Download Difference between a star and a planet

Difference between a star and a planet
STAR
PLANET

A star has its own light.

A planet has no light of its own. It
shines by reflecting the light of the
sun.

Stars twinkle at night.

Planets do not twinkle.

The relative positions of the stars do
 Since planets are very much closer to
not undergo any noticeable change.
the earth than the stars are, their
motion around the sun is noticeable
as a daily shifting of their relative
positions in the sky.

Since the stars are very far away, the
 Most planets on the other hand are
telescope can only make them look near enough to the earth to be
brighter but not larger.
magnified by the telescope.
A star has very high temperature.


Planets have low temperatures.
There are billions of stars in the
There are only nine planets in the
celestial sphere.
solar system.
Eclipse
An eclipse happens when the moon directly aligns with the sun and the Earth.
There are 2 types of eclipse – the solar eclipse and the lunar eclipse.
Lunar eclipses happen at least twice a year, but most aren’t visible everywhere.
Next eclipse visible in Singapore – 15 Apr 2014 Total
Lunar Eclipse
Lunar Eclipse
http://www.neok12.com/video/Eclipse/zX027e52507b754877644063.htm
What causes eclipse?
http://www.neok12.com/video/Eclipse/zX45704e56606151726a0377.htm
Northern Lights is a common name for the Aurora Borealis (Polar Aurorae) in the Northern Hemisphere.
An aurora (plural: aurorae or auroras; from the Latin word aurora, "sunrise" or the
Roman goddess of dawn) is a natural light display in the sky particularly in the high
latitude (Arctic and Antarctic) regions, caused by the collision of energetic charged
particles with atoms in the high altitude atmosphere (thermosphere). The charged
particles originate in the magnetosphere and solar wind and, on Earth, are directed
by the Earth's magnetic fieldinto the atmosphere.
The Northern Lights oval, meaning the area with the highest probability, covers most of Alaska,
northern parts of Canada, the southern half of Greenland, Icelandand Northern Norway and the
northernmost areas of Sweden and Finland, as well as the western half of the Russian north (with the
Kola Peninsula of Murmansk Oblast being the most popular viewing spot).
Regions such as central and southern Scandinavia and the north-central United States as well
as Scotland also frequently see Northern Lights, but not as often as directly under the Northern Lights
oval. Svalbard sees less Northern Lights than Northern Scandinavia, but is a place to observe the
fainter Day Northern Lights during its long Polar night.
Auroral colors[edit]

Red: At the highest altitudes, excited atomic oxygen emits at 630.0 nm (red); low concentration of
atoms and lower sensitivity of eyes at this wavelength make this color visible only under some
circumstances with more intense solar activity. The low amount of oxygen atoms and their very
gradually diminishing concentration is responsible for the faint, gradual appearance of the top parts of
the "curtains".

Green: At lower altitudes the more frequent collisions suppress this mode and the 557.7 nm emission
(green) dominates; fairly high concentration of atomic oxygen and higher eye sensitivity in green make
green auroras the most common. The excited molecular nitrogen (atomic nitrogen being rare due to
high stability of the N2 molecule) plays its role here as well, as it can transfer energy by collision to an
oxygen atom, which then radiates it away at the green wavelength. (Red and green can also mix
together to pink or yellow hues.) The rapid decrease of concentration of atomic oxygen below about
100 km is responsible for the abrupt-looking end of the bottom parts of the curtains.

Yellow and pink are a mix of red and green.

Blue: At yet lower altitudes atomic oxygen is not common anymore, and ionized molecular nitrogen
takes over in visible light emission; it radiates at a large number of wavelengths in both red and blue
parts of the spectrum, with 428 nm (blue) being dominant. Blue and purple emissions, typically at the
bottoms of the "curtains", show up at the highest levels of solar activity.[12]
https://www.youtube.com/watch?v=Lc3FxNXjBs0