Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Astronomy, Part 2
| Term | Definition |
|---|---|
| Photosphere | the luminous envelope of a star from which its light and heat radiate. |
| Chromosphere | a reddish gaseous layer immediately above the photoshere of the sun or another star. |
| Corona | the rarefied gaseous envelope of the sun and other stars.The sun's corona is normally visible only during a total eclipse when it is seen as an irregular shaped pearly glow surrounding the darkened disk of the moon. |
| Solar Wind | the continuous flow of charged particles from the sun that permeates the solar system. |
| Sunspot | a spot or patch appearing from time to time on the sun's surface, appearing dark by contrast with its surroundings. |
| Prominence | the state of being important or famous. |
| Solar Flare | a brief eruption of intense high-energy radiation from the sun's surface, associated with sunspots and causing electromagnetic disturbances on the earth, as with radio frequency communication and power line transmissions. |
| Nuclear Fusion | a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy. |
| Constellation | a group of stars forming a recognizable pattern that is traditionally name after its apparent form or identified wih a mythological figure. Modern astronomers divide the sky into eighty-eight constellations with defined boundaries. |
| Binary Star | a system of two stars in which one star revolves around the other or both revolve around a common center. |
| Light-Year | a unit of astronomical distance equivalent to the distance that light travels in one year, which is 9.4607 × 1012 km (nearly 6 trillion miles). |
| Apparent Magnitude | the magnitude of a celestial object as it is actually measured from the earth. |
| Absolute Magnitude | the magnitude (brightness) of a celestial object as it would be seen at a standard distance of 10 parsecs. |
| Main-sequence star | is any star that is fusing hydrogen in its core and has stable balance of outward pressure from core nuclear fusion and gravitational forces pushing inward. |
| Red Giant | a very large star of high luminosity and low surface temperature. Red giants are thought to be in a late stage of evolution when no hydrogen remains in the core to fuel nuclear fusion. |
| Supergiant | a very large star that is even brighter than a giant, often despite being relatively cool. |
| Nova | a star showing a sudden large increase in brightness and then slowly returning to its original state over a few months. |
| Hertzsprung-Russell Diagram | the graph showing the absolute magnitude plotted against the surface temperature for a group of stars. Also called H-R diagram. Origin of Hertzsprung-Russell diagram Expand. after Danish astronomer Ejnar Hertzsprung (1873-1967) and H. N. |
| Protostar | a contracting mass of gas that represents an early stage in the formation of a star, before nucleosynthesis has begun. |
| Supernova | a star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass. |
| White Dwarf | a small very dense star that is typically the size of a planet. A white dwarf is formed when a low-mass star has exhausted all its central nuclear fuel and lost its outer layers as a planetary nebula. |
| Neutron Star | a celestial object of very small radius (typically 18 miles/30 km) and very high density, composed predominantly of closely packed neutrons. |
| Black Hole | a region of space having a gravitational field so intense that no matter or radiation can escape. |
| Galaxy | a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction. |
| Big Bang Theory | The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution. |
Created by:
3169334
Popular Finnish sets