Space Physics

Question 1

what does the solar system consist of?

Answer 1

a) one star, the sun, which has the most of the mass. it radiated energy to planets in form of infra red, visible light, u.v. radiations
b) 8 planets orbiting sun,
mercury, Venus, earth, mars, Jupiter, Saturn, Uranus, Neptune
c) dwarf planets
pluto, eris, ceres, makemake
d) asteroid belt between mars and jupiter
e) moons, natural satellites that orbit planets
f) smaller bodies
comets, clouds of gas

Question 2

asteroid belt

Answer 2

a region of interplanetary space between orbits of planets where rocks, icy bodies and minor planets are found

Question 3

what is gravitational field strength?

Answer 3

the gravitational force per unit mass

Question 4

gravitational force on the surface of a planet depends on….

Answer 4

• mass of planet (greater mass, greater gravitational force)
• distance between planet and body (closer the planet and body are, greater force it experiences)

Question 5

earth equation

Answer 5

v=2πr/t
WHERE:
r - radius of orbiting about the sun
t - period (365 x 24 x 3600)

Question 6

light year

Answer 6

distance travelled in the vacuum of space by light in one year
1 light year = 9.2x10^15m

Question 7

absorption spectrum

Answer 7

dark lines drawn on a continuous line spectrum

Question 8

what is hubbles law?

Answer 8

the recessional speed at which a galaxy moves away from us is proportional to the distance between us and the galaxy

Question 9

terrestrial planets + their properties

Answer 9

• mercury
• venus
• earth
• mars
  THESE PLANETS HAVE
  1. molten heavy metal core
  2. rocky surfaces with high densities
  3. high surface temperatures
  4. topological features such as valleys, canons, craters etc.
  5. these planets are smaller in size
  6. they have a greater gravitational pull from the sun
  7. have a shorter orbital period

Question 10

Jovian/gas planets + their properties

Answer 10

• jupiter
• saturn
• uranus
• neptune
  THESE PLANETS ARE
  1. gaseous and massive
  2. their surfaces are not solid
  3. have low densities

Question 11

what is the accretion process?

Answer 11

the process by which particles come together to form larger bodies in the formation of solar systems

Question 12

formation of the solar system

Answer 12

1. gases in the cloud undergo a nuclear fusion reaction
2. temperature and pressure increase
3. gas particles clump together and form inner rocky planets while gases orbit further away from the center forming gas giants
4. the center of the accretion disk starts to form a protostar

Question 13

energy from the star is radiated in 3 main electromagmmetic way forms. these are?

Answer 13

• infrared
• visible light
• ultraviolet

Question 14

formation of a star

Answer 14

• accretion begins to pull in clouds of hydrogen gas and dust forming a nebula
• gravity causes the hydrogen isotopes to fuse and temp. at its center increase forming a PROTOSTAR
• fusion process continues until when the inward force of gravity is balanced by outward force due to high temp, & pressure forming a MAIN SEQUENCE STAR (e.g. sun)

Question 15

death of a star

Answer 15

• when hydrogen runs out in the core of the main sequence star, the inward pressure of gravity takes over and the star contracts inwards until it has enough energy to start nuclear fusion again.
• this time however, instead of forming helium it will form a heavier elements up to iron in the periodic table. it will either turn into a red giant or a red super giant
• the red giant eventually explodes to form a hot, solid dense core called white dwarf
• as the white dwarf gets cooler and darker it turns into a black dwarf as there’s no more energy to emit light
• the red super giant explodes as a supernova forming elements heavier than iron
• if the star was very big it will leave behind a neutron star
• if the star was massive it will collapse in on itself and form a black hole

Question 15

the galaxy

Answer 15

consists of billions of stars the sun being one of them in the milky way galaxy. (there are other stars much further)

Question 15

the universe

Answer 15

consists of billions of galaxies which are believed to be continuously moving apart since the universe keeps expanding as per big bang theory

Question 15

what is the dopple effect?

Answer 15

the apparent change in frequency and wavelength of a receded wave due to the relative motion between the wave source and observer

Question 15

how can we tell that galaxies are moving away from us at a faster rate? + equation

Answer 15

when the spectral lines from a distant star in another galaxy is compared with spectral lines in the spectrum of the sun, its observed that dark lines shift towards the redder zone.
the redder end has longer wavelengths than the more violet end
EQUATION
V = Δλ / λ x C OR
Δλ / λ = V / C

Question 15

how does the dopple effect work?

Answer 15

• as a wave source approaches a stationary observer, its frequency increases and wave length decreases
• for a receding wave source, the wavelength increases and the pitch of frequency decreases

Question 15

what is red-shift in light?

Answer 15

this is when a moving light source e.g. star in a distant galaxy increases the wavelength of its light as it moves away from us