Astronomy Flashcards
(39 cards)
How many planets and dwarf planets are their in our solar system
8 planets and 5 dwarf planets
Which is the biggest and which is the smallest planet in our solar system
Jupiter is the biggest and Mercury the smallest
Differences between rocky and gas planets
Rocky planets- terrestrial planets
- mercury,Venus, earth, Mars
- made of rock solid surfaces
-found close to the sun warmer region of solar system
-travel around the sun in nearly circular paths
-small
-few or no moons
-no ring systems
Gas planets- Jovian planets
- Jupiter, Saturn, Uranus, Neptune
-thick gaseous atmosphere with liquid interior
-travels around the sun in nearly circular paths
-far from sun colder regions
-large in size
-many moons
-have ring systems
What is a comet(stella cometa-hairy star)
A body if ice, rock and dust that may be several KMs in diameter, similar to an astroid but with more ice,methane and ammonia which help develop a cloud like shell called a coma(as well as its tail)
How does a comets “tail” form
As it gets closer to the sun solar heat evaporates the ice so that the comet brightens enormously. The tail gets blown away from the head via solar wind from the sun.
What is a solar wind ?
A solar wind is a thin stream of hot gasses continuously ejected from the outermost atmosphere of the sun(corona) at a speed of 400km/second
What is a astroid ?
Large chunks if rock from the astroid belt between the orbits of mars and Jupiter. Made up out if metals and rocky material
What is a meteoroid ?
Space debris smaler than an asteroid, a piece of interplanetary matter that is smaller than a kilometer. Most get vaporised instantly before entering earths atmosphere.
What is a meteor(shooting star) ?
The flash of light we see in the night sky when a small chunk of interplanetary material passes through earths atmosphere.
“Meteor refers to the flash of light not the actual debris.
What is a fireball ?
Term used for a very bright meteor, one with a magnitude brighter than -4 the same as the planet Venus in the morning or evening sky
What is a meteorite ?
Any part of a meteoroid that survives its fall through the atmosphere and lands on earth.
Although most are the size of a pebble some can be the size of a life destroying boulder.
What caused the vredefort dome
A meteorite with a diameter of 10km that hit the earth roughly two billion years ago.
It is assumed that this meteorite strike increased earths O2 levels to a degree allowing for multicellular life to occur.
What is a constellation ?
A grouping of stars that when observed from earth appear in the same form of a pattern. These patterns have stayed the same since they were first observed and named.
Stars that make up these constellations are so far a way they seem to be fixed in space and have not deviated over thousands of years.
Point out omega Centauri
-Follow a line from alpha to beta Centauri then take a 60 degree turn to the left pass through the first star and the next would be omega Centauri.
- when using binoculars it will look like a ball of fuzzy light
- this light is from almost a million stars but because it is so far away it cannot be seen as individual stars
- know as a globular cluster
- forms part of the Centaurus constellation
Point out the jewel box
- can be found close to beta Crusis
- called “the jewel box due to the different coloured stars making up this galactic cluster ( pastel red, blue, green, purple, yellow)
Point out Eta Carina
-Region with a number of star clulsters
- opposite side of the southern cross to the pointer stars
- a patch of stars with extremely high temperatures, they emit UV radiation causing the gasses to glow.
Point out the coal sack
- is a enormous “cloud” of opaque dust that blocks our vision to what ever is behind it.
- found just off to the side of the southern cross although its much further away than the southern cross
Constellations near the southern cross
Identify and describe the megellanic clouds( cape clouds)
Draw a line from the long axis if the southern cross( delta Crusis) through celestial south pole to about the same distance beyond it, two patches of clouds that look like they broke away from the milky way
- two of three examples of other galaxies apart from the milky way wee can see with the naked eye
- large cloud(160000 lightyears away)
Small cloud(180000 lightyears away)
- were originally known as cape clouds by European navigators renamed in honour of Ferdinand Magellan
Identify and describe mensa(tabel mountain) constellation
Small constellation close to celestial south pole. Across most of the southern hemisphere it is circumpolar, but appears highest in the evening sky around December
- only constellation named after a terrestrial land mark
The large magellanic cloud touches its Northern edge
Where did the table mountain( Mensa) constellation get its name from ?
Nicolas louis de Lacaille in 1756 chose the name because table mountain overlooked his observation site when he was charting the southern night sky and recalled the cape cloud( Magellanic) constellations and that table mountain was often covered in clouds hence he made a table under the clouds.
What 4 stars does the Mensa constellation consist out of
alpha, beta, gamma and Eta mensa
What constellation is the faintest of all and why ?
The mensa constellation due to the low magnitude of the stars in this constellation.
Achernar ?
-Ninth brightest star(blue white star)
- one of the most southern stars that old Arab astronomers could see
- meaning end of the river
- 650 times brighter than our sun
