Question | Answer |
geocentric | a model of the universe in which Earth is at the center of the revolving planets and stars |
heliocentric | a sun-centered model of the universe in which the sun is at the center of the revolving planets and stars |
ellipse | an oval shape, which may be alongated or nearly circular |
moon | a nutural satellite that revolves around a planet |
core | central region |
nuclear fusion | hydrogen atoms join together to form helium |
radiation zone | a region of very tightly packed gas where energy is transferred mainly in the form of electromagnetic radiation. |
convection zone | outer-most layer of the sun's interior |
photosphere | the inner layer of the sun's atmosphrere |
chromosphere | the middle layer of the sun's atmosphere |
corona | outer layer, which looks like a white halo around the sun |
solar wind | streams of electrically charged particles |
sunspots | areas of gas on the sun's surface that are cooler than gases around them |
prominences | huge, reddish loops of gas |
solar flares | heating of gas on the sun to millions of degrees celsius, causing the gas to erupt into space |
terrestrial planets | the four inner planets that are small, dense, and have rocky surfaces |
greenhouse effect | trapping of heat by the atmosphere |
gas giants | the four outer planets that are much larger and more massive than earth and do not have a solid surface |
ring | a thin disk of small particles of ice and rock |
comet | a "drty snowball" about the size of a mountain |
coma | clouds of gas and dust that form a fuzzy outer layer |
nucleus | the solid inner core of a comet |
Kuiper Belt | A donut-shaped region that extends beyond Neptune's orbit to about 100 times Earths distance from the sun |
Oort Cloud | a spherical region of comets that surrounds the solar system out to more than 1000 times the distance between pluto and the sun |
Asteroids | rocky objects revolving around the sun that are too small and numerous to be considered planets |
Asteroid Belt | the region of the solar system where most asteroids revolve around the sun between the orbits of Mars and Jupiter |
Meteoroid | a chunk of rock or dust in space |
Meteor | a streak of light in the sky produced by the burning of a meteoroid in Earths atmosphere |
Meteorite | Meteoroids that pass through the atmosphere and hit Earths surface |
Extraterrestrial Life | Life other than that on earth |