111 space science

8/2/2019 111 Space Science

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Space Science and Environment

Dr. Ugur GUVEN

Aerospace Engineer (PhD)Nuclear Engineer (MSc)


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Definition of Space

Legal definition ofspace starts around100 miles (160 km)

Up to 1000 Km ofaltitude, the effectsof molecular flowand drag can be felton spacecraft.

Above 1000 km,microgravity

conditions exist.


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Space Science Distance Definitions

One Astronomical Unit (AU),

is the distance from the Sunto the Earth. It is149,597,870.7 kilometers(92,955,807.3 mi).

One Light Year (ly) is thedistance that light travels invacuum in one year. Equal to

101015

meters=63.24103 AU

Parsec (pc) is equal to 3.26light years (3.11013) km. It is

206,265 AU


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Brightness Measurement Units

The apparent magnitude (m) of a celestial body is a

measure of its brightness as seen by an observer on

Earth, adjusted to the value it would have in the

absence of the atmosphere. The brighter the object

appears, the lower the value of its magnitude.

Absolute Magnitude (M) is the apparent

magnitude a star would have if it were 32.6 light

years (10 parsecs) away from Earth

Luminosity is the amount of electromagnetic

energy a body radiates per unit of time


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Brightness Distance Equations

is the Stefan-Boltzmann constant 5.67108Wm-2K-4

temperature Tand radius R of the star

d in parsecs
http://en.wikipedia.org/wiki/Stefan-Boltzmann_constanthttp://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Stefan-Boltzmann_constanthttp://en.wikipedia.org/wiki/Stefan-Boltzmann_constanthttp://en.wikipedia.org/wiki/Stefan-Boltzmann_constant


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Planet Earth Planet Earth is our first stop in space.


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Moon Moon is our planets natural

satellite. It is also the fifthlargest satellite in the SolarSystem. Its properties are:

- Quarter diameter of the Earth

1/6 of the gravitational pull

Its rotation is synchronous(same face toward Earth)

Perigee :362,570 km Apogee: 405,410 km

It has no atmosphere or

magnetic field.


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Solar System

Our solar system is a very unique structure with its

9 planets, inner & outer belts as well as its

originality in the nearby star systems


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Solar System The overall structure of the charted regions of the

Solar System consists of the Sun, four relativelysmall inner planets surrounded by a belt of rocky

asteroids, and four gas giants surrounded by the

outer Kuiper belt of icy objects.


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Sun Sun is the main component of

our solar system, as all planets,

plenetoids, comets, meteors,asteroids, moons and otherbodies orbit around it.

Its 109 times the size of Earth

75% is Hydrogen, 23.31 % is

Helium and 1.69% is made upof oxygen, carbon, iron andother elements.

It works by fusion (convertingHydrogen to Helium) with 620million metric tons of Hydrogenfusing into Helium releasinglight, energy and heat of thesun.

Sun rotates around the galacticcenter with a period of 225

million years


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Mercury Mercury is a planet that is closest to the sun and it is slightly larger than our moon.

Mercury has a very little atmosphere of escaped atoms due to suns rays.

It orbits the sun in 88 days and it is scorching hot on the day side and it is freezing

on the night side.


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Venus

Venus is a dim world of intenseheat and volcanic activity

Similar in structure and size toEarth, Venus' thick, toxicatmosphere traps heat in arunaway "greenhouse effect. As

a result, The scorched world hastemperatures hot enough tomelt lead.

Venus orbits the sun in 225 days.

Venus' atmosphere consistsmainly of carbon dioxide, withclouds of sulfuric acid droplets

Surface temperature is around

470 Celsius


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Mars Mars is a rocky planet with half

the size of Earth

Red appearance of Mars iscaused by abundance of ironoxide.

Martian atmosphere is about 95

% of CO2 and 3 % of Nitrogenalong with trace gases.

The mean pressure is 0.6 kPawhich is less then 1 % of Earthatmospheric pressure (101.3

kPa) It rotates around the sun in 687

days.

