets closer and closer to the Sun.
- Tail: Formed from the coma, it is a stream of dust and gas that forms when a comet gets closer to the Sun. Solar wind from the Sun pushes the tail so that it always points away from the Sun so that even when the comet, is once again leaving the Sun, its tail is stretched out in front of it. Tails can be up to 250 million km long and are most of what we see.
1st planet to Left NAME - 2 things
Mercury:
Smallest, greatest range in surface temp, no atmosphere
2nd planet NAME - 2 things
Venus:
Day is longer then year
hotest most dense atmosphere
3rd planet Name - 2 things
Earth:
only planet with intelligent life
water
4th planet Name - 2 things
Mars:
Covered in rust
largest canyon in solar system
5th Planet Name
Jupiter:
Largest Planet
Shortest Day
6th planet name 2 things
Saturn:
Most rings
least dense
could float in water
7th planet name - 2 things
Uranus:
Tilted nearly 90 degress on is side
most extreme weather
longest seasons
8th planet name - 2 things
Neptune:
Coldest Planet
Fastest Winds
