P16 -Space Flashcards

(59 cards)

1
Q

What is at the center of the solar system ?

A

The sun
-The Sun is star

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2
Q

How many planets are there ?-There are eight main planets orbitting the sun .

A
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3
Q

In order FROM CLOSESTS TO THE SUN

A

MERCURY , VENUS , EARTH , MARS
-Are relatively small rocky planets .

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4
Q

In order CLOSEST TO THE SUN (2)

A

JUPITER , SATURN , URANU AND NEPTUNE
-are much larger

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5
Q

Then finally … pluto

A

-Beyond the orbit of Neptune , we have a number of dwarf planets .
-One of these is pluto . Dwarf planets , are extremely small .

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6
Q

The solar system contains a number of other objects besides planets . These include moons , asteroids , and comets . ONLY NEED TO DESCIBE MOONS .

A

Moons are natural satellites which orbit planets .
-Most of the planets in the solar system hav at least one moon . Some have a large number of moons .

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7
Q

The solar system is a tiny part of the milky way

A

> <><><><><><>«><><>

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8
Q

What is a galaxy

A

-A galaxy is a massive group of stars.
-The milkyway has hundres of billions of stars .
-aND IN THE UNIVERSE THERE ARE HUNDREDS OF BILLIONS OF GALAXIES .

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9
Q

how do stars form ? NEED TO KNOW

A

-Stars form from clouds of dust and gas . Scientists call a cloud of dust and gas a NEBULA . In a NEBULA the main gas is HYDROGEN

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10
Q

Stage one of the formation of a star .

A

-Gravity causes the cloud of dust and gas to collapse .

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11
Q

Stage two of the formation of a star .

A

-As the dust and particles move faster , the temperature rises to millions of degrees celcius .
-Scientits call this collapsing cloud of hot gas + dust A PROTOSTAR .

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12
Q

Stage three of the formation of the star.

A

-If the temperature of the protostar gets highe nough , then HYDROGEN nuclei join together to form HELIUM . This process is called nuclear FUSION .

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13
Q

Stage four of the formaiton of the star .

A

-At this point , the potostr hs turned into a STAR .
-NUCLEAR FUSION is now releasing a huge amount of energy .

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14
Q

Check diagram on sheet .

A

KEY THERE ARE TWO OPPOSING FORCES ACTING WITHIN A STAR.

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15
Q

One force acting on a star .

A

-The force of gravity acts inwards and tends to make the star collapse .
-The green arrows show the force of gravity .

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16
Q

The second force acting on the star

A

-The energy from nuclear fusion creates a force acting outwards . This force tend to make the star EXPAND .

-SO the force of gravity acting inwards is balanced by the force due to fusion energy acting outwards .
-As these two forces are balances scientist say that the star is in equililibrium .

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17
Q

S1 of a stars life .

A

-A stars life begins as a cloud of dust+gas . Scientists call this a NEBULA .

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18
Q

S2 of a star life .

A

-Gravity cuases the cloud of gas to collapse .

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19
Q

S3 of a stars life

A

-As the particles move gasyer , the temperature rises to millions of degrees celcius . This early stage is called a PROTOSTAR .

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20
Q

S4 of a stars llife .

A

-If the temperature gets high enough , then hydrogen nuclei join together to form HELIUM NUCLEI .
-This process is called nuclear fusion ,a t this point we have a MAIN SEQUENCE STAR .
-Nuclear fusions releases a hue amount of energy , stars can stay in the main sequence for a very long time .

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21
Q

But what happens next depends on the size of the star .

A

NEED TO LEARN THE DETAILS .

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22
Q

What happens to a star that is about the same size as the sun ? S1

A

-Hydorgen nucleir fuse togetehr to form eavier heliumnuclei .
-At some stage in a star , hydrogen beings to run out .

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23
Q

What happens to a star that is about the same size as the sun ? S1

A

-Hydorgen nucleir fuse togetehr to form eavier heliumnuclei .
-At some stage in a star , hydrogen beings to run out .

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24
Q

What happens to a star that is about the same size as the sun ? S2

A

-At this point , the outward force , due to fusion energy , is less than the inward force due to gravity .