Its two moons are Phobos and

Deimos


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Jupiter Jupiter is the biggest planet in our

solar system and it is a gas giant(composed of dense gases)

It is made up of mostly hydrogenand helium as well as ammonia

Jupiter has a total of 50 moons withIo, Europa, Ganymede and Callisto asthe larger ones.

Jupiter has a very powerful magneticfield at least 20,000 times more thenEarth

It completes an orbit around the sun

in 11.86 years.


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Saturn

It is the second largest planet in the solar

system. Saturn's interior is probably composed of

a core of iron, nickel and rock and theouter layer is hydrogen and helium.

Saturn has a ring system that consists of

nine continuous main rings and threediscontinuous arcs, composed mostly ofice particles with a smaller amount ofrocky debris

Saturn has 63 moons with Titan the

largest. (Titan is the second largest moonand it is the only moon in the SolarSystem with an atmosphere)

It takes a 29.5 years for Saturn tocomplete one orbit around the sun.


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Uranus

Uranus has an atmosphere ofmethane, hydrogen andhelium. It is the methane whichgives it the blue color.

Like Venus, Uranus rotates eastto west.

It is an ice giant with two sets

of rings It has 27 moons with Miranda

being the famous one.


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Neptune

Neptune is an ice giant

planet. It is 4.5 billion km away

from the sun and itrotates around the sun in165 years.

Neptune also has largeamounts of hydrogen,helium and methane infrozen form

Neptune has a surfacetemperature of -235 Cand it has 13 moons.

The blue color comesfrom Methane


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Pluto

Pluto is a dwarf planet.

It is fifth of the mass ofEarths moon

Until 2006 it was a full planet It rotates around the sun in

248 years

It consists of rock and ice Temperature is around -230 C

and its atmosphere consistsof nitrogen, methane and

carbon dioxide


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Kuiper Belt Kuiper Belt is the

outer region ofour solar systemwhich consists ofthousands ofrocks andasteroids

It consists ofrock, ice andmetal

Starts at 30 AUand continuesuntil 50 AU

It contains theremnants of presolar systemformation


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Oort Cloud

It is the spherical region around

the Sun whose radius is about50,000 AU

Oort Cloud consists of blocks of

ice of varying shape and sizes.

Some of these ice blocks move

toward the inner solar system

and they will have elongatedorbits to become comets

The outer layer of Kuiper Belt

coincides with the Oort Cloud


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Heliopause

The heliopause is the

theoretical boundary wherethe Sun's solar wind isstopped by the interstellarmedium; where the solarwind's strength is no longer

great enough to push backthe stellar winds of thesurrounding stars

It is hypothesized that the

Sun also has a bow shockproduced in its travelswithin the interstellarmedium

It is about 230 AU away

from the sun


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Solar System and Interstellar Space


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Interstellar Space Interstellar space is the physical

space within a galaxy notoccupied by stars or theirplanetary systems

The average density of matter inthis region is about 106 particlesper m3

Nearly 70% of this mass consists

of lone hydrogen atoms. This isenriched with helium atoms aswell as trace amounts ofheavier atoms


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Nearby Star Systems

The nearest star to our

solar system is theAlpha Centauri systemwhich is a star systemwith Proxima Centaurias the closest star with

4.3 light years ofdistance. It would take40,000 years with ourpropulsion technologyto travel there.

Barnards star is thesecond closest star toour solar system with6 light years of

distance


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Milky Way Galaxy

The Milky Way is a spiral galaxy

100,000-120,000 light-years indiameter containing 200400billion stars.

Earth is located within the galacticplane of this disk, around twothirds of the way out from thecenter, on the inner edge of aspiral-shaped concentration of gasand dust called the OrionCygnus

Arm The galaxy is also moving at a

velocity of 552 to 630 km persecond

It is estimated to be about 13.2

billion years old


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Other Galaxies

There are probably more than

170 billion (1.7 1011) galaxies inthe observable universe

Elliptical galaxy has an ellipse-shaped light profile. Spiral galaxiesare disk-shaped with dusty, curvingarms. Those with irregular orunusual shapes are known asirregular galaxies and typicallyoriginate from disruption by the

gravitational pull of neighboringgalaxies.

Closest galaxy to our galaxy is theAndromeda Galaxy. (2.6 millionlight years)


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