Astros

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Winny Lallesca Vieira

Main Concepts

Universe................................... 1

Galaxies................................... 2

Solar System........................... 3-5

Planets..................................... 6

Asteroid Belt........................... 7

Earth....................................... 8

Life Cycle of Stars................ 9-10Parallax.................................. 11

Agricultural Implication......... 12




Universe,the totality of everything that exist, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Scientific observation of earlier stages in the development of the universe, which can be seen at great distances, suggests that the universe has been governed by the samephysical laws and constants throughout most of its extent and history. There are various multiverse theories, in which physicists have suggested that our universe might be one among many universes that likewise exist.












1

Galaxies,is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an importantbut poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxies (γαλαξίας), literally "milky", a reference to the Milky Way galaxy. Examples of galaxies range from dwarfs with as few as ten million stars to giants with a hundred trillion stars, each orbiting their galaxy's own center of mass.


Comparing galaxies:
|Galaxies|Size |Number of stars |
|Spiral |angular size is over 4 arcmin, |Between 200 and 400 billion stars|
| |corresponding to to a diameter of | |
| |about 200,000 light-years. ||
|Elliptical |over 100 kilo parsecs |1000 billion |
|Irregular |1,000 to 20,000 light years in |About 400 billion stars |
| |diameter. | |


Spiral Galaxy
IrregularGalaxy
Elliptical Galaxy 2

Solar System,consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system'smass is in the Sun.

Formation of the Solar System:
Starting point: A cloud of interstellar gas and dust, the "solar nebula"; Most of it (98%) is hydrogen and helium, but it includes atoms and dust grains of heavier material, formed in previous generations of stars.
Onset of formation: The nebula is already thicker than the average interstellar region, and possibly part of a chaotic regionof star birth; Because of some disturbance that compresses it, such as a supernova explosion, it starts a gradual process of collapse.
Contraction: The cloud starts collapsing under its own gravity; over 100,000 years, it shrinks down to 100 AU, heats up (thermal energy), and compresses in the center.
Accretion disk: The matter around the center spins up and flattens into a disk, while heatvaporizes the dust.
Protostar: Forms in the center, when the core becomes opaque; later will become the Sun. (The gas orbiting the protostar in some cases may start to compress under its own gravity, producing a double star.)
Condensation: The disk radiates away its energy and cools off; some gas condenses into tiny dust grains of metal, rock and, far enough from the forming star, outside the...
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