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 Vocabulary
Unit 2 Vocabulary for 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 photosphere of the sun or another star; a star's outer atmosphere |
| Corona | A rarefied gaseous envelope of the sun and other stars; crownlike shape |
| Solar Wind | The continuous flow of charged particles from the sun |
| Sunspot | A spot or patch appearing from time to time on the sun's surface |
| Prominence | A stream of incandescent gas projecting above the sun's chromosphere |
| Solar Flare | A brief eruption of intense high-energy radiation from the sun's surface |
| Aurora | A natural electrical phenomenon characterized by the appearance of streamers of reddish or greenish light in the sky, usually near the North and South poles |
| 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 named after its apparent form or identified with a mythological figure |
| 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 | Any star that is fusing hydrogen in its core and has a 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 |
| Supergiant | A very large star that is even brighter than a giant, often despite being relatively cool |
| Cepheid Variable | A variable star having a regular cycle of brightness with a frequency related to its luminosity, so allowing estimation of its distance from the earth |
| Nova | A star showing a sudden large increase in brightness and then slowly returning to its original state over a few months |
| Nebulae | A cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter |
| Hertzsprung-Russell Diagram | A two-dimensional graph in which the absolute magnitudes of stars are plotted against their spectral types |
| Protostar | A contracting mass of gas that represents an early stage in the formation of a star |
| 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 |
| Neutron Star | A celestial object of very small radius and very high density, composed predominantly of closely packed neutrons |
| Pulsar | A celestial object, thought to be a rapidly rotating neutron star, that emits regular pulses of radio waves and other electromagnetic radiation |
| 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 |
| Hubble's Law | A law of cosmology stating that the rate at which astronomical objects in the universe move apart from each other is proportional to their distance from each other |
| Big Bang Theory | A theory that deduces a cataclysmic birth of the universe from the observed expansion of the universe, cosmic background radiation, abundance of the elements, and the laws of physics |
Created by:
gracebrown
Popular Earth Science sets