25
What happens to a star that is about the same size as the sun ? S3
-Causing the star to collapse inwards . -The collapse of the star causes the temperature to increase .
26
What happens to a star that is about the same size as the sun ? S4
-Now helium nuclei fuse together to make heavier elements . THe star expands to form a RED GIANT .
27
What happens to a star that is about the same size as the sun ? S5
-At some point , the red giant stops fusing helium . -At this stage , the star shrinks and forms A WHITE DWARF .
28
What happens to a star that is about the same size as the sun ? S6
-As the white dwarf is no longer carrying out fusion , it gradually cools down . -Eventually , it stops releasing any energy and it forms a black dwarf .
29
However STARS MUCH BIGGER THAN THE SUN , follow a different pattern .
NEED TO LEARN
30
STARS MUCH BIGGER THAN THE SUN
-Once those stars (mentioned before) run out of hydorgen , they LEAVE , the main sequence stage and expand into a RED SUPER GIANT . -Once again , helium nuclei fuse together to produce heavier ELEMENTS .
31
REALLY IMPORTANT POINT IN FUSION .
-In the stages seen so far , nuclear fusion cannot make any element HEAVIER THAN IRON . -So where do elements HEAVIER THAN IRON COME FROM .
32
ELEMENTS HEAVIER THAN IRON ;
-aT SOME POINT , THE RED SUPER GIANT stops carrying out nuclear fusion . -At this stage the star EXPLODES - scientist call this explosion a SUPER NOVAAA. -tHE TEMPERATURE OF A SUPERNOVA IS HIGH enough to produe elements heavier than IRON .
33
ELEMENTS HEAVIER THAN IRON ARE ONLY PRODUCED IN A ...
SUPERNOVAAA
34
-wHEN A SUPERNOVA explodes , these elements re distributed throughout the universe .
...
35
After the supernova , the remians of the stars can form two objects .
-A neutrons tar -A black hole
36
What is a neutron star ?
-Consits of neutrond densely packed together /
37
what is a black hole ?
-A black hole has SUCH A LARGE GRAVITY , that not even light can escape .
38
The earth orbitting the sun ;
-Scientists call this a circular orbit , as the Earth follows the path of a circle . -Virtually , the Earth's orbit is circular . -But acutally scientists say that planets oribt in an elliptical shape .
39
-the force of gravity acting between the sun and the Earth , holds the Earth in its orbit .
KEY ; planets orbit the sun and the forceo f gravity holds them in their orbits.
40
THE MOON - is a in a circular orbit around the Earth .
-The moon is a natural satellite . -Once again , the force of gravity holds the mmoon in its orbi .
41
ARTIFICAL SATELLITES
-Are MAN - MADE . -Geostationary satellites orbit once every 24hrs . -Meaning they always point tot he same part of the Earth (other satellites orbit more frequently).
42
Velocity , is the speed of an object ina given direction .
-If the SPEED of the satellite changes , then the radius of the orbit must also change .
43
If the speed of the satellite INCREASES...
...then the raidus of its orbit decreases . -That is because at a higher spped , the satellite needs a greater force of gravity , to prevent it from flying off inot psace .
44
So by moving closer to the Earth ...
the gravitational force on the satellite is greter and the satellite remains in a stable orbit . -This is also true for planets and moons as well
45
In the 1900s , astronomers were looking at light emitted from different galaxies .
-They detected that light from very DISTNT , galaxies ahd an INCREASED WAVELENGTH , compared to light form closer galaxies .
46
If we take light from the sun , and pass it through a prism , then we get a spectrum .
-There are darklines in the spectrum , as certain elements in the sun , absorb light of specific wavelengths , so those wavelengths appear as sarklines .
47
If we take light from the sun , and pass it through a prism , then we get a spectrum .
-There are darklines in the spectrum , as certain elements in the sun , absorb light of specific wavelengths , so those wavelengths appear as sarklines .
47
If we take light from the sun , and pass it through a prism , then we get a spectrum .
-There are darklines in the spectrum , as certain elements in the sun , absorb light of specific wavelengths , so those wavelengths appear as darklines .
48
If we take light fromm a distant galazy and put it through a prism ?
-The lines had shiftedn slightly towards the RED END , of the spectrum , scientitss call this to RRED SHIFT
49
RED SHIFT
-TELLS US THAT GALAZIES ARE MOVING AWAY FROM EACHOTHER . -As the galaxies are mainlu away the light waves are streched . AKA thier observed wavelength has increased .
50
RED SHIFT
-TELLS US THAT GALAZIES ARE MOVING AWAY FROM EACHOTHER . -As the galaxies are mainlu away the light waves are streched . AKA thier observed wavelength has increased .
51
Galaaxies that are further away ...
HAVE A BIGGER RED SHIFT , so these GALAXIES are movign FSTER then glaaxis thar are closerr .
52
Nearby galaxies have a small red shit ...
showing these are moving away .
53
MOre distant glaaxies ...
have a larger redshift , theya re moving away FASTER .
54
VERY DISTANt galaxies...
VERY LARGE REDHSOT , THEY ARE MOIVNG AAWAY VERY FAST
55
The fact that distant galaxies are moving faster than nearby galaxies
provides evdience that the unvierse is expanding
56
THE BIG BANG THEORY
-SCIENTISTS BELIEVE THAT THE UNIVERSE BEGAN FROMA VERY SMALL REGION THAT WAAS CTREMELYHOT AND DENSE . -This region then expnded into the universe ,w e see todya , scientists call this the BIG BNG THEORY .
57
Around 1988 , astronomers discovered something large -they had assumed gravity , would cuase the expansiono f the uiverse to gradually slow down .
-However , observaions of the supernovae , show hat the rate of expnsion is actually increasing . -so rtaher than slowing odwn , the universe is expanding fasyer . -SCIENTSS CAN'T EASILy explain this .
58
In recent years
-scientits suggested that the universe contaisn mtter and energy we cannot detect . -This is called dark matter and egergy . -It is possible that there woudl explain whyt he expansion of the universe is speeding up .